Reports of deadly viral infection from mosquito bites in Australia have risen dramatically in 2011, with the possibility of outbreaks in the summer of 2012.

A Medical Journal of Australia article reports three deaths in 2011, plus 16 confirmed cases of Murray Valley encephalitis virus. 

National Notifiable Diseases Surveillance System data shows zero incidence in 2010 and only four confirmed cases of viral infection in 2009.

According to the authors, the virus is prevalent in the northern part of the country but made a reappearance in 2011 in southeastern Australia. The lead author, Dr. Jack Richards, works for the Victorian Infectious Disease Service at the Royal Melbourne Hospital.

The rise in cases came after some recent flooding that resulted in fatalities in the Northern Territory, South Australia and Western Australia.

The report said the risks in the summer and autumn of 2012 were uncertain, particularly in areas that remained under water, which reminded of Australia’s limited knowledge on the disease epidemiology and the present challenges posed by the need for clinical management and outbreak preparedness.  

The virus causes brain inflammation and has a 15-30% fatality rate and only a 40% complete recovery rate, with 30-50% of survivors having long-term neurological problems. Symptoms comprise of headache and fever, confusion, lethargy and at times seizures. The disease has no known cure and vaccine so far.

Current prevention strategies comprise of pest control, the use of sentinel chicken sera to test viral activity, the application of mosquito repellents, and reducing insect bites by wearing long and loose clothes.

The authors said they are fervently waiting for more experimental intervention data and the development of successful antiviral agents.