Mosquito borne virus alert for Western Australia

By Dr. Ananya Mandal, MDApr 12 2011

There is a mosquito alert for people living and holidaying in northern and central WA after a high number of reports of encephalitis and Ross River virus. According to Department of Health entomologist Sue Harrington, it is confirmed that a Carnarvon resident has been diagnosed with the potentially fatal encephalitis while several other cases are currently being investigated.

This virus infection is characterized by fever, drowsiness, headache, stiff neck, nausea and dizziness. In severe cases, people can have fits, lapse into a coma and may be left with permanent brain damage or die from the virus. The encephalitis is caused by either the Murray Valley or Kunjin strains, which have both been detected in the Kimberley, Pilbara and Gascoyne regions through a surveillance program being run by the University of WA. Ms Harrington said reports of Ross River and Barmah Forest viruses cases had also been on the rise across the regions, and that there is no cure for these diseases. Both viruses lead to painful joints, aching muscles, and lethargy, fever and skin rashes and can last from days to months. MVE cannot be transmitted from person to person; mosquito bites are the only ways a person can become infected said experts.

This is perhaps the worst year for Ross River virus in WA. 613 West Australians have contracted the disease since July with almost twice as many people contracting the mosquito-borne disease compared to the previous year when there were 339 cases. Infection rates sky-rocketed in Perth, the South West and the far north in recent months. Last year, in the South West 105 people contracted the virus while 199 cases have been recorded this year. Infection rates have quadrupled in the Kimberley from 28 people to 116 this year. This is due to the heavier than usual wet season say experts.

Ms. Harrington said, “This is really, at the end of the wet season, the time when you start to see the cases coming in, and certainly the figures for January and February are high. If we keep getting Ross River viruses cases coming in at the rate we're getting them now, it's going to be a pretty extreme year for the Kimberley.”