On April 11 the Centers for Disease Control and Prevention (CDC) announced they had confirmed a causal relationship between Zika infections during pregnancy and the birth defect microcephaly. Along with this finding, the CDC also announced that the new research about Zika indicated the virus was “scarier than we initially thought.”

With that announcement, and the arrival of mosquito season, we received a number of reader questions about Zika, mosquito-borne viruses and pregnancy. Many readers reported they’d read information somewhere else online that was conflicting, confusing or that they wanted us to truth test.

We quickly realized that the best way to get our readers the information they wanted was to go straight to the source: the CDC.

We put out a call on Facebook and Twitter for your questions and brought them to Dr. Peggy Honein of the CDC’s National Center on Birth Defects and Developmental Disabilities (NCBDDD). Below are her answers to your questions.

Question: I’m pregnant and I’ve heard that there have already been confirmed cases of Zika transmission from mosquitoes within the US.  What does the CDC recommend for women that are pregnant or are considering becoming pregnant?

Answer:

As of the latest information available on April 25, 2016, there are no confirmed cases of Zika transmission from mosquitoes in the continental United States.

Until more is known, CDC recommends special precautions for the following groups:

  • Pregnant women
    • Should not travel to any area where Zika virus is spreading.
    • If you must travel to one of these areas, talk to your doctor or healthcare provider first and strictly follow steps to prevent mosquito bites during the trip.
    • If you have a male partner who lives in or has traveled to an area where Zika is spreading, use a condom every time you have sex or do not have sex during the pregnancy. To be effective, condoms must be used correctly (warning: this link contains sexually graphic images) from start to finish, every time you have sex.  This includes vaginal, anal, and oral (mouth-to-penis) sex.
  • Women trying to get pregnant
    • Before you or your male partner travel, talk to your doctor or healthcare provider about your plans to become pregnant and the risk of Zika virus infection.
    • A woman and her male partner should strictly follow steps to prevent mosquito bites during the trip.

Question: Why was CDC unable to say definitively, until April 11, that Zika caused microcephaly, when we’ve known about Zika for several months?  Is it possible that it’s actually Zika and another variable that are responsible for microcephaly?

Answer:

As with most scientific research, no single piece of evidence provides conclusive proof of the causes of a health problem. Instead, increasing evidence from a number of studies and a careful review of causal criteria was needed to conclude a particular factor causes a health problem.

After careful review of existing evidence, and using two sets of scientific and accepted criteria, scientists at CDC have concluded that Zika virus is a cause of microcephaly and other severe fetal brain defects.

While the evidence supports a causal link, many questions still remain. We still do not know the full range of potential health problems that Zika virus infection may cause, and other factors (e.g., another infection occurring at the same time) that might affect the risk for birth defects.

[Editor’s note: Some have claimed that a pesticide/larvacide is responsible for incidence of microcephaly and not Zika. Dr. NAME addressed this rumor earlier on our site] 

Question: Is there a test for Zika that can easily be performed at my OB’s office?  What should I do if I’m pregnant and am concerned I’ve been exposed?

Answer:

Yes, if you have traveled to or live in an area with active Zika and you get sick with a fever, rash, joint pain or red eyes, doctors or other healthcare providers can take a small amount of your blood and test it for Zika virus. After the virus clears from your blood or if you never feel sick, doctors can order a different test to look for evidence that you were recently infected with Zika.

  • Testing can be offered from 2 to 12 weeks after pregnant women return from travel to areas with Zika virus. Information about serologic testing of asymptomatic persons is limited; on the basis of experience with other flaviviruses, we expect that antibodies will be present from 2 weeks after virus exposure and can persist for up to 12 weeks.
    • Pregnant women with possible exposure to Zika virus up to 8 weeks before the start of pregnancy (or 6 weeks before the woman’s last menstrual period) can be offered testing for Zika within 2-12 weeks after the possible exposure.
  • For pregnant women who had sex without a condom with a male partner who had possible exposure to Zika virus, testing is recommended if:
    • The woman has at least one symptom of Zika virus infection OR
    • Her male partner is diagnosed with Zika virus disease or has symptoms consistent with Zika virus infection 

Question: What tests can be done to detect microcephaly in utero?  Are there any treatments that can be done before birth to stop the condition from progressing?

Answer:

Microcephaly can be diagnosed during pregnancy with ultrasound. Microcephaly is most easily diagnosed by ultrasound late in the second trimester or early third trimester of pregnancy.

Fetal ultrasound is generally performed in pregnancies between 18-20 weeks of gestation to assess fetal anatomy as part of routine obstetrical care.

The optimal time to perform ultrasound screening for fetal microcephaly is not known. In the absence of microcephaly, the presence of intracranial calcifications before 22 weeks gestation might suggest a risk for the future development of microcephaly.

There is no treatment available before birth to stop the condition from progressing. In addition, no treatment is currently available for Zika virus infection. Care for these infants is focused on diagnosing and managing conditions that are present, monitoring the child’s development over time, and addressing problems as they arise. 

Question: Does Zika only cause problems when there is an active infection during pregnancy?  What if you’re infected but don’t show any signs of the illness? What if you contract the illness and recover several months before becoming pregnant?

Answer:

Most people infected with Zika virus won’t have symptoms or will have only mild symptoms. Zika virus infection during pregnancy is a cause of microcephaly and other severe fetal brain defects. This means that Zika virus infection in pregnancy increases the chances of a poor pregnancy outcomes. However, Zika virus infection in a mother does not definitely mean a poor pregnancy outcome will occur.

