In Defense of… Parasites?

Parasites are probably the least popular life-form on Earth. For example, Guinea worm disease is a very painful infection cause by a parasite that can be found in areas of Africa without safe drinking water. The details are too gruesome to detail here and there is no treatment. The only good news is eradication efforts are going very well — according to the CDC, annual cases have dropped from 3.5 million in the mid-1980s to 28 in 2018 (

And yet, parasites are an important part of our ecosystem. An estimated 40 to 50% of all animal species are parasitic, and many have complex life cycles that are getting the attention of scientists.

One such scientist is Tommy Leung, a parasitologist at the University of New England in Armidale, Australia. Leung and other researchers are fascinated by the lifestyles parasites have evolved to survive, like flukes that will clone themselves and form a colony inside snails, and fungi that infect ants and sprout “beautiful” fruiting bodies. “Parasitism is actually one of the most challenging lifestyles in this planet,” Leung says. “When you’re in your home, imagine every single appliance, every piece of furniture is actively trying to kill you every time you use them. That’s basically what it’s like for a parasite.”

This line of research is important because so little is known about parasites. We don’t know how many there are, and some of those we have found don’t even have names. And yet they’re an important part of our world. “They are actually performing really important ecosystem services that we never really appreciate,” says Leung. 

Fortunately, most parasites are of no threat to humans. “The majority of parasites that are out there are not infecting people. They don’t have anything to do with human beings or human lives,” says Leung. “They’re like any other wildlife, they’re just living their lives.”

To change our view of parasites, Leung is going so far as creating anime art, Parasite MonMusu, or Parasite Monster Girls, a series of characters inspired by species with unfortunate bad reputations.

An example of  Tommy Leung’s artwork:
Dr. Delilah, Leech Monster Girl Doctor, can see you now.

Why are Leung and other scientists so passionate about their work? “Parasites have as much of a right to exist as any other organism on the planet.”

To learn more about parasites, listen to the Science Friday podcast of August 21, 2020, “Why We Should Defend Parasites” at

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