Pesticides have typically been used to kill the fly, but new control methods must be considered because of environmental concerns and because some insects are growing resistant to pesticides. Eddie Cupp, a medical entomologist, has conducted extensive field research while his wife's expertise has been in the laboratory. It is through the blood feeding that they transfer these disease-causing parasites. The insects' saliva also contains substances that enter the bloodstream and prevent clotting, she said. But there are other complex circumstances that must exist before the fly can transfer disease through its bite.
Black flies contract the parasites by feeding on an already infected person.
The parasites then migrate through the fly's system and into its flight muscles. There, further development begins. When the hungry insect bites its next victim, the parasite is transferred and the stage is set for disease to develop. If we can develop methods to prevent black fly blood feeding and consequently becoming infected with microfilaria, we should be able to interrupt the development of these microfilaria b efore they can reach the disease-causing third stage in their life cycle. Thus, we may be able to better control these pests and the diseases they spread.