Foot and mouth disease outbreak detection and viral serotyping in cattle in selected areas of Burayu sub-city and Horo Guduru Wollega Zone, Oromia, Ethiopia

Abstract

Foot-and-mouth disease (FMD) is a highly contagious transboundary viral disease affecting cloven-hoofed animals and causing substantial economic losses in the livestock sector. A cross-sectional study was conducted from October 2023 to December 2024 to detect FMD outbreaks and identify circulating foot-and-mouth disease virus (FMDV) serotypes in cattle from selected areas of Burayu Sub-City and Horo Guduru Wallaga Zone, Ethiopia. Study areas were purposively selected based on reported FMD outbreak cases during the study period. Clinical samples were collected from clinically affected, unvaccinated cattle. A total of 18 clinical samples, comprising 8 epithelial tissue samples and 10 oral swab samples, were collected. One-step real-time reverse transcription polymerase chain reaction (rRT-PCR) targeting the 3D gene was used for FMDV detection, while serotyping was performed using sandwich enzyme-linked immunosorbent assay (ELISA). Positive samples were further inoculated onto Baby Hamster Kidney-21 (BHK-21) cell monolayers for virus isolation. Of the 18 samples tested, 12 (66.7%) were positive for FMDV by rRT-PCR. Among the positive samples, 8/12 (66.7%) were epithelial tissues, while 4/12 (33.3%) were oral swabs. Serotyping identified serotypes O and A. Cytopathic effects characteristic of FMDV were observed in 10/12 (83.3%) inoculated samples within 24–72 h post-inoculation. The study confirmed the circulation of serotype O and A during FMD outbreaks in the study areas. Therefore, the use of bivalent vaccines and further phylogenetic and vaccine-matching studies are recommended for effective disease control.