Parasites

They’re small, sneaky, and likely to make you sick. From viruses, to bacteria, to pesky protozoa, here are the latest findings on the parasites that live among (and on, and in) the creatures of the Earth.

Related Topics: Insects, Invasive Species

Latest Updates

Artist's illustration of Toxoplasma gondii

One in three people are infected with Toxoplasma parasite — and the clue could be in our eyes

By Justine R. Smith, Joao M. Furtado last updated

Toxoplasma gondii is probably the most successful parasite in the world today. The disease caused by this parasite can scar the back of the eye.

Thousands of vinegar eels swim in unison inside a droplet of water

Watch thousands of 'vinegar eels' swarm through a water droplet in amazing new video

By Brandon Specktor last updated

The microscopic nematodes known as vinegar eels move together in a strange synchronized swimming routine, new research videos show.

This creepy isopod is serving as a prosthetic tongue.

Social vomit and hairy eyeballs: 10 times animals grossed us out in 2021

By Mindy Weisberger published

Here are some of our favorite gross-outs in science news this year.

Why would male flies mate with dead females? A fungus made them do it.

Mind-controlling fungus makes male flies mate with dead, infected females

By Mindy Weisberger published

The pathogenic fungus Entomophthora muscae doesn't just kill the flies it infects; it also turns males into sex-crazed necrophiliacs.

This creepy isopod is serving as a prosthetic tongue

'Tongue-eating' lice invade fish's mouth in this year's creepiest Halloween photo

By Joanna Thompson last updated

Tongue-eating parasites chow down on fishes' mouths and eventually replace their tongues

Scientists captured this image of a tick's head at Ohio State University's Campus Microscopy and Imaging Facility.

Tick transforms into a glowing alien from a sci-fi nightmare in trippy photo

By Mindy Weisberger published

Outstanding examples of stunning microscopy were recently honored in the Nikon Small World contest.

A tongue-eating louse, or isopod (purple) became this fish's living tongue.

Meet the 'vampire' parasite that masquerades as a living tongue

By Mindy Weisberger last updated

Digital models of a fish skull revealed a parasitic stowaway inside its mouth: a "tongue biter" isopod that consumed and then replaced the fish's tongue.

A female anglerfish. Hey, good lookin'!

Evolution turned this fish into a 'penis with a heart.' Here's how.

By Brandon Specktor last updated

Anglerfish are literally missing part of their immune system, but this allows them to permanently fuse during sex, new research suggests

West Virginia University researchers were part of a team that discovered how Massospora, a parasitic fungus, manipulates male cicadas into flicking their wings like females — a mating invitation — to tempt and infect other males.

Mind-controlling fungus makes zombie cicadas lure other cicadas to a zombie fate

By Mindy Weisberger last updated

Not only does the fungus Massospora infect cicadas, eat their bodies and turn them into mind-controlled zombies, it forces them to attract more cicada victims.

In this reconstruction of the Cambrian brachiopod Neobolus wulongqingensis, tubelike parasites cling to its shell.

Cambrian fossils show oldest example of parasites in action

By Mindy Weisberger published

Fossil brachiopods from China were crusted with parasites, which may have hijacked their hosts' feeding structures in order to steal their dinner.

Two white dots (circled in red) are actually a new species of parasitic fungus that lives on American millipedes

'First species discovered on Twitter' is a parasitic fungus that dines on millipede genitals

By Brandon Specktor published

Researchers discovered a new species while looking at Twitter photos. They have named the parasite Troglomyces twitteri.

Feral cats such as this one, photographed on the island of Oahu, Hawaii in Hanauma Bay, introduced a parasite into local ecosystems.

'Mind-control' cat parasite has now reached Hawaii's parks

By Mindy Weisberger last updated

The parasite Toxoplasma gondii has been found on Oahu, Hawaii public lands for the first time.

Lizard embryo.

'Shocked' scientists find brain parasites in baby lizards still in shells

By Nicoletta Lanese last updated

Scientists found parasitic worms in the brains of lizard embryos. How did they get there?

Spores of the parasite H. salminicola swim under a microscope. Those alien "eyes" are actually stinger cells, one of the few features this organism hasn't evolved away.

Scientists discover first known animal that doesn't breathe

By Brandon Specktor last updated

A genomic analysis of the creepy parasite H. salminicola reveals that the creature has no mitochondrial DNA and no way to breathe — two animal firsts.

This image of a muscle tissue cell, magnified 1200X, reveals a cluster of Trypanosoma cruzi organisms.

Heart-warming? More like heart-harming. Here are 5 cardiac parasites ... for Valentine's Day

By Mindy Weisberger published

Some types of parasitic infections can lead to serious heart problems.

As If Ticks Weren't Terrifying Enough, This Giant Bloodsucker Will Hunt You Down

By Mindy Weisberger published

Unlike its more patient tick cousins, this supersize parasite pursues its prey.

The parasite <em>Cyclospora</em> can cause intestinal illness. Above, an image taken with a microscope showing <em>Cyclospora</em> eggs (red) in a stool sample.

Foodborne Parasite Sickens 100 in Massachusetts. No Source Has Been Found.

By Rachael Rettner published

Infections with an intestinal parasite have surged in Massachusetts in recent months, according to health officials.

This semi slug (<em>Parmarion martensi</em> may be a carrier of rat lungworm disease.

Invasive Semislug That Likes to Climb May Be Infecting Hawaiians with Brain Parasite

By Cari Nierenberg published

People may be picking up rat lungworm disease by eating a fast-climbing creature that's part slug, part snail.

A swimming pool.

'Crypto' Outbreaks Linked to Swimming Pools Are on the Rise, CDC Says

By Rachael Rettner published

Not to spoil your summer pool fun, but outbreaks of "crypto," a swimming-related diarrheal illness, are on the rise.

cicadas on fungal hallucinogens

This Fungal Hallucinogen Makes Cicadas Orgy Till Their Butts Literally Fall Off

By Isobel Whitcomb published

Their bodies may disintegrate, but these bugs don’t care.