Hard bitten

The MicroGnome’s been busy lately. While engaged in environmental health assessment field work at a location ‘somewhere to the south of Perth’ he and his companions got thoroughly bitten by a cloud of winged nasties.

We didn’t pause long enough to identify which mosquito species wanted us out of there in a hurry, and beat a hasty retreat as soon as our work was done. Fortunately we appear to have escaped without going down with this season’s hot arbovirus. Once bitten, twice shy: next time we go bush, the tropical strength repellent will be the first item packed.

There has been so much arbovirus activity in southwestern WA this year that it got a mention recently in ProMED. The town of Cockburn (pronounced CO-Burn by the people who live there) reported almost three times the number of confirmed Ross River Virus (RRV) infections since the start of 2012, compared to last year.

Clinical features of RRV infection:

  • constitutional symptoms – lethargy, fever
  • rash
  • joint aches
  • nausea

The onset is generally 3-21 days after being bitten by mosquitoes, and the acute symptoms last for a few weeks. However, joint aches can last several months and can be quite debilitating.

Health experts recommend that people in high risk areas stay indoors around dusk and for at least 3 hours afterwards. However, the risk around brackish water an wetlands can be high, indicating a need for personal preventive measures such as insect repellent and cover-up clothing for those likely to be bitten by mosquitoes.

Now is the time of year when the risk of RRV should be receding, but its unusually high incidence this year make predictions based on previous experience subject to a caveat. It seems other parts of the country are also having a bad time of it.


  1. Is it the Aedes or Anopheles that tend to be RRV vectors? I’m wondering if we will see increases of Dengue and maybe even some malaria further south with all the flooding that has been happening recently.

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