Zika Virus

Zika virus is a cause for concern. The first death from Zika virus in the contiguous United States has now been reported, and we have already seen the impacts of the illness on people in Central and South American countries. Now the reach of the illness could be global as athletes, spectators, dignitaries, and journalists head to Rio de Janeiro for the 2016 Olympic Games. Brazilian officials say the risk will be reduced due to the fact it is winter there and fewer mosquitos are present. However, there is still concern about the lasting health of those attending and competing in games – especially when it comes to reproductive health.

Carrie Byington, MD, a pediatric infectious disease specialist with University of Utah Health is the chair of the United States Olympic Committee’s Infectious Disease Advisory Group. She will be advising the USOC on the best practices on managing infectious diseases during the games, paying particular attention to how issues may affect athletes and staff participating in the upcoming Olympic and Paralympic Games. In addition Byington will monitor at least 1,000 men and women after the games to better understand the impacts of Zika virus as part of a study funded by the National Institutes of Health.

What Is Zika Virus?

Byington: Zika virus is a type of virus that we call a flavivirus. There are others that are well known like the Dengue virus and the Yellow Fever virus. All of these viruses can be carried by a certain kind of mosquito. That mosquito is called the Aedes aegypti mosquito.

How Is Zika Virus Diagnosed?

Byington: About 80% of the infections have no symptoms. So, most people who had Zika virus will not know they had Zika virus. For the 20% that do display symptoms the most common symptoms that we see are fever, rash, and muscle and joint pain. One of the important things that we see clinically with the rash is that it is a very itchy rash.

There are tests for Zika virus – both antibody tests and tests that pick up the nucleic acid of the virus that can be performed to help make the diagnosis.

What Is the Link Between Zika and Birth Defects?

Byington: We can now conclusively saw that the Zika outbreak is the cause of microcephaly. We can see that that virus enters into a pregnant woman's bloodstream, is able to cross the placenta. We know the type of cell that it enters and then it enters into the developing fetus, particularly in the developing fetus' brain. It disrupts the development of the brain. It is a very, very serious consequence of Zika virus infection and one that we are trying to prevent in the United States and in other countries.

The risk for microcephaly following Zika virus infection we believe is greatest in the first trimester. But there have been a few reports of women who have had infection we think in the second trimester. That's one of the reasons that research is so important. Part of the Utah Study will be looking at the timing of infection and the timing of pregnancy to better see if we can identify the risk for individuals.

What Is the Zika study with the U.S. Olympic Team?

Byington: This is a study that will go on for two years and we will be studying the reproductive outcomes of individuals who have travelled to Brazil for the Olympics. We’re hoping to learn about Zika virus from any of those individuals who might become infected. There are lots of questions that we don’t have answers to about how long an individual may be infectious or may be able to spread the virus to others. And there are questions that we need to answer about risk factors for pregnancy. So, those are the things we are going to be studying. This is an opportunity for the United States and for our U.S. Olympic Committee group to contribute new knowledge all around the world. Everyone needs to know how long they may remain contagious when they have Zika virus. They need to know which body fluids could potentially spread the virus in a sexual manner, and they need to know what the risk period is for pregnancy.