You'll Never Walk Alone

By Jeffrey Kluger|Monday, November 01, 1993
RELATED TAGS: HEALTH POLICY
Ralph Lichtenfels has a 25-foot tapeworm--and if you’d care to take a look he’d be happy to show it to you.

Actually, if you have an hour or two, Lichtenfels will let you see a lot more than his tapeworm. He’s got a gigantic family of mites he’d like to show off, as well as a community of ringworms, a population of pinworms, and a nice, Levittown-size colony of intestinal nematodes. In fact, at last count, Lichtenfels had thousands of different species of bugs, larvae, microbes, and other organisms, all falling under the singularly unappetizing rubric parasites.

Fortunately for Lichtenfels--not to mention his friends, family, and the people who rent bowling shoes after him--the parasites in question do not use his body as their principal mailing address. Rather, they are all sponges-in-good-standing in the little-known if widely respected United States National Parasite Collection in Beltsville, Maryland.

To the scientifically untutored, the idea of a national parasite collection could come as a bit of a surprise. For a debt-burdened federal government that has already begun paying most of its bills with shiny buttons, seashell necklaces, and Harmon Killebrew baseball cards, maintaining a collection of the world’s known parasites would seem like a luxury. However, for over a century the Department of Agriculture has kept the United States at the head of the worldwide parasite pack, building a collection of preserved pestilence that is the envy of the global neighborhood. J. Ralph Lichtenfels, a parasitologist, is the eighth in a line of strong-stomached curators who have been charged with the task of overseeing the country’s priceless--and growing--parasite stockpile.

I first learned of the parasite collection and was invited to tour its galleries some months ago, but to be honest, I was reluctant to accept the invitation. Though I’m as fond of house pets and other animals as the next guy, I generally shy away from any creature who defines house as my eyebrows, ears, or lower colon. When I think of parasites, the first image that leaps to mind is the star of Alien--and I don’t mean Sigourney Weaver. Nevertheless, the press material did make the place sound intriguing.

According to the parasite poop sheet, the national collection got its start in 1892, when Department of Agriculture scientists Charles Stiles and Albert Hassall--who evidently had little interest in attracting weekend houseguests--began assembling private parasite collections. Within a few years the collections had grown dramatically, and government officials (not to mention Mrs. Stiles and Mrs. Hassall) suggested that the specimens be moved to a federal facility. The two researchers agreed and decided that upon their deaths, they would donate their collections to the Department of Agriculture in perpetuity. Whether the government might have preferred a nice gravy boat and a set of flatware is unknown, but the bureaucrats accepted the bequest and have been adding to the collection ever since.

What, I wondered, could be the purpose of such a rogue’s gallery of beasts? Who would be visiting a federal parasite collection on any given day? And what on Earth would be for sale in the gift shop? (My parents visited the National Parasite Collection and all I got was this lousy swine worm.) Determining that the answers could only be gotten first- (if rubber- gloved) hand, I screwed up my courage and traveled to Beltsville to meet Lichtenfels and his legions of parasite para-pets.

The parasite collection is located in the Maryland suburbs in one of those blandly designed government office buildings that make the Bauhaus look like Bourbon Street. I didn’t come here expecting Martha Stewart, but haven’t these people ever heard of throw pillows? Nevertheless, from the moment I arrived at the parasite headquarters it was clear that the decor was not the only no-nonsense aspect of this place. I had imagined the parasite collection as a sort of last-resort theme park for people who simply couldn’t afford the trip to Yellowstone, but the Beltsville facility is not usually open to the public. Instead, the museum is intended for people who have decided--evidently after a childhood head trauma--to make parasites their life’s work. There are a few other parasite collections around the world, Lichtenfels told me when I greeted him in his office, but none are as comprehensive as the one we have here. Physicians trying to treat parasitic diseases in humans, veterinarians trying to treat infestations in farm animals, and other scientists simply trying to understand what makes parasites tick all make use of our collection. Currently we have about 100,000 samples, each of which may have thousands of specimens, and we’re growing at a rate of about 1,000 samples a year. These are animals that are definitely worthy of study.

