Clinical presentation of FMD virus SAT1 infections in experimentally challenged indigenous South African goats

Abstract

Foot-and-mouth disease (FMD) is a transboundary animal disease that has a major impact on livestock production and trade. Foot-and-mouth disease virus (FMDV) is a single-stranded RNA virus that infects cloven-hoofed livestock and wildlife. The susceptibility of South African indigenous goats to FMDV Southern African Territories 1 (SAT1) was investigated after experimental challenge with a mixed SAT1 virus pool. In this study, we present the clinical manifestation of FMDV in five naive goats challenged via the intra-dermolingual route with 104.57 50% tissue culture infective dose (TCID50) FMDV virus pool containing SAT1 SAR/8/10, SAR/10/10 and SAR/21/10. The clinical responses of two vaccinated unchallenged goats maintained as in-contacts are also presented. Clinical scoring of FMDV infection and daily rectal temperatures were recorded and temperatures ≥40 °C were defined as fever. All five challenged goats developed fever within 48 h post challenge with a median fever duration of 5 days. The two unchallenged goats developed fever at 5 and 9 days post-contact with FMD lesions appearing at 4 and 8 days post-contact. Additional clinical signs observed included nasal discharge, ulcerative oral mucosal lesions of the lip and ulcerative interdigital cleft lesions. The pooled FMDV SAT1 infection caused mild clinical signs and natural transmission to reduced-dose vaccinated in-contact indigenous South African goats occurred.