Ross River virus disease in Australia, 1886-1998, with analysis of risk factors associated with outbreaks.
Ross River virus (RR) is a mosquito-borne arbovirus responsible for outbreaks of polyarthritic disease throughout Australia. To better understand human and environmental factors driving such events, 57 historical reports on RR outbreaks between 1896 and 1998 were examined collectively. The magnitude, regularity, seasonality, and locality of outbreaks were found to be wide ranging; however, analysis of climatic and tidal data highlighted that environmental conditions act differently in tropical, arid, and temperate regions. Overall, rainfall seems to be the single most important risk factor, with over 90% of major outbreak locations receiving higher than average rainfall in preceding months. Many temperatures were close to average, particularly in tropical populations; however, in arid regions, below average maximum temperatures predominated, and in southeast temperate regions, above average minimum temperatures predominated. High spring tides preceded coastal outbreaks, both in the presence and absence of rainfall, and the relationship between rainfall and the Southern Oscillation Index and La Niña episodes suggest they may be useful predictive tools, but only in southeast temperate regions. Such heterogeneity predisposing outbreaks supports the notion that there are different RR epidemiologies throughout Australia but also suggests that generic parameters for the prediction and control of outbreaks are of limited use at a local level.
Kelly-Hope
Louise A
LA
Infectious Diseases and Immunology Division, Queensland Institute of Medical Research and The University of Queensland, Australian Centre for International and Tropical Health and Nutrition, Post Office Royal Brisbane Hospital, Qld 4029, Australia.
Purdie
David M
DM
Kay
Brian H
BH
D018354:Alphavirus Infections / Q000453:epidemiology* / Q000635:transmission; D001315:Australia / Q000453:epidemiology; D002980:Climate; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D004777:Environment; D005843:Geography; D006801:Humans; D011891:Rain; D012307:Risk Factors; D012398:Ross River virus