Last Updated Jan 15, 2016 7:56 PM EST
Concerns are growing over the mosquito-borne illness known as Zika virus, which has been spreading through Central and South America and is believed to be linked to a surge in serious birth defects in Brazil.
Friday evening, the U.S. Centers for Disease Control and Prevention issued a travel advisory urging pregnant women to consider postponing travel to 14 countries where Zika virus is present. Because of the possible link to birth defects, pregnant women who must travel to affected areas should talk to their doctor or other health care provider first and strictly follow steps to avoid mosquito bites during the trip, the CDC said.
The virus reached Mexico in November and Puerto Rico in December, and earlier this week, the CDC confirmed a case of Zika in Texas in a traveler who recently returned from a trip to Latin America.
Here’s a primer about what you should know about the disease.
What is Zika virus?
Zika virus is an illness transmitted to people through bites from mosquitoes of the Aedes species — the same mosquitoes that spread dengue and chikungunya viruses. It not communicable from person to person but can be transmitted when a mosquito bites someone who’s infected and then bites someone else.
The virus was first discovered in Uganda in 1947 and named after the forest in which it was found.
The current Zika outbreak in Brazil began last May. Authorities there estimate that since then, between 440,000 and 1.3 million people have caught it. Zika has spread to other countries in Latin America and the Caribbean, including Colombia, Venezuela, Honduras and Mexico. Puerto Rico reported its first case of locally transmitted Zika virus in December.
What are the symptoms?
According to the CDC, the most common symptoms of Zika virus are fever, rash, joint pain, and conjunctivitis. Other symptoms can include muscle pain, headache, pain behind the eyes, and vomiting. Symptoms are usually mild, lasting from a few days to a week.
In rare cases, symptoms can become severe and require hospitalization.
There is no specific treatment for Zika except to try to ease the symptoms. There is no vaccine to prevent it.
What do we know about its possible link to birth defects?
Health officials in Brazil say they’ve found strong evidence that Zika has been linked to a sudden rise in the number of babies being born with abnormally small heads, a condition called microcephaly, which often results in mental retardation.
Brazil’s government reports 3,530 babies have been born with microcephaly, up from fewer than 150 in 2014.
Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, explained how the connection was found.
“First we saw a dramatic rise in microcephaly in Brazil coinciding with when Zika was introduced there. This prompted an active search to see if there was a virus behind it and Zika was one of the suspect viruses, even though it was not shown previously to cause congenital birth defects,” he told CBS News. “The researchers there took blood samples and other tissue samples from these babies with microcephaly and found evidence of the virus in the samples. They also sampled the amniotic fluid of mothers who had babies with microcephaly and that really helped confirm the connection.”
While more research is needed to confirm true cause and effect, and experts acknowledge other factors may be at play, researchers say the evidence to support the link is strong. In response, authorities in Brazil have told women to put off pregnancy if they can.
I’m traveling to an affected region. Should I be concerned?
Currently, the CDC recommends that all travelers to affected areas in South America, Central America, the Caribbean, or Mexico take steps to protect themselves from mosquitoes.
“Out of an abundance of caution,” the CDC said it’s advising pregnant women in any trimester to avoid travel to affected areas if possible, or to take extra precautions to avoid mosquito bites if they must be there. Women trying to become pregnant or who are thinking about becoming pregnant should consult with their health care provider before traveling to these areas and take care to protect themselves from mosquito bites.
The countries named in the CDC travel alert are: Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, and Puerto Rico.
“The reality is we don’t have a vaccine so it is very reasonable to inform the public that there is a real risk there,” Dr. Trish Perl, senior epidemiologist and professor of medicine in the division of infectious diseases at the Johns Hopkins University School of Medicine, told CBS News. “I don’t know if we’re going to be able to delay all travel but I’m not sure right now is the time to send someone who’s pregnant to the Amazon for a vacation. You’d probably want to wait on that. Especially with pregnancy, we do err with being more cautious until there’s further data.”
What can I do to protect myself?
The CDC recommends the following steps to avoid mosquito bites:
- Cover exposed skin by wearing long-sleeved shirts and long pants.
- Use an insect repellent approved by the Environmental Protection Agency as directed.
- Higher percentages of active ingredients provide longer protection. Use products with the following active ingredients: DEET, Picaridin, oil of lemon eucalyptus (OLE), IR3535.
- Use permethrin-treated clothing and gear, such as boots, pants, socks, and tents. You can buy pre-treated clothing and gear or treat them yourself.
- Stay and sleep in screened-in or air-conditioned rooms.
- Use a bed net if the area where you are sleeping is exposed to the outdoors.
Will Zika virus become a problem in the U.S.?
Though no locally acquired cases have been reported in the U.S., Zika has been reported in American travelers who recently visited affected locations, such as the patient treated in Texas last week. Experts believe it is inevitable that we will see more cases in the U.S.
“The mosquitoes are here,” Hotez said. “They’re certainly not as abundant in the winter months as they are in the spring, but there are probably a fair number of people here who have visited the Caribbean or Latin America who are already infected with Zika virus. Our mosquitoes are going to bite those individuals, pick up the virus, and transmit it to another person.”
Hotez said immediate action is necessary to minimize the harmful effects of Zika virus.
“We’re seeing rapid spread of the virus and we need to act now,” he said. “The first thing is to undertake a program of active surveillance throughout the Western Hemisphere, not only where it is right now but in places it could soon rise, including the Caribbean and the Gulf Coast of the U.S. Then if we start seeing transmission in these areas, provide appropriate advisories and education materials to women of reproductive age who are pregnant or are planning on getting pregnant.”
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