Ross River Virus Study

The aim of the Ross River Virus (RRV) Study was to investigate the predisposing factors that will improve the management of RRV in the South West of Western Australia.

Back in 1999, the rate of RRV in the South West was 5.5 times higher than the state average. The Lishman Health Foundation funded the Ross River Virus Study from 2002-2004, which was carried out by researchers from the University of WA with logistical support from the Department of Health. The study provided local authorities with evidenced based data about the nature of the virus and the best time to spray to reduce mosquito populations. Up until then, spraying was poorly timed and valuable resources were wasted.\

Key findings from the research include;

  • Outbreaks occur in autumn and are associated with autumn/winter rains
  • The longer a mosquito (which transmits the virus) survives, the greater the chance it has of transmitting the disease from an animal host to humans
  • The risk of outbreaks of RRV can be predicted by studying the immunity of Western Grey Kangaroos and horses, both of which are animal hosts for RRV
  • Peak times for biting are 6pm and 5am
  • Mapping of incidence of RRV in the South West and the knowledge that the majority of mosquitoes remain within a 1km radius of release

Initiatives and policies resulting from this research include;

  • Revised guidelines regarding the spraying for mosquitoes
  • Building permits for houses closer than 3km to high-risk areas now require written acknowledgement of the RRV risks involved

The findings of this research, funded by the Lishman Health Foundation, have directly enhanced the practical mosquito controls for all shires in the South West and resulted in a reduced incidence of RRV in the South West.