Catching a chaotic cycle
by Rebecca Gill
Many
rejoice at the hot weather that summer brings, but few are fond of the
mosquitoes that come with it. And while an itch or a buzz can be
annoying – the tiny pests are also notorious for something more serious
– transmitting diseases.
South Australia periodically suffers outbreaks of two mosquito-borne viral diseases – the Ross River Virus (RRV) and Barmah Forest Virus (BFV) – also known as arboviruses. In 2006, SA has already seen more than 340 cases.
And while most of us will spend our summer dousing oursleves in insect repellant, Dr Craig Williams, from the Mosquito Research Laboratory at UniSA’s Sansom Institute, will be trying his best to get among as many mosquitoes as he can.
He and fellow researcher Dr Michael Kokkinn have been funded $57,000 by the SA Department of Health to investigate the transmission of arbovirus in SA.
"Although arboviruses aren’t fatal, they can be very debilitating conditions. In regional areas particularly, RRV can cause enormous social and economic impact," Dr Williams said.
Transmission cycles for arboviral disease varies from state to state. Dr Williams aims to develop a predictive tool for SA outbreaks.
"We are working on a computer based simulation which acts as an early warning system. Historical data will be analysed before going out into the field and gathering mosquitoes, so that the blood in their stomachs can be analysed," he said.
But because of the unusual characteristics of arboviruses, tracking the disease is no easy task.
"Unlike many other mosquito-borne diseases, which have a human-mosquito-human cycle, RRV and BFV are animal-mosquito-human. So to understand how outbreaks occur, we need to know what animals are carrying them, and which of SA’s 48 mosquito species are responsible for transmitting them."
Transmission cycles generally vary between states, due to climate and species variation and Dr Williams said it’s likely cycles could also vary within SA. This means that in different regions there will be different carriers and transmitters of the virus.
Dr Williams said that the ability to determine where and when an outbreak will occur would be hugely beneficial to regional economy and the social fabric.
"It allows time to undertake preventative mosquito control, even before there is any disease. Interventions can be planned and budgeted for.
"These can be chemical interventions, such as treating the water where the disease-causing species lay their eggs, or it can be as simple as public education," Dr Williams said.
"If you can break the cycle before transmission is out of control, you can save the health system a lot of money."