U.S. National Parasite Collection
U.S. Department of Agriculture
Agricultural Research Service
Research Center (BARC)
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Most of us consider the parasites as the lowest form of life. They feed
off other creatures, usually following the food source straight to the
alimentary canal, often settling at its nether end. We find this exploitative
existential condition unforgivably dirty, nasty and opportunistic, so we
turn it into the stuff of horror films: Dracula, The Tingler, Alien, Cronenberg�s
libidinous pseudo-organs in Shivers. These things get under our skin and
eventually snatch our bodies and our minds...making Pod People wherever
Look at the real parasites--the tapeworms, ticks, flukes, fleas, and
so on--another way, and they can be a case study of life�s marvelous diversity
and determination. Nature�s first law seems to be "find a niche and fill
it," and the parasites just went where no others dared to tread. The same
evolutionary law could apply to scientists. When all the good stuff is
taken, it's time to take up with parasites. But once you join the parasitologists,
you�ll see how important the bugs they study really are.
Not surprisingly, the DC area is one of the greatest places in the world
to view parasites--and not because Congress meets here. In all seriousness,
possibly the world�s largest collection of parasites is housed in nearby
Beltsville, Maryland, on the campus of the USDA's Agricultural Research
Service. It�s just another national treasure we�re lucky to have close
The U.S. National Parasite Collection contains approximately 20 million
specimens, a number rivaled only by the British Museum. The specimens are
contained in more than 100,000 lots, where a lot is a single jar or prepared
microscope slide. Some jars can contain thousands of tiny creatures. These
numbers don�t include several large specialized collections and private
donations. And the collection as a whole grows at the rate of 1,000 to
1,500 lots per year.
That's a lot of little uglies, but better here than in your personal
It's also one of the country's [world's?] oldest parasite collections.
Back in the mid-19th century, Charles Wardell Stiles and Albert Hassall
were studying parasites for the USDA's Bureau of Animal Industry (a precursor
to the Agricultural Research Service) when they decided the nation needed
a big stockpile of creepy crawlies. So in 1892 they pooled their private
piles of parasites to form the Bureau of Animal Industry Collection. Many
of their specimens dated to the earlier 19th century and to Europe, where
they'd both been trained and established their careers. Two years later,
the jars and slides full of worms (aka helminths) were catalogued as the
US National Museum Helminthological Collection and considered part of the
Smithsonian Institution, while the ticks, fleas, microbes and other parasites
still went by the old name. To strengthen the link with the Smithsonian,
the curator of both collections was named a Research Associate of the SI--a
tradition that continues to the present time. The two collections were
reunited in 1936, when all specimens and records were moved to a permanent
home in Beltsville. Over the years, the collection�s name changed several
times, but by 1977 the curators had settled on the current one, the U.S.
National Parasite Collection.
Now curated by J. R. Lichtenfels, Pat Pillett, and Eric Hoburg, the
collection resides in a long rectangular building deep in the sprawling,
7,000 acre BARC campus, surrounded by the suburban roads and shopping plazas
of Beltsville. The BARC complex contains a working farm, an experimental
farm, and 47 laboratories! [NAME some of these labs?] It makes sense that
the complex ranks as one of the largest and most diverse agricultural research
complexes in the world
First road challenge: find the right campus! Driving along Powder Mill
Road, the first BARC area I pass has massive buildings visible from the
road, but I'm turned away by forbidding signs about restricted areas and
police intervention. Further down the road, there's another area that�s
more friendly to visitors. Bicycle and automobile traffic regularly passes
through here, and they even have a visitor�s center, which lies between
me and the parasites. Turning off onto the grounds, I disappear onto farmland,
winding along what look like country roads, passing empty fields, cow pastures,
and the occasional institutional building. Eventually, I arrive at the
Log Lodge, a 1930s relic literally constructed out of massive logs, which
houses the ARS National Visitor Center. A fantastic piece of architecture,
the Log Lodge looks even better on the inside, where the softly rippling
log walls glow with a warm, golden hue. The high, open ceiling reveals
sturdy, barn-like rafters. From the main exhibit space, I can see luxurious
side rooms that seem to be taken from an old mountain ski lodge. And there's
a beautiful, massive spiral staircase constructed out of cut and planed
The visitor center represents many of the Agricultural Research Service�s
projects, including experiments with soybeans, corn, the "industrial uses
of plants," and milk production. I even find a small glass display case
dedicated to the "Fungi in Our Lives." Among the dried, naturalistic specimens,
I'm astonished to see a bowler hat and lady's handbag--both full-sized
and fully functional--and both carved in Hungary from beech tree fungi!
They should be selling copies of them in a gift shop!
