The human brain has earned the reputation of being the most complex structure in the universe. It’s a bold claim, but science backs it up. Nothing else we know matches its intricacy, and that makes the question “how many behavior‑altering organisms exist?” all the more chilling. Our grey matter is delicate, and countless microscopic hitchhikers can slip in, mess with our neural circuits, and change the way we act.

how many behavior are we really facing?

1 Wolbachia the Gender Manipulator

Wolbachia bacteria specialize in taking over insect hosts, and they do it in a way most of us would find astonishing. Once inside an insect, these microbes can rewrite the host’s reproductive script, skewing the sex ratio of the offspring. In the Ostrinia scapulalis moth, for instance, Wolbachia hijacks the chromosomes so that male embryos are eliminated, leaving only females to hatch.

Transmission of Wolbachia is strictly maternal – the bacteria ride inside the egg that a female lays. They never travel through sperm, so the parasite’s survival hinges on having plenty of females around. By wiping out as many males as possible, Wolbachia boosts the odds that its host will be a female, which in turn guarantees another generation of infected eggs. It’s a ruthless but effective reproductive hack.

Fewer males also means reduced competition for food and resources, giving Wolbachia‑carrying females a better shot at thriving. This manipulation is so successful that over half of all arthropod species are now known to harbor Wolbachia, turning a huge swath of the insect world into a laboratory for bacterial gender control.

2 Cordyceps Makes Zombies

If you’ve ever watched The Last of Us, you already know the terrifying image of a fungus turning people into grotesque, mind‑less husks. In reality, cordyceps fungi pull off a similar stunt, just on far simpler creatures. Each cordyceps species has a single preferred host – some target ants, others go after spiders, moths, or even beetles – and they never stray beyond that one niche.

When an ant becomes infected, the fungus stealthily spreads through its body, growing until it’s large enough to pierce the exoskeleton. It then sprouts delicate filaments across the ant’s surface, deliberately avoiding vital organs so the host stays alive long enough to serve the parasite’s needs.

These filaments act like microscopic tendrils that weave through the ant’s muscles, effectively hijacking its locomotion. The fungus essentially puppeteers the insect, forcing it to move in ways it never would have on its own.

The real mind‑bender happens when the fungus infiltrates the ant’s brain. It rewires neural pathways, compelling the insect to abandon the safety of its nest and climb to a spot ideal for spore dispersal – often a leaf or twig at just the right height. There, the ant clamps its mandibles onto the substrate and awaits death.

By the time the ant reaches this death perch, the fungus has commandeered more than half of its brain tissue. It alters serotonin levels, messes with dopamine, and disrupts the chemical cues ants normally use to communicate. Even the ant’s sense of time is scrambled, making it leave the nest at odd hours.

Neurotransmitters that trigger hallucinations, spasms, and hyper‑activity also surge, turning the ant into a zombie‑like climber. The fungus even generates enzymes that destroy the ant’s jaw muscles, ensuring the insect can’t open its mouth and escape. Meanwhile, the host’s immune system is suppressed, allowing the fungus to replace nearly every cell with its own tissue.

Other insects suffer a similar fate. Spider‑infecting cordyceps, for example, forces its arachnid host to ascend a plant stem, while moth‑targeting strains make the moth crawl upward. In each case, the parasite’s ultimate goal is a high perch where spores can rain down on unsuspecting victims below.

Fortunately for us, the fungus can’t survive at human body temperature, and our complex brains are far beyond its reach. So while cordyceps are master puppeteers in the insect world, they’re not a threat to human civilization – at least not yet.

3 Lancet Liver Flukes Also Zombify Ants

If you thought one zombie‑making fungus was enough, meet the lancet liver fluke. Ants that nibble on the tiny fluke larvae end up with a single worm making its way straight to their brain, while its siblings hide in the ant’s stomach. Once the brain‑resident fluke takes hold, it reprograms the ant’s behavior.

The infected ant is compelled to climb a blade of grass, latch onto it with its mandibles, and stay put – essentially turning the ant into a living fishing hook for the next animal in the chain. When a grazing herbivore, such as a cow, chews the grass, it inadvertently swallows the immobilized ant, delivering the flukes straight to its own liver.

Inside the herbivore’s liver, the flukes mature and lay eggs, which are later expelled in the host’s feces. Those droppings become a banquet for snails, which ingest the eggs. Inside the snail, the flukes hatch, multiply, and are eventually released in a mucous‑laden “ball” that attracts searching ants, completing the macabre life cycle.

4 Horsehair Worms Cause Suicide

You’ve probably seen viral clips of a horsehair worm bursting out of a praying mantis or cricket, looking like a strand of actual horse‑hair. These parasites are grotesquely long – some stretching over a foot – and they need water to complete their development.

When the worm reaches adulthood inside its insect host, it hijacks the host’s nervous system, forcing the creature to plunge into a nearby body of water. Once submerged, the parasite tears itself free through the host’s posterior, emerging in a dramatic, often gruesome display.

Sometimes hundreds of these foot‑long worms emerge in a tangled knot, while the host’s body may still be twitching. The freed worms then release their eggs into the water, where they are eaten by insect larvae, restarting the cycle of infection.

5 Toxoplasmosis Removes Fear

About one‑third of the global population – billions of people – carry the protozoan parasite Toxoplasma gondii, which is most famously linked to cats. In rodents, the parasite takes a terrifyingly direct approach to ensuring its own reproduction.

When a mouse or rat becomes infected, the parasite migrates to the brain and dampens the animal’s innate fear of felines. It even heightens attraction to cat urine, making the rodent more likely to wander into a cat’s path, where it gets devoured, allowing the parasite to complete its sexual cycle inside the feline’s gut.

Humans can pick up the infection by handling cat litter, consuming contaminated soil, or eating undercooked meat. Once inside a person, the parasite’s eggs hatch in the stomach, the larvae cross the intestinal wall, and travel via the bloodstream to settle in the eyes and brain. In healthy individuals, the parasite usually remains dormant and causes few symptoms.

However, severe cases have been associated with psychiatric conditions such as schizophrenia, heightened aggression, and even suicide, though a direct causal link remains unproven. Pregnant people are especially cautioned, as the parasite can cross the placenta and harm the developing fetus, which is why changing cat litter is discouraged during pregnancy.

Recent studies suggest that even in otherwise healthy hosts, Toxoplasma may subtly influence behavior, nudging infected individuals toward riskier decisions. The parasite’s ability to tweak the human brain, even faintly, adds another layer to the ever‑growing list of behavior‑altering microbes.

6 Myrmeconema Neotropicum Parasites Change Their Host’s Appearance

Deep within Central American rainforests, a roundworm known as Myrmeconema neotropicum has turned ordinary black ants into eye‑catching red‑bellied look‑alikes of the local berries. Researchers observed infected ants sporting enlarged, crimson abdomens that made them stand out against the forest floor.

The theory is that these vivid ants mimic ripe berries, luring frugivorous birds to pluck them. When a bird snaps up the ant, the parasite’s eggs travel through the bird’s digestive system and are deposited in its droppings, which later fall back onto the forest floor, ready to infect more ants.

Scientists are still piecing together exactly how the worm achieves this dramatic color shift. It may interfere with the ant’s melanin production, introduce a novel pigment, or both. Additionally, infected ants exhibit a markedly thinner cuticle – up to 25 % thinner – as the parasite feeds on their exoskeleton while simultaneously re‑shaping their appearance.

When you hear the phrase 10 types bacteria, you probably picture tiny, invisible organisms that cause disease or help us digest food. What you don’t usually imagine is that some of these microscopic critters possess abilities that sound straight out of a comic‑book universe. From sticking to surfaces like a gecko on steroids to generating electricity and even fighting cancer, the microbial world is packed with real‑life superpowers. Below, we count down the ten most astonishing bacterial marvels ever documented.

10 Types Bacteria: Microscopic Marvels

10 The Super‑Adhesive Bacteria

If you ever watched a gecko scuttle up a wall, you know that its pads can hold hundreds of kilograms of force. Imagine a creature that can out‑adhere a gecko by a factor of seven and beat commercial superglue three to four times over. That’s precisely what Caulobacter crescentus does. This bacterium behaves like a microbial Spider‑Man, secreting a sugary, ultra‑sticky substance that clings to surfaces with a force measured at roughly five tons per square inch—enough to hoist an elephant or a fleet of cars with a tiny patch of its “glue.”

The microbe thrives in any wet habitat, be it freshwater, seawater, or even tap water. It swims around using a whip‑like tail called a flagellum until it finds a suitable spot. One end then latches onto the surface, anchoring itself via thin hair‑like structures known as pili. Once firmly attached, C. crescentus pours out its sugary adhesive, instantly cementing itself in place.

Scientists have already begun to imagine practical uses for this natural superglue. Because the adhesive works in a range of aqueous environments, it could become a game‑changer for surgical sealants, underwater construction, or any application that demands a bond stronger than anything synthetic can offer.

9 Living Magnets

Imagine a tiny organism that can sense Earth’s magnetic field and steer itself like a compass needle. Magnetotactic bacteria (MTB) achieve exactly that by assembling countless iron‑oxide crystals into chain‑like structures called magnetosomes. Though each magnetosome is a fraction of a rice grain, together they act like a miniature compass, pulling the cell toward the magnetic pole where food is most abundant.

