The Florida health department said late Tuesday that it is investigating what could be the first case of locally spread Zika virus in the continental United States.
In a brief statement, the department said it is "actively conducting an epidemiological investigation" of a non-travel-related case in Miami-Dade County in collaboration with the Centers for Disease Control and Prevention. The statement said additional details would be shared as they become available.
The CDC said the state is the lead on the case, which involves someone with no travel history to a country with active Zika transmission.
Florida, Texas and other parts of the Gulf Coast are considered at highest risk of local transmission of the mosquito-borne virus. The region is home to the Aedes aegypti mosquito, the primary vector for transmitting Zika. Florida already has 326 travel-related Zika cases, including 88 in Miami-Dade, the most in the state.
Health officials have been bracing for local spread of Zika across the South and parts of the Southwest during the peak summer months. Florida Gov. Rick Scott has repeatedly appealed to the Obama administration for additional resources so his state could be prepared when cases began to surface.
The virus can also be spread through sexual contact, but the health department statement did not specify how the individual involved was believed to have been infected.
The statement said the department would be providing Zika prevention kits and repellent in the county and in the area of investigation.
Congress left town last week without finalizing legislation to combat the virus, much to the dismay of public health officials, infectious disease experts and children's advocates. Health officials have warned that the $589 million the Obama administration redirected from fighting Ebola to combating Zika earlier this year is insufficient and that lawmakers' failure to approve new funding is holding up work on a vaccine, improved diagnostics to test for Zika and research on the long-term consequences of the virus during pregnancy.
Health and Human Services Secretary Sylvia Burwell and Office of Management and Budget Director Shaun Donovan wrote Republican leaders last week saying that the inaction on a Zika package "will significantly impede the Administration's ability to prepare for and respond to a possible local transmission in the United States and Hawaii and address a growing health crisis in Puerto Rico."
The Florida news comes one day after Utah officials said they were investigating possible person-to-person transmission from an elderly man to a caregiver.
Most people infected with Zika have no symptoms or only mild ones. But the virus can cause severe birth defects in pregnant women, including microcephaly, a rare condition characterized by an abnormally small head and serious brain damage.