Editor’s note: As this issue went to press, a case of sexual transmission of Zika virus was reported Feb. 2 in Dallas. Sexual transmission of the virus has occurred before, but the development jolted a public health narrative that was primarily focused on mosquitoes, pregnancy, and birth defects. The CDC is emphasizing condom use for those returning from Zika transmission areas while working on more detailed guidelines to prevent sexual transmission. Look for full details in the next HEH.

Employee health professionals should advise healthcare workers who are pregnant to strongly reconsider any travel south of the border due to the emergence of mosquito-borne Zika virus. In Brazil and other countries where Zika is actively spreading via mosquitoes, the virus is the prime suspect behind increasing cases of microcephaly — a horrific birth defect that stunts head and brain development. The vast majority of healthcare workers are women, many of whom are of childbearing age and may be concerned about Zika.

As this issue went to press, the virus had not been acquired in the United States, but that is subject to change as travelers return from countries where Zika is spreading. Outbreaks of Zika previously have been reported in tropical Africa, Southeast Asia, and the Pacific Islands, but the first confirmed case in the Americas was reported in May 2015 in Brazil.

“There are 31 travel-associated cases detected in 11 states and the District of Columbia, from the period of 2015 to the present,” Anne Schuchat, MD, principal deputy director of the Centers for Disease Control and Prevention said at a Jan. 28 press conference. “For the U.S. territories, there are 20 laboratory-confirmed cases that we are aware of, 19 from Puerto Rico, and one from the U.S. Virgin Islands. [We are] making this nationally notifiable and laboratory testing for the lab confirmation with the PCR is just increasing, so we really do expect there to be a lot more travel-associated cases. The key thing for people to know and remember is that most of these are very mild illnesses. It’s really the circumstances of pregnant women who are traveling that we want to have heightened awareness of, and we really caution pregnant women to consider postponing travel.”

If there is anything we’ve learned about infectious diseases in this 21st century age of pandemics, it is not to underestimate them. The Aedes mosquitoes that can carry the Zika virus are in the U.S. and similar tropical diseases like dengue have been sporadically transmitted here. That will probably happen with Zika in the U.S. when a traveler returning from a country where the virus is endemic is bitten by a mosquito, who then subsequently feeds on another person and transmits the virus between them. Remember, however, that the infected person does not become a life-long chronic carrier of Zika virus and the window of transmission possibility is thought to be about one week. There is no vaccine to prevent infection or medicine to treat Zika. Four of five people infected with the virus will not develop symptoms, which include fever, rash, joint pain, or red eyes. The infection is thought to be self-limiting and the primary threat is to mother and unborn child. Travel advisories are currently in affect for Mexico, and countries in the Caribbean and Central and South America. Check the CDC for travel updates at: http://wwwnc.cdc.gov/travel/page/zika-information.

The CDC has issued the following questions and answers to address some of the issues of Zika and pregnancy.

I am pregnant. Should I travel to a country where cases of Zika have been reported? Until more is known, CDC recommends special precautions for pregnant women and women trying to become pregnant:

- Pregnant women in any trimester should consider postponing travel to the areas where Zika virus transmission is ongoing. Pregnant women who do travel to one of these areas should talk to their doctor or other healthcare provider first and strictly follow steps to avoid mosquito bites during the trip. (See below.)

- Women trying to become pregnant or who are thinking about becoming pregnant should consult with their healthcare provider before traveling to these areas and strictly follow steps to prevent mosquito bites during the trip.

How will Zika virus affect me or my unborn baby? Zika is primarily transmitted through the bite of infected Aedes mosquitoes. It can also be transmitted from a pregnant mother to her baby during pregnancy or around the time of birth. We do not know how often Zika is transmitted from mother to baby during pregnancy or around the time of birth. There have been reports of a serious birth defect of the brain, microcephaly (a condition in which a baby’s head is smaller than expected when compared to babies of the same sex and age) and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. Additional studies are needed to further characterize this relationship. More studies are planned to learn more about the risks of Zika virus infection during pregnancy.

Is it safe to use an insect repellent if I am pregnant or nursing? Yes. Using an insect repellent is safe and effective. Pregnant women and women who are breastfeeding can and should choose an EPA-registered insect repellent and use it according to the product label.

