big problem in the Solomon Islands and a team of AITHM researchers are working to understand why insecticide treated nets are one of the most effective control strategies.
Stunning vistas, tropical climes
Scientists at James Cook University’s Australian Institute of Tropical Health & Medicine (AITHM) are working with local communities to better understand mosquito
Their research findings are significant: even though mosquitoes have changed their
In the 1960s, a malaria intervention called ‘indoor residual spraying’ – spraying the inside of homes with insecticide to kill mosquitoes – was popular in the Solomon Islands because mosquitoes typically entered homes late at night. But mosquitoes are a challenging foe, and researchers soon
“The Solomon Islands is the first country in which
Thankfully, a more effective intervention was introduced in the mid-1990s that replaced indoor residual spraying in many homes in the Solomon Islands. The big advantage of
“With the nets, the mosquito lands on the net to try to feed on the person under the net,” says Prof Burkot. “Because the net has an insecticide on it, the net kills the mosquito before the mosquito can take a blood meal.
“This is different from indoor residual spraying because when you spray insecticide on the walls of houses, the mosquito will fly into the house and immediately bite someone before resting on the insecticide sprayed wall and being killed. Essentially, the insecticide on the homeowner’s walls protects the
Here’s where it gets particularly interesting. Despite this adaptive strategy of mosquitoes to change their
Over the last eight years, researchers from AITHM have been working with local experts to understand why
“The critical thing we found was that the populations of mosquitoes are not comprised of sub-populations – there's not a group of mosquitoes
“This is significant because whenever a mosquito tries to take a blood meal it's a bit random whether it's going to feed indoors or outdoors. While it's more likely that it will feed outdoors and early, our research found that every feeding cycle a small proportion will feed indoors and late, and therefore potentially be exposed to the insecticide in a net.”
As well as reducing the number of mosquitoes,
“Using nets means the mosquitoes flying around are on average of a younger age than if you didn’t use nets,” says Prof Burkot. “If you can keep all of the mosquitoes from not living to be, say, 10 days old, then you'll have essentially have stopped malaria transmission. You don't have to kill them all – you've just got to keep them from surviving through this period of time in which the malaria parasite can be transmitted from a mosquito to a human.”
Since the introduction of
“There's a tendency to oversimplify and say bed nets won't work because these mosquitoes are ‘outdoor’ mosquitoes, but the reality is bed nets do work and you can see that in the Solomon Islands,” says Prof Burkot.