The US Centers for Disease Control (CDC) has identified a potential risk of Zika virus transmission from donor sperm in the Florida tri-county area.
Zika virus infection during pregnancy can cause brain abnormalities, microcephaly, and congenital Zika syndrome. Now officials have found more people in the area may have been infected by Zika than previously thought, and could have donated infected sperm.
Dr Matthew Kuehnert, director of the CDC's Office of Blood, Organ and Other Tissue Safety, said at a news briefing that 'there have been no suspected cases from donor semen' but that an analysis found 'cases of people who are residents of Palm Beach County and Broward County in which the exposure was uncertain'.
Florida's tri-county area includes Miami-Dade, Broward and Palm Beach. Miami became the first US city to experience active transmission of Zika virus in 2016, and the Florida Department of Health estimated that 280 people acquired the virus in the state, most of them in Miami-Dade County.
However, officials could not determine where infection had originated in an additional 38 cases, leading them to believe more people may have been exposed as many local residents cross county lines on a daily basis.
There are 12 sperm donor banks in the tri-county area. The FDA had previously warned sperm banks not to accept donors who have been diagnosed with Zika, or been to a Zika-endemic area in the past six months, as Zika virus can remain in semen for this duration of time. However, while blood can be easily screened for Zika, there is no straightforward test for Zika in semen, and infections can go undiagnosed because people have mild or no symptoms.
The CDC's warning extends the timeframe of potential concern from 29 July 2016, when officials first identified local transmission of Zika in that area of Florida, back to 15 June 2016, the date of the agency's first Zika travel advisory regarding pregnant women.
'When semen is donated, it can be stored frozen for significant periods of time, and that doesn't necessarily inactivate the Zika virus,' said Dr Peter Marks, director of the FDA's Centre for Biologics Evaluation and Research.
'If you're a woman who is considering using donated semen samples that have been collected during this period of time, you need to have a conversation with your provider about potential benefits and risks of using it,' he advised.