These wonders provide little distraction from my mission: visiting a
rather small, square glass case filled with gruesome ghastlies. Here there
be parasites! On the phone, Pat Pillett told me these are "some of the
best" specimens, but they wouldn't have to be to turn your stomach away
from the idea of foodstuffs. Chief among the horrors: a cat�s head covered
in a bumpy, brown goo obscuring the top of its head and one ear. This feline
affliction has been identified as "scabies or mange," and the whole mess,
head and all, has been bleached white by the surrounding formaldehyde.
In life, the cat had been the pet of one of the collection�s founders,
Dr. Albert Hassall, proof that some people will save anything.
Another jar has been sealed by a guillotine-like, heavy duty metal clamp
that presses the lid tight with a screw mechanism; it�s as if the scientists
wanted to guarantee these suckers never got loose! Inside, a small fish
floats head up with a large worm protruding from its belly. The label helpfully
notes that we�re looking at a "Larval tapeworm in fish," and that the specimen
was drawn from the James River, near Richmond. So no more fishing there,
anyway. Another jar seems full of beans, but no, they�re fly larvae from
a horse's stomach. Looks like part of the stomach's there, too!
I'm also drawn to the unusual mounts made of cardboard squares with
glass bubbles in their centers, under which are preserved various nasties:
one contains a piece of dog skin infested with a dozen or so engorged wood
ticks; another has a beef tapeworm taken from the "intestine of man." They�ve
got a lot more of these mounts further down the road.
Speaking of worms, check out the jar containing an English setter heart
with long curled heartworms emerging. And you can�t miss the jar filled
with a black substance that highlights the elegant curl of the thick, tapered
worm inside; the label identifies this monster as acanthocephala,
noting, "Its head possesses long spines with which to attach in the pig's
intestinal tract." Take that, carnivores! Another jar contains long strands
of something that looks like noodles, but the label identifies as worms.
Nematodes, that is. They're the stars of the U.S. National Parasite Collection,
and I know I must venture forward, even though I�m reluctant to see more
of these things!
The Parasite Collection itself lies a little deeper on the campus. From
the Log Lodge, the short drive on a couple country roads leads past empty
fields and along a vast chain link fence that I can see surrounds a collection
of small white houses off in the distance. I must pass the security gate
and venture into a zone that resembles the set of a z-grade movie about
mad government scientists gone wild with hard radiation, exotic creatures,
and voluptuous assistants.
I find Pat Pillett downstairs in the tiny lunchroom, where she's been
logging new acquisitions at the computer. The specimens themselves lay
on the lunch table. Okay, they're on prepared slides and sealed away in
little vials, but still. A sign on the refrigerator warns, "This is for
food only." Clearly, the curators have grown a little too accustomed to
hanging with parasites. This room apparently functions as the brain cell
of the collection, and from here, I can see a few of the shelves in the
main storage room through the doorway.
I expected the storage room to be larger; it seems too small to hold
the two million (and counting) specimens in the collection. Of course,
parasites are tiny creatures, and the space is maximized by compact shelving
that can be rolled tight together and expanded for easy retrieval. The
first stop on our tour, a pair of old-fashioned wooden cabinets with glass
fronts, stand to the left of the doorway along a wall across from the main
shelving. The cabinet shelves are lined with the same flat cardboard squares
with glass bubbles that I saw in the Visitor's Center. Pat calls them "Riker
mounts." Switching on the cabinet lights creates an instant slide show
revealing segments of flat worms, ribbon-like knots of tapeworm, patches
of skin infested with ticks, or some other infernal blight. Scanning the
illuminated set produces mixed feelings of horror and wonder. One thinks
of plagues and body horrors--the revenges of Doctors Phibes and Moreau.
And yet these geometric forms, stained brown or a dark red, can seem oddly
attractive. One understands how curator Eric Hoburg could declare them
Over on a work desk, a more gruesome sight awaits: a pair of dog kidneys
in a glass box, one cutaway to show the tightly coiled roundworm packed
into the hollowed-out organ. These giant kidney worms--long but very thin--live
in all canids, the group that includes dogs and wolves.
The largest worm in the collection stretches to about 18 inches long
and a finger�s width around. It lies stretched out in a glass tube barely
larger than its contents. Pillet says this is tiny compared to the eighteen
foot monster taken from a whale; that worm now resides in a Russian museum.
Pat moves to one of the long compact shelves loaded with jars in all
shapes and sizes with ominous looking contents. Some jars look like normal
mason jars, with a clamp lid and rubber seal; some have plastic screw top
lids. The oldest are sealed with the screw-top clamps I saw in the visitors
center, only bigger. Between these large jars, the heavy duty seals, and
their macabre contents, I'm beginning to feel like I've entered a medieval
chamber of horrors. After viewing a few choice specimens, I'm struck with
the uncontrollable urge to wash my hands and purge myself. Suddenly, Obsessive
Compulsive Disorder makes sense--one washing may not do. Even reading about
this stuff may send you to a good soaking in antibacterial soap.
