Résumé
Definition of the disease: Tsetse-transmitted trypanosomosis 1 is a disease complex caused by several species of protozoan parasites of the genus Trypanosoma, mainly transmitted cyclically by the genus Glossina (tsetse flies), but also transmitted mechanically by several biting flies (tabanids, stomoxes, etc.). The disease can affect various species of mammals but, from an economic point of view, tsetse-transmitted trypanosomosis, is particularly important in cattle. lt is mainly caused by Trypanosoma congolense, T. vivax and, to a lesser extent, T. brucei brucei. Description of disease: Tsetse-transmitted trypanosomosis is a classically acute or chronic disease that causes intermittent fever and is accompanied by anaemia, oedema, lacrimation, enlarged lymph nodes, abortion, decreased fertility, loss of appetite and weight, leading to early death in acute forms or to digestive and/or nervous signs with emaciation and eventually death in chronic forms. Identification of the agent: Several parasite detection techniques can be used, including the microscopic examination of the wet and stained thick or thin blood films. Diagnostic sensitivity is increased significantly by concentrating the parasites prior to examination in combination with a phase-contrast or dark-ground microscope. The parasite concentration techniques have the added advantage that the packed cell volume, and hence the level of anaemia, can be determined at the individual animal and/or herd level. A highly specific and more sensitive test, used in an increasing number of laboratories, is the polymerase chain reaction (PCR), which can identify parasites at the genus, species or subspecies level, depending on the cases. Serological tests: Two trypanosoma/ antibody detection tests, the indirect fluorescent antibody test and the antibody-detection enzyme-linked immunosorbent assay (EL/SA), are routinely used for the detection of antibodies in cattle. They have high sensitivity and specificity but can only be used for the presumptive diagnosis of trypanosomosis. The antibody-detection EL/SA, in particular,