Zika found in South Beach, Fla.

Associated Press

MIAMI

South Beach has been identified as a second site of Zika transmission by mosquitoes on the U.S. mainland, and containing it there will be difficult because high-rise buildings and strong winds make it impractical to spray the neighborhood from the air, officials said Friday.

Five cases of Zika have been connected to mosquitoes in Miami Beach, bringing the state’s caseload to 36 infections not related to travel outside the U.S., Florida’s governor and health department announced Friday.

The discovery prompted the U.S. Centers for Disease Control and Prevention to announce that it was expanding its travel warning for pregnant women to include an area in Miami Beach known for nightclubs, pedestrian thoroughfares and beaches.

Zika infection can cause severe brain-related birth defects, including a dangerously small head, if women are infected during pregnancy.

The virus’s apparent spread from a Miami neighborhood popular for day trips to the South Beach streets where many tourists sleep has rattled the tourism industry, even in the slower summer season.

Gov. Rick Scott has directed Florida’s health department to offer mosquito spraying and related services at no cost to Miami-Dade County’s hotels, restaurants and tourist attractions. More than 15.5 million people made overnight visits to Miami and nearby beaches in 2015, with an impact of $24.4 billion, according to figures from the Greater Miami Convention and Visitors Bureau.

The CDC previously warned pregnant women to avoid the Wynwood arts district in Miami. In its statement Friday, the agency said pregnant women may also want to consider postponing nonessential travel throughout Miami-Dade County if they’re concerned about potential exposure to the mosquito-borne virus.