The Zika virus may be transmitted by oral sex, according to a recent letter to The New England Journal of Medicine. 

Scientists said there was a recent case in France in which a 46-year-old man who had experienced Zika symptoms in Brazil returned to Paris from Rio de Janeiro and apparently gave the virus to his 24-year-old partner, The New York Times reported.

The pair reportedly had sex seven times between Feb. 11 and Feb. 20, each involving vaginal sex without ejaculation and oral sex with ejaculation. The woman became ill with Zika symptoms on Feb. 20, the Times reported.

According to the report: "Both were tested for Zika infection on Feb. 23. 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. But a vaginal swab was negative for the infection."

An infectious disease specialist told the Times that the case shows "how elaborate the number of avenues of possible transmission can be," and said the most likely transmission route was oral sex.

A baby with Zika-related defects was born in New Jersey Tuesday, health officials said. The baby displayed symptoms of the virus, including microcephaly, a defect in which the baby's head is smaller than expected, and low birth weight.

Zika is transmitted by the bite of Aedes mosquitoes, which is found in all of the Americas, apart from Chile and Canada.