Écologie des stomoxes (Diptera : Muscidae) au Gabon. II. Origine des repas de sang et conséquences épidémiologiques

Abstract

To determine the origin of stomoxyine fly bloodmeals (Diptera: Muscidae) in Gabon, 1,021 flies belonging to seven different species of Stomoxys were captured and dissected in the area of Makokou. In total, 798 were not blood-fed and 223 bloodmeals could be gathered on filter paper. The identification of the origin of these meals was made by amplification of mitochondrial Cytb gene, then heteroduplex technique by using the Gambian rat (Cricetomys gambianus) as driver. Samples of fauna, collected on the local market, consisted of 24 mammal and two reptile blood and muscle samples, to which it is necessary to add human samples (27 potential hosts). 19 meals could not be amplified for technical reasons, 65 were amplified, but the acquired patterns corresponded to none of the tested potential hosts. On the 139 identified meals, 55% were taken on the black-fronted duiker (Cephalophus nigrifrons) and 19% on pig. Stomoxys transvittatus, the most abundant species in Makokou, is very opportunistic: 68 % of meals were taken on six different hosts, among whom 48% on the black-fronted duiker and 32% were not identified using the panel of tested hosts. S. xanthomelas took 50% of its meals on the moustached monkey (Cercopithecus cephus) and 7% on human beings. S. calcitrans, species of anthropised areas, took 33% of its meals on human beings. These three species can therefore take bloodmeals on wild fauna and human beings. They could potentially play an important role in the emergence of zoonotic diseases. The four other species took their bloodmeals only on wild fauna and pig, the only example of domestic fauna in this study. This preliminary study must be followed up using a larger number of specimens and by increasing the diversity of the tested potential hosts.