Acute Communicable Disease Control

Periconceptional Infection
Little is known regarding the risks of periconceptional Zika virus infection (infection during 8 weeks before conception or 6 weeks before last menstrual period). Given the limited information available at this time and the potential for severe birth defects from congenital Zika infection, periconceptual infection is assessed, managed and followed using the same protocols as infection acquired during pregnancy.

• Severe microcephaly resulting in a partially collapsed skull
• Decreased brain tissue with brain damage (as indicated by a specific pattern of calcium deposits)
• Damage to the back of the eye with a specific pattern of scarring and increased pigmentation
• Limited range of joint motion such as clubfoot
• Too much muscle tone restricting body movement soon after birth

For additional abnormalities that have been associated with congenital Zika syndrome see CDC Zika Syndrome and Other Birth Defects.

Travel Recommendations
Public Health recommends that pregnant women, and those planning to become pregnant, delay travel to areas with risk of Zika. If a pregnant woman must travel to an area with risk of Zika, she should be advised to strictly follow steps to prevent mosquito bites and sexual transmission of Zika during the trip. All travelers should continue to take steps to prevent mosquito bites for at least 3 weeks after they return home to prevent spreading Zika to uninfected local mosquitoes. Additional travel recommendations are available from the CDC.

Preventing Sexual Transmission
Pregnant women whose sexual partners have traveled to or lived in an area with risk of Zika should use condoms every time they have sex (vaginal, anal, oral sex, and sharing of sex toys) or not have sex during the entire pregnancy. Additional information is available from the CDC.

• More than one Zika test may be required before a final result is determined
• Previous exposure to Zika virus could affect test results during pregnancy
• There are different types of tests for Zika

Prenatal Care
Given the limitations in the available screening modalities and the absence of effective interventions to prevent and treat congenital Zika virus infection, a shared decision-making model is essential to ensure that pregnant women and their families understand the risks and benefits of screening in the context of the patient’s preferences and values. For example, serial ultrasound examinations might be inconvenient, unpleasant, and expensive and might prompt unnecessary interventions; amniocentesis carries additional known risks such as fetal loss. These potential harms of prenatal screening for congenital Zika syndrome might outweigh the clinical benefits for some patients; therefore, these decisions should be individualized.

- Fetal Ultrasound
Women with possible exposure but without laboratory evidence of Zika virus infection during pregnancy should receive ultrasound screening as recommended for routine prenatal care (between 18-20 weeks of gestation). For pregnant women with confirmed and possible Zika virus infection, the CDC recommends serial fetal ultrasounds (every 3–4 weeks) should be considered to assess fetal anatomy, particularly fetal neuroanatomy, and to monitor growth closely. However, there are no data specific to congenital Zika virus infection to guide these timing recommendations; clinicians may consider extending the time interval between ultrasounds in accordance with patient preferences and clinical judgment.

Given the length of time for the detection of prenatal microcephaly, prenatal ultrasounds should include a detailed fetal anatomy, particularly neuroimaging, to detect other brain or structural abnormalities that might occur before microcephaly. Prenatal ultrasound findings associated with congenital Zika virus infection include intracranial calcifications at the gray-white matter junction, ventriculomegaly, abnormalities of the corpus callosum, microcephaly, and limb anomalies. Additional information about clinical guidelines during pregnancy are available from the CDC.

- Fetal MRI
Fetal MRI is not a screening tool and should be used only to answer specific questions raised by ultrasound or used in occasional, specific, high-risk situations. Interpretation of fetal MRI requires specialized expertise and has limited availability in the United States.

- Amniocentesis
Amniocentesis is not recommended until after 18 weeks of gestation, and the optimal time to perform amniocentesis to diagnose congenital Zika virus infection is not known. A positive Zika virus RNA NAT result from amniotic fluid might indicate fetal infection. However, sequential amniocenteses have demonstrated that Zika virus RNA may only be present transiently; therefore, a negative Zika virus RNA NAT result from amniotic fluid does not exclude congenital Zika virus infection. Amniocentesis is therefore currently not recommended as a test for determining Zika virus infection. If amniocentesis is indicated for other reasons, NAT testing for Zika virus could be considered to assist with the diagnosis of fetal infection.

Delivery and Postnatal Care
Pregnant women with possible Zika exposure and who have not been tested since last exposure should be evaluated for Zika virus at antenatal and delivery hospitalizations.

Birth hospitals may consider collecting infant specimens for concurrent Zika virus testing if maternal testing is being done.

For full description of postnatal care guidelines see Update: Interim Guidance for the Diagnosis, Evaluation, and Management of Infants with Possible Congenital Zika Virus Infection — United States, October 2017..

