D. Ekwem - Tracking livestock movements to understand the patterns and risks of FMD spread

TRACKING LIVESTOCK MOVEMENTS TO UNDERSTAND THE PATTERNS AND RISKS OF FOOT-AND-MOUTH DISEASE SPREAD IN TRADITIONALLY MANAGED SYSTEMS IN EAST AFRICA

Introduction

Livestock are essential to food security and livelihoods in sub-Saharan Africa, but suffer from poor productivity due to infectious diseases such as foot-and-mouth disease (FMD). FMD is endemic in this part of Africa, and outbreaks are frequent, driven mostly by unrestricted livestock movements. To control endemic FMD, comprehensive information on the patterns of spread through herd contacts is needed. However, data on livestock movements across the landscape, and how and where contact occurs remain limited.

Materials and methods

We deployed Global Positioning System (GPS) collars on cattle in 52 different herds to understand fine-scale movements and between-herd contacts in rural areas of western Serengeti, Tanzania, representative of agropastoral systems in East Africa. We used the telemetry data to characterise the patterns of movements and identify locations of interactions between herds that suggest FMD flashpoints. In addition, we examined patterns of contact across a range of spatiotemporal scales, relevant to different FMD transmission scenarios.
Results
We observed that daily movement of cattle increased with herd size and rainfall. Herd contact rates were highest at large spatial and temporal scales. Furthermore, contact was greatest away from household locations, during low rainfall and close to dipping points. Generally, there were higher contacts proximal to resource areas such as grazing and water holes, but only for smaller spatiotemporal contact scales.
Discussion
We demonstrate how widespread movements could heighten the risk of endemic FMD spread. Given that risk is directly related to contact, the probability of FMD spreading between herds could be four times higher when virus survival in the environment increases from one to up to 24 hours. Our results point at times and locations of greatest FMD transmission potential and that could be targeted through tailored control strategies, for example when rainfall levels are low, and around dipping and water points.

D. Ekwem1,
2, T. Lembo1, J. Enright1 , J. Buza2, G. Shirima2, R. Reeve1, G. Hopcraft1, T. Morrison1

1Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Science, University of Glasgow, United Kingdom.
2Nelson Mandela African Institution of Science and Technology, School of Life Sciences and Bioengineering, Arusha, Tanzania.

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