The Southern Oscillation Index and Ross river virus outbreaks
Harley, D.O.; Weinstein, P.
Medical Journal of Australia 165(9): 531-532
1996
ISSN/ISBN: 0025-729X PMID: 8937384 Document Number: 466698
N. Nicholls (1993) [Lancet, 342: 1284-1285] proposed that there might exist a relationship between the Southern Oscillation Index (SOI), a measure of the El Nino-Southern Oscillation (ENSO), and outbreaks of arboviral disease. The authors obtained monthly SOI values obtained from Australia's Bureau of Meteorology, and calculated yearly averages from 1928 to 1995. Years with an average SOI >4.0 were designated 'favourable' for Ross River (RR) virus outbreaks. Years in which literature reports of >50 cases of RR virus infection in a defined geographical area smaller than a State or Territory were designated 'outbreak' years. There was no significant association between a yearly average SOI >4.0 and the reporting of a RR virus outbreak. Similarly, there was no correlation between the SOI and national notifications of RR virus infection, based on the last 5 years of Australian national notifications.