The way Lichtenfels explained it, what all parasites have in common--aside from extremely poor social skills and a lousy eye for attractive apartments--is the singular ability to use another living creature as an unwitting habitat. Throughout the animal kingdom, organisms frequently pair up in symbiotic relationships, but in these arrangements both organisms typically benefit. Parasites, however, said Lichtenfels, typically cause damage to their host organism while giving almost nothing in return.

To me that sounded a little self-evident. If a 25-foot alien life-form had the poor manners to take up residence in my intestines, I wouldn’t expect it to show up with a fruit basket. But the damage these unwelcome guests do can be a lot worse than simply leaving the ashtrays full and the toilet seat up.

Among the best-known parasites are the flatworms, like tapeworms, said Lichtenfels. Most make their home in the intestines, where they attach themselves to the bowel wall and draw nutrients that would otherwise go to you. More common are roundworms, or nematodes, like the intestinal pinworm, which produces microscopic eggs that can contaminate bed linens and clothing and even circulate through the air. Other parasites include the ectoparasites, such as mites, which burrow into the skin and lay their eggs. All told, there are tens of thousands of species.

More impressive than the size of the parasite population is its adaptability. As neither herbivores nor carnivores, parasites fail to qualify for even dessert-and-coffee service in the great buffet line of the food chain. Instead, they simply pick off the plate of whoever happens to be their host at the moment. Parasites have adapted themselves to live in mammals, birds, insects, fish, reptiles, and even other parasites.

Whether Lichtenfels was telling me all this to pique my interest was unclear, but the idea of spending the day looking at animals that, if alive, would be looking back at me as a combination of food source and vacation bungalow was starting to get unsettling. However, I had come here in pursuit of parasites, and as long as I didn’t leave being pursued by them, I thought I’d better proceed.

The parasite gallery itself is located two rooms away from Lichtenfels’s office, directly adjacent to the laboratory lunchroom--a setting that no doubt disqualified the little bistro from even the most charitable Michelin guides. The collection chamber proper seemed anticlimactic. The room was small and narrow, with nothing in front of me as I entered but what looked like a temporary partition. Once we were inside, however, Lichtenfels turned a large, wall-mounted wheel and the partition slid rumblingly back, revealing a corridor of specimen bottles that extended approximately to northern Virginia. Now, I’m not easily awed, but I must say I found this partition trick a wonderful touch--though it probably would have been even more dramatic had the lab assistant with the hump and the lantern who usually handles the wheel not taken the day off.

Lichtenfels began our parasite tour with one of the prizes of the collection: the famed 25-foot tapeworm. Twisted in its display dish, the giant bowel-dweller was an unimpressive sight, resembling nothing so much as a length of flat, segmented ribbon. The tangled beast appeared to my parasitologically untrained eye to occupy a proud spot on the evolutionary ladder just a notch or two above cement, and Lichtenfels’s subsequent description did nothing to change this impression.

Tapeworms enter the body as larvae in beef or pork and spend their entire lives in your intestines, he said. They have no digestive system as we know it and can only absorb nutrients through tiny moving fingers called microvilli that cover their body.

As a result of this extraordinarily simple anatomy, the tapeworm can be a remarkably successful, long-lived pest. The average tenant in the average intestine can stay around for years, often laying linoleum, putting up bookshelves, and installing cable without permission. The standard treatment--short of going co-op--is any one of a number of oral toxins that are poisonous to parasites but safe for their hosts.

Unlovely as the tapeworm was, Lichtenfels had not even begun to push the edge of the odiousness envelope. On another shelf nearby was a specimen jar that contained a small school of preserved fish surrounded by what appeared to be a small nation of tiny roundworms. The fish were known as killifish, the worms were known as Eustrongylides, and the display as a whole was known as gross. Eustrongylides is a species of parasitic roundworm that typically infects only aquatic creatures; on occasion, however, the species has crossed the line to human beings.

There was a story of a group of fishermen who used killifish as bait, said Lichtenfels. At the end of the day they would go back to a bar, and if any of them hadn’t caught anything, they would have to eat their bait. One day nearly all of them came home empty-handed, ate their bait, and within a few days were all sick. An exam revealed that the killifish were infested with Eustrongylides, and as a result the men were, too.

