Researchers from Wisconsin and Australia have found that climate change could expand the range of disease-spreading insects in coming decades, endangering human health.

Scientists from the UW-Madison and three Australian universities identified key biological and environmental factors affecting a type of mosquito that spreads dengue fever.

In the study, to be published online Jan. 28 in the British Ecological Society's journal Functional Ecology, they reported that climate changes in Australia during the next 40 years and the insect's ability to adapt to new conditions may allow the mosquitoes to expand into several populated regions of the continent.

While the current study focuses on the Australian population of the dengue mosquito, this type of mosquito lives around the world and presents a global threat similar in scope to malaria, according to the Centers for Disease Control and Prevention.

"Where would a species with a particular set of properties best survive and function on our planet?" asked University of Wisconsin zoologist Warren Porter.

"By answering this question, we are able not only to calculate what the current distributions are, but even identify places where they might flourish where they don't currently exist."

At present, dengue mosquitoes in Australia are restricted to Queensland in the northeast. But the new work shows that climate changes predicted by 2050 will increase suitable mosquito habitat across much of the continent.

In particular, changes in human water-storage practices driven by reduced rainfall in some cities -- such as rainwater tanks and other open water containers -- produce ideal conditions for mosquito egg laying.

The mosquito's potential for evolutionary change also will come into play.

Software developed by Porter and his colleagues can also be used to study future impacts on other "vectors" that spread use. The model can be applied to animal species living anywhere on the Earth, Porter said.

The study was led by Michael Kearney of the University of Melbourne, and researchers from the University of South Australia and James Cook University participated.

The Capital Times - 1/27/2009 8:52 pm

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