Spraying traditional insecticides to eliminate mosquitoes has had no impact on cutting off dengue, according to the World Health Organization (WHO). With this, questions have emerged about how officials might help in stopping the current spread of Zika virus, which is also a mosquito-borne infection.
Marie-Paule Kieny, Assistant Director-General of WHO, said at a meeting on Wednesday that there is no sufficient evidence that traditional ways of fighting dengue have had any impact on dengue cases. The same challenges might apply to Zika, she said.
In particular, Kieny said using insecticides and other methods to reduce populations of mosquitoes have not been able to stop the insects from transmitting dengue. What's more, it is uncertain whether or not the same methods would work to fight off Zika.
"Certainly it is worth continuing to try to use this method for the lack of other interventions, but what the scientists said is that there is an urgent need to also put in place studies to evaluate whether it has a benefit or not," said Kieny.
Meanwhile, Jorge Kalil, the Butantan Institute Director in São Paulo, Brazil, said everything that was done in the country to control mosquitoes "apparently did not work."
"The problem right now is it's very difficult to fight the (mosquito), there are billions and billions of insects," said Kalil, who attended the three-day Zika research meeting.
Kalil suggested that Brazilian officials may try a more targeted approach, which will involve greater participation from individuals and villages. He was also hopeful that the coming winter season might help reduce the populations of mosquitoes.
Authorities in Brazil have tried to fight against mosquitoes for years. The techniques include sending off insecticide-sprayers into rural areas or dispatching advisers to help citizens identify and clear out breeding places in residences.
Kieny mentioned another possible issue: other mosquito species aside from Aedes aegypti could spread out Zika. A previous study has shown that other mosquito species can become carriers of the virus. However, it is unclear if the vector mosquitoes could transmit it and infect humans.
The three-day meeting talked about whether or not methods such as using genetically modified mosquitoes might be necessary to stop the Zika virus outbreak, but "extreme rigor" must be practiced when it comes to evaluating such tools, Kieny said.
Photo : I. Wood/ITU Pictures | Flickr
