Four locally transmitted cases of the Zika virus have been discovered north of Miami, sparking concerns for people who are traveling to Florida and igniting worry that it could spread further in the U.S. mainland.

Officials believe someone contracted the mosquito-borne virus while out of the country, and was then bitten by a mosquito that bit four others in Florida, spreading the virus.

Zika is already present in New Jersey, so that type of transmission in theory could happen here as well. A total of 69 cases of travel-related Zika have been reported by the Health Department. Bergen And Passaic counties have the most cases with 14 apiece.

As News 12 has reported, outbreaks of the virus are active in Central and South America, and local mosquito-borne transmission of Zika has been reported in Puerto Rico, the U.S. Virgin Islands, and American Samoa, according to the Centers for Disease Control and Prevention. The virus causes fever, rash and pain, and it also causes severe birth defects when pregnant women contract the virus through mosquito bites or from a partner.

"The critical issue is to make sure that those local cases don't become disseminated and don't become sustained and the way you do that is with very aggressive mosquito abatement programs," says Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID).

Spraying for mosquitoes in targeted neighborhoods has already begun in New Jersey. But since there is no cure for Zika or the serious birth defects it causes, precautions like the use of bug repellent is recommended, especially for women who are planning to have a child. The same warning goes for men, as Zika can be sexually transmitted.