EXPERIMENTAL-INFECTION OF GLOSSINA-MORSIT ANS MORSITANS (MALL) BY TRYPANOSOMA-CONGOLENSE (ZRE G143/90)/

This report presents an experimental study of the life cycle of Trypan osoma congolense (ZRE/G143/90) in relation to the Vectorial competence of Glossina morsitans (Mall). The rate of engorgement at the time of an infectious meal and the mortality before day 15 of the life cycle w ere not significantly different between male and female flies. The mes ocyclic forms of trypanosomes were regularly observed in the proventri culus, crop duct, oesophagus, cibarium and proboscis, except in the cr op. On day 12 of the cycle, epimastigote forms were predominant in the proboscis. On day 13 of metacyclogenesis, four out of six rats (67%) used for feeding the flies were positive for trypanosomes upon buffy c oat examination. These results demonstrate the short incubation period of trypanosomes in the vertebrate host and precociousness of the Vect orial competence of some individuals of G m morsitans (Mall). Among th e three cyclic stages, only the procyclic forms in the intestine showe d a significant difference between the sexes, the male flies being mor e infected than the females. Metacyclogenesis undergoes three cleavage s leading to the successive and permanent establishment of the procycl ic, mesocyclic and metacyclic forms in the midgut, proventriculus and proboscis respectively.