The Latest on Zika
Pregnant and traveling? We may not hear as much about Zika in the news, but the virus should still be top of mind.
In 2016, it was hard to avoid news about Zika—how it was tearing through Brazil, Colombia, and Puerto Rico, and making its way up to the mainland U.S. via Miami and South Texas. The collective economic damage to the tourism market was extensive—tens of millions in Puerto Rico alone—and the health crisis devastating.
Today, Zika isn’t the first thing you hear about when you turn on the TV, but it should still be top of mind for pregnant women, as well as women and men who are trying conceive. Below, I interview Dr. Michael Anne Lane, MD of Obstetrics and Gynecology in Houston, on all things Zika: The latest news, how you can prevent contracting the disease, and what you should do if you think you might be Zika positive.
It’s worth noting that findings on Zika change all of the time, so be sure to visit the CDC website and talk to your doctor for the latest information.
We aren’t hearing as much about Zika in the news lately. Is it still a concern for women that are pregnant or trying to conceive?
It is certainly still a concern. After further research, we have fortunately discovered that the transmission rate, as well as the rate of affected pregnancies, is lower than we originally thought. However, if you have an affected pregnancy it results in a range of defects—everything from vision problems to Microcephaly, a birth defect in which a baby’s head is smaller than expected,—some of which can be devastating. Therefore, the Center for Disease Control and Prevention (CDC) and The American College of Obstetricians and Gynecologists (ACOG) are still recommending that, if you are pregnant, considering pregnancy, or not actively preventing pregnancy, that you and your partner should not travel to Zika positive countries.
Over the last few years, news about Zika has changed so much, from reports of how long the incubation and infection periods are to the percentage rates at which babies are born with birth defects. Why is that?
When Zika was first detected, we had very little information. All we knew was that babies were being born with serious defects at an increased rate and that Zika possibly had something to do with it. Today, the CDC is tracking anyone who has tested positive for the virus, so we have much more information from the start. This is the key, as we can determine with better certainty what trimester someone was infected, how long ago she or her partner traveled, and—after the baby is born—what affects we see.
If you contract the Zika virus while pregnant, does it make a difference to your fetus’s contraction risk if you're in your first, second, or third trimester?
During the first trimester, Zika is much more likely to cause a miscarriage. In the second and third trimesters, the affects will vary. We are still tracking the affects, some of which may take years to be established. (Learning disabilities or autism, for example, can take years to see and track.)
How long can Zika live in the body?
The data is constantly being examined, but here’s what we know at this point: The Zika virus has been detected in blood, urine, semen, saliva, female genital tract secretions, cerebrospinal fluid, amniotic fluid, and breast milk for different lengths of time.
In non-pregnant individuals, Zika virus RNA is usually detectable in the blood as late as 81 days following onset of illness. In pregnancy, Zika virus RNA has been detected in the serum (a fluid in the blood) as late as 107 days after onset of illness.
Zika virus RNA has been detected in semen even longer. Zika virus RNA usually clears from semen after about three months, but has been detected in semen up to 188 days after onset of illness. That doesn’t necessarily mean, however, that the virus can be transmitted. Take one study where 184 men with symptomatic Zika virus infection: Zika virus persisted in the semen of some men for more than six months; however, Zika-positive semen samples were infectious in only four percent of cases. (There are reports of sexual transmission of Zika virus as late as 41 days after a partner's onset of symptoms; in the lab, infectious Zika virus in semen has been detected as late as 69 days after the onset of illness.)
So what does this means in terms of trying to conceive? How long should one wait?
The advice varies as we find out more. Initially we recommended waiting at least six months based on the studies that showed how long Zika could live in semen. Then, after finding out that infection rates were incredibly low after three months, the CDC changed its recommendations to waiting three months, and others argue it should be four.
It’s worth noting, though, that this guidance differs from that of the World Health Organization (WHO), which suggests that men and women outside areas of Zika transmission who have traveled to areas with active transmission wait at least six months following their return before having unprotected sex, regardless of symptoms.
Can you be a carrier of Zika and not show any outward signs?
Yes. According to a recent study, it appears that only twenty- to twenty-five percent of infected individuals will show symptoms.
If you are pregnant and have possibly been exposed to Zika, what should you do?
Alert your doctor right away. He or she will record when you were exposed, if you have symptoms, and will assess whether you should be tested or not. If you are tested, your test is filtered through the CDC, and the turn-around time is about two weeks. (Interestingly, a government shutdown, like we had in December 2018, could affect this turn-around time.)
If the result is positive, we don’t test again. If the test is negative, we do another test to ensure it’s not a false negative (which can happen). If that second test is positive or inconclusive, we run a third test.
Even if this test is positive, we typically don’t stop there as the third test may not adequately distinguish between Zika and dengue infection. So we may test again.
Do countries conduct and report their own Zika risk findings, or does an international organization assess Zika risk in all countries?
Both. There is some private funding available but certainly not every country has a global watchdog that is ensuring that the data is correct.
When looking at the CDC’s travel website, whole countries are often blanketed in Zika risk, even in places where mosquitos don’t survive (like in the mountains of Argentina). Why is this?
It is a lot easier to say Zika may be present than to say with certainty that it is not, but it’s worth noting that the CDC map actually has elevation color coded so the mountainous regions are highlighted as low likelihood.
Why is it that countries like Uruguay, which is surrounded by Zika risk countries, has warm weather, and is on the coast where mosquitos thrive, isn’t on the CDC’s risk list? It’s not as if mosquitos stop at country borders.
We rely on countries reporting their own data, but we have to proceed with caution.
If you are trying to get pregnant (but aren’t) and you’ve potentially been exposed to Zika, what should you do? Can you get tested to see if you have it?
If you’ve potentially been exposed to Zika, we recommend using protection and waiting four months to try and conceive. Doctors don’t recommend testing for Zika before you are pregnant. Why? Zika testing is not 100 percent reliable. There are too many false positives (there can be cross-reactivity with other flaviviruses such as dengue virus, as well as cross-reactivity in individuals who have been vaccinated against yellow fever or Japanese encephalitis) and false negatives.
Can you find out if your fetus/baby has been affected before you give birth?
Yes and no. There are soft signs such as the head measuring small, which doctors can start tracking at 16 weeks. You could also do an amniocentesis—a sampling of amniotic fluid—but, as is the case with all fluids, the virus might not be present at the time of testing. Still, that doesn’t mean the virus wasn’t there at some point, and thereby the fetus already affected.
If you have to travel to a country with a Zika risk while pregnant, what precautions should you take?
Don’t go. We know this can be a really difficult call—I’ve had patients who have missed important work events, family reunions, and even weddings where they were maids of honor—but I can’t recommend travel to a Zika positive country to a person who is pregnant or trying to conceive.
If you have a friend or family member (not a sexual partner) who has traveled to a country with Zika and might have contracted it, should you take any precautions around that person within the first three months of their return?
There are no formal recommendations on this as of yet.
Are there any other infectious diseases that are getting less attention but that pregnant women/women trying to conceive should also consider before traveling?
The flu. It can be horrible in pregnancy and if fevers get high enough it can cause serious problems.
Where should we go to get the latest information on where in the world we are at risk for Zika?
The CDC website is the best place to go.