Medline ® Abstracts for References 37,129-136

CDC has developed interim guidelines for health care providers in the United States caring for pregnant women during a Zika virus outbreak. These guidelines include recommendations for pregnant women considering travel to an area with Zika virus transmission and recommendations for screening, testing, and management of pregnant returning travelers. Updates on areas with ongoing Zika virus transmission are available online (http://wwwnc.cdc.gov/travel/notices/). Health care providers should ask all pregnant women about recent travel. Pregnant women with a history of travel to an area with Zika virus transmission and who report two or more symptoms consistent with Zika virus disease (acute onset of fever, maculopapular rash, arthralgia, or conjunctivitis) during or within 2 weeks of travel, or who have ultrasound findings of fetal microcephaly or intracranial calcifications, should be tested for Zika virus infection in consultation with their state or local health department. Testing is not indicated for women without a travel history to an area with Zika virus transmission. In pregnant women with laboratory evidence of Zika virus infection, serial ultrasound examination should be considered to monitor fetal growth and anatomy and referral to a maternal-fetal medicine or infectious disease specialist with expertise in pregnancy management is recommended. There is no specific antiviral treatment for Zika virus; supportive care is recommended.

CDC has updated its interim guidelines for U.S. health care providers caring for pregnant women during a Zika virus outbreak (1). Updated guidelines include a new recommendation to offer serologic testing to asymptomatic pregnant women (women who do not report clinical illness consistent with Zika virus disease) who have traveled to areas with ongoing Zika virus transmission. Testing can be offered 2-12 weeks after pregnant women return from travel. This update also expands guidance to women who reside in areas with ongoing Zika virus transmission, and includes recommendations for screening, testing, and management of pregnant women and recommendations for counseling women of reproductive age (15-44 years). Pregnant women who reside in areas with ongoing Zika virus transmission have an ongoing risk for infection throughout their pregnancy. For pregnant women with clinical illness consistent with Zika virus disease,* testing is recommended during the first week of illness. For asymptomatic pregnant women residing in areas with ongoing Zika virus transmission, testing is recommended at the initiation of prenatal care with follow-up testing mid-second trimester. Local health officials should determine when to implement testing of asymptomatic pregnant women based on informationabout levels of Zika virus transmission and laboratory capacity. Health care providers should discuss reproductive life plans, including pregnancy intention and timing, with women of reproductive age in the context of the potential risks associated with Zika virus infection.

Diagnostic testing for Zika virus infection can be accomplished using molecular and serologic methods. Real-time reverse transcription-polymerase chain reaction (rRT-PCR) is the preferred test for Zika virus infection because it can be performed rapidly and is highly specific (1,2). However, in most patients, Zika virus RNA is unlikely to be detected in serum after the first week of illness (2,3). Recent reports using adaptations of previously published methods (2,4) suggest that Zika virus RNA can be detected in urine for at least 2 weeks after onset of symptoms (3,5-7). Currently, the CDC Trioplex rRT-PCR assay is the only diagnostic tool authorized by the Food and Drug Administration for Zika virus testing of urine (1). Other laboratory-developed tests will need in-house validations to adequately characterize the performance of the assay and meet Clinical Laboratory Improvement Amendments requirements. Further investigation is needed to determine the sensitivity and utility of Zika virus rRT-PCR on urine specimens collected≥14 days after onset of symptoms.

Zika virus is a single-stranded RNA virus in the genus Flavivirus and is closely related to dengue, West Nile, Japanese encephalitis, and yellow fever viruses (1,2). Among flaviviruses, Zika and dengue virus share similar symptoms of infection, transmission cycles, and geographic distribution. Diagnostic testing for Zika virus infection can be accomplished using both molecular and serologic methods. For persons with suspected Zika virus disease, a positive real-time reverse transcription-polymerase chain reaction (rRT-PCR) result confirms Zika virus infection, but a negative rRT-PCR result does not exclude infection (3-7). In these cases, immunoglobulin (Ig) M and neutralizing antibody testing can identify additional recent Zika virus infections (6,7). However, Zika virus antibody test results can be difficult to interpret because of cross-reactivity with other flaviviruses, which can preclude identification of the specific infecting virus, especially when the person previously was infected with or vaccinated against a related flavivirus (8). This is important because the results of Zika and dengue virus testing will guide clinical management. Pregnant women with laboratory evidence of Zika virus infection should be evaluated and managed for possible adverse pregnancy outcomes and be reported to the U.S. Zika Pregnancy Registry or the Puerto Rico Zika Active Pregnancy Surveillance System for clinical follow-up (9,10). All patients with clinically suspected dengue should have proper management to reduce the risk for hemorrhage and shock (11). If serologic testing indicates recent flavivirus infection that could be caused by either Zika or dengue virus, patients should be clinically managed for both infections because they might have been infected with either virus.

The rapid spread of Zika virus across the World Health Organization's Region of the Americas has had a direct effect on the U.S. health care delivery system. Hospitals in New York City (NYC) have been implementing prevention and response efforts consistent with CDC guidance. As of September 21, 2016, a total of 715 cases of laboratory-confirmed Zika virus disease had been diagnosed in New York state among travelers who returned from affected areas, their sexual contacts, or infants infected in utero. This represents the highest number of reported cases in any state to date, and underscores the importance of health care systems preparing to care for patients with possible Zika virus disease (1). Building upon a framework that was established in 2014 to screen patients for possible exposure to Ebola virus disease (Ebola), NYC Health + Hospitals,* the largest municipal health care delivery system in the United States, implemented a Zika Preparedness and Response Action Plan(†) (Zika Action Plan) to address the threat from Zika and ensure appropriate patient care. The plan developed by NYC Health + Hospitals includes universal travel screening, signage depicting areas with active Zika virus transmission, clinical and epidemiologic evaluation for possible Zika virus exposure, diagnostic testing for Zika virus infection and linking of infected patients to appropriate specialists, and education on Zika virus disease and preventive measures (e.g., avoiding travel to areas with active Zika virus transmission).

CDC has released updated guidance online for U.S. laboratory testing for Zika virus infection. The guidance is available at https://www.cdc.gov/zika/laboratories/lab-guidance.html. Frequently asked questions are addressed at https://www.cdc.gov/zika/laboratories/lab-guidance-faq.html. This guidance updates recommendations for testing of specimens by U.S. laboratories for possible Zika virus infection. Major updates to the guidance with clinical implications for health care providers include the following.