Trypanosomes in horse flies and deer flies in central New York State

Tabanids were collected during 2 consecutive summers from 3 counties in New York using a canopy trap and insect net. Twenty-seven per cent of all fly specimens (N equals 641) representing 69% of the species collected (N equals 36) were infected with flagellates. Tabanid intestines harbored amastigote, choanomastigote, and epimastigote forms. Epimastigotes were frequently found, and trypomastigotes and choanomastigotes rarely found in cultures of tabanid intestinal flagellates. Epimastigote and trypomastigote forms closely resembled Trypanosoma theileri-like trypanosomes reported from ruminants.