Does Zika Fever Pose An Imminent Threat To Your Unborn Child?

A recent outbreak of the Zika virus in Brazil has caused alarm world-wide, although the relationship between the virus and birth defects is not certain.

What Is the Zika Virus?

Zika virus is a member of a group of viruses known as arboviruses. These viruses maintain themselves in a cycle traveling from vectors, the insects and ticks that carry them, to hosts, the people they make sick. A blood-feeding arthropod (mosquito, tick, or fly, for example) acquires the virus when feeding on the blood of a human who is already infected. The arthropod regurgitates the virus when it feeds on the next human or animal, causing the infection. 

Zika isn't really new. It was first discovered in 1947 in Uganda in the Zika forest near Lake Uganda. The first medically identified victim of the virus was a monkey, not a human being. Prior to 2007, a worldwide total of only 14 cases of humans infected with virus were known to medical researchers. However, these cases occurred far outside the Zika forest. There were people infected in Uganda in 1969 and 1970, Nigeria in 1971 and 1975, Sierra Leone in 1972, Gabon in 1975, Central African Republic in 1979, Senegal from 1988 to 1991, and Côte d'Ivoire in 1999. Recently, researchers report anecdotally, Zika virus was detected in Senegal in 2011 and 2012. Zika virus infections were reported in Pakistan, Malaysia, and Indonesia in 1977 and 1978, Micronesia in 2007, and Cambodia in 2010. There was a small epidemic in April 2007, when a Zika fever epidemic occurred in Yap island in Micronesia, where there were 49 confirmed cases and 73% of the residents older than 3 years tested positive for recent Zika virus infection.

All of these outbreaks were recorded in the medical literature, but public health officials weren't especially alarmed. Before 2015, Zika virus fever caused relatively mild symptoms, a little like the flu. There would be fever, maybe a rash, conjunctivitis, and joint pain. Pregnant women did not transmit the virus to their children before they were born. There were no reports of birth defects.

By 2015, however, something about the virus had changed. In Paraiba state in northeastern Brazil, a number of women who had seemed fine during pregnancy delivered babies with severe birth defects. These babies had deformed bones and joints, and the bones in their skulls had joined together prematurely so that the head was unusually small. The deformation of the skull, microcephaly, has been getting the most media attention, but it's not the only problem facing these infants. In many of these infants, not only is the skull too small, there are multiple calcifications in the brain, suggesting the brain had become infected and inflamed before the baby was born. When public health officials were informed of the growing numbers of cases, they sent blood samples to the Oswaldo Cruz Foundation in Rio Janeiro, and the results showed that in some of the cases of microcephaly, the mother and child had been infected with Zika virus before birth.

Why would a relatively harmless virus start causing devastating birth defects? It's possible there were actually many more cases in Africa that simply didn't get reported. It's possible that people in Uganda have been exposed to the virus so often that they built up a resistance to it. However, molecular geneticists have found a specific mutation in the Zika virus that seems to have occurred, or to have occurred in observed cases, only since 2012.

READ Has The Zika Virus Triggered An Epidemic Of Birth Defects In Brazil?

Does Zika Virus Really Cause Microcephaly?

Zika virus infection is not the only explanation of microcephaly. West Nile virus, Rubella, cytomegalovirus, and toxoplasmosis are known causes of microcephaly. There are at least eighteen genetic mutations that can cause the condition. The death of an identical twin while still in the womb can cause microcephaly, as can fetal alcohol syndrome or the mother's use of the anti-epileptic drug phenytoin (Dilantin).  Malnutrition, exposure to radiation, the mother's hypothyroidism, poorly controlled gestational diabetes, phenylketonuria in the mother, ischemic or hemorrhagic stroke while still in the womb can also cause microcephaly.

In Brazil, there seem to be many more cases of microcephaly than Zika virus. Here are the statistics as of February 1, 2016:

• There have been 4,180 cases of suspected microcephaly (that is, the baby's skull appeared small), but only 732 babies have been referred to specialists.Of those 732 babies, 460 have been found not to have microcephaly and only 272 have the condition.
• Of the 272 babies who have confirmed microcephaly, only six have microcephaly clearly due to Zika virus. The other babies were were found to have microcephaly due to some other cause.

Six cases of Zika-virus induced microcephaly is a tragedy for the babies and their families, but that doesn't make Zika virus a global health emergency. However, thousands of cases of suspected microcephaly without knowing the cause most certainly is an emergency.

