Combining insecticide sprays and bed nets 'no more effective' in cutting malaria

December 08, 2014

There is no need to spray insecticide on walls for malaria control when people sleep under treated bed nets, according to new research.

Use of insecticide sprayed on internal walls, when combined with insecticide-treated bed nets in homes, does not protect children from malaria any more effectively than using just insecticide-treated bed nets, the research led by Durham University and the Medical Research Council's Unit in The Gambia found.

The researchers said this was important as insecticide-treated nets and insecticide sprayed on walls are commonly used for controlling malaria and in many places both interventions are used together.

Malaria is spread by mosquitoes that bite inside houses at night time so scientists working in The Gambia looked to see if children sleeping in homes that had the walls sprayed with the insecticide DDT, and also slept under an insecticide treated bed net, were sick less often with malaria than those who just used a bed net.

The research, funded by the Medical Research Council (MRC), UK, is published today Tuesday, December 9, in The Lancet.

The study took place in 96 villages in The Gambia and 8,000 children were checked for malaria over two years.

At the end of the study there was no difference in the numbers of cases of malaria where the combination of spraying and nets was used compared with the use of bed nets alone.

Using mosquito traps in houses the researchers confirmed that insecticide sprayed on walls had no extra effect in repelling or killing mosquitoes.

As a result the researchers recommend that DDT, or any other insecticide, is not used for spraying on walls in areas where there is high use of long-lasting insecticide nets and low to moderate numbers of malaria cases.

For the moment every effort should be made to make sure there is a higher use of bed nets, rather than on spraying insecticide on walls, the scientists said.

This will help keep costs down and increase the number of people who are protected, they added.

In 2010 and 2011, the Durham-led researchers monitored 8,000 children aged six months to 14 years, for signs of malaria. They found no difference between clinical episodes of malaria in children where bed nets were used to protect them against mosquitos when compared to children where bed nets were used in combination with DDT sprayed on walls.

As bed net use is high - at over 80 per cent - in this area of The Gambia, the researchers believe that concentrating resources on additional bed nets and encouraging the correct use of these in other areas, would be a more cost-effective solution to combatting malaria.

Professor Steve Lindsay, in the School of Biological and Biomedical Sciences, at Durham University, said: "There has been a gradual decline in malaria in The Gambia, linked to wider distribution of long-lasting insecticide treated bed nets."

"Our research looked at whether or not a combination of bed nets and spraying homes with insecticide could reduce further cases of malaria, but we found no evidence that this was a more effective method of combatting mosquitos than using treated bed nets on their own.

"Our advice is that high bed net coverage is sufficient to protect people against malaria in areas of low or moderate transmission.

"However, where net coverage is low, the cost-effectiveness of additional control using indoor residual sprays such as DDT should be considered."
-end-
The study was carried out in collaboration with the MRC Unit in The Gambia; the National Malaria Control Programme, The Gambia; and the London School of Hygiene and Tropical Medicine.

The researchers added that it was important that more studies were carried out in areas with differing transmission rates of malaria to further assess the effectiveness in these areas of combining insecticide sprays with treated bed nets.

Durham University

Related Malaria Articles from Brightsurf:

Clocking in with malaria parasites
Discovery of a malaria parasite's internal clock could lead to new treatment strategies.

Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the UmeƄ University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.

Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.

New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.

Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.

Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.

Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.

Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.

Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.

The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.

Read More: Malaria News and Malaria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.