How gross could it be? You had to ask.
Check out this jar containing a small, bleached-out fish that�s been
choked with long, thin spiraling worms. This fish was among those collected
from some Baltimore fishermen who had been using them as bait--and, in
a moment of desperation, as snacks! According to Pat, they ate them "with
their beer." As we pause for a moment to gag, a few reasons NOT to eat
wormy fish come to mind. First, it's gross. Second, you can get peritonitis,
like the fishermen did, and this can be fatal. Quick-acting parasitologists
saved the men and, not incidentally, collected samples of the scourge.
Pat shows off a jar filled with the very worms taken from the affected
Here's a jar containing a section of a horse's colon infested with larval
botfly. Pat launches into an invaluable lecture on the botfly life cycle,
including how their grubs bore through the side of the horse so they can
fall to earth, pupate, and emerge as flies. Imagine calling in sick with
that little problem!
Another jar contains no liquid, but it doesn't need it to preserve the
dry vertebrae inside. This section of a pig's backbone displays conspicuous
holes bored through it--the work of a nematode specialized to this lifestyle.
At this point, Pat tells me that the collection teaches important lessons
about how parasites adapt to specific creatures and attack specific organs.
Some parasite life cycles can be very complicated, Pat notes, with certain
worms moving from snails to sheep to man and back to earth--remarkable
for its dependence on three species!
How can Pat remain so calm, so enthusiastic about these nasty things?
You'd sort of expect that from someone who's made parasites their life's
work. She's been a curator here since 1977, and worked for BARC for ten
years before that, focusing on plant nematodes. (Sure, plants have parasites,
too. So even vegetarians aren't safe!) But Pat's home here was established
long before that. Her father, Allen McIntosh, was curator of the collection
from 1930 to 1962. She recalls visiting the lab as a girl, cleaning her
father�s office and gazing at the specimens.
"I grew up with those Riker mounts," she says. While her sister retreated
in disgust, Pat settled down to listen to her father discuss his work.
"He'd talk about what he did, who sent him something," she remembers. "You
knew when he'd sealed some nematodes, because he used creosote and it smells
"Basically, I grew up with this, so it�s second nature to me," Pat continues.
"I grew up with all the guys that were here." She even remembers accompanying
them on outings with their bowling league!
The shelves stretch on. The limitless supply of shocking samples can
seem, well, shocking. Pat calls my attention to several extra-special specimens.
Take a look at the preserved puppy's head with nematodes emerging from
his cute little nose. Well, it was cute until the formaldehyde bleached
everything the same off-white color. As if the implications for cross species
infection of this specimen weren't entirely clear, Pat rapidly recites
how an infected dog might poop in a sandbox where the worm�s larvae could
move to your kids. This anecdote turns into a lecture about recent findings
by curator Eric Hoburg proving that man actually first transmitted these
parasites to the wolves they domesticated! It�s only fair that they should
give them back.
Pat scans the cluttered rows of jars and comes up with one filled with
what looks like leaf-shaped pieces of gray rubber about two inches long
and an inch wide. You sure don�t want one of these where the sun don�t
shine. "I like these because they�re so big," she says. "They�re liver
flukes taken from deer."
A much smaller jar contains a single creature that resembles a large
pillbug. This isopod lives in a fish�s mouth, feeding on scraps of food
as they go down the fish's gullet, thus robbing the host of nutrients.
The male and female isopod will snuggle in there together, resting above
the fish�s tongue. Even as she recounts these facts, Pat herself is incredulous:
"Show me where a fish has a tongue! I guess I haven't cut the heads off
Pat picks up a regular mason jar, turning it in her hand to swirl the
liquid and the thin, pasta-like things in it, while rattling off their
scientific name. "There's probably thousands, thousands of worms in this
There are millions more just waiting on the shelves to be examined.
In a way, I'm glad I don't have time to visit them all.
Visiting the Collection
Given the small staff, cramped quarters, and security gauntlet, the
U.S. National Parasite Collection has not been set up to receive visitors.
Casual parasite observers will get an eyeful at the ARS National Visitor
Center, where they can temper the horrors with the glories of the Log Lodge
(and the fungus hat). You can schedule a tour of the BARC campus by calling
the Visitor Center in advance [at 301/504-9403], and they'll bring you
by the main parasite compound. Once in a while, Pat admits, with advance
notice she can accommodate small groups of enthusiastic visitors.
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