Foodborne Pathogens at the Livestock-Wildlife-Human Interface in Rural Western Uganda.

Foodborne pathogens are an important cause of morbidity and mortality worldwide. To assess the presence of Salmonella, Campylobacter and Arcobacter spp. in livestock, wildlife, and humans from different regions across western Uganda, 479 faecal samples were tested by PCR. Salmonella and Campylobacter spp. were more frequently detected in livestock (5.1% and 23.5%, respectively) compared to wildlife (1.9% and 16.8%, respectively). Wildlife from remote areas showed lower Salmonella and Campylobacter spp. occurrence than in areas where interactions with livestock are common, suggesting that spill-over may exist from livestock or humans. Further studies are needed to better understand the transmission dynamics of these pathogens at the wildlife-livestock-human interface in western Uganda.

Wildlife-livestock interactions and risk areas for cross-species spread of bovine tuberculosis.

The transmission of diseases between livestock and wildlife can be a hindrance to effective disease control. Maintenance hosts and contact rates should be explored to further understand the transmission dynamics at the wildlife-livestock interface. Bovine tuberculosis (BTB) has been shown to have wildlife maintenance hosts and has been confirmed as present in the African buffalo (Syncerus caffer) in the Queen Elizabeth National Park (QENP) in Uganda since the 1960s. The first aim of this study was to explore the spatio-temporal spread of cattle illegally grazing within the QENP recorded by the Uganda Wildlife Authority (UWA) rangers in a wildlife crime database. Secondly, we aimed to quantify wildlife-livestock interactions and cattle movements, on the border of QENP, using a longitudinal questionnaire completed by 30 livestock owners. From this database, 426 cattle sightings were recorded within QENP in 8 years. Thirteen (3.1%) of these came within a 300 m-4 week space-time window of a buffalo herd, using the recorded GPS data. Livestock owners reported an average of 1.04 (95% CI 0.97-1.11) sightings of Uganda kob, waterbuck, buffalo or warthog per day over a 3-month period, with a rate of 0.22 (95% CI 0.20-0.25) sightings of buffalo per farmer per day. Reports placed 85.3% of the ungulate sightings and 88.0% of the buffalo sightings as further than 50 m away. Ungulate sightings were more likely to be closer to cattle at the homestead (OR 2.0, 95% CI 1.1-3.6) compared with the grazing area. Each cattle herd mixed with an average of five other cattle herds at both the communal grazing and watering points on a daily basis. Although wildlife and cattle regularly shared grazing and watering areas, they seldom came into contact close enough for aerosol transmission. Between species infection transmission is therefore likely to be by indirect or non-respiratory routes, which is suspected to be an infrequent mechanism of transmission of BTB. Occasional cross-species spillover of infection is possible, and the interaction of multiple wildlife species needs further investigation. Controlling the interface between wildlife and cattle in a situation where eradication is not being considered may have little impact on BTB disease control in cattle.