In a highly unusual travel warning, health officials advised pregnant women to avoid Miami's Wynwood neighborhood where mosquitoes are apparently transmitting Zika directly to humans.
The US Centers for Disease Control and Prevention (CDC) warned pregnant women Monday to avoid the impacted area that is just north of downtown Miami and told couples who have been there recently to put off having children for at least two months.
Expectant mothers should get tested for the virus if they have visited Wynwood since mid-June.
Government health officials announced last Friday that mosquitoes have apparently started spreading Zika on the US mainland, citing four cases they strongly believe were caused by bites.
Ten more cases were announced Monday, even though Florida authorities have yet to find any mosquitoes actually carrying the virus. All 14 cases are thought to have occurred in Miami's Wynwood arts district.
Zika infections in pregnant women can cause severe brain-related birth defects, including extremely small skulls. More than 1,650 cases of Zika have been reported in US states. Nearly all have been the result of travel to a Zika-stricken country or sex with someone who was infected abroad.