The 'kissing bug disease' occurs when a bug's parasite-laden poop gets into your blood

More than half of the 7,000 'kissing bugs' locals sent to Texas A&M University had parasites

Texas A&M University scientists began a community science program in 2012 asking people to send in kissing bugs (any of the 11 species of bugs potentially infected with Trypanosoma cruzi parasites). About 1,500 people sent in over 7,000 bugs for scientific research, and about 55% of the bugs were infected with the parasite that causes Chagas disease.

Chagas disease can be transmitted to a fetus during pregnancy

Researchers estimate that 63 to 315 cases of congenital Chagas disease occur annually in the US. Roughly 20 to 30 percent of all Chagas disease cases will progress to cardiac or gastrointestinal disease.

See this diverse list of vector-borne diseases

Human illnesses caused by parasites, viruses, and bacteria, and transmitted by a living organism—often small, bloodsucking ones like mosquitoes, ticks, and sandflies—are known as vector-borne diseases. That carrier is called a vector. These diseases disproportionately affect the poorest populations in tropical and subtropical areas.

Lyme disease is caused by bacteria transmitted through the bite of infected ticks

It's an infectious disease caused by Borrelia burgdorferi bacteria. It's spread through the bite of two species of infected ticks, the Western blacklegged ticks on the West Coast, and Blacklegged ticks found throughout the eastern US. The ticks can transmit the disease at both the nymph and adult stage. It's not known to be transmitted from one person to another via kissing or sex.

Mosquito saliva acts as an anticlotting agent

The bug's piercing mouthpart, the proboscis, is actually several tubes—one for sucking, one for spitting. But the chemicals in its spit actually help its blood meal to flow, combating its victim's ability to clot at the puncture site.

More than 20 mosquito-borne and tick-borne diseases are found in the US

Children, older adults, and people with compromised immune systems are at particular risk of poorer health outcomes from these diseases. But dog owners and outdoor enthusiasts are among those at particular risk of contracting these illnesses, which include Lyme disease, Zika, and the condition Alpha-gal Syndrome.

See this graphic of the complex malaria transmission lifecycle

Female Anopheles mosquitoes contract malaria by feeding on the blood of a human already infected with the disease-causing parasite. The parasite then develops in the mosquito's gut for one to two weeks before it migrates to the mosquito's salivary glands. Next, when the mosquito bites another person the parasite is delivered into the bloodstream of another human. This graphic further details what happens inside the human body during infection.

'Sloth fever' is an emerging health threat, especially to pregnant women

This disease, caused by the Oropouche virus, is found in animals including sloths, primates, and birds. It primarily spreads through the bite of midges—insects commonly called "no-see-ums." It's endemic to the Amazon region, but US travelers are increasingly contracting it internationally.

Treating black fever can result in a complication that spreads the deadly disease

Black fever, a deadly parasitic disease second only to malaria, threatens more than 1 billion people across more than 83 countries. Also known as kala-azar or visceral leishmaniasis, the disease is caused by parasites that spread through sandfly...

Explore inside a mosquito factory where millions of mosquitoes are bred weekly

In Medellin, Colombia, scientists are infecting Aedes aegypti mosquitoes with Wolbachia, a bacterium that wouldn't otherwise infect the species, but does block its ability to transmit dengue, Zika, yellow fever, and chikungunya. In the wild, infected mosquitoes would breed with wild mosquitoes, pass down Wolbachia, and thus reduce disease transmission.

Hand, foot, and mouth disease spreads easily—including via fomites

The common ailment spreads through respiratory droplets, touching infected secretions like poop, but also by touching virus-laden fomites, which are contaminated objects such as doorknobs or toys.

Scientists found that if cats in the lab ate infected rodents they could get West Nile

But beyond the lab setting there have been no known cases of cats or dogs contracting the virus this way. Instead, those animals have been sickened when an infected mosquito bit them—just as with human infection.

Cryptococcus neoformans, a growing threat, causes infections in the brain and lungs

This inhalable, microscopic pathogen is found worldwide. It rarely causes illness, but it can take root in those with compromised immune systems, including people with advanced HIV/AIDS. Symptoms of cryptococcal infection—such as a stiff neck, vomiting, and confusion—can begin weeks or months after breathing in spores, though sometimes symptoms won’t appear for years. There are no known cases of transmission between people or between people and animals.

