Did God Create Parasites?

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by Dr. David W. Boyd, Jr. on November 1, 2017; last featured October 2, 2022
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The name “large roundworm” is scary. Even the first part of its scientific name—Ascaris lumbricoides—is scary, if you sound it out: “A-Scare-Us!”

This revolting nematode lives in human intestines and can grow up to a foot long and almost one-quarter inch in diameter. The US Centers for Disease Control and Prevention estimates that more than one billion people worldwide are infected with this worm. The scariest fact is you could have one in your small intestine for a long time before you even noticed.

Other roundworms can cause anemia, blindness, or a gross enlargement of the limbs called elephantiasis. Most pet owners treat their animals for a roundworm called heartworm that is spread by a mosquito and can kill dogs. And nematodes infect all sorts of other animals and plants. How did these disgusting parasites become part of God’s “very good” creation?

The simple answer is that God created nematodes during creation week as a normal, beneficial part of the environment.

Evolutionists like Carl Zimmer believe roundworms are just part of the dog-eat-dog (or nematode-eat-dog) world that he thinks has persisted for millions of years. In his book Parasite Rex, he mockingly suggests Adam must have been “created” already loaded with parasites. Or, he says, maybe there was “a second creation, an eighth day added on to that first week—‘and on the following Monday God created parasites.’”

Not all symbiotic relationships are parasitic.

By definition, all parasites live at least part of their lives in or on another organism and cause harm. But not all symbiotic relationships are parasitic. And that may hint at an answer to the origin of parasites.

For example, termites have protozoans and bacteria in their guts to help them digest wood. Also, most plants have fungi that help their roots absorb nutrients. These types of relationships are mutualistic (the opposite of parasitic). In many cases, they are so important that one of the organisms couldn’t survive without the other. Humans are an example. We couldn’t live without the trillions of mutualistic microorganisms in our intestines and elsewhere in our bodies.

Roundworms are not all parasitic either. Some help remove decaying plants and are harmless. Another example of a roundworm with a nonparasitic lifestyle is the threadworm, Strongyloides stercoralis. It lives in the soil, feeding on bacteria and helping the soil ecosystem thrive. However, when living conditions become less favorable, the next generation of threadworm develops into a parasitic stage that lives in human intestines.

God created roundworms as part of his good creation.

God created roundworms as part of his good creation. They lived harmoniously in plants or animals or the soil, helping maintain the balance of nature. Only after the fall did some roundworms take on a parasitic role, as part of the curse on creation. So, Zimmer was partly right! God included roundworms in his creation.

He may even have created humans already equipped with beneficial roundworms.

Dr. David W. Boyd, Jr. earned a PhD in entomology from Clemson University in 2001 and served for five years as a research entomologist with the USDA. He is the head of the department of biology at Bob Jones University.

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