Microbiologist and guest blogger Jennifer German discusses Zika virus and whether there’s an increased risk for pregnant women.
Although the East Coast is rebounding from a record snowfall, a summertime pest has been the focus in the news. Mosquitos have grabbed international headlines along with a virus that they spread. Suddenly, Zika virus is everywhere. With the onslaught of information, I decided to sit down and clarify some of the salient points about Zika and how it relates to pregnancy health.
Let’s start with the basics. Zika virus is a Flavivirus, which puts it in the same family as some other, much nastier relatives, including Dengue virus, West Nile virus and Yellow fever virus. Normally, infection with Zika isn’t all that bad; only about 20% of infected people develop symptoms and those symptoms tend to be relatively mild and flu-like, such as fever, general malaise, aches, chills, etc. For this reason, Zika has maintained a low profile until now.
Its known origins date back to 1947, when it was first isolated from the Zika forest in Uganda. It’s considered endemic in Africa, meaning it’s in constant circulation. When the mosquito populations spike, the locals simply deal with it, much like how we deal with the flu each year. Over the last sixty-odd years, Zika has slowly made its way around the world. And it might have remained a low-profile annoyance, but for one new and troubling development.
ZOMG. Zika Virus.
Coinciding with its arrival in Brazil in the spring of 2015 was a startling and simultaneous rise in cases of another condition: microcephaly, a congenital condition that results in an abnormally small head and incomplete brain development. In each of the two years preceding the arrival of Zika in that country, the number of reported cases of microcephaly, was around 150. In 2015, the number spiked sharply, with over 4000 cases initially reported.
That number has been reduced by Brazilian health officials (and a final total is still being determined), but the fact remains that the number of cases significantly increased. In November 2015, a newborn with microcephaly was confirmed to be infected with Zika. Several other newborns with microcephaly had mothers that tested positive for the virus. This correlation led some health officials to suggest a link between Zika and microcephaly.
Correlation is not causation.
This is where it gets tricky. This correlation is not definitive proof that Zika causes microcephaly. Thus, the current advice from the WHO and CDC for pregnant women traveling to areas where Zika is epidemic comes from the uncertainty surrounding Zika and its relationship to microcephaly development, not an absolute knowledge that one is the cause of the other. That’s a critical point.
Without studies showing an infected individual developing the condition we can only make a best guess as to what is happening. Furthermore, many health officials have reported a drop in cases of microcephaly in the region, suggesting that the previous cases may have been misdiagnosed.
Personally, I believe that while Zika virus infection may be compounding a situation resulting in microcephaly development, the root cause is due to a number of factors and not Zika infection alone. In countries where the virus is endemic, there has been no indication that infection and microcephaly are linked, suggesting that either Zika virus has changed in South America or there are unique environmental or genetic factors at play in that region.
As far as immunization, there are several labs working on a vaccine. It may take a few years to be available, but in that time, it may be discovered that Zika is not the cause or at least not the sole cause for the birth defect. It’s a matter of waiting for the science to tell us more.
Consider taking your babymoon in cooler climes.
So, what can you do to protect yourself? The best advice is to follow the WHO and CDC guidelines. Avoid traveling to areas where the virus is epidemic, such as South America, Central America and the Caribbean. If travel to these areas is unavoidable, limit mosquito exposure as much as possible:
Wear long sleeves and pants.
Use a repellent. Compounds containing 25-30% DEET are recommended and there are several studies that suggest that compounds containing Lemon Eucalyptus or Eucalyptus oils at similar concentrations are also effective deterrents.
Avoid being outside at dusk and dawn. The mosquitos that carry Zika virus are considered "daylight" mosquitos, meaning that they are potentially active throughout the day. However, these mosquitoes prefer shade and cooler temperatures and are therefore more likely to be out at dusk and dawn
Use mosquito netting and close windows at night, if possible.
Keep a fan going. Mosquitos are not very strong fliers so having a current of air moving in the room can often keep them from reaching you.
When planning travel, it’s important to note that, if Zika infection is related to microcephaly, it’s likely a more serious issue in the first and second trimester when the brain is developing.
All of this makes many women, pregnant or planning to become so, understandably nervous. All in all, the threat of Zika virus is not as great as many have been led to believe. When discussing Zika on social media, one friend said of the media response, “They make it sound like it’s all Children of Men here.”
If you are pregnant or looking to become so, take the above precautions. Talk to your midwife or OB and be sure to keep them in the loop if you plan to travel anywhere that might harbor Zika. Keep up to date on developments from reputable news sources and government health agencies. But don’t make yourself crazy. Most of all, enjoy your pregnancy. Stress is a far more likely threat than Zika.
Jennifer German teaches in the University of Maryland’s First-year Innovation & Research Experience, where she leads a lab examining pathogen contamination in the Chesapeake Bay watershed. She holds a PhD from the University of Maryland in Biology with a focus in molecular virology, in which she examined immune responses to West Nile Virus.
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