What Women And Their Families Can Do About Zika Fever

Most women who are or who are planning to become pregnant who read stories about Zika fever understandably want to protect their unborns. There are some very basic steps women can take to avoid Zika virus infection.

• Pregnancy is a bad time to move to or to take a trip to northeastern Brazil, central Africa, or Micronesia. Avoid travel to these areas if at all possible.
• Women who are pregnant should avoid contact with mosquitoes. This means avoiding outdoor exposure at times mosquitoes are most likely to bite (at dawn and at dusk), wearing pants and long sleeves, and using natural mosquito repellents. When you do go outside, favor direct sunlight; mosquitoes prefer shade. 
• It's more important to avoid the infection during the first and second trimesters than the third, although women should not let up their guard until the baby is born. Once babies are born, infection even with the mutated, new form of Zika virus only causes mild-flu like symptoms.
• Since mosquitoes spread the disease from person to person, it's important that anyone in the same household with a pregnant woman who gets unidentified flu-like symptoms after travel to the tropics consult a doctor. Chances are it won't be Zika virus, but it's best to know for sure.
• If you haven't been exposed to mosquitoes in the tropic, don't panic (yet). Although some of the cases of babies born with birth defects have occurred in women who did not show symptoms of Zika fever while they were pregnant, the fact that you don't have symptoms doesn't mean you do have Zika fever.

READ Zika: The Terrifying Virus Responsible For Booming Microcephaly Cases Might Be An STD?

The whole family can get involved with keeping your environment as mosquito-free as possible.

• Change water in pet dishes at least once a day. Change water in wading pools and bird baths every other day.
• Cover trash containers so they will not collect water. Irrigate lawns and gardens with care so water does not stand for several days.
• Cover your hot tub when you are not using it. Get a friend or neighbor to take care of it if you are out of town. Use a water filter (with a safety cover) in your swimming pool to keep water agitated so it does not provide mosquitoes with a breeding ground.
• Empty or get rid of buckets, bottles, cans, old tires, pots, plant saucers and other containers that hold water.
• Fill in low areas in your lawn that catch water.
• Fill in holes in trees that catch water.
• Keep drains and ditches clear of trash and weeds to keep water from collecting.
• Keep gutters clear of areas that could collect standing water. Remove standing water around your house and from flat roofs after rains.
• Place screens over rain barrels and openings to cisterns and rain water catchments.
• Repair all leaking plumbing indoors and outdoors. Don't leave faucets dripping (except to keep pipes from freezing).
• Stock ornamental ponds in your garden with fish that eat mosquitoes.

If you think you could have Zika fever, you need to see a doctor. If you live in the United States, here are the guidelines for what your doctor will need to do.

• Your doctor will look at other concerns unless you have traveled to an area where there is currently a Zika fever outbreak. The cases in the United States have occurred in people who are returning from the tropics. They didn't catch the infection here (as of February 1, 2016).
• If you don't have any symptoms of Zika fever, the first step for your doctor is to order ultrasound of your unborn to make sure there are no indications of the disease.
• If you have possible symptoms of the disease, your doctor will order a test called reverse transcription-polymerase chain reaction (RT-PCR) testing of maternal serum. It's a blood test, of the mother's blood. Amniocentesis is not part of the protocol for diagnosing the disease, especially in the first trimester.
• If you test positive for the disease, the only treatments are those for fever and pain. Unfortunately, right now there is nothing the doctor can do for your baby except to support your health in every other way possible. Even so, the Centers for Disease Control directs doctors to collect the placenta and umbilical cord after birth for viral testing if the mother or baby shows signs of infection. (This is not required of every mother after every birth.)
• Babies born to mothers who may have been exposed to the Zika virus should be checked for eye problems before they leave the hospital, and for hearing problems in the first month, even if they display no other symptoms of the disease.
• Follow up doctors during the first year of life to make sure the baby's brain is growing normally is a must, as is repeated testing of hearing and sight.

The Centers for Disease Control are not expecting a major outbreak of Zika fever in the United States in 2016. Americans use air conditioning during the summer, and keep their windows closed. Urban areas in the United States are not as densely populated as those in Central and South America, so it will be harder for the mosquitoes to travel from person to person to spread the virus. Nonetheless, they are expected up to four million Americans to be infected with the virus over the next five years, during which there will be no vaccine.

There are many more causes of microcephaly than just Zika fever. Nonetheless, it's only prudent to be on the lookout for possible symptoms of the virus, and to work even more closely with your doctor during pregnancy.