First U.S. cases of Zika recorded

Florida mosquitoes likely culprits, health officials say

The Zika virus has arrived in the United States.

On Friday, health officials confirmed that Florida has become the first state in the continental U.S. to detect Zika infections that were likely transmitted by local mosquitoes.

Four patients, three men and one woman, are believed to have been infected in early July, Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, said Friday. None had symptoms requiring hospitalization and health officials have not disclosed whether the woman is pregnant.

Frieden said an explosive U.S. outbreak is unlikely, but he would not be surprised to see more cases. Urgent efforts are now underway to investigate the extent of the outbreak and kill the Zika-spreading mosquitoes.

“At the CDC, we’ve been saying for months . . . that individual cases and small clusters of Zika are possible in the U.S.,” Frieden told reporters in a telephone press conference.

“As we’ve anticipated, Zika is now here.”

Frieden clarified that investigators have not yet found the virus in local Aedes aegypti mosquitoes — a surprisingly difficult task that he likened to “finding a needle in a haystack.” But all signs point to the conclusion that mosquito-borne transmission has occurred, he said.

While the Florida patients reside in different counties — Miami-Dade and Broward, which contains Fort Lauderdale — investigators are homing in on the Wynwood district, a popular arts hub north of downtown Miami.

At least two people were infected near each other in this area and investigators are focusing on it as a priority hot spot, since the Zika-carrying mosquito flies only up to 150 metres in its lifetime, Frieden said.

He added that the CDC is not recommending travel restrictions to that area, though that could change if cases continue to emerge even after rigorous mosquito-control efforts have been deployed.

Once thought to only cause mild disease, Zika has now been linked to serious neurological disorders, including birth defects and microcephaly, a condition associated with underdeveloped brains.

The Florida cases come as no major surprise to U.S. health officials, who have been warning for the past year that Zika’s arrival was inevitable in areas where the Aedes aegypti mosquito is found.

Florida, a top tourist destination for Canadians, has long been suspected as Zika’s likeliest gateway into the continental U.S.

Miami is one of the nation’s busiest ports of entry from countries where Zika is spreading and other viruses transmitted by the Aedes aegypti, such as dengue and chikungunya, have popped up in Florida before. The state has also seen the highest number of cases imported into the U.S., with 383 infections linked to travel.

On Friday, the White House called the developments in Florida a “wake-up call” and blasted Congress for stalling a $1.9 billion (U.S.) proposal to fund an emergency response to Zika.

That money would have gone a long way toward helping local counties prepare for Zika’s arrival, said Peter Armbruster, a mosquito researcher with Georgetown University.

Armbruster acknowledged that it’s impossible to predict whether other Florida counties — and other states — might soon start seeing locally transmitted Zika cases, too.

“That’s the million-dollar question,” he said. “It could just be an isolated outbreak; it could be that we will see it spread. The message for now is that people should be vigilant, but not panic.”