Health authorities in Dallas, Texas, said they have received confirmation of the first transmission of the Zika virus through sexual contact.
Zachary Thompson, Director of Health and Human services in Dallas County, confirmed on Wednesday that that the case involved an individual who was infected with the virus after contracting it in another country where the Zika virus was present.
He said the individual from Dallas County had sexual contact with the patient, who acquired the virus.
Mr. Thompson said it has been cleared that the original infection occurred outside the U.S.
The official said now that it has been established that Zika virus can be transmitted through sex, there would be increases in awareness campaign by educating the public about protecting themselves and others.
The World Health Organisation (WHO) and other public health authorities are alarmed about the Zika virus because it is suspected of causing a birth defect called microcephaly through mother-to-child transmission.
Microcephaly is a congenital condition in which babies are born with abnormally small heads.
According to WHO findings, babies born with microcephaly have unusually small heads and brains.
It said the symptoms of the virus in adults are relatively minor, as they include fever, rash, joint pain and conjunctivitis lasting from several days to a week.
On Monday, WHO had declared a public health emergency over the Zika virus.
Brazil, the country most affected, would receive international assistance to counteract the outbreak and spread of the virus.