Health officials in Florida are bracing for the results of an investigation that could add the United States to the list of nations where the Zika virus is a threat. Four possible cases of local transmission have been identified.

CCTV America’s Nitza Soledad Perez reports from Miami.

Those patients do not appear to have traveled to a Zika-affected country, which, if confirmed, could mean that Zika has officially arrived in the United States.

Florida ranks second in overall U.S. Zika cases, after New York, with more than 380 at the last count, and more than 50 of them involve pregnant women.

As a caution, the federal government is advising South Florida blood banks to stop all collections until donated blood can be tested.

Authorities are going door-to-door in suspect neighborhoods, delivering information, inspecting homes and trapping mosquitoes for testing.

Scientists are also surveying people who live within a 140 meter (459 feet) radius of the cases – the flying range of a mosquito.

In addition, they request urine samples to test for possible new cases. But Florida is running short of funds to deal with the issue.

Florida has received more than $2 million of Zika-specific federal funds, and the promise of at least $5.5 million more. But the U.S. Congress adjourned for summer recess without acting on an Obama administration request for nearly $2 billion in additional aid for states.

Local officials are doing what they can to educate the public.

To date, no mosquitoes in South Florida have tested positive for Zika. But the Aedes mosquitoes known to spread the virus are common in the region. And now, with these new infections, health officials say it may be just a matter of time.