Ticks are extremely hard to kill

These arachnids can transmit more than a dozen diseases to humans, and they're very resilient: Some can survive extreme heat and cold, live for years without a blood meal, and even survive multiple days underwater.

The American cockroach is actually from Africa—an apparent hitchhiker aboard ships carrying enslaved people—with evidence suggesting it may have arrived in the New World as early as the 1600s

This podcast delves into the history of Periplaneta americana and explores why the bugs elicit such fear, disgust, and, at times, shame. The bug likely climbed aboard the slave ships because they had both unprotected food sources and places to hide during their journey.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

More than 2 billion people across the globe include bugs in their diets

Entomophagy is the practice of eating insects. It has been around for millennia. Bugs are nutritious and, in some places, considered a delicacy.

How bedbugs have evolved immunity against pesticides

Bedbugs, once nearly eradicated in the United States due to the use of pesticides like DDT, have made a resurgence, with New York being declared the most bedbug-infested city. The primary reason for the return is the evolution of resistance in...

Learn how cholera bacteria sicken humans

Once a person has ingested large amounts of the bacteria, typically through contaminated water, cholera bacteria begin producing and releasing a toxin inside their host. It attacks the mucosal lining of the intestine, making it hard to absorb liquids. This process leads to cholera's characteristic symptoms, like voluminous, watery diarrhea.

Epstein-Barr virus—the cause of 'kissing disease' mononucleosis—may be the leading cause of MS

A Harvard study with data from more than 10 million US military personnel found that people that contracted Epstein-Barr virus had a roughly 32-fold increased risk of developing multiple sclerosis. The work, published in 2022, found that Infection of the virus preceded MS onset by a median of five years, raising questions about better Epstein-Barr virus management and potential disease prevention.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

People can—and have—contracted leprosy from armadillos

A 2011 study linked multiple human cases to the handling of armadillos or the consumption of their meat. The research couldn't document direct transmission, but did find that the animals and humans shared the same exact strain of the disease.

Watch Cordyceps, a parasitic fungus, turn an ant into a ‘zombie’

This National Geographic TV clip shows how a parasitic Cordyceps species—sometimes colloquially called the “zombie ant fungus”—controls an ant’s behavior and kills its host. The fungus can rapidly wipe out entire insect colonies.

Hookworm infection, though risky, may help fight certain health conditions

Early clinical trial research suggests that the parasites trigger the production of specific proteins that quiet our immune systems. This keeps the parasites from being killed, but it also quiets the inflammatory response that underpins allergies, type 2 diabetes, celiac disease, and other autoimmune conditions. Researchers still caution that infection with too many hookworms can cause serious medical complications and that this is not a standardized or approved medical treatment.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Eating street food while traveling isn’t recommended, but there are ways to do it more safely

The US Centers for Disease Control and Prevention urge people to stay away from street food while traveling. But if you still want to eat it, the agency recommends making sure it’s cooked food and that it’s served steaming hot. Also, avoid eating any raw vegetables as they may be more likely to harbor pathogens.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

The disease no one survives (yet)

Creutzfeldt-Jakob disease is currently incurable and can cause one's death within months of symptoms appearing. It involves misfolded proteins that, for some reason yet unknown to science, aren't cleared by the brain as typical and instead trigger similar proteins to misfold. These malformed major prion proteins—prion being a portmanteau of protein and infection—clump inside nerve cells, blocking signals crucial to processes ranging from speaking to organ function.

Ebola infects and disables immune cells, triggering a cascade of events that leads to small blood clots throughout the body, weakening blood vessels and interrupting blood flow to key organs.

Candida albicans is a natural body-dwelling yeast, but it can cause yeast infections

This fungus is naturally occurring on the body, but C. albicans can become a problem when the natural balance of bacteria on the body is off-kilter, allowing this yeast to spread. It can cause anything from diaper rash to a yeast infection in the throat or vagina. It’s typically treated with doctor-prescribed antifungal medications.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

View the ten deadliest tornadoes in US history.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Brandi Chastain, the star of the 1999 US victory over China in the 1999 Women's World Cup, was a last-second choice to take the penalty kick that sealed the victory.

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.