Fortunately for the fishermen, who no doubt wished their bar fish had come from the far safer, far crunchier species Pepperidge Farm, the species of worm in question does not reproduce all that quickly, and with the help of intestinal surgery the men were restored to health. Though the experience was a hair-raising one, it did help science prove two key points: a) parasites indigenous to one host can sometimes adapt to another, and b) it is possible to spend too many hours watching fishing shows on ESPN.

If the killifish display didn’t send me fleeing for the exits, the dog-heart-with-worms specimen certainly should have. As anyone who owns a dog can tell you, canines in their later years can tend to get the tiniest bit lazy, often moving from the rug or porch only for meals, walks, and the occasional shift of a continental plate. In some cases, of course, this is just part of the federally sponsored Dog Retirement Plan, which requires dogs to adopt the energy level of the typical lawn ornament the moment they reach their fifteenth birthday (85 in Lorne Greene years). In other cases, however, the cause is the appropriately--if revoltingly--named heartworm.

Heartworms are mosquito-borne nematodes adapted to living in a blood-rich environment, Lichtenfels said. They circulate as larvae throughout the body and come to rest in the heart because of the generous supply of blood. In some cases, heartworm infestation can cause death, but more often it leads to laziness and shortness of breath.

To illustrate his point, Lichtenfels offered the preserved heart of an unfortunate dog who, by all appearances, was the Ellis Island of the canine community (Give me your tired, your poor, your cardiac-dwelling nematodes). Near as I could tell, there was more worm than heart in the jar, and had Lichtenfels displayed it just a second or two longer, there would have been none of me in the lab. Happily, Lichtenfels sensed my discomfiture and, before I could leave him with his heart in his hand, turned to the display that he proudly admits draws the loudest squeals when he makes presentations at local public schools: the mangy cat head.

Sealed in a sample jar was the decapitated head of a cat that, Lichtenfels explained, lost its ninth life more than a century ago. From the pained look on its face and the tattered fur on its head, it appeared that lives one through eight weren’t exactly a picnic either.

This is an example of a cat suffering from some type of mange, probably scabies, Lichtenfels said. The mites burrow under the skin and cause itching and irritation. The combination of the parasites and the cat’s scratching eventually causes the fur to grow sparse.

In humans, scabies can be treated relatively easily with a cream or lotion that contains a parasite toxin. This cat, however, evidently never got around to making an appointment at the free clinic, and the scabies infection eventually occluded its breathing passages and led to its untimely death.

None of the other displays in the collection have as much parasitic pathos as the bodiless cat, but they all leave a powerful impression. There is the two-inch leaf-shaped trematode, a species of flatworm that makes its home in the liver of the elk (but apparently avoids the far rarer Shriner, Legionnaire, and Knight of Pythias); there is the swatch of swine intestine with a multitendriled collection of Ascaris suum worms that could make you swear off pork sausage, moo shu pork, and Porky Pig for the rest of your natural life; there is the pig backbone infested with a species of worms that should infect the kidney but that evidently took a very wrong turn somewhere around the spleen.

The true parasite aficionado could, no doubt, spend days perusing the thousands of specimens in the collection. However, having other places to be that afternoon--and wanting to be able to eat at least a bland diet again before the end of the millennium--I decided to leave after a couple of hours. Besides, I figured, if you encourage the government collectors too much, there’s no telling where it will all end. Nearby on the Beltsville compound, researchers have already established another, almost as cringe-inducing creature trove: the U.S. National Fungus Collections. Boasting tens of thousands of specimens, the fungus assortment features what the government calls the largest collection of dried fungi anywhere in the world (with the possible exception of Bob Dole, Tom Foley, and the rest of the leadership of the 103rd Congress). If this compulsive collecting goes on, however, what other exhibits will we one day see? The National Loogie Gallery? The Federal Roadkill Museum? The International Sour-Milk-With-Lots-of-Big-Chunks-in-It Archives? You’d probably be smart to avoid the collections altogether, stay home, and rent a movie. Just try to make sure it’s not Alien.
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