Background: Members of the Anopheles gambiae complex are important vectors of lymphatic filariasis (LF) in sub-Saharan Africa, but little is known about the relative contributions of all mosquitoes to lymphatic filariasis transmission in this area.

A prospective entomological survey was conducted in four sentinel villages in central Nigeria from 1999-2002, to assess the impact of annual, single-dose, mass drug administrations (MDA), with a combination of ivermectin and albendazole, on the transmission of Wuchereria bancrofti. As they were also endemic for human onchocerciasis, the four villages had received annual MDA based on ivermectin alone for 7 years prior to the addition of albendazole. Resting Anophelines gambiae s. l., An. funestus and Culex species were collected from 92 sequentially sampled households and dissected. Mosquitoes harbouring any larval stage of W. bancrofti were classified as 'infected', and those containing the third-stage larvae of the parasite were classified as 'infective'. Over the 41-month observation period, 4407 mosquitoes were captured and dissected, of which 64% were An. gambiae s. l., 34% An. funestus, and 1% Culex species. The baseline data, from dissections performed before the addition of albendazole to the MDA, showed high prevalences of mosquito infection (8.9%) and infectivity (2.9%), despite apparently good treatment coverages during the years of annual ivermectin monotherapy. Only the anopheline mosquitoes were found to harbour W. bancrofti larvae. After the third round of MDA with the ivermectin-albendazole combination, statistically significant decreases in the prevalences of mosquito infection (down to 0.6%) and infectivity (down to 0.4%) were observed (P<0.0001 for each). The combination of albendazole and ivermectin appears to be superior to ivermectin alone for reducing the frequency of W. bancrofti infection in mosquitoes.

The influence of larval diet, body weight at imago, size of blood-meal and age on the fecundity of Culex quinquefasciatus was investigated. The mean weights of mosquitoes at adult.emergence varied significantly with larval diet. Larvae reared on liver diet grew into heavier adults, and produced more eggs than those reared on milk. The volume of blood engorged by the female mosquitoes apparently remains constant during each gonotrophic cycle. However, the number of eggs produced is a function of both the blood-meal size and age of the mosquitoes. These results were discussed in relation to the need for full knowledge of the reproductive potential of this species of filaria vectors.Resume-L'influence due regime larvaire, du polds (du corps) a imago, de la quantity due sang suce et de l'age sur la recondite de Culex quinquefasciatus a ete etudiee.Le poids moyen des moustiques quand ils emergent a l'age adulte varie considerablement selon le regime larvaire. Les larves eleve'es sur un regime de foie sont devenues des adultes pesant plus lourd et produisant un nombre plus ilevi d'oeufs que celles elevens sur un regime de lait. Le volume de sang englouti par les femelles demeure apparemment inchange tout le long de chaque cycle gonotrophique. Cependant, le nombre d'oeufs produit depend non seulement de la quantite due sang suce mais aussi de l'age physiologique des moustiques.Ces resultats ont ete examines par rapport a la necessite d'avoir une connaissance plus complete due potentiel reproductif de cette espece de vecteurs filaires.

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