Dourine is a chronic or acute contagious disease of breeding equids that is transmitted directly from animal to animal during coitus. The causal organism is Trypanosoma (Trypanozoon) equiperdum. Trypanosoma equiperdum is primarily a tissue parasite that is rarely detected in the blood.

ELISA assay, for detection of specific antibodies to Trypanosoma equiperdum in equine sera.