Predictive study for Ross River Virus infections in the Darwin area of Australia published

Susan P Jacups of Charles Darwin University, Darwin, Australia publishes an elegant study in the upcoming issue of Tropical Medicine and International Health about predictive indicators for Ross River virus infection in the Darwin area of tropical North-Eastern Australia. Ross River virus is an Alphavirus, a close relative of chikungunya and Barmah Forest Virus, causing  similar symptoms of fever, joint pain and rash. The study is based on the statistical analysis of laboratory confirmed cases of RRV infection between 1991 and 2006 as well as climatic, tidal and mosquito data collected from 11 trap sites weekly in the study area. The authors identified the best predictors of RRV infections using three multivariate Poisson models. The best global model included rainfall, minimum temperature and the average monthly trap numbers of three implicated mosquito species populations (Culex annulirostris, Aedes vigilax, Aedes notoscriptus), and explained 63.5% of the deviance while predicting disease accurately. The model also indicated that predicted anthropogenic global climatic changes may increase RRV infections. My favourite point is that the predictors in the global model, since they all have a lag time of either 1 or 3 months, can be used as an early-warning system for potential RRV outbreaks. Such location-specific early-warning systems are badly needed for other vector-borne diseases, such as e.g. West Nile, dengue and chikungunya.