Water storage may lead to spread of dengue

January 27th, 2009 - 5:00 pm ICT by ANI  

Sydney, Jan 27 (ANI): A team of Australian researchers has found that human behaviour, in the form of storing water to deal with shortages, will be the main factor in the spread of the Aedes aegypti mosquito that causes dengue.

According to a report by ABC News, the team believes that the finding has major implications for public health strategies in Australia and other regions of the world affected by dengue.

In Australia, Ae. aegypti is currently restricted to the northern state of Queensland, according to researcher Dr Michael Kearney, of the University of Melbournes Department of Zoology.

But, Kearney and colleagues have shown that Ae. aegypti could again be seen in Sydney and Perth backyards.

Kearney said that Ae. aegypti is believed to have arrived in Australia in the 19th century on ships carrying water barrels infested with the larvae.

At the peak of its presence in the country the mosquito spread west to Perth, north to Darwin and south to the NSW/Victorian border.

By the late 1960s, it had been restricted to Queensland, due in part to the removal of old galvanised rainwater tanks and the installation of piped water.

According to Kearney, Ae. aegypti is particular about breeding in flooded artificial containers such as birdbaths, plant bowls, buckets and tanks.

For the study, researchers predicted the mosquitoes range based on two types of breeding containers - a 3600-litre rainwater tank and a 20-litre bucket - in the shade and in the sun.

The modelling also took into account factors other than climate.

For this study, the team took a bottom-up approach looking at how the mosquito could adapt to climate change, and biological limitations such as larvae tolerance to cold and egg tolerance to dry conditions.

Kearney said that under the bucket scenario, the mosquito remained restricted to its current range with new hot spots predicted to be in the Bowen/Proserpine region of north Queensland, the Gold Coast region of southwest Queensland border and Port Macquarie in New South Wales.

However, under the tank scenario, the mosquito was quite okay to survive in most of Australia.

What was most surprising was how the water container type affected the range, which indicates that changes in water-storage practices could have a greater impact than temperature increases, Kearney said. (ANI)

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