A rare case of the Zika virus being transmitted through sex, not a mosquito bite, has been reported in the US.
The BBC reports that the Centers for Disease Control (CDC) said a patient infected in Dallas, Texas, is likely to have been infected by sexual contact.
The person had not travelled to infected areas but the partner had returned from Venezuela.
Zika is carried by mosquitoes and has been linked to thousands of babies being born with underdeveloped brains.
It is spreading through the Americas and the World Health Organization has declared the virus a global public health emergency.
This case in Dallas would be the first known infection to take place in the mainland US, though Texas has seen seven other Zika cases all related to foreign travel.
A principal deputy director for CDC, Anne Schuchat, said this was the first case it had dealt with involving a “non-traveller”.
“We don’t believe this was spread through mosquito bites, but we do believe it was spread through a sexual contact.”
A statement issued by the CDC said the best way to avoid Zika virus infection was “to prevent mosquito bites and avoid exposure to semen from someone who has been exposed to Zika”.
The case is “significant” if it was definitely transmitted through sexual contact.
“This significance is parallel with the HIV/Aids case. It’s worse in some ways, because there are two modes of transmission,” a senior fellow for public health at the UN Foundation, Alaka Basu, explained.