Air Date: Week of November 17, 2000

Living On Earth’s Cynthia Graber reports on how the key to preventing the tropical disease leishmaniasis may be found in a tiny sandfly, the disease’s carrier.

Transcript

GRABER: The disfiguring disease leishmaniasis strikes millions of people in the tropics. It's transmitted by a sand fly and causes skin ulcers and sometimes even death. Now, a new study shows that the key to preventing the disease may be in the saliva of the sand fly itself. Here's why: after repeated bites from an uninfected sand fly, people develop an allergic reaction. These red, itchy welts are actually our immune system fighting off the bug's saliva. But as it happens, this reaction also kills the leishmaniasis parasites that live in the saliva. Scientists say this could explain why people who live in the tropics often come down with a much milder version of the disease. The U.S. Army has been trying to develop a sand fly repellent to protect soldiers from leishmaniasis. But scientists now say a few bites from uninfected sand flies may be just want the doctor order. That's this week's health update. I'm Cynthia Graber.