Livestock movement informs the risk of disease spread in traditional production systems in East Africa

Abstract

In Africa, livestock are important to local and national economies, but their productivity is constrained by infectious diseases. Comprehensive information on livestock movements and contacts is required to devise appropriate disease control strategies; yet, understanding contact risk in systems where herds mix extensively, and where different pathogens can be transmitted at different spatial and temporal scales, remains a major challenge. We deployed Global Positioning System collars on cattle in 52 herds in a traditional agropastoral system in western Serengeti, Tanzania, to understand fine-scale movements and between-herd contacts, and to identify locations of greatest interaction between herds. We examined contact across spatiotemporal scales relevant to different disease transmission scenarios. Daily cattle movements increased with herd size and rainfall. Generally, contact between herds was greatest away from households, during periods with low rainfall and in locations close to dipping points. We demonstrate how movements and contacts affect the risk of disease spread. For example, transmission risk is relatively sensitive to the survival time of different pathogens in the environment, and less sensitive to transmission distance, at least over the range of the spatiotemporal definitions of contacts that we explored. We identify times and locations of greatest disease transmission potential and that could be targeted through tailored control strategies.

Foot-and-mouth disease in Cameroon: A systematic review to support its progressive control

“…Additionally, the study in the North identified that herders who practised grazing of small ruminants with other animal species reported high FMD contamination. Mixed livestock grazing practice leads to high animal contact and has been reported as a risk factor for FMD spread in west, central, east and southern Africa [32,33,34] and Asia [35] . It has been highlighted that dearth of information on good management practices by herders could be attributed to the disorganized nature of the herders, where only a few of them belong to farmer organizations.…”

Non‐local effects of human activity on the spatial distribution of migratory wildlife in Serengeti National Park, Tanzania

“…Illegal livestock incursions into the protected areas could displace wildlife and may account for the negative effects of the hard edges on wildebeest and zebra occupancy. Despite a growing consensus that moderate stocking densities of livestock are compatible with the conservation of native savanna biodiversity (Keesing et al., 2018; Reid, 2012; Sitters et al., 2020; Young et al., 2018), at high densities, livestock have deleterious impacts on native biodiversity by consuming large quantities of the most palatable grass species, suppressing savanna fires and changing the competitive balance between grass, forbs and trees (Sitters et al., 2020; Young et al., 2005) as well as pathogen transmission (Ekwem et al., 2021). Intensive livestock grazing can result in the encroachment of non‐palatable woody species and non‐native plants (Kimuyu et al., 2017) and these changes in the vegetative composition and structure may affect animal movement by presenting different availability of resources and risks (Hopcraft et al., 2014).…”

“…Such forays into protected areas present a direct pathway through which wildlife species may be displaced; for instance, herders and their dogs may harass wildlife which may subsequently avoid these areas. Both the agro‐pastoral communities that live along the western boundary of the ecosystem (adjacent to Mbalageti and Tabora transects) as well as the pastoralist Masai communities in the east (adjacent to the Kuka transect) keep moderate to high densities of livestock (Ekwem et al., 2021; Ogutu et al., 2009). Therefore, if livestock incursions were responsible for displacing wildebeest and zebra, then we should observe similar patterns on both the east and west sides, and these effects should be seasonal (i.e.…”

“…as well as the pastoralist Masai communities in the east (adjacent to the Kuka transect) keep moderate to high densities of livestock (Ekwem et al, 2021;Ogutu et al, 2009). Therefore, if livestock incursions were responsible for displacing wildebeest and zebra, then we should observe similar patterns on both the east and west sides, and these effects should be seasonal (i.e.…”

Local and wide-scale livestock movement networks inform disease control strategies in East Africa

“…In both these systems, livelihoods depend on the ability to move livestock to communal areas to access resources critical for their survival, such as pasture and water 6 . Such movements tend to be local, but they cover variable distances depending on the season, as seasonality in uences resource availability 7 . Livestock movements are also motivated by nancial gains associated with trade along market channels.…”