Rift valley fever virus infection among livestock handlers in Ibadan, Nigeria.

Livestock handlers are occupationally exposed to Rift Valley fever virus (RVFV) because of frequent and longer contact with mosquito vectors, animal blood and other tissues. We determined the seroprevalence of RVF virus infection among livestock handlers in Ibadan, Nigeria. Blood samples were collected from 265 workers in two major livestock markets and a livestock farm. Questionnaires were administered to obtain information on risk factors that may be associated with RVF virus transmission. The blood samples were tested using enzyme-linked immunosorbent assays (ELISA) to detect multispecies anti-RVF virus IgG/IgM and human anti-RVF virus IgM. In total, 14 (5.3%) of the 265 participants tested positive for anti-RVFV IgG. Seropositive individuals were more among livestock keepers (5.6%) than butchers (3.6%). Workers that frequently visited the livestock rearing areas of the northern part of Nigeria had a statistically significant (P = 0.004) higher rate of infection compared to those that did not. Very few (0.8%) of these workers knew about RVF virus while none had been vaccinated against the virus infection. This study indicates that RVF virus continues to circulate sub-clinically in Nigeria, thus the need to educate and vaccinate individuals who are occupationally at risk of infection.

Molecular Identification and Phylogenetic Analysis of Acetylcholinesterase-2 Gene From Culex pipiens And Culex quinquefasciatus (Diptera: Culicine) in Nigeria.

West Nile virus (WNV) is maintained in an enzootic cycle between ornithophilic mosquitoes and birds. There is paucity of information on population density of these vectors and the molecular details in Nigeria. We determined relative abundance and employed molecular methods to detect Culex species. Mosquitoes were caught from April 2013 to February 2014. Genomic DNA extraction was carried out and acetylcholinesterase 2 gene amplified by Polymerase Chain Reaction in different Culex species. Culex pipiens quinquefasciatus and Cx. p. pipiens were identified in different locations, while some other Culex species could not be identified. Culex p. quinquefasciatus were sequenced by Sanger's method. Vector density was 100 Culex species per man hour. Identification of Culex pipiens and Cx. quinquefasciatus from different locations in Ibadan, Nigeria reaffirms the presence of vectors and highlights possibility of enzootic transmission of WNV. Surveillance should be sustained in equine population and bird reservoirs.