A 16th Zika infection has been found in a Miami neighborhood, according to local health officials.

The Florida Health Department said it discovered a new non-travel related case of Zika in a one-square mile area of Miami.

"This individual was tested as one of the 26 close contacts around the two original cases," the department said.

The cases, which stem from mosquito bites, are in the Miami neighborhood of Wynwood, which is about a mile north from downtown.

Health officials say they believe that the outbreak, which is the first in the continental U.S., is limited so far to the neighborhood.

"One case does mean active transmission is taking place and that's why the department conducts a thorough investigation by sampling close contacts and community members around each case to determine if additional people are infected," the department said.

Florida officials are going beyond the neighborhood to see if the outbreak is spreading, with officials saying they have tested 11 individuals with no positive results.

They added that the department has tested people within a 10-block radius of the Wynwood neighborhood.

More than 1,800 cases of Zika have been found in the continental U.S., but the vast majority are people who got it from another country or territory.

The virus creates a mild illness in most people, but it also can cause the birth defect microcephaly, which causes babies to be born with underdeveloped brains and abormally small heads.