SEROSURVEY OF WEST NILE VIRUS IN HOUSEHOLD"REARED PIGEONS IN BAUCHI METROPOLIS, NIGERIA

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Department of Medicine

ABSTRACT
West Nile virus (WNV) is a mosquito-borne virus and belongs to the genus Flavivirus of the family Flaviviridae. It is an reemerging global pathogen, with transmission cycles involving a variety of birds and Culex species mosquitoes. Humans and most other non-avian species are incidental hosts. Not much is known about WNV and its potential zoonotic transmission from pigeons.The study was a cross-sectional study designed to determine the occurrence of WNV antibodies in pigeons reared in households, the knowledge on mosquito-borne diseases, and associated risk factors related to WNV in households of Bauchi metropolis. The serological detection was done using competitive enzyme linked immunosorbent assay and a pretested interviewer administered questionnaire was administered to collect information regarding socio-demographics and history of pigeon keeping among owners, knowledge of mosquito-borne diseases, and risk factors related to WNV in household. A total of 156 households were enumerated for the study and a total of 376 pigeon serum samples were collected and tested for WNV antibodies. Thirteen (3.5%) of the pigeon sera were positive for WNV antibodies. Highest seroprevalence of 14.3 %, 12.5 % and 11.8 % were found in Tura, Unguwan Jaja and Unguwan Ganjuwa areas of Bauchi metropolis respectively. Respondents of only 0.6% had knowledge on mosquito-borne diseases apart from malaria, 5.8 % knew that diseases could spread by mosquitoes to pigeons, 43.6% knew that diseases can cause high mortality in pigeons; while no respondent had knowledge on diseases of pigeons transmitted by mosquito. Risk factors of WNV in households indicated that 49.6% emptied all their containers around their houses that can hold water, 5.8 % had blocked or stagnant gutters that were not flowing, 73.7 % had mosquito nets at the windows and doors of their houses, and 13.5% of families regularly used mosquito repellent at night, and also while outdoor. Only 12.8 % respondents used any other mosquito control measures while outdoors. Discarded tires that may have accumulated on the property was admitted by 7.1 % whereas 60 % had drainage holes that were located on the outside of the house collecting enough water for mosquitoes to breed. Mosquitoes were seen in and around 17.3% and 16% of pigeon housing and drinkers respectively. Overall, respondents had low knowledge of mosquito-borne diseases. Not having blocked or stagnant gutter that is not flowing, and having mosquito nets at the windows and doors of respondents were found to be protective against WNV (OR=0.69 95% CI 0.21-2.29; OR= 0.46 95% CI 0.14-1.56). Having plastic containers, ceramic pots or similar water holding containers that have accumulated on properties, and having drainage holes located outside of the house collecting enough water for mosquitoes to breed were likely predisposing factors to WNV spread in the households surveyed, OR= 1.4 (95% CI 0.43-4.55); OR=2.14 (95% CI 0.56-8.25). The study has established the presence of WNV antibodies in pigeons in Bauchi metropolis. There is need for further studies on WNV in other species of birds, and also to educate the populace on its zoonotic transmission.