These microbes usually dwell in low‑oxygen swamps and sediments, using flagella to swim until they encounter the right chemical conditions. When the surrounding mud becomes too dense for flagellar propulsion, the magnetosome chain provides thrust, allowing the bacteria to glide along magnetic lines of force. Researchers have even loaded MTBs with extra magnetosomes and then zapped them with alternating magnetic fields, a technique dubbed “magnetic heat,” to destroy harmful pathogens.

Because MTBs can be coaxed into carrying magnetic particles, they hold promise for targeted drug delivery, environmental cleanup, and even novel ways to eliminate viral infections on a large scale.

8 The Little Giant

While most bacteria are invisible specks, Thiomargarita namibiensis blows that notion out of the water. Discovered along the Namibian coast in 1997, this organism can swell to a staggering 0.75 mm—large enough to see without a microscope. To put that into perspective, a single cell of T. namibiensis is to an ordinary E. coli cell what a blue whale is to a newborn mouse.

The extraordinary size stems from a clever nutritional strategy. The bacterium oxidizes sulfide and uses nitrate as an electron acceptor, but nitrate is scarce in its environment. To compensate, it hoards nitrate inside a massive central vacuole, which occupies roughly 98 % of the cell’s volume. This internal storage depot lets the bacterium survive long periods without external nutrients.

Visually, the cells appear white because of the many sulfur granules they accumulate. By converting sulfide to less toxic forms, these microbes help detoxify marine sediments, fostering healthier ecosystems. In the wild, they often link together in mucus‑bound strings, resembling a necklace of tiny pearls—hence the name “Sulfur Pearl of Namibia.”

7 Living Computers

From cave paintings to silicon chips, humanity has always searched for ways to archive knowledge. Now, a humble microbe called Escherichia coli is joining the lineup. By inserting synthetic DNA strands that encode pictures and short videos, scientists have turned these bacteria into living data storage devices.

In a landmark experiment, researchers at Harvard cultivated 600,000 engineered E. coli cells, then encoded a human hand image and a galloping horse video into a custom DNA sequence. After shocking the bacteria to trigger their natural DNA‑uptake mechanisms, each cell incorporated the new genetic script. When the scientists later sequenced the bacteria’s DNA and translated it back into digital files, the reconstructed images matched the originals almost perfectly, differing only by a handful of pixels.

This isn’t the first time E. coli has been used to ferry information. In 2003, a team encoded song lyrics, and in 2011 a Canadian writer embedded a poem that made the bacteria glow red and “write” its own verses. Given that a gram of DNA can theoretically hold 455 exabytes—about a quarter of all data ever created—future biocomputing could rely on swarms of engineered bacteria as ultra‑dense, self‑replicating storage media.

6 Electric Microbes

Electrogenic bacteria are a class of microbes that can literally turn chemical energy into electrical currents. Among them, Shewanella oneidensis stands out for its ability to “breathe” metals instead of oxygen. Discovered in New York’s lake sediments, this organism attaches itself to mineral surfaces, then extends slender filaments called nanowires that act like microscopic power lines.

Through these nanowires, the bacterium shuttles electrons from its interior to external metal oxides such as iron, manganese, or lead. In doing so, it generates a steady flow of electricity that can be harvested for various purposes. Sometimes the process works in reverse, with the microbes pulling electrons from metals to fuel their metabolism—essentially living on electricity.

Because of this unique capability, researchers are exploring S. oneidensis for wastewater treatment, bio‑energy generation, and even space missions. NASA has already sent samples aboard the International Space Station to see whether these microbes could help sustain life‑support systems on future planetary outposts.

5 Ice‑Maker

Just as Marvel’s Iceman can freeze water with a touch, the bacterium Pseudomonas syringae can trigger ice formation at temperatures where pure water would stay liquid. This microbe lives on crop leaves and in snowy regions worldwide, using its icy powers to infiltrate plant tissues for nutrients—often to the detriment of agriculture.

Scientists discovered that the bacterium’s outer‑membrane proteins act as ice‑nucleating agents. They rearrange surrounding water molecules into a crystalline lattice and simultaneously extract heat, forcing the water to solidify even when it’s far above the normal freezing point. In laboratory tests, a single droplet of P. syringae can instantly freeze 600 mL of water that has been chilled to just –7 °C (19.4 °F), whereas pure water would need to reach about –40 °C (–40 °F) to freeze on its own.

Beyond harming crops, these microbes play a role in atmospheric processes. When wind lifts them into clouds, they can serve as nuclei for raindrop and snowflake formation, influencing weather patterns. Their ice‑inducing abilities are already being harnessed to produce artificial snow at ski resorts, and researchers are probing additional biotechnological applications.

4 World Destroyer

When you think of a supervillain, you probably picture a cape‑clad mastermind, not a microscopic soil dweller. Yet the genetically altered strain of Klebsiella planticola earns that title by virtue of its capacity to annihilate plant life on a massive scale. Normally, this bacterium lives harmlessly in plant roots, breaking down dead organic matter and recycling nutrients.

German scientists rewired the microbe so that, while decomposing plant material, it simultaneously produced ethanol and a potent fertilizer. The idea was to create a dual‑purpose organism for agriculture and bio‑fuel production. Early 1990s trials were poised to test the strain in real fields.

However, an experiment at Oregon State University revealed a terrifying side effect. Researchers grew two identical soil beds: one inoculated with the native bacterium, the other with the engineered version. Although seeds sprouted in both, every plant in the modified‑bacteria plot died within a week. The engineered strain generated ethanol at concentrations 17 times higher than plants could tolerate, poisoning them. Moreover, it encouraged soil‑dwelling worms that devoured the beneficial fungi plants rely on, starving the seedlings of essential nutrients.

Even though the modified K. planticola persisted longer in soil than most engineered microbes, the experiment was halted, and the strain was never commercialized. Nonetheless, its potential to wipe out vegetation across continents remains a cautionary tale about the unintended consequences of synthetic biology.

3 The Microbe From Hell

In the early 1980s, scientists uncovered the first hyper‑thermophilic organisms—microbes that love boiling temperatures. While most of these belong to the archaea domain, a handful of bacteria have also mastered the art of surviving near‑boiling water. The genus Aquifex is a prime example, thriving in underwater hydrothermal vents where temperatures can soar to 95 °C (203 °F) and even exceed the boiling point of water.

Imagine a creature that can comfortably exist in a cauldron of 212 °F. Aquifex does exactly that, making it the toughest bacterial survivor known. Even more impressive, it is one of the few aerobic hyper‑thermophiles, meaning it can breathe oxygen when it’s present, albeit at low concentrations. When oxygen is scarce, the bacterium can switch to using nitrogen as a terminal electron acceptor.

The name “Aquifex” translates to “water‑maker,” reflecting its unique metabolism that produces water as a by‑product while extracting energy from heat. This extraordinary resilience has sparked interest in using Aquifex for industrial processes that require extreme temperatures, such as bio‑catalysis in harsh chemical environments.

2 Ancient Bacteria

Humans may live up to about 70 years, some turtles push two centuries, and ancient trees can stretch their lives to five millennia. Yet even that pales in comparison to the longevity of certain microbes. In 2007, a team from the University of Copenhagen unearthed bacteria trapped in ancient ice layers from Canada, Russia, and Antarctica that were still alive after an estimated 600,000 years.

These icy survivors exhibited remarkably intact DNA, a surprise because genetic material typically degrades over time. Instead of entering a deep dormancy that halts metabolism, the bacteria maintain a low‑level metabolic activity that continuously repairs their own genome, allowing them to persist for half a million years without succumbing to lethal mutations.

While there have been reports of even older microbes—such as 250‑million‑year‑old bacteria found in salt crystals—those claims remain controversial due to potential modern contamination. The 600,000‑year‑old specimens, however, passed rigorous contamination controls, solidifying their status as some of the oldest living organisms ever documented.

1 The Anti‑Cancer Fighter

Cancer claims the second‑largest share of global deaths, with nearly ten million fatalities recorded in 2018 and projections soaring to 23.6 million new cases by 2030. In a surprising twist, researchers at the University of California discovered that a common skin resident, Staphylococcus epidermidis, can throw a molecular wrench into tumor development.

The bacterium secretes a small chemical called 6‑hydroxymethyl‑2‑pentylamine (6‑HAP), which resembles a component of DNA. Laboratory tests revealed that 6‑HAP halts the replication of cancer cells by blocking DNA synthesis, yet leaves healthy cells unharmed because they possess enzymes that deactivate the compound.

In animal studies, mice injected with 6‑HAP and then exposed to intense UV radiation still developed tumors, but the tumors were on average 60 % smaller than those in untreated mice. A second experiment applied the bacteria directly onto the backs of mice; those colonized with S. epidermidis produced only a single tumor after radiation, while control mice developed up to six. Although further research is required, these findings suggest that harnessing this skin microbe could become a novel strategy for preventing—and perhaps treating—various cancers, not limited to skin malignancies.

10 ways parasites, bacteria, and viruses have been the scourge of humanity as long as we have been here, but disease has reshaped our history and influenced our evolution. Parasites helped give our immune systems the boost it needed to get up and running, and the humble bacterium has helped dictate the form this planet has taken. Sometimes, it seems that we humans are simply playthings in their hands, but they haven’t just been capricious forces that toss us around like rag dolls. These microorganisms have also done incredible things to help humanity.

