Scientists say a New York City woman infected her male partner through sex, marking the first time female-to-male transmission has been documented.
Zika virus is most commonly spread by mosquitoes, but doctors have worried about the germs passing from mother to baby, through blood transfusions and via sexual intercourse.
In the U.S., for example, health officials confirmed the country’s first case of Zika virus transmitted through sex. A woman was infected after having sex with her partner who had just returned from a country battling the mosquito-borne virus.
This time around, the Centers for Disease Control and Prevention says a woman in her 20s had sex without a condom with a male partner on the day she returned from a country grappling with Zika virus.
She had a headache and cramping, along with numbness and tingling in her hands and feet. By day three, experts found Zika virus in her blood and urine samples.
Seven days after the couple had sex, her partner ended up with a fever, rash, joint pain and red, runny eyes. Three days after that, doctors confirmed he had contracted Zika virus, too.
He had not travelled outside of the United States this year.
“All previously reported cases of sexually transmitted Zika virus infection have been spread from men to their sex partners,” the CDC said in its advisory.
Its warning all pregnant women who have sexual partners who have travelled to or lie in areas battling Zika virus to use a condom – or “barrier methods” – when they have sex or to avoid sex during pregnancy.
“Although no cases of woman-to-woman Zika transmission have been reported, these recommendations now also apply to female sex partners of pregnant women,” the CDC warned.
Like Dengue, West Nile and Yellow fever, Zika virus is a mosquito-borne tropical disease, meaning they transmit the disease to humans.
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In short, mosquitoes draw blood from the infected animal then re-inject the blood – with the virus in tow – into others at their next meal.
Health officials in El Salvador, Brazil, Jamaica, Ecuador, Honduras and Colombia told residents to stave off pregnancy until as far ahead as 2018 as doctors better understand if the infection tampers with brain development in infants.
So far, it’s been linked to a 20-fold increase in a rare defect called microcephaly in babies, in which the newborns are born with irregularly small heads and underdeveloped brains.