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Recipe for Tick Soup:

Just Add Roundworms or Fungi

Does just thinking about finding a tick on you gross you out?

If so, steer clear of Dolores Hill and Patricia Allen's laboratory in Beltsville, Maryland. There, the two scientists keep - yes, keep! - hundreds of black-legged deer ticks. They store them inside tiny glass vials and plastic-foam containers. Makes your skin crawl just to think about it!

This creepy collection helps Hill and Allen test new, natural weapons against the litttle blood-suckers. Some ticks, such as the deer tick, pose a major health threat. Their bites can infect people with Lyme disease. In 1996, more than 16,000 cases were reported.

But now it could be payback time--time for some Lyme-aid.

Hill, a parasitologist (PAIR-ih-si-TOL-ih-jist) is plotting revenge in the form of a spray that's alive with a deadly ingredient: hundreds of millions of tiny roundworms called nematodes.

When sprayed onto fallen leaves or soil, the nematodes slither about in search of a nearby tick. What happens next isn't pretty, says Hill, at ARS' Parasite Biology and Epidemiology Laboratory in Beltsville.

The worms wiggle into the tick's mouth, pores and other body openings. One type of nematode actually chews into the tick's body, using a single, sharp tooth like a mini-pickaxe.

Hill has watched the ticks fight the nematodes under a microscope. "They bat away at the nematodes that are trying to get into them," she says.

But resistance is futile, as the Borg on Star Trek often say. Once infected, a tick usually dies within about 24 hours. That's because the nematodes unleash bacterial helpers from their stomachs. The bacteria release chemicals that liquefy the tick's innards into a soup that the nematodes feed on. Yum!

Still not gross enough? Check out Pat Allen's research. She's testing a different approach, infecting ticks with spores of fungi like Metarhizium anisopliae and Gliocladium roseum.

As spores, these fungi ooze enzyme chemicals that eat away the tick's outer covering, or cuticle. The fungi then move into its body and feed and grow. It's another grisly death, but don't worry, the fungi don't infect people--just ticks, which are arachnids, and certain insects, like termites.

Allen is drawing on her expertise as a chemist to mix the fungi into a formula that can be sprayed on hiking trails and bike paths. The idea is to take out the ticks before they latch onto people.

Ditto for Dolores Hill. She's testing an experimental nematode spray for use in areas like backyards, where people may get bitten by ticks infected with Lyme disease.

 By Jan Suszkiw, Agricultural Research Service, Information Staff

If you're not too grossed out, and want to learn more about this tick research, check out a story in the March 1998 issue of Agricultural Research magazine:



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