What You Need to Know About Zika Virus and Microcephaly

The World Health Organization’s (WHO) recent announcement of a public health emergency of international concern has many individuals searching for information on the Zika virus. Larry Kociolek, MD, Infectious Diseases at Lurie Children’s explains the virus, addresses the concern for risk in pregnant women and how you can prevent contracting the illness.

What Is Zika Virus?

Zika virus is a rare virus that was discovered in the 1940s in Africa. In the last year or so, health officials started to see an increase in Zika virus infections in South America, Central America, Mexico and the Caribbean.

How Is Zika Virus Transmitted?

According to the Centers of Disease Control and Prevention (CDC), Zika virus is carried by the Aedes species of mosquito and can be transmitted primarily to an individual through the bite of an infected Aedes species mosquito. However, recently, it has been reported that the virus has been spread through blood transfusion and sexual contact.


Only one out of five people infected with the Zika virus will have any symptoms. The Zika virus causes a relatively mild illness. Symptoms include fever, rash, red eyes, and joint pain. Symptoms last several days to a week and resolve without treatment.

See your healthcare provider if you develop the symptoms described above and have visited an area where Zika is found in the previous two weeks.

Risk of Zika Virus in Pregnancy

Currently, public health officials have not yet scientifically proven there is an exact link between Zika virus and microcephaly. However, public health officials strongly suspect that Zika virus can lead to microcephaly when the infection occurs in a pregnant woman. With the increase of Zika virus cases in South America, health officials have also seen a dramatic increase in babies born with microcephaly to women who may have had the Zika virus infection.

The term microcephaly literally means “small head.” There are many causes of microcephaly, including infection, genetic causes, and medical conditions affecting a woman during pregnancy.  When the term is used clinically, it refers to a baby whose head circumference is much smaller than that of the average circumference of a baby’s head of the same age, gender, and gestational age.  If a pregnant woman develops Zika virus, the virus can cross the placenta and infect the baby. If the baby is in its critical stages of brain development, the infection can result in poor development of the fetal brain and being born with microcephaly.

The impact on the fetus is highly variable and depends on a number of things such as the severity of infection in the mother and stage of fetus development. The earlier you are in pregnancy and the more severe the infection, the greater the impact on the developing fetus- possibly resulting in profound abnormalities and cognitive deficits. With a more mild infection or later infection in pregnancy, the neurological complications of a Zika virus infection to the baby can be much milder or even unapparent.

Precautions You Can Take

Until we know more details and specific risks of Zika virus in pregnancy, the CDC is recommending pregnant women avoid travel to areas with active Zika virus transmission- primarily South America, Central America, Mexico, and the Caribbean. The regions with active transmission might increase significantly over the next several weeks to months. Discuss any travel plans to these areas with your healthcare provider.

If travel is necessary, it is recommended that all travelers, and especially pregnant women, take appropriate precautions to prevent mosquito bites. These precautions include:

  • Staying indoors as much as possible
  • Staying in lodging with air condition and
    screened windows; if your lodging does not have air condition or screened
    windows, purchase a mosquito net to protect yourself
  • Wear clothing that cover arms and legs
  • Use insect repellent at every opportunity;
    Children under two months of age should not use insect repellent

With several reports suggesting sexual transmission of Zika virus and until more is known about this route of transmission, the CDC advises pregnant women (or women attempting to become pregnant) to avoid sexual contact or use condoms with individuals who have recently traveled to an area with Zika virus transmission.


Unlike many infections such as malaria, yellow fever and typhoid, that have medications or vaccines to reduce the risk of developing infection, Zika virus does not. Currently, the CDC and scientists are working on developing a vaccine and medications to protect patients from developing infection and to reduce the risk to the fetus.

If you do contract Zika virus, drink plenty of fluids, get plenty of rest and take medication such as acetaminophen for pain and fever. For more information, rely on the CDC and public health officials. If you have travel plans that include regions with active Zika virus transmissions, talk to your healthcare provider to fully understand the risks.

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