10 The Viruses We Carried Out Of Africa Helped Us Survive

Thanks to the science of viral molecular genetics, we now know quite a bit about the bugs that infected us along our evolutionary path, and we have found that these hitchhikers have done quite a bit to help us along the way. For example, it was the evolutionary pressure they placed upon our immune system that made it as robust as it is today. Additionally, viruses may have played a role in the loss of specific receptors that we once possessed on the surface of our cells that infectious agents could latch onto and use to cause disease. By ridding the human body of this source of disease, viruses created a safer environment for themselves, benefiting everybody involved.

But they may have also played a role in ensuring that, among competing hominid species, it Homo sapiens that came out on top. While our species was developing, disease and parasites encouraged genetic diversity and weeded out the unfit. Once the first Homo sapiens left the continent, they brought their infectious agencies and parasites with them. If you’ve read about North American and European smallpox, you know how this goes.

While it wouldn’t have been the only factor, viral parasites would spread to other hominids like Homo neanderthalensis (Neanderthals), who wouldn’t have had any previous exposure to the new bugs and possessed a nasal structure that was less efficient at filtering air and keeping new viruses at bay. They would have devastated other hominid species, because the bugs were primed to live in similar environments, but the hominids were not primed to receive them. Models have shown that if Neanderthals had a mortality rate only 2 percent higher than humans, it would have been sufficient to cause their extinction after 1,000 years of competition. While disease was doubtless not the only factor, it would have certainly played a large role.

Most models of human disease evolution claim that they mainly evolved during the Neolithic era, after man moved out of Africa and populations increased, so there is some evidence of this selective viral pressure. Many of these early viruses have even been so successful that their genes have literally become a part of our DNA. For example, the human genome has been found to contain genes from the borna virus that were gained about 40 million years ago. In fact, scientists have isolated about 100,000 elements of human DNA that have come from viruses, mostly within what is called our “junk DNA.” The viruses that make up the majority of our junk DNA are called endogenous retroviruses, and they are so much a part of us that a scientist recently brought one “back to life” and even infected hamsters and cats with it.

9 Day Medical Uses Of Leeches And Maggots

For thousands of years, the European leech (Hirudo medicinalis) was used in medicine for bloodletting purposes, treating a wide range of disorders from hemorrhoids to ear infections. The practice goes so far back that an Egyptian painting from 1500 B.C. depicts their use. While some nations have never stopped using them, the practice fell out of favor in the Western world with the knowledge of bacteria and subsequent focus on the germ theory for medical treatment.

In the 1970s and 1980s, though, leeches made a comeback. Cosmetic and reconstructive surgeons found that they were an effective method for draining blood from swollen faces, black eyes, limbs, and digits. They are also helpful for reattaching small body parts like ears and flaps of skin, because they draw away blood that could clot and interrupt the healing process. Leeches have saved people from amputations and may even relieve the pain of osteoarthritis. Even veterinarians sometimes use them.

Maggots, on the other hand, are nature’s clean-up crew. They’re great for eating away dead or infected flesh, revealing the healthy tissue below in a process called debridement. They have also been found to be an effective treatment for ulcers, gangrene, skin cancer, and burns, among other things.

Maggots and leeches, as gross as they may be, are so effective that the FDA classified them as the first “live medical items” in 2010, paving the way for an entire industry called biotherapy. An organization called Biotherapeutics Education and Research Foundation (BTERF) has even sprung up to raise awareness of the new uses for these old critters, and there are several companies that sell them.

8 Evolved To Protect Us From Allergies

Researchers studying the effects of gastrointestinal parasites have come up with an astonishing theory: After parasites first colonized our gastrointestinal systems, they evolved over millions of years the ability to suppress our immune systems. At the same time, our own bodies evolved to partially compensate for the effect.

The astonishing part, and what this means for human health, is that once parasites and harmless microorganisms present in water and soil have been largely removed from their natural environment inside of us in developed nations through the use of modern medicine, our immune systems actually overcompensate for their loss, leading to allergies and even increased chances for asthma and eczema.

This “old friends” hypothesis (sometimes referred to as the “hygiene hypothesis,” though it’s actually more of a complementary theory) has gained more support in recent years as we identify new ways microorganisms have helped us survive over the eons. Clinical trials have been conducted using worms to test against multiple sclerosis, IBD, and allergies.

The main proponent of the old friends hypothesis is Graham A.W. Rook of University College London. He first proposed it in 2003, and since then, it has also been proposed as a possible cause of some forms of stress and depression.

Some people have taken the old friends hypothesis to its ultimate logical conclusion that if removing our parasites from society has led to health problems, we should put them back. In 2008, University of Wisconsin professor of neurology John Fleming conducted a clinical study in which he infected multiple sclerosis patients with parasitic worms to test their effectiveness against the disease. Over a period of three months, patients who had an average of 6.6 active lesions around the brain’s nerve cells were reduced to an average of two. When the trial was over, the number of lesions shot back up to 5.8 within two months. In earlier trials, the parasites appeared to have positive effects upon ulcerative colitis and Crohn’s disease as well.

Parasite therapy is still in the experimental phases, however, and probably has negative effects that outweigh the positive ones. As of now, the FDA has classified the worms as biological products that cannot be sold until proven safe. Only one species, Trichuris suis, has been approved for testing under Investigational New Drug (IND) status.

7 Virotherapy

One of the most exciting and promising branches of medicine in recent decades is virotherapy, a biotechnology technique to reprogram viruses to treat disease. In 2005, researchers at UCLA announced that they had turned one of humanity’s deadliest enemies into a cancer‑killer when they reprogrammed a modified strain of HIV to hunt down and destroy cancer cells. Around the same time, researchers at the Mayo Clinic in Rochester, Minnesota modified the measles virus to do the same.

The technique is similar to the one used to breed genetically engineered plants, in that a virus is used as a gene‑delivery vehicle. It has long been recognized as the most efficient means of gene transfer. This system is used for the production of useful proteins in gene therapy and has great potential for the treatment of immunological disorders such as hepatitis and HIV.

Viruses have been known to have the potential to treat cancer since the 1950s, but the advent of chemotherapy slowed its progress. Today, virotherapy is proving to be extremely effective against tumors without harming the healthy cells around it. Clinical trials of oncolytic virotheraphy have shown low toxicity and promising signs of efficacy. In 2013, a drug called talimogene laherparepvec (TVEC) became the first drug based on a tumor‑killing virus to succeed in late‑stage testing.

One of the biggest challenges facing researchers is how to deliver the virus where it will do the most good before the body recognizes it as an intruder and mounts a defense. Current research is looking into finding natural tumor‑targeting “carriers,” cells that can deliver the virus without either the cell or the virus losing its normal biological functions.

6 Using Viruses To Cure Bacterial Infections

Bacteriophages are viruses that specifically attack bacteria. First recognized by Frederick Twort in 1915 and Felix d’Herelle two years later, they have been used to study many aspects of viruses since the 1930s. They are especially common in soil, where many species of bacteria make their home.

Because phages disrupt the metabolism of bacteria and destroy them, it has been long recognized that they could play a role in treating a wide range of bacterial diseases. Because of the innovation of antibiotics, however, phage therapy was mostly shelved until the rise of antibiotic‑resistant bacteria generated a renewed interest in the field.

An individual phage species is generally only effective against a small range of bacteria or even one specific species (its primary host species), which was originally seen as a disadvantage. As we have learned more about the beneficial aspects of our natural flora, though, it has come to be recognized as the advantage that it is. Unlike antibiotics, which tend to kill bacteria indiscriminately, bacteriophages can attack the disease‑causing organisms without harming any other bacteria living inside us.

While bacteria can develop resistance to both antibiotics and phages, it only takes a few weeks rather than a few years to develop new strains of phages. Phages can also have an easier time penetrating the body and locating their target, and once the target bacterium is destroyed, they stop reproducing and soon die out.

5 Vaccines

Beginning in the 1790s, when Edward Jenner developed the world’s first vaccine against smallpox using a less virulent strain called cowpox to inoculate patients, vaccines have saved countless millions of lives. Since then, several different types of vaccines have been developed. Attenuated or “live” vaccines use live viruses that have been weakened or altered so that they do not cause illness, while inactivated or “killed” vaccines contain dead microorganisms or toxins that are usually used against bacterial infections. Some vaccines—including subunit and conjugate vaccines, as well as recombinant and genetically engineered vaccines—only use a segment of the infectious agent.

When a vaccine is injected, the pathogen goes to work, but there is not enough of it to replicate at the rate it needs to in order to take hold. The body mounts an immune response, killing the pathogen or breaking down the toxin responsible for disease. The body’s immune system now knows how to fight the disease and will “remember” if it comes across it again. In other words, scientists have figured out how to get a pathogen to help its own target defend itself against it. They have even taken the first steps toward developing vaccines for several forms of cancer, with three vaccines approved by the FDA for the hepatitis B virus (which causes liver cancer), human papillomavirus types 16 and 18 (which cause cervical cancers), and metastatic prostate cancer in some men.

Thanks to vaccines, several diseases have been driven to virtual extinction. Smallpox is the most famous example, but polio, though not totally eradicated, comes in at a close second. Several other diseases might be gone by now if vaccines weren’t so hard to come by in the underdeveloped nations that still struggle with them. Things are getting worse instead of better, with diseases coming in from an unexpected source: affluent, educated Westerners who should know better.

Unfortunately, the anti‑vaccination movement is making a comeback in regions where these diseases were once under control. Before the introduction of the measles vaccine in 1963, approximately 500,000 people per year were infected in the US, 500 of whom—mostly children—ended up dead. By 1983, there were only 1,497 cases reported, and after a brief resurgence in the ’80s and ’90s, reported cases were down to just 37 in 2004. After the anti‑vaccination movement began gaining traction, 118 cases were reported in the US alone in 2011. That number keeps growing, fed by travelers coming in from areas with higher rates and finding less resistance. Whooping cough, once thought to be gone forever in the US, is also on the rise.

