| Summary: | <p>Abstract</p> <p>Background</p> <p>Urban malaria is a major health priority for civilian and militaries populations. A preliminary entomologic study has been conducted in 2006-2007, in the French military camps of the two mains towns of Gabon: Libreville and Port-Gentil. The aim was to assess the malaria transmission risk for troops.</p> <p>Methods</p> <p>Mosquitoes sampled by human landing collection were identified morphologically and by molecular methods. The <it>Plasmodium falciparum </it>circumsporozoïte (CSP) indexes were measured by ELISA, and the entomological inoculation rates (EIR) were calculated for both areas. Molecular assessments of pyrethroid knock down <it>(kdr</it>) resistance and of insensitive acetylcholinesterase resistance were conducted.</p> <p>Results</p> <p>In Libreville, <it>Anopheles gambiae s.s</it>. S form was the only specie of the <it>An. gambiae </it>complex present and was responsible of 9.4 bites per person per night. The circumsporozoïte index was 0.15% and the entomological inoculation rate estimated to be 1.23 infective bites during the four months period. In Port-Gentil, <it>Anopheles melas </it>(75.5% of catches) and <it>An. gambiae s.s</it>. S form (24.5%) were responsible of 58.7 bites per person per night. The CSP indexes were of 1.67% for <it>An. gambiae s.s </it>and 0.28% for <it>An. melas </it>and the EIRs were respectively of 1.8 infective bites per week and of 0.8 infective bites per week. Both <it>kdr-w </it>and <it>kdr-e </it>mutations in <it>An. gambiae </it>S form were found in Libreville and in Port-Gentil. Insensitive acetylcholinesterase has been detected for the first time in Gabon in Libreville.</p> <p>Conclusion</p> <p>Malaria transmission exists in both town, but with high difference in the level of risk. The co-occurrence of molecular resistances to the main families of insecticide has implications for the effectiveness of the current vector control programmes that are based on pyrethroid-impregnated bed nets.</p>
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