The Human Impact

Potentially dangerous breed of malaria mosquito found in Kenya

September 17, 2012

Scientists have discovered a new malaria-transmitting breed of mosquito which may pose an unknown threat in Kenya, where malaria is the leading cause of death.

Malaria, a preventable and curable disease, is generally known to be caused by the Plasmodium parasite and transmitted to humans by the bite of the Anopheles mosquito, which rests indoors and feeds on humans at night.

However, the newly-discovered mosquito has different habits.  It is active outdoors and bites humans earlier in the evening, soon after sunset, according to researchers at the London School of Hygiene & Tropical Medicine (LSHTM).

“These unidentified mosquitoes are potentially dangerous because they are outdoor active and early-biting, and so may evade the current indoor-based interventions to control mosquitoes,” Jennifer Stevenson, a research fellow at the school, said.

Current preventative programmes include spraying insecticide in homes and using bed nets for people to sleep under at night.

Malaria caused an estimated 655,000 deaths worldwide in 2010, mostly among African children, according to the World Health Organization (WHO).

NO SUPER MOSQUITO

Scientists conducted their research by setting up mosquito traps in a village in the highlands of western Kenya where there is seasonal malaria transmission.

They found malaria infection rates in five out of 300 mosquitoes, which is considered quite high, Chris Drakeley, director of LSHTM’s Malaria Centre, said.

Malaria is the leading cause of death in Kenya, with 25 million out of a population of 34 million Kenyans at risk of the disease, the report said citing the Kenya Medical Research Institute (KEMRI).

“The findings are interesting and serve to highlight the fact that in certain ecological scenarios the mosquito will evolve or will have different methods of avoiding control,” Drakeley told AlertNet.

“While we think this is an important discovery, we really don’t know the true impact yet.”

Ultimately scientists could develop a drug or transmission-blocking vaccine to prevent the spread of malaria transmitted by this new type of mosquito, he said.

Insecticides and other techniques can be used to try and kill mosquitoes at source.

“One tool isn’t going to fix everything and malaria control needs to be multi-faceted and target both the vector and the parasite within the human and the mosquito,” Drakeley said.

“At the moment it’s an isolated finding – there’s no evidence that it’s a ‘super mosquito’,” he added.

Related factbox: What is malaria?

Picture credit: Undated handout picture shows “species a” mosquito. LSHTM/Jennifer Stevenson

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