Risk factors for foot-and-mouth disease in Zambia, 1981-2012.

The aim of this study was to describe the spatial distribution of foot-and-mouth disease (FMD) outbreaks in Zambia for the period January 1981-December 2012 and to quantify the association between geographical features (proximity to roads, national parks, wetland areas) and the spatial distribution of FMD using a Poisson point process model. Details of FMD outbreaks retrieved from the Zambian Department of Veterinary and Livestock Development included the date of onset of clinical signs and the name of the ward in which the index case enterprise was located. A total of 62 FMD outbreaks occurred throughout the study period. Outbreaks occurred in the south of the Southern province along the border with Namibia and Botswana (n=5), in the Western province (n=2), in the Southern and Central provinces on the Kafue flood plains (n=44), and in the north east of the country close to the border with Tanzania (n=11). Increases in distance to the nearest major international border crossing, distance to the nearest major road, distance to the wetland area of the Kafue flood plain, wetness index and elevation were all associated with a decrease in FMD-outbreak ward intensity. Our analyses support the hypothesis that in drier areas of the country cattle are more likely to aggregate around communal drinking pools. Aggregation of cattle provides conditions suitable for FMD spread and detection.