A survey for haemagglutination-inhibiting antibody to West Nile virus in human and animal sera in Nigeria.

A survey for West Nile Virus (WNV) haemagglutination-inhibition (HI) antibody was carried out in humans and domestic animals. Human sera were collected from Ibadan, while the animal sera were collected from both Ibadan and Maiduguri. Out of 304 human sera tested, 123 were positive (40%). There was a higher prevalence of HI antibody in adults than children. Sex distribution of positive sera showed that 37% of males and 43% of females had WNV HI antibody. There was no significant difference in the prevalence of HI antibody in both sexes. On the 123 WNV HI positive sera tested, 104 (85%) and 78 (75%) had yellow fever and Potiskum HI antibody respectively. Monotypic WNV virus reactions were frequently found in children while polytypic reactions were frequently found in adults. A total of 200 animal sera were examined, 50 camels, 50 goats, 49 cattle and 51 sheep. The highest prevalence of HI antibody was found in camels (26%), followed by sheep (20%). Percentage of positive sera in other species were: goat (18%) and cattle (6%). Of the 35 WNV HI positive animal sera, 26 and 20% reacted with Yellow fever and Potiskum virus antigens respectively.