[Distribution and ecology of the Savannah human African trypanosomiasis vectors in disturbed forest zone in south Cameroon: about case in the Doumé forest]. / Distribution et écologie des vecteurs de la trypanosomose humaine africaine de type savanicole en zone de forêt dégradée au sud Cameroun: cas du foyer de Doumé.

Vector control through trapping in the foci of humid forest areas is rather difficult because of the wide spreading of tsetse flies and transmission sites of human African trypanosomiasis. In fact, traps should be a priori set up everywhere to stop the transmission. The identification of the disease transmission sites enables efficient trapping through localisation of dangerous tsetse flies habitats needing vector control measures. The study of adult tsetse flies and teneral tsetse flies spatial distribution and human vector contacts was conducted in Doumb to determine the transmission of human African trypanosomiasis for efficient vector control. Glossina fuscipes fuscipes was the only tsetse fly captured with a very low apparent density of 0.13 tsetse flies per trap and per day. Furthermore, the disease transmission in the focus was not found uniform. In fact, human vector contacts are high in two villages (Paki and Mendin) located in the highly disturbed forest zones. These contacts occur in humid shallows where teneral tsetse flies were only captured around streams and forest galleries. The Doumé focus presents therefore characteristics of savannah focus where river banks and nearby biotopes are the main target sites for vector control campaigns.

Tsetse fly host preference from sleeping sickness foci in Cameroon: epidemiological implications.

To determine the tsetse fly host preferences in two sleeping sickness foci of southern Cameroon, four entomological surveys (two in each focus) were carried out. For the whole study, 4929 tsetse flies were caught: 3933 (79.8%) Glossina palpalis palpalis, 626 (12.7%) Glossina pallicera pallicera, 276 (5.6%) Glossina nigrofusca and 94 (1.9%) Glossina caliginea. One hundred and thirty-eight blood meals were collected and the origin of 118 (85.5%) meals was successfully identified: 38.4% from man, 23.9% from pig, 20.3% from sitatunga (Tragelaphus spekeii), 2.2% from sheep and 0.7% from golden cat (Profilis aurata). The number of Glossina palpalis palpalis with man blood meals is more important in the Human African Trypanosomiasis (HAT) focus showing endemic evolution (Campo) than in the focus (Bipindi) presenting a flare up of the disease. The consideration of both results of the prevalence of Trypanosoma brucei gambiense in vertebrate hosts and those of the tsetse fly host preferences indicates a wild animal reservoir of Gambian sleeping sickness and three transmission cycles (human, domestic and wild animals' cycles) in southern Cameroon HAT foci.

Malaria transmission and the sensitivity of aggressive mosquitoes to insecticides in a poorly urbanized area of the Deido health district in Douala (Cameroon).

The design of an appropriate strategy for mosquito control in urban areas must take into account the local ecoclimate and its particularities. This study sought to determine the dynamics of malaria transmission and the level of insecticide susceptibility of aggressive mosquitoes in Ndogbong, a poorly urbanized district of Douala. Mosquitoes were captured on volunteers in 4 houses and outdoors for 2 consecutive nights a month, from April to September 2014, and identified by molecular and morphologic techniques. The infectivity of vectors was determined by a circumsporozoite protein (CSP) ELISA test. The susceptibility of vectors to DDT, deltamethrin, and permethrin was also assessed. Overall, 3794 mosquitoes belonging to 6 species were captured in 96 person-nights. The aggressive mosquito fauna comprised : Culex pipiens (57.83%), Cx. poicilipes (1.45%), Anopheles gambiae s.l. (39.01%), Aedes albopictus (1.51%), and An. paludis (0.10%). An. coluzzii accounted for 97% of members of the Gambiae complex captured and was the only species found to be infected with P. falciparum, with an average infection rate of 1.9% (95% CI : 0.82-4.41). The mean entomological inoculation rate was estimated at 0.3 ib/p/n. Susceptibility testing on female An. gambiae s.l. and Cx. pipiens revealed mortality rates lower than 85 % and thus suggested strong resistance to insecticides. An. Coluzzii develops well in poorly urbanized built-up areas of Africa and appears to be the major malaria vector in Ndogbong, especially during the rainy season. The high resistance to insecticides observed requires the development of new formulations for insecticides.