University mosquito research adds sting to disease control
Mosquito breeding habitat and life cycle research at the University of Queensland could help reduce epidemics of serious diseases such as Ross River and Barmah Forest viruses in the urban south-east of the state.
Dr Tonya Watson's PhD thesis Ecology and behaviour of Aedes notoscriptus: Implications for arbovirus transmission in south-east Queensland will aid in the development of efficient control strategies against the mosquito.
Based on the approximate 250-to-300-metre flight range of the species, its large population, human blood feeding habit and ability to transmit Ross River and Barmah Forest viruses, Dr Watson found Aedes notoscriptus could play an important role in urban epidemics in south-east Queensland.
Aedes notoscriptus was found in a 1994 Queensland Institute of Medical Research (QIMR) study to be carrying Ross River virus. Subsequent laboratory studies, which formed part of Dr Watson's research, confirmed the mosquito is capable of being infected by, and transmitting, Ross River and Barmah Forest viruses.
Both viruses are responsible for up to 8500 clinical cases of human disease reported annually in Australia, approximately 60 per cent of which are in Queensland.
Field studies were performed in western Brisbane to identify the important breeding sites of the species, and to determine how far adult mosquitoes fly in urban areas.
The studies identified that Aedes notoscriptus readily exploited any standing water in people's backyards, with general rubbish items and the bases of pot plants found to be significant breeding sites.
Dr Watson said while it was impossible to eradicate the mosquito, her research would help minimise its breeding in urban backyards.
Chapel Hill was chosen for the adult dispersal study because it is well-established, in a protected gully and heavily-treed, providing many protected resting sites for adult mosquitoes.
Another attraction was the co-operative attitude of residents, who agreed to allow researchers a daily visit to the traps on their properties.
"We had to have a fairly receptive resident population because we needed to have people tramping into their backyards for around two weeks to set and collect the mosquito traps," Dr Watson said.
A cloud of either pink or blue fluorescent dye was gently sprayed onto the adult mosquitoes before they were released from a central point within the 300-metre-radius study site.
Use of a fluorescent light on the daily contents of the 32 traps allowed movements to be monitored and led Dr Watson to conclude the mosquito is unlikely to travel any further than 300 metres in this environment.
The research into Aedes notoscriptus has provided accurate and up-to-date information for local governments in the south-east to use in their own control campaigns, and in the public education material the distribute to households and at visits to schools.
Dr Watson's thesis was supervised by Associate Professor Brian Kay of the QIMR and Associate Professor Gail Williams of the Australian Centre for International and Tropical Health and Nutrition, the University of Queensland.
For further information, contact Dr Watson on 3362-0351 (day).
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