Zika is here. Four people in the Miami area infected with the mosquito-borne virus were likely bitten by Florida mosquitoes, reports the Associated Press. These are the first cases of local transmission in the continental United States — the more than 1,650 U.S. infections were previously linked to travel or were sexually transmitted. Florida health officials said no mosquitoes in the area have tested positive for Zika, but they’re increasing testing to see if others may be infected. The Miami Herald reports that officials believe the infected mosquito struck in just a small area — about one square mile — of downtown Miami, and the city will double down on spraying.