If a woman who is not pregnant is bitten by a mosquito and infected with Zika virus, will her future pregnancies be at risk? We do not know the risk to the infant if a woman is infected with Zika virus while she is pregnant. Zika virus usually remains in the blood of an infected person for only a few days to a week. The virus will not cause infections in an infant that is conceived after the virus is cleared from the blood. There is currently no evidence that Zika virus infection poses a risk of birth defects in future pregnancies. A women contemplating pregnancy, who has recently recovered from Zika virus infection, should consult her healthcare provider after recovering.

Should a pregnant woman who traveled to an area with Zika virus be tested for the virus? See your healthcare provider if you are pregnant and develop a fever, rash, joint pain, or red eyes within two weeks after traveling to a country where Zika virus cases have been reported. Be sure to tell your healthcare provider where you traveled.

Is it safe to get pregnant after traveling to a country with Zika virus? If infected, Zika virus usually remains in the blood of an infected person for about a week. The virus will not cause infections in a baby that is conceived after the virus is cleared from the blood.

Can a pregnant woman be tested for Zika weeks or months after being in a country with Zika? At this time, and for several reasons, we do not recommend routine Zika virus testing in pregnant women who have traveled to a country with known transmission. First, there can be false-positive results due to antibodies that are made against other related viruses. Second, we do not know the risk to the fetus if the mother tests positive for Zika virus antibodies. We also do not know if the risk is different in mothers who do or do not have symptoms due to Zika virus infection.

What can people do to prevent becoming infected with Zika? There is no vaccine to prevent Zika. The best way to prevent diseases spread by mosquitoes is to avoid being bitten. Protect yourself and your family from mosquito bites. Here’s how:

- Wear long-sleeved shirts and long pants.

- Stay in places with air conditioning or that use window and door screens to keep mosquitoes outside.

- Use Environmental Protection Agency (EPA)-registered insect repellents. All EPA-registered insect repellents are evaluated for effectiveness. Always follow the product label instructions. Reapply insect repellent as directed. Do not spray repellent on the skin under clothing. If you are also using sunscreen, apply sunscreen before applying insect repellent.

- If you have a baby or child: Do not use insect repellent on babies younger than 2 months of age. Dress your child in clothing that covers arms and legs, or a covered crib, stroller, and baby carrier with mosquito netting. Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin. Adults: Spray insect repellent onto your hands and then apply to a child’s face.

- Treat clothing and gear with permethrin or purchase permethrin-treated items. Treated clothing remains protective after multiple washings. See product information to learn how long the protection will last. If treating items yourself, follow the product instructions carefully. Do NOT use permethrin products directly on skin. They are intended to treat clothing.

- Sleep under a mosquito bed net if you are overseas or outside and are not able to protect yourself from mosquito bites.

What is the treatment for Zika? There is no specific medicine to treat Zika virus infections. Treat the symptoms:

- Get plenty of rest.

- Drink fluids to prevent dehydration.

- Take medicine such as acetaminophen to reduce fever and pain.

- Do not take aspirin or other non-steroidal anti-inflammatory drugs.

- If you are taking medicine for another medical condition, talk to your healthcare provider before taking additional medication.

How is Zika diagnosed? See your healthcare provider if you develop symptoms (fever, rash, joint pain, red eyes). If you have recently traveled, tell your healthcare provider. Your healthcare provider may order blood tests to look for Zika or other similar viral diseases like dengue or chikungunya.

What should I do if I have Zika? In addition to treating the symptoms, you can protect others. During the first week of infection, Zika virus can be found in the blood and passed from an infected person to another mosquito through mosquito bites. An infected mosquito can then spread the virus to other people. To help prevent others from getting sick, avoid mosquito bites during the first week of illness. See your healthcare provider if you are pregnant and develop a fever, rash, joint pain, or red eyes within 2 weeks after traveling to a country where Zika virus cases have been reported. Be sure to tell your healthcare provider where you traveled.

Does Zika virus infection cause Guillain-Barre syndrome (GBS)? GBS is a rare disorder where a person’s own immune system damages the nerve cells, causing muscle weakness and, sometimes, paralysis. These symptoms can last a few weeks or several months. While most people fully recover from GBS, some people have permanent damage and in rare cases, people have died. We do not know if Zika virus infection causes GBS. It is difficult to determine if any particular pathogen “caused” GBS. The Brazil Ministry of Health is reporting an increased number of people affected with GBS. CDC is working to determine if Zika and GBS are related.