The increasing uncertainty stems not only because of the first case reported in Minnesota but also because a Texas case was attributed to sexual contact, amid previous assertions that only infected Aedes aegypti species of mosquitoes spread the disease, which presents the greatest risk to fetuses.
“There is a lot we don’t understand about the virus and exactly how it is transmitted,” said Dr. David McNamara, an infectious disease specialist at Gundersen Health System in La Crosse.
The illness usually is mild, with symptoms lasting from several days to a week. Severity requiring hospitalization is uncommon, and fatalities are rare, according to the federal Centers for Disease Control and Prevention.
Nonethless, the CDC has escalated its cautions in recent days.
In addition, the American Red Cross announced Wednesday that it will not accept blood donations from people who acknowledge that they have traveled to Mexico, the Caribbean or Central or South America within 28 days before they want to donate.
“We think people who are infected may have the virus in their blood,” McNamara said. “We don’t have large-scale testing for the Zika virus like we do for HIV.”
The Red Cross’s identification of those particular regions mirrors the CDC advisories that have expanded cautions to 30 countries and territories because Zika outbreaks involving millions have been reported in those areas.
The Red Cross also asked that anyone who develops symptoms of the Zika virus infection within 14 days of donation to notify the agency immediately so it can quarantine the blood.
Those symptoms include fever, rash, joint pain and red eyes, as well as include muscle pain and headache, according to the CDC. About 80 percent of the people who are infected with the Zika virus don’t even develop symptoms, the World Health Organization says.
No vaccine or medicine is available for the virus, which was discovered in the Zika Forest of Uganda in 1947.
In contrast to federal officials’ earlier comments that seemed to pooh-pooh even the idea of a U.S. outbreak, McNamara said, “I think there very well could be transmission, particularly in typical areas where the mosquito is most common — Florida, Texas and the Gulf Coast, mostly the southeast states.
“I would hope it would be pretty limited,” he said.
The Aedes aegypti species, which also spreads dengue, chikungunya and yellow fever, is common in those warmer, humid areas, said Dave Geske, vector control manager for La Crosse County and 12 area counties.
“None will maintain here,” he said. “Now, down the road, maybe in 20 years, there is a potential” as the mosquitoes evolve.
The Anoka County, Minn., woman in her 60s who developed symptoms Jan. 1 recently had returned from Honduras. She did not require hospitalization and is expected to make a full recovery, health officials said.
In the Texas case, a man who had traveled to Venezuela and had sexual relations with his wife upon his return later fell ill, health officials said. Tests for the Zika virus found that both had the virus. The woman, who is pregnant, had not left the United States since 2008, so health officials deduced that he must have contracted it from a mosquito bite and passed the virus to her sexually.
In light of that case, the CDC updated its advisory to say, "Until we know more, if your male sexual partner has traveled to or lives in an area with active Zika virus transmission, you should abstain from sex or use condoms the right way every time you have … sex for the duration of the pregnancy.”
Although the fetus reportedly is OK in this case, the virus can cause infant microcephaly, an abnormally small head connected with an undeveloped brain.
Gundersen’s Dr. McNamara confirmed that assessment, saying, “The real risk is mainly for an unborn fetus and a malformed brain.”
In addition to the Minnesota and Texas cases, the fact that Florida cases grew from nine to a dozen Wednesday prompted Gov. Rick Scott to expand the state of emergency he had declared earlier from four counties to five, including Broward, Miami-Dade, Hillsborough, Lee and Santa Rosa.
All of those who were diagnosed with the virus contracted it while traveling outside the country, in areas where transmission of the Zika virus is continuing, Scott said.
None had contracted the virus from mosquito bites while in Florida, he said, although an Aedes aegypti mosquito that bites an infected person can pass it on to any ensuing individuals it injects.
"We can prepare for the worse and hope for the best," the governor said. "We are going to do everything we can to stay ahead of the Zika virus.”
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©2016 the La Crosse Tribune (La Crosse, Wis.)
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