Reposted with the permission of Children’s Hospital Colorado
With the Zika virus in the spotlight for media attention and public concern, we asked one of our experts to answer common questions about the mosquito-borne infection. Here’s what Samuel Dominguez, M.D., PhD., medical director of the clinical microbiology laboratory, microbial epidemiologist and pediatric infectious disease specialist at Children’s Hospital Colorado, had to say.
1. Question: What is the Zika virus?
Answer: Zika virus is a flavivirus, which is in the same family of viruses as West Nile virus and Dengue virus. It was first isolated from primates in the Zika forest of Uganda in 1947 and isolated in humans in 1968. The Zika virus was most likely introduced into Brazil in 2014, and has led to a wide epidemic that is still ongoing.
Read information about Zika virus prevention from the Center for Disease Control (CDC).
2. Question: How do you get the Zika virus?
Answer: Zika virus is transmitted to people through mosquito bites. The most common mosquitos that transmit this virus are Aedes mosquitos. These mosquitos typically lay eggs in and near standing water and are aggressive daytime biters.
A mother could transmit Zika virus to her baby during any trimester of pregnancy, but we don’t yet know if this risk changes at different times during the pregnancy.
Zika virus can also be spread during sex by a man infected with the virus to his partners.
Zika virus may also be spread through blood transfusions.
Learn about areas affected by Zika virus.
3. Question: If a pregnant woman has traveled to an affected area and is concerned about the Zika virus, what should she do? Should she get tested, and if so, where is the best place to start?
Answer: Any pregnant woman who has traveled to an area where Zika is currently circulating should talk to her healthcare provider (OB-GYN or primary care physician) about being tested. Testing should be offered up to 12 weeks after return from travel. The recommended test is a blood test looking for an antibody (IgM) to the Zika virus.
A negative test can rule out a recent infection with Zika virus. A positive test does not necessarily indicate a recent Zika infection, as the test can cross-react with other similar viruses.
Due to the potential for sexual transmission, couples in which a man has traveled to an area of active Zika virus transmission should consider using condoms during sex or abstaining from sexual activity for the duration of his partner’s pregnancy. The Centers for Disease Control and Prevention (CDC) also recommends that men who have been diagnosed with or had symptoms of ZIKA should consider using condoms during sex or abstaining from sexual activity for 6 months from the onset of symptoms.
The Center for Disease Control and Prevention (CDC) may change these recommendations as more information becomes available.
Get resources for pregnant women from the CDC.
4. Question: I’ve been told not to worry about the Zika virus if I don’t exhibit symptoms within two weeks of travel. However, if only 20% of people have symptoms, what does that mean for the other 80%?
Answer: The other 80% have what is called an “asymptomatic infection.” This means that they have been infected with the Zika virus but did not develop any symptoms. This is a common scenario for a variety of viruses – different people can experience different symptoms (and sometimes no symptoms at all) when exposed and infected with the same virus. The reason why some people develop symptoms and others do not is not known. At this time, pregnant women should be tested whether or not they have symptoms.
5. Question: If I am pregnant and become infected with the Zika virus, what impact will it have on my baby?
Answer: Zika virus is a cause of congenital microcephaly and other severe fetal brain and eye defects in babies of mothers who were infected with Zika virus while pregnant.
It is not known, however, how often microcephaly develops in babies of pregnant women who are infected with Zika. It is also not known if the risk is greater or less at different times during pregnancy. Studies are currently underway to better understand this association and to see what role other factors might play (such as prior or concurrent other infections, nutrition, environmental or genetic factors). Since the affected children were only recently born, we also do not have information about long-term effects associated with this congenital microcephaly.
Learn more about microcephaly.
6. Question: The CDC recommends that all pregnant women suspend travel to areas were Zika virus is active. But I am pregnant and have an upcoming vacation in active region. Should I cancel my travel? How serious is this ban? And how long will it last?
Answer: The safest thing to do is to follow the CDC’s recommendation and cancel your trip. If you decide to still travel, you should follow steps to avoid mosquito bites during the trip. It is unknown at this time how long the ban will last.
Learn more about how to prevent mosquito bites.
7. Question: If I’m not pregnant and don’t plan to be anytime soon, is the Zika virus still something to worry about for me or my children?
Answer: Most people (80%) who become infected with the Zika virus have no symptoms. For the 20% who do develop symptoms, the most common findings are fever, rash, joint and muscle pains, headaches and red eyes. Most illnesses with Zika are mild and last for 3-7 days. At this time, we don’t have any evidence that a past Zika infection will impact a future pregnancy.
8. Question: Could the Zika virus spread to Colorado?
Answer: The Zika virus is not present in Colorado. The climate in Colorado is not ideal for the kind of mosquito that carries Zika and, therefore, outbreaks are unlikely to occur here. It is likely there will be cases in travelers returning from countries where there are outbreaks.
Read answers to other common questions about the Zika virus.
9. Question: Do the mosquitos that carry Zika virus also carry other viruses that I need to worry about?
Answer: The same mosquitos that carry Zika virus can also carry dengue, chikungunya and yellow fever. Over the past few years, dengue and chikungunya have also been introduced in the Americas with associated large outbreaks and ongoing current transmission.
As with Zika, there are no vaccines or treatments for these viruses, and so prevention from mosquito bites is critical. These viruses have not been associated with causing microcephaly in pregnant women but can cause similar and sometimes more severe disease than Zika.
Yellow fever is endemic in parts of South America and Africa and can cause serious, life-threatening liver disease. Anyone traveling to countries where yellow fever exists should receive the yellow fever vaccine prior to travel.
10. Question: The World Health Organization (WHO) has declared the Zika virus a “public health emergency.” Is this a safety danger for people anywhere in the Unites States?
Answer: The mosquitos that carry and spread the Zika virus are found in the southern and eastern parts of the U.S. It is possible that a person returning from a country with Zika transmission could be carrying the virus in their blood and then be bitten by one of these mosquitos in the U.S. This could then cause local spread of the virus. The CDC and local health departments are closely monitoring for this possibility.
Additional resources for Zika virus information:
• World Health Organization
• Contagious Comments (a newsletter from the Department of Epidemiology at Children’s Colorado which addresses topics related to infectious disease)
• University of Colorado Hospital
• CDC Fact Sheets Available in multiple languages
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You may also be interested in our easy-to-read Zika Infographic: 