4 Bacterial Waste Breakdown

Some of the smallest and simplest of creatures on Earth play some of the most important roles in safeguarding all of life. Bacteria have perhaps the most important role of all: breaking down and recycling waste.

The dead remains of animals and plants, along with the excrement of all organisms, contain vital nutrients and stored energy. Without a way to reclaim these nutrients, though, the available sources would be quickly depleted. Luckily, many bacterial species feed upon these energy sources, breaking them down to their smallest molecules and returning them to the soil, where they reenter the food chain.

As helpful as this process already is, humans have found many ways to exploit it for a variety of even more advantages. Bacteria are used in sewage treatment, industrial waste management, and the clean‑up of oil spills, leaked pharmaceuticals, and wastewater. They have also been useful in the development of aqua‑farming, algae control, and waterless toilets. Researchers and engineers are currently looking into their potential use in the production of environmentally friendly bioplastics, glues, and building materials. They may even be used to break down plastic waste.

3 We Would Quickly Die Without Our Gut Bacteria

Poorly understood until recently (and there is still quite a bit of research to be done), the natural bacteria that lives in our guts works with our immune system to drive out pathogens, produce vitamin K, stimulate peristalsis, and perhaps most importantly, digest our food. Without our gut bacteria, we wouldn’t be able to perform any of these functions, and we would quickly die.

The more we learn about beneficial strains of gut bacteria, the more we can incorporate that knowledge into healthy living. After it was determined that certain gut bacteria can play a role in obesity, probiotics became all the rage. Probiotics are the bacteria that reside in fermented foods and are now sold as supplements. Bacteria like some species of bifidobacteria, found in most yogurts, can create a highly acidic environment in which less‑beneficial microorganisms cannot survive. Fatty foods and stress can also play a role in the health of our stomach flora, killing beneficial bacteria while favoring the more harmful kind that cause gas, bloating, and “leaky gut syndrome.”

In a huge breakthrough in the study of our gut bacteria and what they do, a team of Chinese and Danish researchers have recently developed a new way to identify these microorganisms using DNA sequence data. They identified over 500 species of benign bacteria and 800 new species of viruses that could live off them, providing hope for new ways to treat diseases associated with them, such as diabetes, obesity, and asthma.

2 Skin Bacteria Serve As Our First Line Of Immune System Defense

The moment you emerged from your mother’s womb, you were set upon. They ambushed you in mere moments and colonized every inch of your skin, and they have been with you ever since. They are prokaryotes and other bacteria, and without the evolutionary partnership humans forged with them millions of years ago, you would have been dead soon after being born.

One of the most common skin bacteria is Staphylococcus epidermidis, a bug that we now know plays a role in fighting off Leishmania major, the cause of a nasty disease called leishmaniasis that results in skin boils and open sores that don’t heal. The good bug triggers an immune response called IL‑1 that the body can’t produce on its own, making Staphylococcus a necessary part of the human body, as vital to our existence as any organ.

Prokaryotes, which also colonize the digestive tract, cover every exterior surface on the skin. Along with the rest of our beneficial skin microbiota, they became a part of us when they started competing against less‑benevolent microorganisms for real estate. Along with the immune cells in our skin, they protect us against both pathogenic bacteria and opportunistic fungi that try to invade. This allows our bodies to spend less energy defending our exteriors and focus more on things like fighting viruses and precancerous cells.

While there is still much to learn before we can really use this knowledge in our health regimens, we are already looking to a future that involves the purposeful use of skin bacteria. A start‑up based in Massachusetts called AOBiome, for example, has created a body spray made of live cultured chemoautotrophic bacteria called Nitrosomonas. They claim that their spray can “replenish healthy skin bacteria” and even replace showering, as the bacteria live off the ammonia in our sweat.

1 Life As We Know It Wouldn’t Be Here Without Cyanobacteria

Cyanobacteria, or blue‑green algae, are possibly the oldest still‑living species on Earth, with fossils dating back 3.5 billion years. They are unicellular bacteria that grow in colonies, and if it weren’t for them, you wouldn’t be here, and neither would nearly every other form of life.

Cyanobacteria were the world’s first photosynthesizers. They used energy from the sun along with chemicals in primordial oceans and inert nitrogen in the atmosphere to make their food. As a waste product, they generated oxygen, a poison to virtually every other form of life at that time and the cause of early mass extinction events. Over a period of roughly 300 million years, all this oxygen generation helped form the atmosphere as we know it, during the Archaean and Proterozoic eras.

That wasn’t the only way this bacteria kick‑started life as we know it. Sometime during the Proterozoic or early Cambrian era, they formed a symbiotic relationship with certain eukaryote cells, making food for the cell in return for a stable environment to call home. These were the first plants, as well as the origin of eukaryotic mitochondria, which is essential for animal life. This truly titanic event is now known as endosymbiosis.

While several forms of cyanobacteria are toxic, a species named Spirulina was an important food source for the Aztecs and eaten regularly by many Asian nations. Today, it is often sold in powder or tablet form as a health food supplement.

You are not going to make it through life without getting sick. It happens to the best of us. What kind of sickness you end up with depends on a number of factors. Some illnesses are far easier to get over than others, while others feel like a death sentence the instant they’re diagnosed.

What 8217 s the Most Dangerous Microbe?

1 The Basics

Generally speaking, a virus tends to be more hazardous than a bacterium, though that’s a blanket statement that comes with a big “but.” The common cold virus is far less threatening than, say, botulism‑producing bacteria. Context matters.

Bacteria are single‑celled organisms that can survive on their own. Most are harmless, and many actually help us—our gut alone hosts roughly 100 trillion bacteria that aid digestion. Only a tiny fraction cause trouble. In size, bacteria are roughly ten to a hundred times larger than viruses, ranging from one to three microns, with Salmonella as a familiar example.

Viruses, on the other hand, can’t live independently. They act like parasites, hijacking a host’s cells to reproduce, which often results in illness or death. Their size is minuscule—about 20 to 200 nanometers across.

Parasites belong to the eukaryote kingdom, meaning they have a nucleus and internal structures, making them larger than both viruses and many bacteria. Some parasites are entire organisms, like tapeworms, that take up residence inside us.

Fungi most often appear as spores or molds. A common example is athlete’s foot, a fungal infection that thrives in damp environments.

2 Bacteria Breakdown

A solitary bacterium is a fully formed, single‑cell microbe capable of surviving outside the human body. They flourish in soil, rotting food, on skin—anywhere conditions are right.

The most dangerous bacteria can wreak havoc in several ways. Many produce deadly toxins that can paralyze or outright destroy our cells, disrupting normal function. Others multiply so aggressively that they outcompete healthy cells for resources.

Antibiotics have revolutionized medicine by either killing bacteria or halting their growth. They achieve this by either breaking down the bacterial cell wall or interfering with the organism’s ability to reproduce.

Because bacteria reproduce rapidly—every 20 to 30 minutes in ideal conditions—they also mutate quickly. This rapid evolution has given rise to antibiotic‑resistant strains. Some bacteria produce enzymes that deactivate antibiotics; others pump the drugs out before they can act.

Common culprits like Salmonella, gonorrhea, and Campylobacter have developed resistant strains, turning once‑easily‑treated infections into potentially lethal threats.

The ever‑changing nature of bacteria makes naming a single “worst” organism impossible. In 2024, the World Health Organization highlighted 15 drug‑resistant bacteria as especially dangerous. Near the top sits Mycobacterium tuberculosis, the bacterium behind TB, responsible for roughly 1.7 million deaths each year.

3 Virus Breakdown

Viruses aren’t cells or independent living entities. They consist of a tiny packet of genetic material wrapped in protein. Outside a host, a virus is inert—without a living cell to commandeer, it can’t replicate or cause disease.

Once a virus infiltrates a host, it hijacks the host’s cellular machinery to make copies of itself. This process often destroys the host’s cells, leading to infection. Their minute size even allows them to infect bacteria and fungi, and they can be inhaled, transmitted via insects, or spread through bodily fluids—pathways unavailable to larger microbes.

The immune system attempts to generate antibodies to neutralize the invader. If the virus replicates faster than the body can mount a defense, illness ensues and can be fatal. The viral replication cycle inherently damages host cells.

A fever is one of the body’s first defenses; many viruses can’t survive the elevated temperature, though prolonged fevers can be dangerous for the patient as well.

Antibodies are the second line of defense, but they require prior exposure to a pathogen to be produced. When encountering a novel virus, the immune system may be caught off‑guard.

Ebola is a stark example of extreme lethality, with mortality rates reaching up to 90 percent. Its rapid, deadly course, however, limits its spread compared with less‑virulent viruses.

HIV, by contrast, has spread worldwide and has claimed around 32 million lives. Modern antiretroviral therapies have dramatically reduced mortality, but the virus remains a historic heavyweight.

The 1918 influenza pandemic, often called the Spanish Flu, caused an estimated 50‑100 million deaths globally, underscoring how a seemingly ordinary virus can become catastrophic.

Rabies is another terrifying virus—once symptoms appear, the fatality rate is essentially 100 percent without prompt treatment.

Viruses that humanity has largely eradicated, such as smallpox, once killed roughly 300 million people before vaccination campaigns eliminated them.

