The first known case of Zika virus transmission in the United States was reported by local health officials in Texas on Tuesday.
In a potentially alarming development, the Texas case is believed to have been contracted through sex, and not a mosquito bite. News of the Texas case came a day after the World Health Organization declared an international public health emergency.
Zika virus poses a special concern for pregnant women — with an enormous increase in birth abnormalities in South America. Wisconsin Division of Public Health epidemiologist Diep Hoang Johnson said this week that pregnant women should avoid travel to the affected regions.
She said there are specific recommendations — including ultrasounds — for pregnant women who have made such a trip.
“There is a concern that even if they don’t have symptoms, the virus can cross the placenta, and can affect the fetus,” Johnson said. “If they come back and they don’t have symptoms, they still need to talk to their physicians.”
Zika virus can be transmitted from the mother to the baby during pregnancy. The virus has been reported in more than 30 countries and linked to microcephaly, in which babies have abnormally small heads and improperly developed brains.
Zika is in the same family of viruses as West Nile, another mosquito borne illness that has become familiar in Wisconsin.
About 80 percent of people who are infected with Zika virus may not have any symptoms. Illness may develop in 20 percent of infected people within 3 to 7 days after a bite from an infected mosquito. Symptoms are generally mild and can last for several days to a week. Common symptoms of Zika virus infection include fever, rash, joint pain, conjunctivitis (red eyes), photophobia (sensitivity to light), muscle pain or headache.
Severe symptoms and fatalities are uncommon. There is presently no vaccine, prophylactic or specific medication available to treat Zika virus illness.