Dengue fever: rainwater tanks a dengue risk
10 April 2009
The increasing use of domestic rainwater tanks to combat water shortages could drive a resurgence in the frequency and distribution of dengue fever.
Government-subsidised water tanks, currently being installed in large numbers, contained design flaws that could attract the Aedes aegypti mosquito (the type of mosquito that transmits dengue), and required regular maintenance to ensure they were not used as breeding grounds by the mosquito, said Dr Nigel Beebe, an entomologist with the University of Queensland and CSIRO.
‘They need to be thoroughly checked annually, and must not be altered from their original installation,’ Dr Beebe told the recent Greenhouse 09 conference in Canberra.
Dr Beebe said many of the commonly used tanks could clog at the pipe connection, leading to detritus build-up and overflow.
‘Many people are no doubt widening the entry hold to allow for this, but even a slight gap is enough for the A. aegypti mosquito to colonise. Also, the mesh used on most tanks is black, which is a powerful visual cue for this species [of mosquito].’
Most people didn’t realise that the species once had a much wider range, he said. In the 1940s, it occurred as far south as outer metropolitan Sydney, and as far south as Victoria.
‘There were serious dengue outbreaks in NSW in the 1920s and 1940s, but since then its range has declined with the decline of domestic water tanks… but it can, and most likely will, spread in the future.’
Dr Beebe said a public education campaign on maintenance of tanks was needed.
‘We wouldn’t want to discourage people from installing a valuable water conservation tool, but they need to be vigilant and aware of the risk,’ he said.
Last Reviewed: 10 April 2009
