A second case of Zika virus possibly acquired locally is being investigated in Florida, just days after the first potential case was announced in Miami, officials said Thursday.
Until now, there have been hundreds of cases of Zika virus in Florida but all involved people who were infected while traveling to areas where the mosquito-borne virus is spreading.
If confirmed, the Florida infections mark the arrival of the homegrown virus on the US continent for the first time.
Zika can be spread by mosquito bites or by sexual contact, and can cause birth defects if women are infected while pregnant.
“The Florida Department of Health announced that it is conducting an epidemiological investigation into a possible non-travel related case of Zika virus in Broward County,” said a statement, referring to the county just north of Miami, which includes Fort Lauderdale and Hollywood.
Health officials are working with “mosquito control to ensure trapping, reduction and prevention activities are conducted in the area of investigation,” the department added.
The department urged people living in the area and visiting to respond to requests for blood and urine samples.
“These results will help the department determine the number of people affected,” it said.
Regarding the possible non-travel case of Zika in Miami-Dade county, a health department spokeswoman told AFP the investigation is ongoing, and that sexual transmission “related to travel has not been ruled out.”
Few other details have been released about that possible case, which was first announced Tuesday. The Zika infection has been confirmed, but the mode of transmission has not.
As of Thursday, mosquitoes in the Miami area have tested negative for Zika, the spokeswoman added.
Zika virus has spread through dozens of countries in Latin America. One way it could arrive in the United States is if a person who was infected with Zika while traveling elsewhere comes into the country and is bitten by a mosquito, which then bears Zika and bites another person, spreading the infection.
As of mid-July, there have been 1,306 cases of Zika in the continental United States, nearly all involving people who had traveled to areas in Latin America and the Caribbean basin that are affected by the current outbreak.
Fourteen of the cases were transmitted by sexual contact between those who had traveled and their US-based partners.
Earlier this week, a case emerged in Utah in which a caregiver appeared to have been infected by an elderly patient, though the exact route of transmission remains unknown.
Zika is a concern because if a pregnant woman is infected, she faces a higher risk of bearing a child with microcephaly, in which the skull and brain are malformed and smaller than normal.
President Barack Obama spoke by phone with Florida Governor Rick Scott on Wednesday and said the US Centers for Disease Control and Prevention would be sending another $5.6 million to Florida for Zika funding, in addition to $2 million in federal funds the southern state has already received.