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Friday, March 11, 2016

The advice is right there, on the website of the Centers for Disease Control and Prevention. To avoid contracting Zika, treat your clothing with an insecticide known as permethrin or buy apparel that is already treated with it.

If you live in or plan to visit Puerto Rico, there’s just one problem with that recommendation. The Aedes mosquitoes that transmit the virus on this Caribbean island have developed resistance to permethrin. The chemical isn’t working here.

And it’s not just Puerto Rico. Other places, including parts of Mexico, are reporting that Aedes mosquitoes are no longer quelled by permethrin, said Roberto Barrera, chief of entomology and ecology activity at the CDC’s dengue branch.

“It’s probably not going to work well in the places where it has been used as the main insecticide for many years,” Barrera told STAT in a recent interview. “You’re not going to be able to kill off most of the mosquitoes.”