Evaluation of the efficiency of bird-baited traps for sampling potential West Nile Fever mosquito vectors (Diptera: Culicidae) in Senegal

Abstract

Summary:The efficiency of bird-baited traps and collection heights for sampling potential West Nile mosquito vectors was studied during the 2006 rainy season (between September 27 and November 26) in Barkedji area situated in the sahelian area of Senegal (West Africa). Each night, two traps were set on the ground-level and two on the canopy-level (~ 3 m) each containing either a chicken or a pigeon, the traps being rotated the following nights. A total of 1,030 mosquitoes were collected using 66 traps-nights. Culex species were predominant and represented 92.2 % of the fauna of which 63 % belonged to Cx. neavei group Theobald whereas 23.8 % were Cx poicilipes (Theobald). The species of the Cx. neavei group were mainly collected by the pigeon-baited trap at canopy while Cx. poicilipes was captured similarly by pigeons and chickens placed at the canopy and ground. The implication of these results in West Nile vectors surveillance is discussed. (Taylor et al., 1956). WNF outbreaks concern principally humans and horses and many other vertebrates as accidental hosts (Campbell et al., 2002). in Senegal, WNV has been isolated from several mosquito species including Cx. poicilipes (Theobald) and species of the Cx. neavei group Theobald (Traorelamizana et al., 1994;. This group includes two species (Cx. neavei et Cx. univittatus) difficult to identify on morphological characters -only adult males were firmly identified in Madagascar (Fontenille & Jupp, 1989) -they were pooled here. Previous studies conducted in Barkedji area have shown that: i) Cx. poicilipes and species of Cx. neavei group reach their highest abundances at the end of the rainy season in octoberNovember, ii) the two species are attracted by chicken, horse and human, and iii) they have been regularly associated with WNV between 1990 and 2003(Ba et al., 2006 Crora, 2005). Thus, for a better surveillance of WNV amplification, entomological studies should focus on these species. Such kinds of investigations need the accumulation of knowledge of which the search for the most efficient sampling method is important. Thus, the most efficient method for sampling these mosquitoes is still being explored. information about the most efficient bird bait species and level to collect these vectors in a focal enzootic transmission area of WNV are lacking. Previous studies have shown that some Culex species Article available at http://www.parasite-journal.org or http://dx.doi.org/10.1051/parasite/2010172143 Diallo D., Ba Y., Dia i. et al. Evaluation of thE 144Note de recherche Parasite, 2010, 17, 143-147 involved in the transmission of WNV feed mainly on the canopy-level (anderson et al., 2004;Darbro & Harrington, 2006) or at equal efficiency on the ground and canopy (Drummond et al., 2006). The purpose of this study was to compare the efficiency of bird-baited traps using pigeons and chickens and collection heights for sampling potential WNV vectors in the Sahelian area of Senegal. Materials and MethodsT he study was conducted at the edge of the Niakha ponds located...

Feeding behaviour of potential vectors of West Nile virus in Senegal

“…In the Ferlo region of Senegal, 175 km south-east from Ross Bethio, Cx. neavei was also found more abundant in the tree canopy than on the ground, using both pigeon- and chicken-baited traps [9]. …”

“…naevei, Mymomia spp., Mymomia hispida, M. lacustris, M. splendens, Aedomya africana [5], A. vexans and Mansonia uniformis [9]. All these species have a nocturnal feeding behaviour.…”

Arboviruses isolated from the Barkedji mosquito-based surveillance system, 2012-2013

“…Mosquito were collected monthly in villages and biweekly in ponds. In 2013, ponds were sampled biweekly with the traps listed above as well as bird-baited traps [20]. In November 2013, 3 ponds and 1 village were sampled once in Thiargny (50 km from Barkedji) following suspicion of an arbovirus outbreak.…”

Full-Genome Characterization and Genetic Evolution of West African Isolates of Bagaza Virus

“…Sharing these motifs of virulence mostly with MBFVs, NKVFs and CxFV than with AeFV showed that BAGV could be more closely related to MBFVs transmitted by Culex mosquitoes and could explain frequent BAGV isolations mainly from mosquitoes of Culex genus and its capacity to infect vertebrates such as wild birds [ 1 , 4 , 5 , 9 , 10 ]. In addition, The West African BAGV isolates characterized in our study were mainly isolated from Culex poicilipes and Culex neavei mosquitoes which have been reported as potential vectors for flaviviruses such as WNV [ 63 ]. Culex neavei was also found as a competent vector able to transmit flaviviruses such as USUV and WNV [ 64 , 65 ].…”