4 Fungi Breakdown

Pop‑culture has turned fungal infections into something of a horror‑movie staple. Articles about bizarre fungi eventually inspired the video‑game series The Last of Us, where a cordyceps‑type fungus decimates humanity.

In reality, cordyceps infect insects, forcing them to climb and cling to vegetation before the fungus erupts from their bodies. Humans, with far more complex immune systems, are not susceptible to this particular pathogen—unless it somehow mutates.

Other fungi, however, pose real threats. In 2023, the CDC warned about Candida auris, a drug‑resistant yeast that spreads in hospitals and can invade the heart, lungs, bloodstream, eyes, bones, and other organs.

Cryptococcus neoformans, another ubiquitous yeast found in soil, can cause meningitis with mortality rates between 41 % and 61 %, especially in immunocompromised patients.

Aspergillus fumigatus, a common mold that thrives on decaying foliage, carries a mortality rate as high as 90 % in invasive infections. Everyone inhales dozens of spores daily, but most remain harmless—unless the immune system is weakened.

Fungal infections receive far less research funding than bacterial or viral diseases, yet they claim roughly 1.7 million lives each year—more than malaria and double the deaths from breast cancer. Over 150 million severe, non‑fatal fungal infections are reported worldwide.

5 Parasite Breakdown

Parasites are arguably the most unsettling microbes. While not always fatal, their size and life cycles make them especially creepy. They are living organisms that settle inside a host, often entering through disturbing routes.

Take Strongyloides, a nematode that thrives in contaminated soil. Walking barefoot can let its larvae burrow through the skin, travel via the bloodstream to the lungs, trigger a cough, and then be swallowed back into the gut, where they can reside for years, potentially turning lethal if the host’s immunity falters.

Giardia, a microscopic parasite, spreads through fecal‑contaminated water or food. Ingesting cysts leads to diarrheal illness, especially in areas with poor sanitation.

Tapeworms, contracted by eating undercooked meat harboring eggs, can stretch up to 12 feet inside the intestine, with some rare cases exceeding 50 feet and persisting for decades.

Brain‑eating amoebas, such as Naegleria fowleri, infiltrate the body through the nose when swimming in warm, stagnant water, leading to a near‑100 % fatality rate.

Parasites can also trigger sepsis and a host of other complications. Malaria, caused by Plasmodium parasites transmitted by mosquitoes, resulted in about 600 000 deaths in 2022 alone.

Most parasites don’t aim to kill their host; they need a living environment to survive. Roughly one in seven people worldwide harbors an intestinal parasite, and some estimates suggest up to half of humanity carries one at any given time.

6 So Which Is Worst?

It’s impossible to crown a single pathogen as the absolute worst. Each category—bacteria, parasites, fungi, viruses—contains a dizzying array of organisms with wildly different traits, transmission methods, and mortality rates. Variables such as geography, health status, and access to medical care dramatically shift the danger level.

The safest advice is simple: avoid infection whenever possible, regardless of the microbe. Prompt diagnosis and treatment are essential if you ever find yourself infected, whether the culprit is a bacterium, virus, fungus, or parasite.

10 places you might not suspect are teeming with bacteria are scattered across our planet, from the deepest underground shafts to the most sterile human‑made environments. Humans share the Earth with a staggering multitude of microbes, distant microbial cousins that inhabit every conceivable niche and perform countless roles—some beneficial, some hostile. Roughly 5×10^30 bacterial cells call our planet home, amounting to a total mass that outweighs all plants and animals combined.

We tend to picture bacteria only where other life thrives—our guts, kitchens, forests, ponds. Yet many microbes require none of those comforts and thrive in truly obscure, unexpected places on Earth and even beyond.

10 places you might not expect to host bacteria

10 Inside Solid Rock

For ages, scientists assumed sunlight was a non‑negotiable ingredient for life, even for organisms tucked away inside other creatures. The prevailing thought was that any microbe not basking in sunlight must still rely on organic matter originally forged with solar energy.

That notion was upended when researchers probing a South African gold mine uncovered bacterial colonies more than one and a half miles beneath the surface, living solely off radioactive waste. These microbes thrive in an environment saturated with uranium, thorium and potassium, using the minute energy released by radioactive decay to fuel their metabolism.

The radiation splits water molecules, yielding hydrogen peroxide and sulfates. Hydrogen peroxide reacts with pyrite—fool’s gold—producing sulfate ions, which the bacteria eagerly consume. Unlike the rapid‑dividing everyday microbes such as E. coli, these rock‑dwelling bacteria take their time, dividing anywhere from once a year to once every three hundred years.

9 The Cleanest Place On Earth NASA Clean Rooms

If you’ve ever scrubbed your kitchen or bathroom until it gleamed, you’ve likely felt a surge of triumph, convinced you’ve banished every microscopic intruder. Now picture working for NASA, where the goal is to craft “clean rooms” so immaculate that anyone entering must be encased in triple‑layer, sterilized suits. The stakes are astronomical because the spacecraft itself is treated like a patient in an operating theater.

Mike Weiss, Hubble’s technical deputy program manager at Goddard, likens these rooms to hospital operating suites: “Surgeons wear sterile gowns, gloves and masks during surgery, and operating rooms must be kept free of germs to keep patients healthy. In our case, the spacecraft is the patient.”

Entry into a clean room is a ritual: first, a lobby with adhesive strips that strip dirt from shoes; next, a high‑pressure air shower; finally, a full‑body protective suit that seals the wearer from head to toe. This rigorous process makes the discovery of a new bacterial genus all the more startling.

Scientists identified Tersicoccus phoenicis—named after the Latin word for “clean”—in two separate NASA clean rooms. This hardy microbe has mastered evading the most aggressive industrial cleaners and sterilization protocols, and NASA now keeps samples on hand to compare against any alien microbes that might hitch a ride back from space.

8 Sheets Of Ice

When we think of ice, we imagine frozen stillness, a realm where life moves at a glacial pace—or not at all. Freezers in our homes preserve food by slowing chemical reactions, and we assume such chilly environments are barren of thriving microbes.

Surprisingly, massive populations of bacteria have carved out long‑term homes within the world’s largest glaciers. Some strains have persisted for millions of years, locked in ancient ice. The Transantarctic Mountains host the oldest known ice on Earth, and the microbial cells trapped within outnumber the entire human population by a factor of over ten thousand.

As global temperatures rise and glaciers melt, these ancient microbes are being released into the oceans, where they must adapt to a new, potentially more hospitable environment, reshaping ecosystems in ways scientists are only beginning to understand.

7 Boiling Water

Every scout knows the rule: boil any natural water source before drinking to kill harmful microbes. Yet some bacteria have evolved tricks that let them survive the rolling boil most of us rely on for safety.

Clostridium botulinum, the culprit behind botulism—a paralytic illness caused by a potent nerve toxin—thrives in low‑oxygen environments. It can linger in camp kettles, sealed cans, and other anaerobic niches, persisting even after the water reaches a full boil.

Because botulism can demand aggressive antibody treatment and hospital care, the best defense is to employ extreme measures: bleach, sodium hydroxide, and temperatures soaring to around 120 °C (248 °F) are required to reliably eradicate this resilient pathogen.

6 The Lowest Place On Earth

The Mariana Trench, a yawning chasm east of the Philippines and north of New Guinea, plunges to a staggering depth of roughly 11,000 meters. This abyss, especially its Challenger Deep, represents the planet’s most extreme low‑pressure, high‑gravity environment.

Researchers have uncovered heterotrophic bacteria thriving at these crushing depths. These microbes subsist on minute organic particles that drift down from the sunlit surface, breaking down compounds such as sulfur and ammonia to survive beyond the reach of sunlight.

The presence of such bacteria in the darkest oceanic realms challenges our understanding of life’s limits and hints at biochemical pathways that could function under conditions once thought uninhabitable.

5 The Upper Atmosphere

When we picture bacteria, we usually imagine them nestled in soil, water, or living hosts. Yet scientists have discovered a surprisingly abundant microbial community floating high above us, suspended in the upper atmosphere.

Even at altitudes of six miles or more, bacteria find sustenance in the carbon particles that drift upward. Studies suggest that roughly twenty percent of the tiny particles in the upper atmosphere are bacterial, riding the wind currents and weather systems.

The exact mechanisms that loft these microbes skyward remain a mystery, but high winds and shifting atmospheric pressures likely act like elevators, whisking microorganisms from the surface into the stratosphere, where they persist as part of the planet’s aerial ecosystem.

4 Your Eyeball

It’s common knowledge that the human body hosts more bacterial cells than human cells, most of which reside peacefully in the gut, assisting digestion and producing vital chemicals. Yet a more unsettling bacterial presence lurks on a very visible part of us: the eye.

The conjunctiva, a mucus membrane covering the sclera, can harbor Chlamydia trachomatis and Neisseria gonorrhoeae. These pathogens, which cause chlamydia and gonorrhea respectively, can colonize the eye despite tears containing lysozyme and other antimicrobial enzymes that strive to keep them at bay.

Because these bacteria are capable of causing eye infections, maintaining proper ocular hygiene is essential to prevent uncomfortable and potentially serious conditions.

3 Antarctica

If you’re a seafood aficionado, you’ve likely heard warnings about mercury accumulation in fish. A newly discovered Antarctic bacterium, Nitrospinia, adds a microbial twist to this concern.

