Isolation and molecular characterization of foot-and-mouth disease viruses from small ruminants in Nigeria

Foot-and-mouth disease (FMD) poses significant economic challenges to the livestock industry in Nigeria due to its widespread prevalence and detrimental impacts on animal health and international trade. Documented FMD outbreaks in the endemic areas of West and Central Africa consistently highlight the role of cattle as the indicator species for FMD. However, the role of small ruminants (SR) is poorly understood. Aiming to improve our understanding of the role of SR in the epidemiology of the disease, this study investigated FMD outbreaks on farms where cattle intermixed with sheep and goats. Blood and oral swabs (n = 177) were collected from 138 sheep and 39 goats in nine local government areas (LGAs) of Plateau State, Nigeria. Additionally, epithelial tissue samples were obtained from suspected cases of FMD in six sheep and three goats in four of the LGAs. The majority (71.2%, 95% CI 64-77) of SR sampled seroconverted to FMDV measured by a 3ABC non-structural protein (NSP) enzyme-linked immunosorbent assay (ELISA) where 77.5% (95% CI 70.7-84.5) of sheep and 48.7% (95% CI 33-64.4) goats tested positive for FMDV-NSP antibodies. FMDV genomic RNA was detected in 36.6% (95% CI 25-49) of oral swabs samples collected from SR and two FMDV serotypes: O and A were detected using antigen-ELISA. Phylogenetic analyses of the VP1 coding sequences indicate that these viruses were closely related to those identified from cattle in the same farms and to those previously published from the same region. The findings from this study demonstrate that SR should be considered when developing FMD risk-based surveillance and control strategies in Nigeria.