A new report from France suggests that the Zika virus can be transmitted through oral sex.
Zika is typically spread through the bite of the Aedes Aegypti mosquito, but the new case adds to building evidence that the virus may be transmitted through sexual contact more readily than thought.
Zika symptoms are typically mild in most people. However, the virus can cause a catastrophic birth defect known as microcephaly in babies born to women who become infected while pregnant. These infants are born with abnormally small heads and underdeveloped brains.
In the face of the growing reality of sexual transmission of Zika, UN health officials announced updated guidelines this week. The advisory urges that women planning to become pregnant wait at least eight weeks before trying to conceive if they or their partner live in -- or are returning from -- areas where the Zika virus is active. The guidelines had previously recommended a four-week waiting period.
And if the male partner has had symptoms of Zika infection, couples should wait six months before trying to have a baby, the World Health Organization officials added.
In the new report, doctors said a 24-year-old woman in Paris came down with Zika symptoms after having sex seven times with a 46-year-old man. The man had developed Zika symptoms just before leaving Brazil and arriving in Paris last February.
Each time, the couple had vaginal sex without ejaculation and oral sex with ejaculation, according to the report.
Dr Yazdan Yazdanpanah, report co-author and an infectious disease specialist at the National Institute of Health and Medical Research in Paris, told The New York Times that the couple was using oral sex as a method of birth control.
The woman became sick shortly afterwards, and both she and the man were tested for presence of the Zika virus, according to the report.
The man had high levels of the virus in his semen and urine, but none in his blood or saliva. The woman had the virus in her urine and saliva, and antibodies to the virus in her blood. However, the doctors noted that they found no sign of Zika in a vaginal swab taken from the woman.
The French doctors added they can't rule out vaginal transmission or even infection during deep kissing, since the man's saliva was not tested while he had symptoms.
The report was published June 2 in the New England Journal of Medicine.
The vast majority of Zika infections have occurred in Latin America, with Brazil the hot zone with an estimated 5 000 cases of microcephaly. There have been no reports of Zika-induced microcephaly contracted in the United States. But two babies have been born in the United States with the birth defect after their mothers contracted the virus while traveling during pregnancy in countries where Zika is active.
And US health officials have said they expect to see Zika infections in Gulf Coast states such as Florida, Louisiana and Texas as the summer mosquito season picks up.
Earlier this month, US health officials reported that the number of pregnant women in the United States infected with the Zika virus had tripled because cases were now being counted in a more comprehensive way.
So far, an estimated 280 infected women are being followed in the United States and its territories, according to two registries that have been created by the US Centers for Disease Control and Prevention.
Previously, only cases of pregnant women who had Zika-related symptoms or pregnancy complications were being tallied, CDC officials said. But recently published reports have found that some pregnant women show no symptoms of Zika infection, yet still give birth to babies with microcephaly.
To limit any potential spread of Zika virus via mosquitoes, health officials on the federal, state and local level are deploying a three-pronged strategy: improving mosquito control; expanding their ability to test for Zika; and urging the public to protect themselves against mosquitoes.
Women of child-bearing age who live in an active Zika region should protect themselves from mosquito bites by wearing long-sleeved shirts and long pants, using mosquito repellent when outside, and staying indoors as much as possible, according to the CDC.
To see the CDC list of sites where Zika virus is active and may pose a threat to pregnant women, click here.