Infants should be tested for Zika virus either if their mothers had a positive or inconclusive test for the virus, or if they were born with microcephaly or intracranial calcifications and their mothers resided in or traveled to an area with Zika virus transmission, according to CDC interim guidelines.

In the event of a positive or inconclusive test, pediatricians should report the case and assess the infant for possible long-term sequelae, stated J. Erin Staples, PhD, of the CDC in Atlanta, and colleagues.

However, a negative test should be evaluated and treated for other possible etiologies, they wrote in an early edition of the Morbidity and Mortality Weekly Report.

The first step for any potentially infected infant is to test the mother, and then the infant for the Zika virus. Even if the infant test is negative, the authors recommended an ophthalmologic evaluation within the first month of life and a repeat hearing test at 6 months, as reports of abnormal eye findings and delayed hearing loss have been present in infants potentially infected with the virus.

If the test is positive or inconclusive, but the infant does not present with microcephaly or intracranial calcifications, the authors suggested a comprehensive physical examination, including evaluation for neurologic abnormalities, and full body photographs to check for dysmorphic abnormalities. The infant should also have a cranial ultrasound, unless a prenatal ultrasound showed no brain abnormalities in the third trimester.



Infants presenting with microcephaly or intracranial calcifications should have the diagnosis confirmed. The authors noted that microcephaly is defined as occipitofrontal circumference less than the third percentile, based on standard growth charts for sex, age, and gestational age. Infants with microcephaly or intracranial calcifications, but a negative Zika virus test, should be evaluated for other possible etiologies.

Those infants with a positive test should be referred to a clinical geneticist or dysmorphologist, as well as a pediatric neurologist, and potentially a pediatric infectious disease specialist. The infant should then be tested for other congenital infections, undergo a complete blood and platelet count, and have liver function and enzyme tests.

Mothers who have not undergone any Zika virus testing during pregnancy should be tested only if they report symptoms of the virus during or within 2 weeks of time spent in area where Zika virus is present during their pregnancy. However, mothers are still encouraged to breastfeed even in areas where Zika virus is found.

Any confirmed cases of Zika virus should be reported to the state, territorial, or local health departments.

The CDC has urged expectant mothers or women planning to get pregnant to avoid visiting multiple countries, including Brazil, Honduras, Martinique, Mexico, Panama, Paraguay, Barbados, Bolivia, Ecuador, and Samoa.

An outbreak of Zika virus infection was first recognized in northeastern Brazil in early 2015, and authorities reported a sharp increase in the number of reported cases of microcephaly in areas affected by the outbreak in September.