U.S. Zika cases may be transmitted through sex
Reports suggest far higher risk than previously thought
Health authorities in the United States said they were investigating 14 new reports of the Zika virus possibly being transmitted by sex, including to pregnant women. If confirmed, the unexpectedly high number would have major implications for controlling the virus, which is usually spread by mosquito bites.
Scientists had believed sexual transmission of Zika to be extremely rare. Only a few cases have ever been documented. While the U.S. health authorities emphasized that the new reports were preliminary, with just two confirmed so far, the spectre of so many cases — all within the continental United States — brings fresh complexity to the medical mystery of Zika.
The virus is suspected to cause birth defects and a rare condition of temporary paralysis.
“We were surprised that there was this number,” said Dr. Anne Schuchat, the deputy director at the Centers for Disease Control and Prevention, in an interview. “If a number of them pan out, that’s much more than I was expecting.”
Officials at the CDC reported the potential cases in an alert to health care providers on Tuesday. In addition to the two confirmed cases, in four others the preliminary evidence suggests Zika, but the virus has not been confirmed, the CDC said.
The eight other cases are still being investigated. In all the cases, women in the continental United States had sex with men who had travelled to countries where the virus is circulating. The travellers reported symptoms within two weeks of the onset of their non-travelling female partner’s symptoms.
The agency did not say exactly how many of the women were pregnant, but it reiterated its recommendation that people returning from Zika-infected areas use condoms or abstain from sex for the duration of their partner’s pregnancy. The alert said there was no evidence that women could transmit Zika virus to their sex partners, but added that more research was needed to be sure.
This country has become a laboratory, of sorts, to test the sexual transmission of Zika, as scientists race to understand the disease.
Transmission by mosquitoes is not yet happening in the continental United States because it is still winter, so health officials believe that any infection of a U.S. resident who has not travelled to a place where Zika is circulating has likely been contracted through sex.
“In the U.S. where most people aren’t travelling to these areas, we may be able to uncover the potential risk,” Schuchat said.
In all, the United States has around 90 cases of Zika, according to the most recent count from the CDC.