A computerised system for the accurate forecasting of the annual prevalence of fasciolosis.

Abstract Fasciolosis is a serious economic disease of cattle and sheep with a world-wide distribution. In the annual control of the disease, it is highly desirable that the issue of specific veterinary advice on the strategic use of control measures should be based on accurate forecasts of the prevalence of risk of the disease in the ensuing year. A national computerised information and retrieval system has been established in Northern Ireland to analyse specific condemnation data from all cattle, sheep and pigs slaughtered in abattoirs since 1969. Liver condemnations due to fasciolosis thus reflect the prevalence of the disease in the cattle and sheep populations. The system integrates with a concurrent meteorological database which facilitates the quantification of the effect that individual weather variables have on the occurrence of certain diseases. This paper describes how the computerised system has been used in the formulation of an autoregressive, multivariate model, which accurately forecasts the level of disease in any year. The model accounts for 95% of the variation in an 18-year time series of the prevalence of fasciolosis. The computer system is used at the end of August to forecast the following year's prevalence of fasciolosis in Northern Ireland. This enables the formulation of an effective control strategy, based on the expected prevalence of the disease, to be implemented in September. The computerised forecasting system may be applicable for use in any region of the world where relevant abattoir condemnation and meteorological data are available.