Pregnant women should talk to a doctor or other healthcare provider if they or their male sex partners recently traveled to an area with Zika, even if they don’t feel sick.

Zika virus usually remains in the blood of an infected person for about a week. Currently, there is no evidence to suggest that past Zika virus infection poses a risk of birth defects for future pregnancies.  

Question: I don’t want to become pregnant, but I don’t have access to reliable birth control. I can’t afford an unplanned pregnancy or a baby that has a high risk of special needs, like microcephaly. Are there any programs that can help me access reliable birth control?

Answer:

Zika virus infection in pregnancy is linked to adverse pregnancy and birth outcomes, including pregnancy loss, microcephaly, and other congenital brain defects.

A primary strategy to reduce Zika-related pregnancy complications is to prevent pregnancy in women who do not want to become pregnant. CDC is partnering with other organizations within the Department of Health and Human Services to develop a collaborative and coordinated response to contraceptive access issues in the US in response to Zika. 

Question: Are there any areas of the US and Canada where the mosquitos that can transmit Zika don’t live? I heard the type of mosquitos that carry Zika only bite in the day time, is this true?

Answer:

This link has maps and more information about the estimated range of these two mosquitoes in the United States.

  • There are many species of Aedes Not all Aedes species spread Zika virus. At this time, we don’t know if there are other non-Aedes mosquito species that could spread Zika virus.
    • Aedes aegypti mosquitoes live in tropical, subtropical, and in some temperate climates. They are the primary vector of Zika, dengue, chikungunya, and other arboviral diseases. Because Aedes aegypti mosquitoes live near and prefer to feed on people, they are considered highly efficient at spreading these diseases.
    • Aedes albopictus mosquitoes live in tropical, subtropical, and temperate climates. They have adapted to survive in a broader temperature range and at cooler temperatures than Aedes aegypti. Because these mosquitoes feed on people and animals, they are less likely to spread viruses like Zika, dengue, or chikungunya. The strain of albopictus in the US came from northern Japan in 1985 and is capable of living in more temperate climates.

Mosquitoes that spread Zika are aggressive daytime biters, however, they can also bite at night.  

Question: Are commercial bug sprays with DEET safe to use during pregnancy?  Besides using bug spray, is there anything else I can do to prevent mosquito bites?

Answer:

Commercial bug sprays are safe to use during pregnancy. CDC recommends using EPA-registered insect repellents with one of the following active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol. Choosing an EPA-registered repellent ensures the EPA has evaluated the product for effectiveness.

Insect repellents registered by the EPA repel the mosquitoes that spread Zika and other viruses like dengue, chikungunya, and West Nile.

When used as directed, EPA-registered insect repellents are proven safe and effective even for pregnant and breastfeeding women.

To protect your child from mosquito bites:

  • Do not use insect repellent on babies younger than 2 months old.
  • Do not use products containing oil of lemon eucalyptus or para-menthane-diol on children younger than 3 years old.
  • Dress your child in clothing that covers arms and legs
  • Cover crib, stroller, and baby carrier with mosquito netting.
  • Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin.
  • Adults: Spray insect repellent onto your hands and then apply to a child’s face.

Here’s what you can do outside of your home:

  • Install or repair and use window and door screens. Do not leave doors propped open.
  • Once a week, empty and scrub, turn over, cover, or throw out any items that hold water like tires, buckets, planters, toys, pools, birdbaths, flowerpot saucers, or trash containers. Mosquitoes lay eggs near water.
    • Tightly cover water storage containers (buckets, cisterns, rain barrels) so that mosquitoes cannot get inside to lay eggs.
    • For containers without lids, use wire mesh with holes smaller than an adult mosquito.
    • Use larvicides to treat large containers of water that will not be used for drinking and cannot be covered or dumped out.
  • Use an outdoor flying insect spray where mosquitoes rest. Mosquitoes rest in dark, humid areas like under patio furniture, or under the carport or garage. When using insecticides, always follow label instructions.
  • If you have a septic tank, repair cracks or gaps. Cover open vent or plumbing pipes. Use wire mesh with holes smaller than an adult mosquito.
  • Hire a pest control expert to treat your yard and outdoor areas with long-lasting insecticide or larvicide to control mosquitoes up to several weeks.

Here’s what you can do inside your home:

  • Use air conditioning when possible.
  • Keep mosquitoes from laying eggs inside your home. Once a week, empty and scrub, turn over, cover, or throw out any items that hold water like vases and flowerpot saucers.
  • Kill mosquitoes inside your home. Use an indoor flying insect fogger* or indoor insect spray* to kill mosquitoes and treat areas where they rest. These products work immediately, but may need to be reapplied. Always follow label directions. Only using insecticide will not keep your home free of mosquitoes.
    • Mosquitoes rest in dark, humid places like under the sink, in closets, under furniture, or in the laundry room. 

Question: I read that Colombia has more cases of Zika than any other country, but they don’t have any instances of associated microcephaly, is this true?

Answer:

Colombia reported local transmission of Zika virus disease in October 2015. If the highest risk to the fetus from Zika is associated with Zika virus infection during early pregnancy, we would expect to see birth defects in infants born in April or May 2016. Preliminary reports of birth defects among babies born to women who had Zika virus infection during pregnancy are starting to emerge in Colombia and are being carefully investigated.

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Categories: Infectious Disease + Vaccines, Policy, Politics, + Pop Health, Pregnancy, Birth + Family Planning