Demonstrating freedom from equine influenza in New South Wales, Australia, following the 2007 outbreak.

Abstract

OBJECTIVE: To quantify the probability of freedom from equine influenza (EI) in New South Wales (NSW), Australia, based on analysis of polymerase chain reaction (PCR) testing. METHODS: Testing in the infected areas of NSW during the period 1 January to 30 April 2008. RESULTS: Data from the random survey were collated and analysed to provide estimates of the probability of detecting EI if it was present at a prevalence ranging from 0.01% to 0.5%. The sensitivity estimates were then combined with a prior estimate of the probability of freedom in a simulation model, to estimate the posterior probability of freedom from EI (given the negative results of the random survey). CONCLUSIONS: The very large volume of PCR tests performed provided a very high level of confidence that EI had been successfully eradicated from NSW.