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The Zika virus has been locally transmitted in the United States for the first time

Two small counties in Florida are the first places in the United States where Zika has been transmitted locally.

The first cases of Zika transmitted within continental United States were discovered Friday, infecting a woman and three men in Florida — and the number of cases in the area could continue to grow.

The outbreak occurred in the Miami-Dade and Broward counties, across a one square-mile radius. The Florida Department of Health announced that although no nearby mosquitoes have tested positive for Zika, the virus was locally contracted. Blood donations have halted in the region, and local authorities are going door-to-door asking for urine samples to see how far the virus has spread.


"They are all active Zika cases, but have not exhibited symptoms to be exhibited to the hospital," Gov. Rick Scott said in a press conference. "The Department of Health is aggressively testing people in the affected area to ensure there are no other cases of this virus."

The virus, which was originally discovered in 1947, has recently made headlines for outbreaks in parts of South America — particularly Brazil. Zika is most commonly transmitted through mosquitoes, but can also be spread through bodily fluids and sexual activity. Because 80 percent of Zika patients don't show any symptoms, it can be difficult to gauge who else in the area may have contracted the disease.

There have been a total of 386 Zika cases in Florida, all of which involved patients who had traveled to affected countries. The new cases are believed to be the first cases contracted locally.

The virus became a household name after an outbreak in Brazil in late 2015 yielded sinister effects, particularly birth defects in babies born to women who contracted Zika before or during pregnancy.

On February 1, following the outbreak in Brazil, the World Health Organization announced a public health emergency. Currently, over 60 countries and territories have seen transmissions of the virus within their borders. There is no cure of vaccine for the virus at the moment, but the sickness caused by Zika usually comes and goes in ways similar to a flu. Hospitalization and death are uncommon.

As of Thursday, the CDC has reported almost 1,700 cases of Zika in the country, 15 of which were transmitted sexually. The virus has appeared in every state except for Alaska, Idaho, South Dakota, and Wyoming. Experts say those in the Southeast should continue to be vigilant during mosquito season, recommending that people wearing repellent and practicing safe sex.

Follow Adam Hamze on Twitter: @adamhamz