Efficacy and Microfilaricidal Kinetics of Imatinib for the Treatment of Loa Loa

Background: Many people who live in west or central Africa are at risk for infection from a very small worm called Loa loa. This infection is acquired through the bite of a fly. Baby worms called microfilariae live in the blood. The infection most commonly causes skin itching, mild temporary limb swelling, and sometimes a adult worm can be seen in the white of the eye of an infected individual. Very rarely, people with this infection can develop problems with the kidneys and heart as a result of the worm's effect on the immune system. Because the vast majority of people with the infection have minimal symptoms, people in Cameroon usually do not get treated. But infection with Loa loa can cause serious problems in people who are being treated for infections with other parasites (namely, river blindness and lymphatic filariasis). Researchers want to find out of a drug called imatinib can treat Loa loa infection so that patients with this infection can safely receive other drugs to cure river blindness and lymphatic filariasis. Researchers believe imatinib can be a safe drug to use on Loa loa, because in the lab this drug kills the worms slowly, whereas other drugs which can cause treatment reactions usually kill the worms very quickly. Objective: To test if imatinib can treat Loa loa infection by killing the worms slowly. Eligibility: People ages 18-65 with non-severe Loa loa infection who are otherwise healthy Design: Participants will be screened with a physical exam and blood and urine tests. Participants will have a baseline visit. This will include a physical exam and blood and urine tests. It may include a stool sample. Participants will be randomly assigned to get 1 dose of either imatinib or a placebo. Participants will return to the clinic every day for 1 week, then once a week for 3 weeks. Visits will include a physical exam and blood tests. They will have urine tests in the first week. Participants will have follow-up visits 3, 6, and 12 months af