[Complement: a sign of infestation of sheep by Trypanosoma brucei brucei in an experimental model: its evolution following treatment].

Broad variations in complement levels are seen during the course of many infectious diseases, particularly human and animal african trypanosomiasis. In this study, sheep complement is measured by means of its haemolytic activity expressed in 50% haemolytic complement units per ml (HCU50/ml). In healthy sheep, the average value is 23.3 HCU50/ml. Complement levels dramatically decrease five days after subcutaneous inoculation of Trypanosoma brucei brucei and remain undetectable until death of non treated infected animals. Eight infected sheep are treated with graded dosages of melarsoprol when central nervous system involvement appeared. Complement levels rapidly recover normal values after efficient treatment (0.9 and 1.8 mg/kg/d).