Surface layer effectively kills malaria mosquitoes in rice paddies

A thin, liquid layer applied on the surface of inundated rice paddies effectively kills malaria mosquito larvae without having an impact on other aquatic life. Rice yield remains the same and water was saved because of the anti-evaporative properties of the layer.

These conclusions were reached by scientists from Wageningen University and the Kenya Medical Research Institute who tested a silicone-based known as polydimethylsiloxane or , and commercially available as Aquatain. The results were published in this week’s edition of PLoS ONE and suggest that the surface layer is a suitable tool for controlling malaria in rice-agro ecosystems.

Malaria is still a major threat to public health in many areas with an estimated 225 million cases of malaria and 781,000 deaths each year. Most of these occur in sub-Saharan Africa and South East Asia, where many people rely on agriculture as their main source of income. Agricultural activities, such as irrigation, have been associated with increased numbers of malaria cases. Especially rice paddies provide ideal breeding sites for . Control of these mosquitoes is challenging due to the large size and vegetation in these paddies, but simple tools such as evaluated by the Dutch and Kenyan researchers could be an important step forward.

Aquatain was originally designed as an anti-evaporation liquid to reduce water loss. It has the ability to self-spread, even around vegetation and debris, and cover the entire water surface. Aquatain does not negatively affect water quality and is certified for use on drinking water. The active agent, PDMS, is commonly used in shampoo conditioners, contact lenses etc. Therefore, the use of Aquatain as a mosquito control tool poses a minimal risk to the environment.

Based on initial laboratory results and the spreading properties of Aquatain, the researchers carried out a study at the Ahero rice irrigation scheme in western Kenya. Here, Tullu Bukhari and colleagues showed that application of the surface layer reduced the emergence of adult malaria mosquitoes from rice paddies up to 93%. This study also showed that there were minimal effects on non-target organisms and that the growth and development of rice plants in treated rice paddies was not affected.

Future research will focus on the operational feasibility of Aquatain application and determining its impact on reducing cases in various epidemiological settings.

More information: Bukhari T, Takken W, Githeko AK, Koenraadt CJM (2011) Efficacy of Aquatain, a monomolecular film, for the control of malaria vectors in rice paddies. PLoS ONE 6(6): e21713. doi:10.1371/journal.pone.0021713

Provided by Wageningen University

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Floating spores kill malaria mosquito larvae

Feb 21, 2011

There are over 200 million cases of malaria each year and, according to the World Health Organisation, in 2009 malaria was responsible for 781,000 deaths worldwide. Malaria is spread by mosquitoes which breed in open water ...

Water-stingy agriculture reduces arsenic in rice markedly

Jul 28, 2008

A new farming method first developed to conserve precious irrigation water may have the added benefit of producing rice containing much less arsenic than rice grown using traditional rice-farming methods, researchers in the ...

Edible fish feasts beats malaria

Aug 09, 2007

The emerging threat of pesticide resistance means that biological malaria control methods are once again in vogue. New research published in the online open access journal BMC Public Health shows how Nile tilapia, a fish ...

Recommended for you

NY and NJ say they will require Ebola quarantines

4 hours ago

The governors of New Jersey and New York on Friday ordered a mandatory, 21-day quarantine for all doctors and other arriving travelers who have had contact with Ebola victims in West Africa.

WHO: Mali case may have infected many people

8 hours ago

The World Health Organization says a toddler who brought Ebola to Mali was bleeding from her nose during her journey on public transport and may have infected many people.

Two US nurses are declared cured of Ebola

10 hours ago

Two American nurses were declared cured of Ebola on Friday, and one was healthy enough to leave the hospital and meet President Barack Obama for a hug.

User comments