The Centers for Disease Control and Prevention has updated its interim guidelines on treatment of infants born to mothers who may have been exposed to Zika virus during pregnancy, adding new protocols and expanding the scope of its guidance to include all children under age 18 years.
The updated guidelines, which were released Feb. 19, call for “routine care” for infants whose mothers traveled to or resided in areas with Zika virus transmission during pregnancy but did not receive Zika virus testing, provided that the infant has a normal head circumference, normal prenatal and postnatal ultrasounds, and a normal physical examination ( Morb Mortal Wkly Rep. 2016;65[early release]:1-6 ).
If an infant’s mother has traveled to a Zika-endemic area, the first step is screening the infant for microcephaly or intracranial calcifications, either prenatally or at birth. If such defects are found, a complete physical examination and Zika virus tests should be performed on the infant.
If tests are positive or inconclusive for Zika virus infection, an additional clinical evaluation is warranted, as well as an assessment for possible long-term sequelae.
Even if no microcephaly or intracranial calcification is detected in the infant, the guidelines state that the mother should still undergo testing for Zika virus infection. If test results are negative, then “routine care” of the infant can proceed; however, positive or inconclusive results should be followed by a physical examination of the infant.
For laboratory testing of congenital Zika virus infection, infant serum should be tested for Zika virus RNA, immunoglobulin M (IgM), dengue virus IgM, and related neutralizing antibodies. If testing on a placenta or umbilical cord sample, use Zika virus immunohistochemical staining, while reverse transcription–polymerase chain reaction (RT-PCR) should be used on fixed or frozen tissue.
Acute Zika virus infections should be tested via RT-PCR for Zika virus RNA of either the serum or cerebrospinal fluid in children who have been symptomatic for less than 7 days. If symptoms have been present for 4 or more days, but Zika virus RNA has not been detected, then the serum or cerebrospinal fluid should be tested for Zika virus IgM and dengue virus IgM, along with related neutralizing antibodies.
All children under age 18 years should be considered likely for Zika infection if they have traveled to or resided in a Zika-endemic area within the previous 2 weeks and have at least two of the following known symptoms of Zika virus infection: fever, rash, conjunctivitis, and arthralgia. The same criteria apply to infants during the first 2 weeks of life if the mother has been to an area where Zika is endemic and if the infant exhibits any two symptoms of the virus.
“Arthralgia can be difficult to detect in infants and young children, and can manifest as irritability, walking with a limp (for ambulatory children), difficulty moving or refusing to move an extremity, pain on palpation, or pain with active or passive movement of the affected joint,” according to the guidelines.
NSAIDs should not be used to treat potential Zika virus infections until dengue virus infection has been definitively ruled out as the cause of illness, because of “the potential for hemorrhagic complications of dengue fever.” Further, no child under age 6 months should be prescribed NSAIDs, and no children of any age who present with acute viral illness should be given aspirin, because of associations with Reye syndrome.
Although Zika virus RNA has been isolated in breast milk, there have been no reported cases of the virus being transmitted via breastfeeding. The CDC considers breastfeeding by mothers with Zika virus infections to be safe, saying that “the benefits of breastfeeding outweigh the theoretical risks of Zika virus transmission through breast milk.”
For infants and children, the best way to avoid Zika virus infection is to avoid getting bitten by mosquitoes. The most effective ways to prevent mosquito bites are by “using air conditioning or window and door screens when indoors, wearing long-sleeved shirts and long pants, using permethrin-treated clothing and gear, and using insect repellents.” The CDC also warns against using oil of lemon eucalyptus on children under age 3 years.
“Persons with Zika virus infection should take steps to prevent mosquito bites for at least the first week of illness to decrease the risk for human-to-mosquito-to-human transmission,” the updated guidelines state.
Information on areas where Zika virus is currently prevalent, and what precautions to take when traveling to these areas, can be found on the CDC website .