Thursday, April 02, 2009

Mosquito outbreaks linked to changes in sea level and tides

From: Adelaide Advertiser

CLARE PEDDIE SCIENCE REPORTER

March 24, 2009 12:20pm

RESEARCHERS have found a way to predict plagues of disease-carrying mosquitoes up to two months ahead.

The warning system could be the latest weapon in the fight against dengue and Ross River fever, University of Adelaide ecologist Associate Professor Corey Bradshaw says.

“This model is a tool that helps predict when there is going to be a higher-than-average outbreak so that population control efforts can be implemented when they are going to be most effective and are most needed,” he said.

The researchers analysed 15 years of data on the northern Australian mosquito that transmits the Ross River and Barmah Forest viruses. They compared population size to environmental factors, such as tides and rainfall.

“Basic environmental monitoring data can be coupled with relatively simple population models to assist in predicting the timing and magnitude of mosquito peaks which lead to disease outbreaks in human populations,” Associate Professor Bradshaw said.

Salt-loving species tend to peak after very high tides. But the frequency of high tides and the amount of rainfall in the preceding months when mosquito numbers are low are critical - dictating the magnitude of eventual peaks.

“Previously, we didn’t know how big that peak would be,” he said.

“With this model, mosquito control efforts can be scaled according to the expected size of a future peak.”

Associate Professor Bradshaw said the same model could be applied to other mosquito species, for example dengue- or malaria-transmitting species, and others in tropical regions worldwide.

The research is detailed in a paper published online in the Public Library of Science journal PLoS Neglected Tropical Diseases at www.plosntds.org

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