Florida Zika cases 'came from mosquitoes in Miami area'
Florida appears to have the first cases of Zika transmitted by mosquitoes on the US mainland, according to the state governor.
Rick Scott said during a news conference in Orlanda that no mosquitoes in the state have tested positive for Zika, but one woman and three men in Miami-Dade and Broward counties probably contracted the virus through mosquito bites.
More than 1,650 Zika infections have been reported in the US, but the four patients in Florida would be the first not linked to travel outside the US mainland.
Mr Scott said health officials believe the infections occurred in a small area just north of central Miami.
Zika primarily spreads through bites from tropical mosquitoes. In most people, the virus causes only mild illness, but infection during pregnancy can lead to severe brain-related birth defects for the foetus.
Miami-Dade County has reported 96 Zika cases, the most in Florida so far, and Broward County has 55. Until Friday, health officials said all the cases stemmed from international travel.
Zika is mainly spread by mosquitoes and can also be sexually transmitted. There is no vaccine.
The tropical mosquito that spreads Zika and other viruses is found in the southern US. While health officials have predicted that mosquitoes in the continental US would begin spreading Zika this summer, they have also said they expect only isolated clusters of infections and not widespread outbreaks.
The US Food and Drug Administration has told blood centres in Miami-Dade and Broward counties to suspend collections until they can screen each unit of blood for the Zika virus with authorised tests.
The FDA also has recommended that neighbouring counties implement the same precautions, and visitors to south Florida in the last month are urged to defer donations as well.
The FDA previously advised US blood banks to refuse donations from people who had recently travelled to areas outside the country that have Zika outbreaks.
Florida's main supplier of blood, OneBlood, said it was working as quickly as possible to comply with the FDA's "unanticipated" request and would start testing all its collections for Zika straight away.
Mr Scott said: "This is not just a Florida issue. It's a national issue - we just happen to be at the forefront."
Health officials believe the infections occurred in the popular Wynwood arts district, he added.
It is the only part of the state being tested for potential local transmissions of Zika, he said. Women in the area who are pregnant or thinking about becoming pregnant are urged to contact their doctors and the county health department for Zika prevention kits.
Federal health officials have not recommended that pregnant women avoid travel to south Florida.
US surgeon general Vivek Murthy said: "There are a series of factors we'll have to look at. The number of cases, the relationship in geography of those cases, how closely linked they are in time, as well as a series of other factors that we will use to determine what recommendations we issue in terms of travel guidance."
Orange County mayor Teresa Jacobs said potential visitors to Florida should not think twice about going to the Sunshine State.
Ms Jacobs, whose jurisdiction covers the major theme parks in the Orlando area, said Florida's attractions have some of the best mosquito control measures that she knows of and the parks are safe.
But she encouraged visitors to take precautions such as wearing insect repellent and getting rid of any standing water.