Assessing the risk of wind-borne spread of foot-and-mouth disease in Australia

The effect the environment has on the spread of animal disease depends on the particular disease and can vary from being minor to being almost the sole determinant. An assessment of the risk of a particular disease outbreak and its consequences must combine the epidemiology of the disease with the variability of the environment. Foot-and-mouth disease is a highly contagious animal disease that spreads readily by close contact with infected animals and infected product. For such spread, the environment has little consequence. However, occasionally, wind-borne viral particles can spread the disease considerable distances. This paper concentrates on the methods used in a study undertaken to assess the potential for the wind-borne spread of foot-and-mouth disease under Australian conditions. The conditions suitable for the virus to persist as an aerosol, the amount of virus produced during an outbreak, and the dose-response to wind-borne virus were determined by considering the epidemiology of the disease. Environmental components considered included an analysis of weather records and livestock distribution data to identify areas at risk, and the use of a Gaussian plume model to estimate the extent of spread. (C) 1999 Elsevier Science Ltd.