SWATHES of insecticide-laced netting stretched across the walls of people’s homes may help control malaria-carrying mosquitoes, say scientists from the University of Pretoria (UP).
Preliminary tests on an insecticide-impregna ted polymer mesh patented by the institution found it kills all the mosquitoes that land on it, UP Centre for Sustainable Malaria Control senior project co-ordinator Taneschka Kruger said.
"Most malaria control in Africa is based on indoor residual spraying (IRS) and insecticide-treated bed nets. The problem with IRS is that the (insecticide) attaches to dust particles and hangs in the air, and it is dangerous to inhale," she said. "We are not saying stop the spraying, but we are looking for safer alternative methods (as) all insecticides have some effects on people and the environment."
Malaria is caused by a parasite, which is transmitted between humans by the blood-sucking female Anopheles mosquito. In 2012, there were 207-million malaria cases worldwide with 627,000 deaths, 90% of which were in sub-Saharan Africa.
The government is trying to eliminate local transmission of malaria by 2018, and appears to be on track to meet this ambitious goal, using a combination of strategies that include spraying insecticides inside houses, working closely with affected neighbouring states, and monitoring the emergence of drug and insecticide resistance.
Malaria cases in South Africa fell 89%, from 64,500 to 6,847, between 2000 and 2012, while malaria deaths fell 85%, from 460 to 70, according to a report released in October by Roll Back Malaria.
But researchers cannot afford to be complacent as climate change may enable malaria to reclaim areas such as Pretoria and Durban, where it was eliminated decades ago, said Dr Kruger.
She and her colleagues have just completed a six-month pilot project in Vhembe to gauge the efficacy of different variations of the mesh, Netlon. In the pilot study, 40 homes were given Netlon impregnated with either deltamethrin or alphacypermethrin. Half the houses were mud huts, and the rest were reconstruction and development programme-style bricks-and-mortar houses, she said.
Preliminary results, which have yet to be published in a peer-reviewed journal, indicate Netlon killed all the mosquitoes it came into contact with. People also reported it killed other insects, particularly cockroaches and moths, she said.
The next step is a three-year study to gauge the durability of the mesh, Dr Kruger said.
University of the Witwatersrand malaria entomology research unit director Maureen Coetzee questioned the practical application of Netlon beyond South Africa, saying there was widespread resistance to the insecticides used in the trial. However, it was important for scientists to develop technologies that could be used to apply new classes of insecticides currently in development, she said.
On Monday, the National Institute for Communicable Diseases warned travellers that April and May were the peak malaria transmission months in South Africa and neighbouring countries, and reminded them to protect themselves from mosquito bites and take appropriate anti-malaria drugs in high-risk areas.
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