French scientists are developing an insecticide designed to destroy mosquito larvae before the mosquitoes are able to hatch and transmit Zika. The trials are against the mosquito Aedes aegypti, which is the main vector for Zika virus disease.
The study, performed at the University of Notre Dame’s Eck Institute for Global Health, is using novel larvicdes. In laboratory tests the lead product has killed 100 percent of mosquito larvae in tests under controlled conditions. The next step is to carry out tests in the general environment, for this a site in Belize has been selected.
Commenting on the research, lead scientist Professor Molly Duman Scheel said, in an interview with Laboratory Manager, that her research facility has a long history of mosquito research, especially with vector control.
The use of a larvicide has come from mathematical models to better understand the dynamics of infectious disease transmission and control. This is based on earlier work with mosquitoes that carry the malaria parasite (a paper titled “The epidemiology of residual Plasmodium falciparum malaria transmission and infection burden in an African city with high coverage of multiple vector control measures”).
The new research is progressing well, although it has yet to be published in a peer reviewed journal.
The issue of larvicides is controversial in some quarters. In Brazil, for example, there was a rumour that the use of a larvicide, rather than Zika itself, was causing microcephaly. In response to this a team of World Health Organization (WHO) scientists reviewed data on the toxicology of the leading larvicide — pyriproxyfen. This review found no evidence that the larvicide altered the course of pregnancy or adversely affected the development of a fetus.
WHO remains of the view that larvicides are an important weapon in dealing with mosquito related diseases. This is particularly so in cities with no piped water and where people tend to store drinking water in outdoor containers. This is because such sources of water function as ideal breeding grounds for mosquitoes. Larvicides like pyriproxyfen are sometimes used in water storage containers to kill the mosquito in its larval stage.
Where the Notre Dame’s Eck Institute for Global Health research comes in is in reviewing the effectiveness of this practice and in determining whether it can be rolled out on a larger scale, such as adding the larvicide to ponds.
