By Brenda Goodman, MA
WebMD Health News
Reviewed by Hansa D. Bhargava, MD
Jan. 28, 2016 -- Public health officials said Thursday they're concerned about the fast-spreading Zika virus, and they're racing to understand its relationship to the troubling rise in birth defects seen in Brazil and other countries.
"The level of alarm is extremely high," said Margaret Chan, MD, director-general of the World Health Organization, as she briefed the executive board.
Chan said she was worried about the rapidly evolving situation for four reasons:
- The virus has been tied to severe birth defects, including babies born with brain damage to infected mothers.
- The mosquito that carries the virus, the yellow fever mosquito, is found in nearly every country in North and South America except Canada and Chile.
- People in these countries have never been exposed to the virus before, so there's very little natural immunity to the virus in the general population.
- There is no vaccine that can prevent the infection, very few tests available to detect it, and no treatments for it.
Chan said the WHO will meet on Monday to decide whether to declare an international public health emergency in response to Zika, a move that would step up international efforts to fight it.
Bruce Aylward, MD, assistant director-general of the WHO, said he expects there will be 3 million to 4 million Zika infections in the Americas over the next 12 months.
In a separate press briefing held by the CDC, U.S. officials admitted there were more questions than answers about the virus right now.
"We know many people are concerned or scared," said Anne Schuchat, MD, principal deputy director of the CDC.
Schuchat stressed that most people aren't in any serious danger from Zika, which is carried by mosquitoes.
What has health officials most worried, she said, is that "increasing lines of evidence suggest that some women infected with Zika during their pregnancies may go on to deliver a baby with a serious brain injury."
The CDC has issued a travel warning for women who are pregnant or want to become pregnant covering 24 nations and territories in Central and South America, and the Caribbean.
Outlook for the United States
Right now, there's no sign that mosquitos in the U.S. have the virus, said Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases.
The only recent cases reported in this country -- we're up to 31 people in 11 states and the District of Columbia, according to the CDC -- have been among travelers returning from areas where the infection is being passed locally from mosquitoes to people. That hasn't yet happened in the continental U.S. There have been 19 confirmed infections in Puerto Rico and one in the U.S. Virgin Islands. Those cases are still under investigation. Officials aren't sure if those were locally acquired or not.
Officials expect local spread of the virus will eventually happen in the U.S., though, probably in areas that have also seen locally passed dengue fever infections, like the southern tips of Florida and Texas, Fauci said. Dengue is carried by the same species of mosquito that also carries the Zika virus.
Even if Zika does take root in the U.S., it's not likely to cause widespread misery the way it has in Brazil, Fauci said, in part because more people use air conditioners here and use screens on their windows and doors.
"Most of these are very mild illnesses," Schuchat said. "For the average American who is not traveling, this is not something to worry about."
Since late October, Brazil has seen more than 4,000 cases of microcephaly, a rare birth defect that stunts the growth of a baby's brain and head. Many children with microcephaly have some degree of mental disability, and the condition is linked to a shorter life span.
The cause of most of those cases is still under investigation, though. Only six cases in Brazil have been definitively linked to Zika. And no one knows how the virus might be causing microcephaly or other birth defects, though other viruses -- including toxoplasmosis, cytomegalovirus, and rubella -- are known to cause the same problems.
"If you are pregnant, please take this seriously," Schuchat said. "We recommend you consider postponing travel to a region with ongoing Zika virus transmission. If you must travel, or you live in an affected area, protect yourself against mosquito bites."
That means you should wear long sleeves and long pants, and use a mosquito repellent like DEET, which the CDC says is safe to use during pregnancy.
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SOURCES: Margaret Chan, MD, director general, The World Health Organization, Geneva, Switzerland. Bruce Aylward, MD, assistant director general, The World Health Organization, Geneva, Switzerland. Ann Schuchat, MD, principal deputy director, The U.S. Centers for Disease Control and Prevention, Atlanta. Anthony Fauci, MD, Director, of the National Institute of Allergy and Infectious Disease, Baltimore.
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