African swine fever is a devastating hemorrhagic fever of pigs, caused by the African swine fever virus (ASFV). In Africa, the presence of a sylvatic cycle involving warthogs and soft ticks means that the risk of introduction of ASFV into domestic swine is always present. Bushpigs (Potamochoerus larvatus) are nocturnal, susceptible to ASFV and share a natural interface with both warthogs and domestic pigs. The role of the bushpig in the epidemiology of ASFV if any is not understood, yet control strategies of the disease in areas with probable contact between bushpigs and domestic pigs would depend on such information. This study used a molecular and ecological approach to investigate the role of the bushpig in the epidemiology of African swine fever at the wildlife-livestock interface in Uganda. The GPS/GSM tracking collars were used to monitor the movement patterns of free-ranging domestic pigs and bushpigs. Four free-ranging domestic pigs and five bushpigs were collared and their movements monitored for two weeks and two months respectively. Domestic pigs had a peak daily distance of 2,521m; mean home range of 43,239m2 (ranging from 3,929–143,822m2) with a mean core utilization area of 13,328m2 (ranging from 744–47,416m2). The domestic pigs mainly roamed around homesteads, gardens, water points and rubbish pits during both day and night. The bushpigs were active from the evening and throughout the night wandering between game reserves and domestic farmlands with minimal activities during daytime. This study describes a new bushpig peak daily distance of 15.3Km, home range of 8.5Km2 in Uganda. There was some overlap between free-ranging domestic pigs and bushpig activity times, indicating the possibility of interaction between the two species. The ASFV detection was done in domestic pig and bushpig samples. Thirteen (8.9 %) domestic pig blood samples were positive for ASFV. One (7.1 %) bushpig sample tested positive for ASFV with Ct value of 35.8. There was probable evidence of interaction between the potentially ASFV positive bushpig and free ranging pigs indicating that the bushpig could be playing a role as an ASF epidemiological link at the wildlife-livestock interface between the sylvatic and non-sylvatic cycles. However this observation requires deeper and full genome sequencing to compare the ASFV genetic characteristics for a robust conclusion.
Date of publication:
RUFORUM Theses and Dissertations
RUFORUM (Grant no. RU/2014/GRG-088)
Charles Masembe; Karl Stahl