Seroprevalence and serotypes of foot-and-mouth disease virus in apparently clinically healthy small and large ruminant populations in selected districts of the Karamoja Sub-Region, North-Eastern Uganda

Abstract

Foot and mouth disease (FMD) is a highly contagious disease affecting cloven-hoofed animals like cattle, sheep, and goats. It causes significant economic loss to the Uganda livestock industry due to livestock movement restrictions and trade bans. Despite these measures, outbreaks persist due to inadequate surveillance, poor vaccination strategies and inadequate vaccination coverage. This study aimed to determine FMDV seroprevalence and circulating serotypes in apparently healthy ruminants in the Karamoja subregion. Using ID Screen® ELISA kits that detect 3ABC FMDV NSP and not vaccine antigens, serum samples from 2,122 small ruminants and 2,400 cattle were screened. Positive samples were further tested for serotypes A, O, SAT1, and SAT2 using serotyping kits by Pirbright Institute. FMD seroprevalence in small ruminants was 20.6% [95% CI:18.9% - 22.4%] while that in cattle was 45.1% [95% CI: 43.1% - 47.1%]. Amudat district had the highest FMDV seroprevalence for both small [49.1%; 95% CI: 44.3% - 53.9%] and large [69.8%; 95% CI: 65.1% - 74.0%] ruminants, while Karenga had the lowest in both small [10%; 95% CI: 7.0% - 15.1%] and large [38.5%; 95% CI: 34.2% - 43.1%]. Age was strongly associated with seroprevalence of FMDV in both small ruminants [P <0.05] and cattle [p <0.001]. Similarly, Kaabong and Karenga [p <0.01] had lower odds of association with FMDV seropositivity compared to Amudat. FMDV serotypes A [84.7%] and SAT1 [60.1%] were most prevalent in small ruminants, whereas serotypes O [6.4%] and SAT2 [10.1%] were infrequently detected. Serotypes A [49.3%] and SAT1 [54.2%] were the most prevalent in cattle compared to O [7.2%] and SAT2 [5.6%] which were infrequently detected. The high prevalence of FMDV in Karamoja region indicates that FMDV is still an impediment to ruminant production in this region. This means that there is need to design and implement a risk-based FMDV control program involving cattle and small ruminant vaccination with vaccines made up of FMDV serotypes A, O, SAT1 and SAT2.The currently used FMDV vaccines contain FMDV serotypes O, SAT1and SAT2. They therefore don’t protect cattle and small ruminants against serotype A which is one of the commonly encountered serotypes in Karamoja region.