Florida mosquitoes likely spreading Zika

Aedes aegypti

BAD BITE  Health officials suspect Aedes mosquitoes (Aedes aegypti shown) in Florida have infected four people with the Zika virus.

James Gathany/CDC

Mosquitoes in Miami now appear to be transmitting Zika virus.

Four cases of Zika infection in Florida were probably acquired via the bite of local mosquitoes, the state’s health department announced July 29. These are the first cases of local transmission of the virus in the continental United States.

“Zika is now here,” Tom Frieden, director of U.S. Centers for Disease Control and Prevention, said in a news briefing July 29.

No mosquitoes trapped yet have tested positive for the virus, but officials suspect Aedes aegypti mosquitoes in a several-block area in north Miami are to blame. “Everything we’ve seen so far indicates that this is mosquito-borne transmission,” Frieden said.

Florida’s small cluster of cases does not necessarily foreshadow an epidemic, he said. The four infected people probably were bitten in early July. Since then, Florida has stepped up efforts to stamp out mosquitoes — including going door-to-door to get rid of standing water and spraying insecticides by truck and by people on foot.

“We believe that widespread transmission in the continental U.S. is unlikely,” Frieden said. “But it’s not impossible.”

Two other mosquito-borne diseases, dengue and chikungunya, have spread locally in Florida in the past. But, Frieden said, those diseases generally dead-end after infecting just one person. 

Meghan Rosen is a staff writer who reports on the life sciences for Science News. She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.

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