This strain excels at converting inorganic mercury into methylmercury, a far more toxic form that readily accumulates in marine food webs. Fish that consume these bacteria ingest the methylmercury, which then makes its way onto our plates, posing developmental risks, especially for children.

As commercial fisheries push further south to compensate for dwindling stocks elsewhere, the potential for increased exposure to this bacterial mercury conversion process becomes a pressing environmental and public‑health issue.

2 Your Glabela

The glabella—the smooth patch of skin between the eyebrows and above the nose—might seem an unlikely bacterial hotspot, given its exposed nature. Yet it hosts a tiny yet formidable resident: Demodex folliculorum, commonly known as the eyelash mite.

These microscopic arachnids roam the forehead, feeding on skin oils and dead cells. While generally harmless, they can occasionally trigger acne vulgaris, leaving unsightly blemishes right between the eyes.

Understanding the role of these mites helps explain why some people develop stubborn forehead acne, pointing to a microscopic culprit rather than just hormonal or dietary factors.

1 The Dead Sea

Given its name, the Dead Sea seems an unlikely venue for life. Its hyper‑saline waters repel most organisms, yet a clever group of bacteria has found a loophole by exploiting fresh‑water springs that intermittently feed the basin.

Over the past decade, researchers have uncovered prokaryotic life that tolerates both extreme salinity and fresh water, thriving on rocks at the sea’s bottom where underwater craters spew fresh water and sulfides, forming a thin white film.

This discovery shatters the notion that microbes must choose between fresh‑water or salt‑water habitats, proving that some bacteria can adapt to wildly fluctuating conditions and survive where few others dare.

When you think about tiny organisms, the phrase “size doesn’t matter” suddenly feels literal. These microscopic marvels wield enough power to reshape ecosystems, generate clean energy, and even flirt with quantum physics. Below are 10 bizarre finds that highlight just how extraordinary bacteria can be.

10 Bizarre Finds Uncovered

10 New Ocean Food Source

A 2018 expedition into the abyss of the Clarion‑Clipperton Fracture Zone (CCFZ) uncovered a bustling community of deep‑sea bacteria living roughly 4,000 meters (13,000 ft) beneath the waves. At such crushing depths, scientists once assumed the only sustenance came from detritus drifting down—dead fish, plankton, and other organic debris.

Contrary to observations from the North Atlantic, the Pacific microbes dominated the consumption of this “rain” of material, outcompeting the typical bottom‑dwelling fauna. Even more astonishing, these bacteria were found to siphon massive amounts of carbon dioxide into their own biomass through a still‑mysterious biochemical pathway.

The implications stretch far beyond a quirky feeding habit. By converting CO₂ into organic matter, these microbes generate a potential food source for deep‑sea creatures that otherwise lack nutrition. In effect, they turn a greenhouse gas liability into a dietary asset for the ocean’s hidden ecosystems.

Calculations suggest that the bacterial community could sustain the entire CCFZ region, potentially recycling about 200 million tons of CO₂ each year—an impressive natural carbon‑capture engine operating in the planet’s darkest corners.

9 Source Of Clean Energy

Household sewage and industrial wastewater are teeming with organic compounds that could be harvested for energy—if only there were a cheap, efficient extraction method. Enter purple bacteria, the phototropic powerhouses that harvest light to drive biochemical reactions.

In 2018, researchers demonstrated for the first time that these light‑loving microbes could be coaxed into recycling waste streams. Unlike conventional water‑treatment facilities, the bacteria performed their work under illumination, emitted zero carbon emissions, and did so at a fraction of the usual cost.

This bio‑refinery approach captures nearly 100 % of the carbon present in the waste, regardless of its source. The process also spits out hydrogen gas, a clean fuel that can be fed directly into electricity generators.

The secret lies in the bacteria’s metabolism: they gorge on organic molecules rather than on CO₂ and H₂O, making waste an ideal buffet. During photosynthesis, they extract carbon, nitrogen, and electrons, converting them into valuable products.

By‑products include protein‑rich biomass, hydrogen gas, and even biodegradable polyester—each a useful commodity in its own right. Researchers also discovered that applying a mild electric current to the purple bacteria accelerates their feeding cycle, taking advantage of the organisms’ electron‑rich interiors.

All told, this green technology showcases how microbes can transform what we consider trash into a suite of clean‑energy resources.

8 The Titanic’s Doom

The legendary RMS Titanic, which vanished in 1912, lay undiscovered for more than seven decades before a 1985 expedition located its rust‑caked hull roughly 530 km (329 mi) southeast of Newfoundland. A later 2010 dive brought back an unsettling surprise.

Scientists retrieved a previously unknown bacterium, christened Halomonas titanicae in homage to the ship. Ironically, this microbe is actively devouring the very metal structure that bears its name, feeding voraciously on the rust that blankets the wreck.

Resting at a depth of about 3.8 km (2.4 mi), the Titanic is beyond any practical recovery effort. Its slow but relentless decay means that preserving the iconic vessel is virtually impossible.

The silver lining, however, is that the rust‑loving bacteria could be harnessed to dismantle unwanted maritime structures—such as derelict ships or offshore oil rigs—offering a biological solution to metal waste. Moreover, insights from H. titanicae are informing the development of antibacterial coatings for industrial equipment.

Scientists warn that, at the current rate, the Titanic may disappear entirely within the next two decades, leaving only a ghostly legend and a handful of microscopic scavengers.

7 Brain Bacteria

For years, the brain has been regarded as a sterile sanctuary, with any bacterial presence signaling disease. In 2018, a team of scientists set out to compare the brains of individuals with schizophrenia to those of neurotypical donors, hoping to uncover subtle differences.

What they stumbled upon was a startling visual: high‑resolution scans revealed countless rod‑shaped structures peppered throughout the tissue. These turned out to be bacteria, an unexpected find that could rewrite neurobiology textbooks.

To rule out contamination, the researchers verified that the brain samples were healthy and free of overt infection. Subsequent investigations using mouse brains—carefully kept free from external microbes—showed identical bacterial clustering, suggesting the presence was genuine and not an artifact.

DNA sequencing identified the microbes as members of the Firmicutes, Proteobacteria, and Bacteroidetes families—groups commonly residing in the human gut. While the gut‑brain axis is well‑established, this was the first direct visual evidence of bacteria cohabiting the brain itself. The functional role of these brain‑dwelling microbes remains an intriguing mystery.

6 Epic Nose Battles

Within the nasal passages of mice, a microscopic showdown unfolds between two bacterial rivals: Streptococcus pneumoniae and Haemophilus influenzae. While each can live harmlessly on the damp lining, they also have the capacity to trigger severe illnesses such as pneumonia and meningitis.

Researchers probing this tiny battlefield discovered that when the two species encounter one another, a fierce competition erupts. H. influenzae cleverly manipulates the host’s immune defenses, recruiting white blood cells to attack its competitor, often eradicating S. pneumoniae from the nose entirely.

In retaliation, certain strains of S. pneumoniae boast a sugary capsule that comes in roughly 90 variants. The most robust capsules shield the bacteria from immune attack, allowing them to infiltrate tissues and cause disease. This microbial duel suggests that many respiratory infections may be collateral damage from bacteria battling each other rather than a direct assault on the host.

Given the similarity between mouse and human nasal environments, it’s plausible that analogous rivalries play out in our own airways, shaping the landscape of everyday infections.

5 Electric Mushrooms

In 2018, a New Jersey laboratory set out to engineer a renewable power source using something as humble as a button mushroom. The recipe combined three ingredients: the fungus itself, photosynthetic cyanobacteria, and ultra‑thin graphene nanoribbons (GNRs) that serve as conductive electrodes.

The design leveraged each component’s strengths. Cyanobacteria harvest light and generate electrons, while the GNRs conduct those electrons efficiently. The mushroom provided a natural, moist matrix that nurtured the bacteria and kept the nanoribbons in place—a synergy impossible to achieve on a purely synthetic surface.

Using 3‑D printing, researchers embedded the GNRs and bacteria directly onto the mushroom’s flesh. When illuminated, the cyanobacteria kicked into gear, converting light into an electric current that traveled through the graphene pathways into external wires.

Although the prototype produced only a modest current, the proof‑of‑concept demonstrated that living organisms could be integrated with nanomaterials to generate electricity. Future refinements aim to boost power output, potentially delivering a scalable, green energy source that grows as easily as a mushroom.

4 Increasing Risk Of Plague

The Black Death, which swept across Europe in the 14th and 15th centuries, claimed up to 200 million lives. The culprit was the bacterium Yersinia pestis, a pathogen that thrives under certain climatic conditions.

Today, climate scientists warn that rising global temperatures may awaken dormant pathogens trapped in permafrost. As ice melts, ancient bacteria—including plague‑causing strains—could re‑emerge, posing a renewed public‑health threat.

This scenario is not purely speculative. In 2016, thawing Siberian permafrost released anthrax spores, leading to over 40 human infections, the death of a child, and the loss of roughly 1,500 reindeer—a stark reminder of nature’s hidden hazards.

Historical climate data indicate that a modest 1.5 °C (2.7 °F) temperature rise coincided with the surge of the Black Death. If similar warming patterns repeat, permafrost‑bound bacteria could resurface, potentially sparking new pandemics beyond the infamous plague.

3 Living Tattoos

MIT’s 2017 3‑D‑printing venture turned bacterial cells into a living form of body art. By embedding engineered microbes into a hydrogel “ink,” the team printed intricate designs—such as tree silhouettes or electronic‑circuit motifs—directly onto human skin.

