[Glossina feeding habits and diversity of species of trypanosomes in an active focus of human African trypanosomiasis in Gabon].
Feeding host is an important factor upon which depend the Glossina infection rate and the proportion of different species of trypanosome. Glossina feed both upon animals and humans. In order to identify species of trypanosomes present in the Komo-Mondah focus and to verify whether there is any relationship between the prevalence of sleeping sickness and the feeding habits of Glossina, we have carried out an entomological survey in this focus of Gabon. Flies were dissected and organs were analysed by PCR, while the origin of blood meals was determined by ELISA. Three species of trypanosomes were found: Trypanosoma congolense "forest type" (14/104; 13.46%), Trypanosoma vivax (11/104; 10.58%) and Trypanosoma brucei s.l. (65/104; 62.5%) with 13.46% (14/104) of mixed infections of T. brucei s.l. and T. congolense Glossina palpalis palpalis was caught in all biotopes investigated (91.85%) and was infected by all these species of trypanosomes. Glossina caliginea was not infected and Glossina fuscipes fuscipes was infected by T. brucei s.l. Tsetse flies feed more on animals than on humans in almost all villages, but there was no significant difference between the number of blood meals taken upon these two groups of vertebrates (Chi 2 = 7.43; p > 0.05). A negative correlation was found between the zoophylic/anthropophylic index and the prevalence of HAT. This result is insufficient to conclude that this index can be used as an indicator of the degree of prevalence of HAT. In contrary, the trypanosomian risk seems to be an appropriate indicator of the prevalence of HAT in an area. The identification of the reservoir hosts in this focus would be useful for a good understanding of the HAT epidemiology.
Kohagne Tongué
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Programme sous régional de lutte contre la trypanosomiase humaine africaine, Organisation de coordination pour la lutte contre les endémies en Afrique centrale (OCEAC), BP 15665, Yaoundé, Cameroun. kohagne_oceac@yahoo.fr
Mengue M'Eyi
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Mimpfoundi
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Louis
F J
FJ
D000818:Animals; D005247:Feeding Behavior; D005681:Gabon / Q000453:epidemiology; D005843:Geography; D006801:Humans; D008403:Mass Screening / Q000379:methods; D015995:Prevalence; D014353:Trypanosomiasis, African / Q000453:epidemiology / Q000635:transmission; D014370:Tsetse Flies / Q000033:anatomy & histology / Q000145:classification / Q000502:physiology*