Female Aedes aegypti mosquito while getting a ‘blood meal’.
The U.S. Food and Drug Administration on Wednesday requested that Miami-Dade County and Broward County in Florida temporarily stop accepting blood donations after four people in the area inexplicably contracted Zika infections.
The four cases were not immediately explained by travel to an area with an outbreak of the mosquito-borne virus, nor by having sex with an infected person – the two main ways US residents become infected. This has led some health officials to speculate, but not confirm, that local mosquitoes may be transmitting the virus to residents in those areas.
If local transmission is confirmed, the cases would represent the first outbreak of Zika in the continental US. It would also suggest that Zika infections, which are associated with birth defects in pregnant women but otherwise mild illnesses in adults, may be spreading unnoticed among Floridians. It is therefore conceivable that residents could unknowingly donate blood that contains infectious viruses.
To protect blood recipients from Zika, the FDA called on the two counties, as well as neighboring counties, to halt donations until health officials could screen blood donors for Zika or set up technology that would inactivate Zika viruses in donated blood.
Infectious disease experts from the CDC and NIH have predicted small, contained local Zika transmission in the continental US, particularly Florida. So far there have been 1,658 Zika cases, almost all travel-related, in the US. Florida has reported 381 cases statewide.
“At this time, we are not recommending a travel restriction to South Florida,” said U.S. Surgeon General Vivek Murthy. The Wall Street Journal Thursday. For now, residents of the affected areas, especially pregnant women, are advised to take precautions to avoid being bitten by mosquitoes.