DALLAS — A person in Texas has been infected with the Zika virus after having sex with an ill person who had returned from a country where the disease was present, Dallas County health officials said Tuesday.
It’s the first case of the virus being transmitted in the U.S. during the current outbreak of Zika, which has been linked to birth defects in the Americas. Dallas County Health and Human Services said it received confirmation of the case from the U.S. Centers for Disease Control and Prevention.
Health officials did not release any details about the Texas patient, citing privacy issues. In a tweet, Dallas health officials said the first person infected had been to Venezuela, but did not detail when and where that person or the second person was diagnosed.
The CDC says that in this case there’s no risk to a developing fetus.
The Zika virus is usually spread through mosquito bites, but investigators have been exploring the possibility the virus also can be spread through sex. There was report of a Colorado researcher who caught the virus overseas and apparently spread it to his wife back home in 2008, and it was found in one man’s semen in Tahiti.
“That gives you the plausibility of spread, but the science is clear to date that Zika virus is primarily transmitted to people through the bite of an infected mosquito,” Dr. Anne Schuchat of the CDC said during a recent news conference about Zika.
In the epidemic in Latin America and the Caribbean, the main villain identified so far is called Aedes aegypti — a species of mosquito that spreads other tropical diseases, including chikungunya and dengue fever. It is found in the southern United States, though no mosquito-borne transmission has been reported in the continental United States to date.
Texas Department of State Health Services said that case announced Tuesday is the first one contracted in the state. But the agency noted that there are seven other cases of the virus in Texas, all related to foreign travel.
The World Health Organization on Monday declared a global emergency over the rapidly spreading Zika virus, saying it is an “extraordinary event” that poses a threat to the rest of the world. The declaration was made after an emergency meeting of independent experts called in response to a spike in babies born with brain defects and abnormally small heads in Brazil since the virus was first found there last year. Officials in French Polynesia also documented a connection between Zika and neurological complications when the virus was spreading there two years ago, at the same time as dengue fever.
WHO officials say it could be six to nine months before science proves or disproves any connection between the virus and babies born with abnormally small heads.
Zika was first identified in 1947 in Uganda. It wasn’t believed to cause any serious effects until last year; about 80 percent of infected people never experience symptoms.
The most common symptoms are fever, rash, joint pain and red eyes. The illness is usually mild with symptoms lasting several days to a week. Symptoms usually start two days to a week after being bitten by an infected mosquito.
The CDC says it will issue guidance in the coming days on prevention of sexual transmission of Zika virus, focusing on the male sexual partners of women who are or may be pregnant. Health officials noted that sexual partners can protect themselves by using condoms to prevent spreading sexually transmitted infections.