INFANT TESTING AND FOLLOW-UP

Infants with Clinical Findings Born to Mothers with Possible Zika Virus Exposure in Pregnancy (regardless of mother's Zika test result)

• Zika virus RNA PCR should be performed on both infant serum and urine, concurrently with Zika virus IgM on serum, ideally in the first two days of life. If non-negative IgM and negative Zika virus PCR, confirm with PRNT.
• Testing cerebral spinal fluid (CSF) for Zika virus RNA PCR and Zika virus IgM antibody testing should be considered, especially if serum and urine testing are negative and another etiology has not been identified.

Clinical Evaluation and Management
In addition to a standard evaluation, infants should have a head ultrasound and a comprehensive ophthalmologic exam performed by age 1 month to detect subclinical brain and eye findings. Infants should also be referred for automated ABR by age 1 month if newborn hearing screen was passed using only otoacoustic emissions methodology. Healthcare providers should watch for the appearance of other clinical findings associated with congenital Zika syndrome. Diaphragmatic paralysis swallowing dysfunction and signs of increasing intracranial pressure should prompt neuroimaging to assess for postnatal hydrocephalus.

• Infectious disease for evaluation of other congenital infections and assistance with Zika virus diagnosis, testing, and counseling;
• Clinical genetics for confirmation of the clinical phenotype and evaluation for other causes of microcephaly or congenital anomalies;
• Neurology by age 1 month for comprehensive neurologic examination and consideration for other evaluations such as advanced neuroimaging and EEG.

The initial clinical evaluation, including subspecialty consultations, can be performed before hospital discharge or as an outpatient. Follow-up requires a multidisciplinary team to follow recommendations, coordinate care, and ensure that abnormal findings are addressed.

Infants without Clinical Findings Born to Mothers with Laboratory Evidence of Possible Zika Virus Infection During Pregnancy*
*This includes includes mothers with history of possible Zika exposure who are awaiting confirmation of result by PRNT. If PRNT is negative, go to: Infants without Clinical Findings Born to Mothers with Possible Zika Virus Exposure During Pregnancy but without Laboratory Confirmation During Pregnancy.

• Zika virus RNA PCR should be performed on both infant serum and urine, concurrently with Zika virus IgM on serum, ideally in the first two days of life. If non-negative IgM and negative Zika virus PCR, confirm with PRNT.
• If CSF is collected for other purposes, RNA PCR and IgM antibody testing should be performed.

Clinical Evaluation and Management
In addition to a standard evaluation, infants should have a head ultrasound and a comprehensive ophthalmologic exam performed by age 1 month to detect subclinical brain and eye findings. Infants should also be referred for automated ABR by age 1 month if newborn hearing screen was passed using only otoacoustic emissions methodology. Healthcare providers can consider additional evaluation in consultation with families. If findings consistent with congenital Zika syndrome are identified at any time, referrals to the appropriate specialists should be made, and subsequent evaluation should follow recommendations for infants with clinical findings consistent with congenital Zika syndrome.

Infants without Clinical Findings Born to Mothers with Possible Zika Virus Exposure During Pregnancy but without Laboratory Evidence of Possible Zika Infection During Pregnancy*

Laboratory Testing
Testing infants in this group for Zika virus infection is not routinely recommended.

Clinical Evaluation and Management
Infants should have a standard evaluation performed at birth and at each subsequent well-child visit along with routine preventive pediatric care and immunizations. Further clinical evaluation for congenital Zika virus infection beyond a standard evaluation and routine pediatric care is not routinely indicated.

Infants with Laboratory Evidence of Congenital Zika Virus Infection
Laboratory evidence of congenital Zika virus infection includes a positive Zika virus NAT or a non-negative Zika virus IgM with confirmatory neutralizing antibody testing if PRNT confirmation is performed. Further clinical evaluation for infants with laboratory evidence of congenital Zika virus infection should follow recommendations for infants with clinical findings even in the absence of clinically apparent abnormalities.

Infants without Laboratory Evidence of Congenital Zika Virus Infection
If adequate laboratory testing is performed (e.g., concurrent testing on infant serum and urine within the first few days after birth), there is no laboratory evidence of congenital Zika virus infection (i.e., negative NAT and IgM on infant samples). Additionally, if the clinical evaluation is normal, then congenital Zika virus infection is unlikely. Infants should continue to receive routine pediatric care, and health care providers should remain alert for any new findings of congenital Zika virus infection.

If findings consistent with congenital Zika syndrome are identified at any time, referrals to the appropriate specialists should be made and further evaluation should follow recommendations for infants with clinical findings consistent with congenital Zika syndrome.

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