Scores at risk as new breed of mosquito foils malaria prevention methods

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Published time: September 16, 2012 17:14
Edited time: September 16, 2012 21:14

Annual deaths could jump by the hundreds of thousands because of a new species of mosquito, which bites people in the early evening rather than at night, making bed nets useless in the battle against malaria.

The new strain of mosquito, which was discovered in the highlands of western Kenya by scientists from the London School of Hygiene and Tropical Medicine, feeds while people are outside in the early evening, according to a Sunday report by the Independent.

Malaria is already one of the world’s top killers, with nearly one million people a year dying from the disease.

And if not for mosquito nets that number would be much higher, as nets prevent the insects from biting at night, when the female anopheles mosquito sucks blood as part of its egg-production cycle. As many as one million people are thought to have dodged death by sleeping under mosquito nets covered with insecticide over the last 12 years.

Even more distressing is that scientists have as yet been unable to match the DNA of the new species to that of any existing variety.

Jennifer Stevenson, a scientist in the London School research group, told the Independent, “We observed that many mosquitos we caught – including those infected with malaria – did not physically resemble other known malaria mosquitoes.”

Stevenson, whose team set up outdoor and indoor traps to catch the species, added, “the main difference that came through from this study is that we caught 70 per cent of these species A – which is what we named them because we don’t know exactly what they are – outdoors before 10:30pm, which is the time when people in the village usually go indoors.”

Jo Lines, a colleague of Stevenson and a former co-coordinator for the World Health Organization’s global malaria program, also said, “we do not yet know what these unidentified specimens are, or whether they are acting as vectors [transmitters] on a wider scale, but in the study area they are clearly playing a major and previously unsuspected role.”

Scientists are now calling for wider controls to deal with the outdoor transmission of the disease.

Andrew Griffiths, from the children’s charity World Vision, said the findings are a setback in the fight against the disease. “It’s concerning because bed nets are one of the important tools in combating malaria and we’ve seen deaths go down dramatically. It would mean that one of the important parts in the response to malaria would be taken away. We have to be talking about protecting yourself at different times of the day and put even more focus on the community and other systems,” he said.

In a separate development, scientists in the UK and the US are developing genetically-modified mosquitos, which could prove effective in the battle against mosquito borne-diseases like malaria.