2 Florida counties halt blood donations, as evidence mounts for local Zika transmission

The U.S. Food and Drug Administration has requested that two Florida counties — Miami-Dade and Broward — postpone blood donations as officials investigate the possible local transmission of Zika virus, which is linked to birth defects.

The temporary ban arrived Wednesday, the same day Florida health officials announced an investigation into two cases of the mosquito-borne disease that do not appear linked to travel. Last week, the Florida Health Department reported two other cases of suspected transmission by local mosquitoes.

Surveillance officials will head door-to-door over the next few days to collect samples and provide information on the outbreak. The virus is primarily spread by mosquitoes, but rare cases of sexual transmission have been recorded too. As of yesterday, more than 1,400 cases of Zika had been reported in the U.S., but only 15 involved sexual transmission.

To officially confirm local transmission, these disease detectives “must survey households and neighbors within a 150-yard radius around the residence of the person who has Zika, which constitutes the flying range of the mosquitoes that carry the virus,” according to Reuters.

For months, models have predicted Florida and Texas as the most at-risk locations for local Zika outbreaks, a point echoed by officials at the Centers for Disease Control and Prevention. In the past few decades, South Florida has been struck by small outbreaks of similar tropical viruses, such as chikungunya and dengue. So far this year, Florida has recorded 383 cases of Zika virus, with 55 cases involving pregnant women.

“At this time, state and local officials in Florida are leading these investigations to determine how transmission occurred,” a senior CDC spokesperson wrote in an email to NewsHour. “CDC has been working with state, local, and territorial health officials to prepare for the possibility of locally transmitted Zika infection in the United States.”

The FDA is also recommending that blood banks across the country deny donations from people who have traveled to Miami-Dade or Broward counties within the last four weeks. A blood screening test for Zika virus has been available since late March, but Florida Surgeon General Celeste Philip only mandated its use at blood banks earlier this week.

Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, advised blood banks in neighboring counties to implement the test too. However, he stopped short of a mandate for blood collection establishments in those regions or elsewhere in the U.S.