Hoarding rainwater could 'dramatically' expand range of dengue-fever mosquito

Wiley-Blackwell, ENN

Article appears courtesy of ENN

mossie Ecologists have developed a new model to predict the impact of climate change on the dengue fever-carrying mosquito Aedes aegypti in Australia — information that could help limit its spread.

According to the study, published in the new issue of the British Ecological Society's journal Functional Ecology, climate change and evolutionary change could act together to accelerate and expand the mosquito's range. But human behaviour — in the form of storing water to cope with climate change — is likely to have an even greater impact.

Lead author, Dr Michael Kearney of the University of Melbourne says: "The potential direct impact of climate on the distribution and abundance of Ae. aegypti is minor when compared to the potential effect of changed water-storage behaviour. In many Australian cities and towns, a major impact of climate change is reduced rainfall, resulting in a dramatic increase in domestic rainwater storage and other forms of water hoarding."

"Water tanks and other water storage vessels such as modified wheelie bins are potential breeding sites for this disease-bearing mosquito. Without due caution with water storage hygiene, this indirect effect of climate change via human adaptation could dramatically re-expand the mosquito's current range," he says.

Ae. aegypti probably arrived in Australia in the 19th century on ships carrying mosquito larvae-infested water barrels. During the late 19th century, Ae. aegypti was widespread in urban Australia, stretching as far south as Sydney and Perth. By the late 1960s, Ae. aegypti was restricted to the northern half of Queensland (where it currently resides) thanks in part to removal of old galvanised tin rainwater tanks, installation of piped water, insecticides and new power lawnmowers that helped people keep their back yards tidy.

The study has major implications for public health interventions in Australia and other areas of the world affected by dengue and other mosquito-spread diseases. According to Dr Scott Ritchie, a mosquito control expert and contributing author: "The better we understand the underlying processes, the better we will be able to manage disease risk into the future. Our results highlight that dengue-vectoring mosquitoes can spread to areas where they are currently not found once suitable breeding sites, such as containers, become available. Our research can help target water hygiene education campaigns to areas most at risk of dengue mosquito establishment."

The predictions come from a new "bottom-up" model that takes into account the mosquito's biology and its physiological limitations, such as the ability of its eggs to tolerate drying out.

To construct the model, Kearney and his colleagues needed to predict the microclimates mosquitoes experience. "Like all mosquitoes, the dengue mosquito has an aquatic larval phase and it is very particular about breeding in artificial containers like water tanks, buckets and old tyres. So we developed a model of the temperature and depth of water in different containers as a function of climate. We modelled two extreme types of container — a large (3600 litre) water tank receiving rainwater from a roof catchment, and a small (20 litre) bucket only receiving rainwater from directly above. We considered each container type in high and low shade," Kearney says.

The authors also took evolution into account — the first time this has been done in such models. According to Professor Ary Hoffmann, a coauthor of the study: "Evolution happens all the time in nature and can be very rapid, taking only a few generations to influence the fitness of populations. Our results show that evolution can make a very large difference when predicting changes in species ranges under climate change."

Related Reading:
Jellyfish Swarms: Our Earth Bites Back
Wastewater to Feed the World?

Image Credits:
www.medicinapreventiva.com.ve

2 comments

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I want to know if I can find out right away because I got bitten by a mosquito last night and I want to find out if it was a dengue mosquito and If I am infected by it. So how soon can I have my blood tested if I am really infected by it? I am getting paranoid

http://www.biblehealth.com/dengue-fever/signs-of-dengue-fever.html

Written in May 2011

Dear Rain Harvesters,

Please be careful when collecting water. Some places have laws preventing the collection of rainwater. For example, some states, here in the United States ban rainwater collection not just because they want to control people but because it is a serious health issue. Safety can extend a lot farther than someones own back yard.

Look at the last sentence on page 20.
http://www.cdc.gov/nceh/ehs/Docs/When_Every_Drop_Counts.pdf

West Nile virus never use to exist here in the united states. Now it does. It has an opportunity to spread faster when humans are careless. Mosquitoes get the virus from by biting infected birds. Then the mosquito bites a person. It can be painful and fatal for the person who has been bitten.

http://www.cdc.gov/healthywater/global/
http://www.cdc.gov/ncidod/dvbid/westnile/index.htm

Videos I liked regarding West Nile:

This one is from the University of Colorado via Youtube.
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This one is from sciencenorth.ca in Canada.
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Further Reading:
Analyses of Dengue Fever and Aedes aegypti
http://scholarlyrepository.miami.edu/oa_dissertations/18/

Post Script,

If you see little wiggly things, tell them there is no room for wiggle room!

Post Post Script

The following article for example does not mention these risks and and ways to prevent them.

http://www.naturalnews.com/029286_rainwater_collection_water.html

(Last But Not Least).....

......A Nefarious Creature.

" rel="nofollow">
Mosquito laying eggs, eggs hatching (#311) by nature1upclose

Written in September 2012

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