Cattle herds tracked to determine risk of disease spread in East Africa

Scientists teamed with farmers from rural areas of Tanzania to track herds of cattle using satellite Global Positioning System (GPS) devices, to better understand how diseases can pass from one herd to another.

The results of the study – led by the University of Glasgow and published in Scientific Reports – suggest that targeted interventions at specific locations and at specific times could reduce the burden of diseases such as foot-and-mouth disease, peste des petits ruminants and anthrax and would require fewer resources than broad-scale blanket vaccination schemes.

GPS collars were deployed on 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.

The study found that the cattle moved surprisingly long distances each day, to and from shared grazing lands, at an average of 7.5 km, with occasional movements up to 12 km. The riskiest places were those where animals had to congregate for extended periods, such as at water holes and cattle plunge dips, where livestock are periodically treated for parasites such as ticks.

Dr. Divine Ekwem, a veterinary epidemiologist in the Institute of Biodiversity, Animal Health & Comparative Medicine at the University of Glasgow, said: “We had no idea how far farmers moved their livestock each day, let alone where contacts between herds were most likely.”

Dr. Tiziana Lembo, a co-author at University of Glasgow, said: “The biology of the pathogen is particularly important when working out these risks. Some livestock pathogens require close physical contacts for transmission, while others can be carried in the air or water over long distances, or can remain infectious in the environment for extended periods of time.”

The team found that these differences in transmission times and distances had large impacts on which areas were most risky, suggesting disease control requires pathogen-specific strategies.

Article: Ekwem, D., Morrison, T. A., Reeve, R., Enright, J., Buza, J., Shirima, G., Mwajombe, J. K., Lembo, T., Hopcraft, J. (2021). Livestock movement informs the risk of disease spread in traditional production systems in East Africa. Scientific Reports, 11(1), 16375, doi: 10.1038/s41598-021-95706-z

[SOURCE: University of Glasgow]