Eleventh international meeting on Trypanosoma evansi: report of the Working Group. Paris, 17 May 1990.

Three objectives have been achieved by the Working Group since its creation in 1983: more detailed information (and consequently better awareness) of zones infected by T. evansi; refinement of diagnostic techniques and the development of test kits suitable for field use; development of a new synthetic trypanocide. Exchange of strains between specialist laboratories should be encouraged in order to compare isolates from Africa, Asia and South America by using current techniques of biotechnology, and to open the way to better knowledge of the pathogenicity of T. evansi and to the discovery of effective prophylactic measures. Research reported to the meeting was concerned with the taxonomy and genetics of T. evansi, the cloning and sequencing of nuclear and kinetoplastic DNA (kDNA), chromosomal polymorphism in relation to antigenic variation, the detection of lymphocytic interleukin 2 and its receptors in infected ponies, the use of monoclonal group antibodies to detect T. evansi, and the importance of natural receptivity of the host. A text concerning the diagnosis of surra (T. evansi infection) was drafted and forwarded to the Office International des Epizooties (OIE) for incorporation in the OIE Manual of recommended diagnostic techniques and requirements for biological products. A concise dossier was presented on the pharmacology and pharmacodynamics of the new trypanocide, melarsomine (proprietary name Cymelarsan). The recommended active dosage was 0.25 mg/kg body weight, given as a single intramuscular or subcutaneous injection. Laboratory tests were also reported with ronidazole, demonstrating its trypanocidal activity in rats.