Bacteria were chosen for their resilience; they survive the harsh printing process and thrive within the hydrogel matrix. The microbes were genetically modified to emit fluorescent colors, turning the printed patterns into glowing works of art once activated.

The process began by engineering the bacteria to produce distinct pigments. Next, an ink blend containing the living cells, nourishing nutrients, and a supportive hydrogel was formulated. This viscous medium could be extruded with a resolution of 0.03 mm, allowing for fine‑detail designs.

After printing the pattern onto a pre‑treated skin surface, the bacteria sprang to life, lighting up in vivid hues when exposed to specific chemical triggers. While still a novelty, the technology hints at future wearable patches that could deliver medicines—such as insulin or glucose—directly through the skin on demand.

2 They Produce Solid Gold

Cupriavidus metallidurans is a soil‑dwelling bacterium with a taste for toxic metals—and an uncanny ability to excrete solid gold. First identified in 2009, this microbe’s alchemical feat was fully elucidated in a 2018 study.

Unlike most life forms, C. metallidurans thrives in environments saturated with heavy metals. Its cell envelope comprises two membranes, creating a periplasmic space that functions as a detoxification chamber.

Normally, the periplasm stores excess copper, a metal essential for the bacterium’s metabolism but lethal in overload. The enzyme CupA shuttles surplus copper into this compartment, keeping the cell safe.

Gold ions, however, pose an even greater threat. When they infiltrate the periplasm, they can destabilize the copper‑handling system. To survive, the bacterium employs a second enzyme, CopA, which transforms volatile gold ions into stable, inert gold particles inside the periplasm.

Once the periplasmic vault fills with gold, the outer membrane ruptures, releasing microscopic gold nuggets—sometimes as large as sand grains—into the surrounding soil. This natural gold‑producing process offers intriguing possibilities for biotechnological metal recovery.

1 They Touch The Quantum World

In 2018, researchers set out to pinpoint where the quantum realm ends and the macroscopic world begins. While quantum physics governs particles at infinitesimal scales, the everyday world—humans, bacteria, trees—has traditionally been viewed as separate.

The prevailing view held that quantum effects fade away as systems grow larger. To challenge this, scientists revisited a 2016 experiment from the University of Sheffield, which placed photosynthetic bacteria inside a mirrored chamber bathed in a specific light frequency.

Only a handful of the bacteria displayed quantum coupling—a tenuous link between their photosynthetic molecules and the incoming photons. The 2018 review suggested the original findings underestimated the phenomenon.

New experiments revealed clear signs of quantum entanglement within the bacterial cells, a phenomenon previously never observed in living organisms. Entanglement allows two entities to share a linked state regardless of the distance separating them.

These results hint that bacteria may have evolved mechanisms to harness quantum effects, opening a frontier of possibilities for biology and physics alike.

Scientists are at it again. This time, they’re creating new viruses and bacteria in their laboratories. In this roundup of the 10 deadly viruses and bacteria engineered in labs, we explore how researchers tinker with pathogens, the controversies that follow, and why these creations matter for global health.

10 Deadly Viruses Overview

10 Horsepox

Scientists at the University of Alberta have created horsepox, a lethal virus closely related to the equally deadly smallpox. Unlike smallpox, horsepox does not affect humans and is only fatal to horses. The scientists created the virus during a six‑month study sponsored by pharmaceutical company Tonix. The researchers purchased DNA pieces via mail order and arranged them to form the virus. The entire project was not expensive. The DNA pieces used to create the virus cost just $100,000.

The study caused a dilemma at the time it was revealed. Other scientists were concerned that governments or even terrorists could use the knowledge to create smallpox virus for biological weapons. A smallpox epidemic could become deadly for us today. We no longer get vaccinated for it because we eradicated the disease in 1980.

The researchers clarified that they created the virus because they wanted to develop improved smallpox vaccines. Tonix later revealed that it had produced a smallpox vaccine with the horsepox virus. Other scientists say that the researchers could have extracted horsepox from wild horse populations instead of creating it from scratch. Tonix said they would have done just that if they had known they had natural access to the virus. However, lead researcher David Evans said they recreated the virus because Tonix would have been unable to commercialize the horsepox virus taken from the wild.

9 Black Death

Between 1347 and 1351, millions of Europeans were afflicted with a mysterious disease that killed over 50 million people. Today, we know this disease is the Black Death, which is caused by the Yersinia pestis bacteria. Although the Black Death is still around, it is not as potent as it used to be.

A few years ago, researchers from several schools, including the University of Tubingen in Germany and McMaster University in Canada, recreated the deadly bacteria from DNA samples extracted from the teeth of a victim who died during the plague. They got only 30 milligrams of the bacteria from the teeth, but that was enough to recreate it.

As a result, researchers confirmed the original bacteria’s relationship to the Black Death around today. Some scientists had claimed that the bacteria were of different strains, but they are now confirmed to be the same. The one we have around today only became less deadly after it mutated.

8 Polio

Like their counterparts at the University of Alberta, scientists at the State University of New York have created a deadly artificial virus by buying DNA pieces via mail order. This time, it is polio, and it is as potent as the natural one. Mice exposed to the artificial polio got sick just as they would have if exposed to natural polio.

The laboratory‑created polio was controversial among scientists. The researchers who produced it had taken its code from databases available to almost anybody. Other researchers fear that people with ulterior motives could develop their own artificial polio, which is much easier to make than other dangerous viruses like smallpox.

Smallpox’s genetic code is 185,000 letters long while polio’s is just 7,741 letters long. Although we are already at the brink of eradicating polio, scientists fear that we will still need to be vaccinated against the disease because it could be recreated.

7 Mousepox

A few years ago, researchers at the Australian National University and the Commonwealth Scientific and Industrial Research Organization (CSIRO) produced a deadly mutated strain of mousepox by mistake. Mousepox is another lethal virus that belongs to the same family as horsepox and smallpox.

The researchers were trying to develop birth control for mice at the time that they mistakenly created the virus. They inserted a gene that promoted the creation of interleukin 4 (IL‑4) into mousepox, which they injected into some mice. The mice were vaccinated and were not supposed to be harmed by the mousepox.

Instead of making the mice infertile as researchers had expected, the weakened virus turned lethal and destroyed the immune systems of the mice, killing them in nine days. The new mousepox was so dangerous that it was resistant to vaccination. Half of the other vaccinated mice exposed to the mutated mousepox also died.

The researchers were so scared by their invention that they did not want to publish their findings. They even met with the Australian military to confirm if it was safe to publish. Scientists fear that human smallpox could also mutate and become deadlier if injected with IL‑4. However, they are unsure because no one has tried it yet. We know it’s only a matter of time before some scientist does.

6 SARS 2.0

Severe acute respiratory syndrome (SARS) is a lethal virus. More than 700 people were killed during a SARS epidemic that infected 8,000 people in 29 countries between 2002 and 2003. Now, scientists have made it deadlier.

The new mutant SARS virus was created by a group of researchers led by Dr. Ralph Baric of the University of North Carolina. They call it SARS 2.0. The researchers developed the virus by adding some protein to the naturally occurring SARS. SARS 2.0 is immune to vaccines and treatments used to cure the naturally occurring SARS virus.

The team said that the research was necessary because the natural SARS virus could mutate and become immune to our vaccines. By creating a deadlier and mutated virus, we could develop stronger vaccines that will save us from a more lethal SARS epidemic. That is, if the natural SARS ever mutates.

However, other scientists are concerned because the SARS 2.0 that is supposed to save us from a deadly SARS epidemic could start that epidemic if it ever escapes from the lab.

5 MERS‑Rabies Virus Hybrid

Scientists have created a MERS‑rabies hybrid virus. The idea is to use the virus to develop a vaccine that will protect us from both viruses. Rabies is a deadly disease that can be transmitted to humans through the bites of infected dogs that usually have the virus in their saliva.

Middle East Respiratory Syndrome (MERS) is a new virus that appeared in Saudi Arabia a few years ago. It is closely related to SARS and is spread from bats to camels and, finally, to humans. MERS infected 1,800 people at the time of its first epidemic and killed over 630. Its fatality rate is around 35 percent.

As we mentioned in the previous entry, SARS infected over 8,000 people during a 2003 epidemic but killed just over 700. Although SARS caused more deaths in absolute terms, it has a lower fatality rate than MERS. Only about 10 percent of SARS victims died. And for now, we do not have any vaccine for MERS.

To create the MERS‑rabies hybrid, researchers took some proteins from the MERS virus and added it to rabies. They used the new virus to develop a new vaccine that made mice resistant to rabies and MERS. They believe that the vaccine can also be used for humans and camels at risk of getting MERS.

4 Phi‑X174

Phi‑X174 is another artificial virus we have produced in laboratories. It was created by researchers at the Institute of Biological Energy Alternatives in Rockville, Maryland. The researchers modeled the artificial virus after the natural phiX virus. PhiX is a bacteriophage, a category of viruses that infect and kill bacteria. However, it has no effect on humans.

The researchers created the artificial virus in 14 days, yet it resembles the natural virus so much that it is impossible to tell them apart. The researchers hope that the new virus is the first step in developing mutant and artificial bacteria that can be used for the benefit of man.

3 Unnamed Virus

Researchers from University College London and the National Physical Laboratory have created an unnamed virus that kills bacteria and behaves like a real virus. Like phi‑X174, it is a bacteriophage but deadlier.

