Description of Events Where African Buffaloes (Syncerus caffer) Strayed from the Endemic Foot-and-Mouth Disease Zone in South Africa, 1998-2008

Abstract

African buffaloes (Syncerus caffer) are reservoir hosts of Southern African Territories (SAT) foot-and-mouth disease (FMD) virus strains. In South Africa, infected buffaloes are found in the FMD-infected zone comprising the Kruger National Park (KNP) and its adjoining reserves. When these buffaloes stray into livestock areas, they pose a risk of FMD transmission to livestock. We assessed 645 records of stray buffalo events (3124 animals) from the FMD infected zone during 1998-2008 for (i) their temporal distribution, (ii) group size, (iii) age and gender composition, (iv) distance from the infected zone fence and (v) outcome reported for each event. A maximum entropy model was developed to evaluate spatial predictors of stray buffalo events and assess current disease control zones. Out of all buffaloes recorded straying, 38.5% escaped from the FMD infected zone during 2000/2001, following floods that caused extensive damage to wildlife fences. Escape patterns were not apparently influenced by season. The median size of stray groups was a single animal (IQR [1-2]). Adult animals predominated, comprising 90.4% (620/686) of the animals for which age was recorded. Of the 315 events with accurate spatial information, 204 (64.8%) were recorded within 1 km from the FMD infected zone. During late winter/spring (June-October), stray buffaloes were found significantly closer to the FMD infected zone (median = 0.3 km, IQR [0.1-0.6]). Less than 13% (40/315) of stray groups reached the FMD protection zone without vaccination, posing a higher risk of spreading FMD to these more susceptible livestock. Model outputs suggest that distance from the FMD infected zone, urban areas and permanent water sources contributed almost 85% to the spatial probability of stray buffalo events. Areas with a high probability for stray buffalo events were well covered by current disease control zones, although FMD risk mitigation could be improved by expanding the vaccination zone in certain areas.

Transmission of foot and mouth disease at the wildlife/livestock interface of the Kruger National Park, South Africa: Can the risk be mitigated?

“…The main difference is that contacts between buffalo and cattle herds around water sources inside KNP should allow a larger number of domestic and wild individuals to interact with each other, increasing the probability of transmission between individuals whereas outside KNP, contacts mostly occur between one or two escaped buffaloes (Van Schalkwyk et al, 2014) and scattered herds of grazing cattle. From that perspective, a realistic option to mitigate the risk of FMD emergence would be to influence communal farmer's behaviour to prevent cattle herds from getting inside the KNP.…”

“…The study area is the KNP wildlife/livestock interface, described in detail by Jori et al (2009) and other authors (Van Schalkwyk et al, 2014). The KNP and adjacent private wildlife areas, inhabited by free-ranging buffalo populations, are recognised as the FMD-infected zones of the country (Figure 1).…”

“…The annual number of buffaloes escaping from the KNP was obtained from historical data recorded because those years experienced massive buffalo evasions due to exceptionally high rainfall and were subsequently considered as rare events (Bruckner et al, 2002;Jori et al, 2009;Van Schalkwyk et al, 2014). Therefore, the average number of stray buffalo escaping from KNP during that period was evaluated at 70 individuals per year.…”

Molecular detection of Bartonella species and haemoplasmas in wild African buffalo (Syncerus caffer) in Mozambique, Africa

“…Moreover, buffaloes are known to harbour other economically important infectious pathogens, such as Mycobacterium tuberculosis, foot-and-mouth disease virus and Brucella abortus (Godfroid, 2002;Michel et al, 2006;Van Schalkwyk et al, 2016). Although widely distributed throughout sub-Saharan Africa, the African buffaloes are currently confined to protected areas.…”

“…Additionally, the African buffalo plays a role as reservoirs for vector-borne pathogens and may represent a serious threat to the livestock industry (Andrew and Norval, 1989;Allsopp et al, 1999;Eygelaar et al, 2015;Van Schalkwyk et al, 2016).…”