New mosquito threatens to bypass current safety measures

A potentially dangerous new malaria transmitting mosquito has been discovered in Kenya by scientists from the London School of Hygiene & Tropical Medicine. This species, which has previously been unknown, poses a threat because it bites humans at times when they are not protected by current malaria control techniques.

The commonly caught Anopheles mosquitoes that transmit malaria in Africa generally prefer to rest indoors and feed on humans at night. This led to the development of programmes to stop the spread of malaria, such as spraying insecticide in homes and issuing bed nets for people to sleep under. However, this mosquito was found to be active outdoors and bite people, earlier in the evening and soon after sunset.

Researchers said the discovery is worrying because the insect does not behave like normal mosquitoes. Already nearly one million people a year die from malaria caused by bites. But that number would be much higher if not for mosquito nets.

They prevent the female Anopheles, the main cause of the disease from biting at night, when it sucks blood as part of its egg production cycle. Nearly one million people are thought to have cheated death over the past 12 years by sleeping under nets coated with insecticide.

The new type of mosquito, however, does not wait until night time; it bites while people are outdoors in the early evening. Even more worrying for the scientists is that they are as yet unable to match the DNA of the new species to any existing mosquito variety.

Jennifer Stevenson of the London School of Hygiene and Tropical Medicine, who was part of the research group, said, “We observed that many mosquitoes we caught including those infected with malaria did not physically resemble other known malaria mosquitoes. Analysis indicated that their DNA differed from sequences available for known malaria transmitting mosquitoes in Africa.”

Researchers are worried that the daytime feeding pattern of the new tropical bug, posed a serious challenge to controlling the disease. Andrew Griffiths, from the children’s charity World Vision, said, “The findings are a setback in the worldwide battle against malaria. It’s concerning because bed nets are one of the most important tools in combating malaria and we’ve seen deaths go down dramatically.”

He added, “That while nets are not the only answer to reducing the incidence of the disease, they are one of the main ways. 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, without too much reliance on bed nets.”

The researchers concluded by saying that, “As these mosquitoes had so far been seen only in one location in Kenya, it was essential that tourists still protected themselves with a mosquito net, treated with a long lasting insecticidal treatment whilst travelling.”