SURVEY FOR ANTIBODIES AGAINST FLAVIVIRUSES IN SLAUGHTER CAMELS (CAMELUS-DROMEDARIUS) IMPORTED TO NIGERIA

A slaughter house survey for antibodies against flaviviruses in 269 camels was carried out in Borno State, Nigeria. Sera were tested by haemagglutination-inhibition (HI) tests against six flavivirus antigens: Wesselsbron, Yellow Fever, Potiskum, Uganda S, Dengue type 1 and Banzi viruses. Ninety-eight percent of sera tested were positive for flavivirus HI antibodies. Antibody prevalence against flaviviruses was noted as follows: Wesselsbron (60.2%), Yellow Fever (54.0%), Potiskum (66.2%), Dengue type 1 (4.5%), Banzi (5.2%) and Uganda S (0%). There was a significant difference in antibody prevalence between virus antigens. The degree of cross-reactivity among the virus antigens was also statistically significant. Potiskum, Yellow Fever and Wesselsbron viruses were closely related when compared with other virus antigens (Dengue type 1 and Banzi), which were markedly different from them. We suggest that cross-protection between flaviviruses has an influence upon the epidemiology of this group of viruses in Africa, and that the high prevalence of flavivirus antibodies in slaughter camels imported to Nigeria may have serious public health implications.