The World Health Organization on Tuesday urged countries affected by the Zika virus to think outside the box and consider the use of sterilized mosquitoes, larvae-eating fish or other techniques to wipe out pesky insects that are ferrying the disease across Latin America.
Citing Zika’s suspected link to birth defects, the global health agency said it is looking into the pros and cons of novel strategies to wipe out the Aedes aegypti mosquito, including the mass release of genetically modified males that disrupt mating patterns.
“Given the magnitude of the Zika crisis, WHO encourages affected countries and their partners to boost the use of both old and new approaches to mosquito control as the most immediate line of defense,” WHO said in a statement posted on its website.
The Zika virus is transmitting in at least 30 countries, mostly in Latin America, and has been linked to an uptick in babies born with abnormally small heads — a condition known as microcephaly. Scientists are also researching a possible link to Guillain-Barre syndrome, which can lead to paralysis.
The mosquito that carries Zika is particularly nettlesome. It hides in homes and bites during the day, and it prefers human blood, which contains proteins the female uses to develop her eggs.
Health officials in Brazil and elsewhere are still pleading with citizens to knock out areas of standing water where mosquitoes can breed, calling to the most effective way to cut the insects’ ranks.
SEE ALSO: Zika virus: U.S., Latin America declare war on Aedes mosquito
But it is also recommending new field trials to determine if genetically modified organisms (GMOs) are an effective tool.
A British company, Oxitec, last month reported that its genetically modified male aegypti, which mate with wild females to produce offspring that do not survive for long, were able to reduce wild mosquito larvae by 82 percent during trials in Piracicaba, Brazil, in 2015.
The company acknowledges that there could be unforeseen consequences of its method, “as with any new technology.” But Oxitec insists that its upside far outweighs any potential risks, and that it is targeting aegypti mosquitoes that are invasive to Latin America, anyway.
“To me, there are no drawbacks. These GMO mosquitoes are sterile males and do not persist,” said Amesh A. Adalja, senior associate at the University of Pittsburgh Center for Health Security. “If human life is the standard of value used, GMO mosquitoes are a crucial tool.”
The WHO is also studying a technique in which male mosquitoes are sterilized with low doses of radiation and then released. A female mosquito that attempts to mate will be unable to lay eggs and will not seek a new partner, due to chemical signals transmitted to it by her first partner.
“She’s done for life,” said Zach Adelman, an associate professor of entomology at Virginia Tech.
SEE ALSO: CDC chief: Link between Zika, birth defect ‘increasingly certain’
Scientists also could release mosquitoes that carry Wolbachia bacteria into the infected population. The bacteria has been shown to disrupt mating cycles and slow the transmission of a related virus, dengue, in Australia, Brazil, Indonesia and Vietnam.
Other countries are opting for biological solutions. For instance, the WHO says El Salvador is using larvae-eating fish to eliminate newborn mosquitoes from water storage tanks.
Among better-known techniques, the WHO says spraying the adult mosquito population isn’t ideal, as it can lead to insecticide resistance in some populations. Plus, the Aedes aegypti mosquito that’s plaguing Brazil and other hard-hit nations tends to set up inside buildings, so spraying is impractical.
Though Zika is not transmitting on the continental U.S., it is spreading in Puerto Rico and has come back with travelers who visit Latin America. It could become a homegrown problem, however, as summer approaches and temperatures climb.
The good news is that Aedes aegypti populations tend to be limited to a few Southern states, such as Florida and Texas, and many American homes and businesses employ air conditioning or have screened-in windows, forcing the mosquitoes outside.
However, a second species — the Aedes albopictus — is a known vector of Zika and more prevalent in the U.S.
• Tom Howell Jr. can be reached at thowell@washingtontimes.com.
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