Research questions treated mosquito nets efficacy

A new research from the Institut de Recherche pour le Development in Senegal has found that mosquitoes develop rapid resistance to insecticide used to impregnate bed nets.

The report is coming just as the American government is announcing  a $189 million funding to tackle malaria in 14 African countries.

The World Health Organization is of the view that if the treated nets are used properly by the people it could prove an effective way of fighting malaria. It has been reported that in the last five years about six million nets have been distributed in Senegal. Since its introduction, the number of malaria cases began to fell significantly.

The study published by Lancet Infectious Disease however raised doubts about the efficacy of the nets which was promoted by the World Health Organization and formed the bulk of African countries health budget spending.

In the study, the researchers looked at a small village in Senegal and tracked the incidence of malaria both before and after the introduction of treated nets in 2008.

“Within three weeks of their introduction the scientists found that the number of malaria attacks started to fall.Incidence of the disease was found to be 13 times lower than before the nets were used,” the study said.

The researchers reported that between September and December 2010 which was 27 to 30 months after the nets had been given out , malaria attacks in adults and older children increased to even higher levels than before.

Upon testing mosquitoes in the village, the team also reported that 37 percent were resistant to deltamethrin in and that the genetic mutation which gives them resistance increased from eight percent in 2007 to 48 percent in 2010.

The researchers said they thought the rebound in malaria attacks, particularly in older children and adults, was the result of a combination of reduced immunity because of a lack of exposure to malaria in the years when the disease rates went down, coupled with the insecticide resistance that increased their exposure to A. gambiae mosquitoes. “Strategies to address the problem of insecticide resistance and to mitigate its effects must be urgently defined and implemented,” they warned.

The study investigated malaria attack rates in 504 inhabitants of the village before and after the introduction of insecticide treated bed nets, between 2007 and 2010.

The findings of the study led by Dr Jean-Francois Trape according to experts were very disquieting, largely because the durable, insecticide-treated bed nets have thus far been deemed the cheapest and most effective weapon to combat malaria.

With the nets having been widely distributed to people in Africa and other countries over the last few years, the World Health Organization has been reiterating that the proper deployment of these nets can reduce malaria rates by as much as 50 percent.

The authors are worried that their study has implications beyond Senegal. “These findings are a great concern since they support the idea that insecticide resistance might not permit a substantial decrease in malaria morbidity in many parts of Africa,” they said.

In the war against malaria, the cheapest and most effective weapon to date has been the long-lasting insecticide-treated bed net. Over the last few years the nets have been widely distributed in Africa and elsewhere.

In a related development the United States has allotted $189 million to support Africa’s fight against malaria, a disease regarded as the number one killer on the continent.

A total of 14 countries in Africa would be benefiting from the support which seeks to expand the indoor residual spraying programme for malaria prevention being implemented by US.

The programme is being implemented by the U.S. Agency for International Development while the Centres for Disease Control and Prevention, would provide technical and financial support for building the capacity of the health ministries and national malaria control programmes in Angola, Benin, Burkina Faso, Ethiopia, Ghana, Liberia, Madagascar, Mali, Mozambique, Nigeria, Rwanda, Senegal, Zambia and Zimbabwe.

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Posted by AfricaSTI on August 21, 2011. Filed under Health, Senegal. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry