title: New observations on cyclical development of Trypanosoma vivax in Glossina.
abstract: It is widely held that cyclical development of Trypanosoma vivax in Glossina is confined to the proboscis. This view has been re-examined in a series of experiments. Teneral G. morsitans centralis were fed on a goat infected with T. vivax IL 1392 and dissected 1-2 h after feeding. The infection rates in the labrum and hypopharynx were 40% and 0%, in contrast to 82% and 58%, respectively, observed in a control group dissected on day 25. This suggested that in a significant number of tsetse, cyclical development of T. vivax was initiated at sites other than the proboscis. Subsequent experiments revealed the presence of trypomastigotes, pre-epimastigotes and epimastigotes in the cibarium/oesophageal region of tsetse dissected 1-48 h after an infected feed. To investigate this further, tsetse proboscides were excised at intervals beginning 1 h after an infected feed, and transferred to in vitro culture conditions. Parasite multiplication and full cyclical development were only observed in proboscides excised 4 h or later after the infected bloodmeal. Thus, it would appear that at least in a number of tsetse, T. vivax cyclical development initially occurs in the cibarium/oesophageal region from where parasites migrate to the food canal of the proboscis and development is completed to infective metatrypanosomes in the hypopharynx.
authors.affiliation: International Laboratory for Research on Animal Diseases, Nairobi, Kenya.
authors.forename: S K
authors.initials: SK
authors.lastname: Moloo
authors.forename: M A
authors.initials: MA
authors.lastname: Gray
mesh_terms: D000818:Animals; D006041:Goats; D006790:Host-Parasite Interactions; D008297:Male; D014345:Trypanosoma / Q000254:growth & development*; D014370:Tsetse Flies / Q000469:parasitology*