Health News of Monday, 2 September 2013
A study has revealed that malaria control method that targets mosquito larvae and pupae as they mature in standing water could be an important supplementary measure in the fight against the disease.
The study by the London School of Hygiene and Tropical Medicine in collaboration with Durham University and other researchers was the first systematic review looking at using Larval Source Management (LSM) to control malaria, which causes an estimated 660,000 deaths worldwide every year.
The study dubbed: “Mosquito larval source management for controlling malaria (Review)”, which was published by the Cochrane Library, was made available to the Ghana News Agency on Thursday.
The study revealed that the method could significantly reduce both the number of cases of malaria by up to 75 per cent, and the proportion of people infected with the malaria parasite by up to 90 per cent when used in appropriate settings.
It said: “LSM is a method that targets immature mosquitoes found in standing water, before the females develop into flying adults that are capable of transmitting malaria.
“This is done by permanently removing standing water for example, by draining or filling land, making temporary changes to mosquito habitats to disrupt breeding, for example by clearing drains to make the water flow; or ‘larviciding’ by adding chemicals or biological ‘larvicides’ to standing water to kill larvae.
“Currently, the use of long-lasting insecticide treated bed nets and indoor residual spraying of homes are widely used for malaria transmission control and are having a major impact on the burden of the disease.”
The study, however, noted that this success is now threatened by factors such as a growing resistance to insecticides among mosquitoes.
It said complementary methods of mosquito control such as LSM might become increasingly necessary in helping tackle the disease.
The statement said some malaria-endemic countries in Sub-Saharan Africa were already implementing LSM programmes, but there was lack of consensus on how effective the method could be and in which settings it is appropriate.
A few studies have so far been conducted to rigorously evaluate the intervention.
In this review, researchers identified 13 eligible studies from countries such as Eritrea, The Gambia, Kenya, Mali, Tanzania, India, the Philippines, Sri Lanka and Greece.
The findings also suggested LSM could contribute to a reduction in the prevalence of splenomegaly in children (an enlargement of the spleen caused by repeated malaria infections).
The study said LSM could, therefore, be particularly effective in urban areas, rural areas with high population densities or obvious breeding sites like small streams or swamps, highland regions and desert fringes.
It suggested interventions such as adding ‘larvicide’ to abandoned mine pits, streams, irrigation ditches and rice paddies where mosquitoes breed, and building dams, flushing streams and removing water containers from around people’s homes.
Current World Health Organization (WHO) guidelines on the use of LSM distinguished between urban and rural areas, and WHO does not generally recommended ‘larviciding’ in rural Sub-Saharan Africa unless particular circumstances limit larval habitats.
However, the reviewers said, LSM could be an important strategy in the control of malaria and should be applied in appropriate urban and rural locations with proper management and funding.