Scientists are seeking to solve some of the mysteries of the parasites that live within us

Solving Microscopic Mysteries

03-01-1997 // Mark Wexler

Whether you like it or not, there's no escaping parasites. The little creatures are everywhere, living by the billions in our food, our water, our soil, our furniture, even our eyelids. "If, magically, every part of the planet were to disappear except for parasites, you would still see the outline of the Earth," says U.S. Department of Agriculture scientist J. Ralph Lichtenfels.

Fortunately for those of us who cringe at the thought of having legions of minute monsters foraging all around us, there are people like Lichtenfels to help keep us safe and sane. For nearly three decades, the parasitologist has cloistered himself in the basement of an obscure research facility in Beltsville, Maryland. His charge: To discover which of these little beasties harm us and which do not. To accomplish that goal, Lichtenfels has surrounded himself with more than 100,000 bottles and slides filled with specimens--a sort of "who's who" of nematodes, protozoa, tapeworms, mites and more. He is the eighth in a line of inquisitive men who over the past century have served as head curator of the National Parasite Collection--the world's most comprehensive assortment.

Few parasites will kill you, but many can cause aggravating problems. Worms and other creatures living in large food animals alone cause an estimated $2 billion annually in losses to U.S. agriculture. "Physicians and veterinarians need to know what they are dealing with before they can prescribe proper treatment," says Lichtenfels. "So they turn to us for identifications. A good collection of specimens is essential in the search for cures and controls of parasites."

In the past few years, Lichtenfels and his staff have helped scientists identify a nematode that was ravaging surf clams and scallops in the southeastern United States, another that was harming horses in Maryland and a third that was killing lambs along the East Coast. Parasites have also wreaked havoc with people in recent years. In 1993, one such menace entered Milwaukee's water supply and caused nearly 400,000 cases of intestinal illness among residents.

In Beltsville, the curator's office is plastered with pictures of microscopic monsters that most people would call repulsive. But not Lichtenfels, who discovered the world of creatures living within other creatures while studying road kills on highways in his native Pennsylvania during his undergraduate days. Parasitology was the next logical step. "These are really elegant individuals," he says. "They look beautiful under a microscope."

Historically, some parasitologists intentionally infected themselves with a parasite as part of their studies. Other researchers sometimes have become infected unintentionally. Not long ago, for instance, a Department of Agriculture scientist was sitting at her Beltsville desk when a 9-inch worm suddenly crawled out of her nose. Apparently, she picked up parasitic eggs from food while working in Egypt. Fortunately, she didn't have to go far to find out what kind of creature had invaded her body.

In the temperature-controlled chamber adjacent to Lichtenfels' office where the collection is housed, the shelves are lined with samples of almost every known parasite. The largest specimen is a 25-foot tapeworm that once resided in a human body (tapeworms as long as 66 feet have been found in people). Among the smallest is the larva of a pinworm, a parasite common to children.

One jar holds 3-inch roundworms that came from the stomach of some Baltimore men who a few years ago went fishing together. After failing to catch any fish, the men retired to their favorite South Baltimore watering hole. There, in a fit of macho madness, they proceeded to eat their bait. Unfortunately, the bait was peppered with parasitic worms, and the men eventually became ill. The roundworms removed from their bellies wound up at the Beltsville lab.

"You shouldn't be afraid of parasites," says Lichtenfels. "But you should know about them so you don't do stupid things." Such as not washing your hands before fixing meals, or eating your fish bait.

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