The unnamed virus attacks any bacteria around it. Within seconds, it breaks into smaller parts that attach and create holes on the bodies of the bacteria. The holes quickly become larger, forcing the bacteria to leak their contents. The bacteria die soon after.

Despite its scary potency, the unnamed virus is not dangerous to humans and did not attack human cells during tests. However, it could enter human cells just like natural viruses. Researchers hope the results will be used for treat and study bacterial diseases in humans. The virus could also be used to alter the human gene.

2 Bird Flu

Some Dutch scientists have created a mutant and deadlier version of the already‑lethal bird flu. Natural bird flu is not easily transmitted among humans. However, the researchers altered it so that it could be. To test their new virus, the researchers exposed some ferrets to it. Ferrets were chosen because they had similar bird flu symptoms to humans.

Ten generations later, the already‑changed virus mutated again and became airborne. Natural bird flu is not an airborne disease. The study was controversial in the science community. It became even more so when the Dutch researchers attempted to publish the process to create the deadly virus.

Although scientists fear that terrorists could use the study to produce a deadly biological weapon that could kill half the people in the world, the researchers involved say that the study was necessary to allow us prepare for a mutated bird flu epidemic.

1 H1N1 Virus

In 1918, the world witnessed the arrival of a deadly flu epidemic. This was the H1N1 virus. By the time it was over, up to 100 million people were dead. The flu caused blood to seep into the lungs of victims. They released blood from their noses and mouths before drowning in the blood inside their lungs.

The flu returned in 2009. But it was less lethal even though it was mutated and deadlier than it should have been. Scientist Yoshihiro Kawaoka took samples of the mutated strain that caused the 2009 epidemic and used it to create a deadlier strain that was resistant to vaccines. This strain was similar to the one that caused the 1918 epidemic.

Kawaoka was not planning to produce a more lethal version of the flu at the time. He only wanted to create the original version of the flu so that he could study how it mutated and was able to bypass our immunity. The deadly virus is stored in a lab and could become fatal if ever released.

When you hear the phrase 9 horrifying ways, you might picture monsters under the bed, but the true terror often lives on the kitchen counter or in your bathroom cabinet. Ordinary products that promise convenience can sometimes flip the script, turning helpful tools into hidden hazards. From cosmetics that can induce a coma to dental creams that lead to permanent paralysis, the everyday world holds more danger than most of us realize.

9 Higher Blood Pressure

Most of us learned about mouthwash from a snappy TV ad that promised a fresh smile and a clean mouth in seconds. The commercial’s message is simple: swish, spit, and all the bad bacteria are gone. However, a 2019 study raised a red flag. Researchers wondered whether eradicating all oral microbes might have unintended consequences.

To test the idea, volunteers jogged on a treadmill for thirty minutes, then immediately rinsed with either a commercial mouthwash or a placebo. Those who used the mouthwash didn’t enjoy the usual drop in blood pressure that comes after exercise, while the placebo group saw the expected decline. The discrepancy pointed to a hidden physiological link.

The culprit is nitric oxide, a molecule produced during physical activity that relaxes blood vessels and lowers pressure. Normally, nitrate—produced as a waste product—gets converted into nitrite by specific oral bacteria, and nitrite then helps generate nitric oxide. When mouthwash wipes out those helpful microbes, the conversion stalls, leaving blood vessels tighter and preventing the blood‑pressure‑lowering effect of exercise.

8 Werewolf Syndrome

Picture a typical pediatric visit: a concerned parent gives their infant a spoonful of prescribed syrup to soothe acid reflux. In Spain, 2019 saw a bizarre twist on this routine—seventeen babies began sprouting an abnormal coat of hair, resembling little werewolves. One toddler even sported eyebrows thick enough for an adult.

The condition, medically known as hypertrichosis or “Werewolf Syndrome,” is usually congenital. Yet these children displayed an acquired form, developing excessive hair growth after birth. Health officials traced the common denominator to a reflux syrup that contained the drug omeprazole, which by itself has never been linked to such side effects.

Investigators discovered the syrup’s manufacturing plant had mislabeled batches. While the bulk shipment of omeprazole was pure, the factory repackaged smaller bottles and mistakenly affixed the omeprazole label to a different product that contained minoxidil—a medication that actively promotes hair growth. Fortunately, doctors expect the extra fuzz to thin out as the children age.

7 Explosions And Burns

Hoverboards burst onto the scene in the 2015‑2016 holiday season, promising a futuristic gliding experience. In reality, many of those two‑wheeled scooters harbored a serious flaw: poorly designed battery packs that could overheat, catch fire, and even explode while riders were in motion.

The U.S. Consumer Product Safety Commission logged 99 complaints, 18 of which involved injuries—mostly burns to hands, arms, and necks. The danger was so severe that campuses, railways, and airlines banned the devices outright. Ultimately, over half a million hoverboards across ten manufacturers were recalled.

6 Permanent Paralysis

In 2017, a 62‑year‑old man from the United Kingdom began feeling a tingling sensation in his fingers, followed by numbness and pain that crippled his legs. Within six months he relied on a cane, and eventually became housebound. Doctors initially suspected a neurological disorder and ordered an MRI.

The scan revealed copper‑deficiency myelopathy, a rare condition where insufficient copper damages the spinal cord. Such a severe deficiency is unusual, prompting doctors to hunt for an external cause. The culprit turned out to be an excess of zinc, which interferes with copper absorption.

The source of the zinc overload was the man’s denture cream. He had been slathering up to four tubes a week for years to improve the fit of his false teeth. Once the cream was discontinued and copper supplements introduced, the condition could not be reversed, leaving him permanently wheelchair‑bound.

5 Pierced Lungs

Acupuncture enjoys a reputation as a gentle, needle‑based therapy, yet not all points are created equal. One such spot, Gallbladder 21, sits near the shoulder and, if mishandled, can jeopardize the lungs. In 2019, a 33‑year‑old New Zealander sought treatment for an arm injury that impaired her breathing.

During the session, the practitioner inserted a pair of needles into the Gallbladder 21 point. The patient felt sharp pain and sensed the needles were too deep. After thirty minutes, she reported an odd, airy sensation around her chest. The acupuncturist advised rest, but the woman soon experienced worsening discomfort.

That night her husband rushed her to the hospital, where doctors diagnosed bilateral apical pneumothoraces—both lung tops had been punctured, causing partial collapse. Studies show that Gallbladder 21 is responsible for roughly 30 % of acupuncture‑related lung injuries.

4 Second‑Degree Burns

When actress Gwyneth Paltrow championed vaginal steaming as a wellness trend, many followers eagerly tried the practice—hovering over a pot of herbal steam in hopes of “cleansing” the vagina. In 2019, a 62‑year‑old Canadian woman with a diagnosed vaginal prolapse turned to steaming as a remedy.

Instead of relief, she arrived at the emergency department with second‑degree burns covering her vaginal walls and cervix. Scientific reviews have found no health benefits from vaginal steaming; the procedure actually disrupts the natural bacterial flora and poses burn risks.

Because of the injuries, the woman’s scheduled prolapse surgery was postponed while she recovered, underscoring the danger of unproven, celebrity‑driven health fads.

3 Skull‑Eating Infection

A 37‑year‑old woman, identified only as Jasmine, visited her doctor because she struggled to hear properly. An examination revealed an infection, and she was prescribed antibiotics, yet her hearing did not improve.

Jasmine habitually cleaned her ears with cotton swabs daily. One night she noticed blood on the swabs. A specialist, shocked by her routine, ordered a CT scan that exposed a terrifying sight: cotton fibers had accumulated in her ear canal for up to five years, fostering a bacterial infection that was literally eroding the bone behind her ear. The infection had thinned the skull to a paper‑thin layer.

She underwent a five‑hour surgery to excise the infected tissue and reconstruct the ear canal. While the operation cleared the infection, the damage to her auditory nerve was permanent, leaving her with lasting hearing loss in the affected ear.

2 Blue Blood

In 2019, a 25‑year‑old woman walked into a Rhode Island emergency room declaring, “I’m blue.” Her skin had taken on a faint azure hue, and a quick blood draw revealed a dark navy‑blue liquid. Doctors diagnosed methemoglobinemia, a condition where hemoglobin can’t carry oxygen effectively.

The patient’s oxygen saturation had fallen to a dangerous 67 % (below the 70 % safety threshold). She explained that the night before she had used a generous amount of a benzocaine‑containing tooth‑numbing gel to soothe a toothache.

Benzocaine can oxidize the iron in hemoglobin, preventing it from binding oxygen and turning the blood a striking blue. Prompt treatment with methylene blue restored her blood’s normal color and oxygen‑carrying capacity, saving her life.

1 Coma

In 2019, a 47‑year‑old mother of five from Sacramento followed her usual beauty regimen, slathering on a favorite anti‑wrinkle face cream twice daily. This time, after applying the lotion, she suddenly felt her extremities go numb, struggled to speak, and lost the ability to walk.

She was rushed to the hospital, where she slipped into a semi‑comatose state. Blood tests revealed a staggering mercury concentration of 2,630 µg per liter—far above the typical 5 µg per liter found in healthy adults. The mercury was present as methylmercury, a highly toxic form often used in industrial applications.

The cream, imported from Mexico and sold informally, contained this dangerous ingredient. While the exact reason for its inclusion—whether accidental contamination or intentional addition—remains unclear, the incident marks the first known case of mercury poisoning from a cosmetic product in the United States.

Doctors are uncertain whether the woman will ever fully recover from the coma, highlighting the severe risks of unregulated beauty products.