Recognizing, Managing, and Reporting Zika Virus Infections in Travelers Returning from Central America, South America, the Caribbean, and Mexico
Distributed via the CDC Health Alert Network, Friday, January 15, 2016, 19:45 EST (7:45 PM EST) CDCHAN-00385
In May 2015, the World Health Organization reported the first local transmissionof Zika virus in the Western Hemisphere, with autochthonous (locally acquired)cases identified in Brazil. As of January 15, 2016, local transmission had beenidentified in at least 14 countries or territories in the Americas, includingPuerto Rico (See Pan American Health Organization [PAHO] link below forcountries and territories in the Americas with Zika virus transmission).Further spread to other countries in the region is likely.
Local transmission of Zika virus has not been documented in thecontinental United States. However, Zika virus infections have been reported intravelers returning to the United States. With the recent outbreaks in theAmericas, the number of Zika virus disease cases among travelers visiting orreturning to the United States likely will increase. These imported cases mayresult in local spread of the virus in some areas of the continental UnitedStates, meaning these imported cases may result in human-to-mosquito-to-humanspread of the virus.
Zika virus infection should be considered in patients with acute onsetof fever, maculopapular rash, arthralgia or conjunctivitis, who traveled toareas with ongoing transmission in the two weeks prior to illness onset. Clinicaldisease usually is mild. However, during the current outbreak, Zika virusinfections have been confirmed in several infants with microcephaly and infetal losses in women infected during pregnancy. We do not yet understand thefull spectrum of outcomes that might be associated with infection duringpregnancy, nor the factors that might increase risk to the fetus. Additionalstudies are planned to learn more about the risks of Zika virus infectionduring pregnancy.
Healthcare providers are encouraged to report suspected Zika virusdisease cases to their state health department to facilitate diagnosis and tomitigate the risk of local transmission. State health departments are requestedto report laboratory-confirmed cases to CDC. CDC is working with states toexpand Zika virus laboratory testing capacity, using existing RT-PCR protocols.
This CDC Health Advisory includes information and recommendations aboutZika virus clinical disease, diagnosis, and prevention, and provides travelguidance for pregnant women and women who are trying to become pregnant. Untilmore is known and out of an abundance of caution, pregnant women shouldconsider postponing travel to any area where Zika virus transmission isongoing. Pregnant women who do travel to these areas should talk to theirdoctors or other healthcare providers first and strictly follow steps to avoidmosquito bites during the trip. Women trying to become pregnant should consultwith their healthcare providers before traveling to these areas and strictlyfollow steps to avoid mosquito bites during the trip.
Zika virus is a mosquito-borne flavivirus transmitted primarily by Aedesaegypti. Aedes albopictus mosquitoes might also transmit the virus.Outbreaks of Zika virus disease have been reported previously in Africa, Asia,and islands in the Pacific.
About one in five people infected with Zika virus become symptomatic.Characteristic clinical findings include acute onset of fever, maculopapularrash, arthralgia, or conjunctivitis. Clinical illness usually is mild withsymptoms lasting for several days to a week. Severe disease requiringhospitalization is uncommon and fatalities are rare. During the currentoutbreak in Brazil, Zika virus RNA has been identified in tissues from severalinfants with microcephaly and from fetal losses in women infected duringpregnancy. The Brazil Ministry of Health has reported a marked increase in thenumber of babies born with microcephaly. However, it is not known how many ofthe microcephaly cases are associated with Zika virus infection and whatfactors increase risk to the fetus. Guillain-Barré syndrome also has beenreported in patients following suspected Zika virus infection.
Zika virus infection should be considered in patients with acute onsetof fever, maculopapular rash, arthralgia, or conjunctivitis who recentlyreturned from affected areas. To confirm evidence of Zika virus infection,RT-PCR should be performed on serum specimens collected within the first weekof illness. Immunoglobulin M and neutralizing antibody testing should beperformed on specimens collected ≥4 days after onset of illness. Zika virus IgMantibody assays can be positive due to antibodies against related flaviviruses(e.g., dengue and yellow fever viruses). Virus-specific neutralization testingprovides added specificity but might not discriminate between cross-reactingantibodies in people who have been previously infected with or vaccinatedagainst a related flavivirus.
There is no commercially available test for Zika virus. Zika virustesting is performed at the CDC Arbovirus Diagnostic Laboratory and a few statehealth departments. CDC is working to expand laboratory diagnostic testing instates, using existing RT-PCR protocols. Healthcare providers should contacttheir state or local health department to facilitate testing.
No specific antiviral treatment is available for Zika virus disease.Treatment is generally supportive and can include rest, fluids, and use ofanalgesics and antipyretics. Because of similar geographic distribution andsymptoms, patients with suspected Zika virus infections also should beevaluated and managed for possible dengue or chikungunya virus infection.Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) should beavoided until dengue can be ruled out to reduce the risk of hemorrhage. Inparticular, pregnant women who have a fever should be treated withacetaminophen. People infected with Zika, chikungunya, or dengue virus shouldbe protected from further mosquito exposure during the first few days ofillness to reduce the risk of local transmission.
No vaccine or preventive drug is available. The best way to preventZika virus infection is t
- Avoid mosquito bites.
- Use air conditioning or window and door screens when indoors.
- Wear long sleeves and pants, and use insect repellents when outdoors. Most repellents, including DEET, can be used on children older than two months. Pregnant and lactating women can use all Environmental Protection Agency (EPA)-registered insect repellents, includingDEET, according to the product label.
Recommendations for Health Care Providers and Public HealthPractitioners
- Zika virus infection should be considered in patients with acute fever, rash, arthralgia, or conjunctivitis, who traveled to areas with ongoing transmission in the two weeks prior to onset of illness.
- All travelers should take steps to avoid mosquito bites to prevent Zika virus infection and other mosquito-borne diseases.
- Until more is known and out of an abundance of caution, pregnant women should consider postponing travel to any area where Zika virus transmission is ongoing. Pregnant women who do travel to one of these areas should talk to their doctors or other healthcare providers first and strictly follow steps to avoid mosquito bites during the trip. Women trying to become pregnant should consult with their healthcare providers before traveling to these areas and strictly follow steps to avoid mosquito bites during the trip.
- Fetuses and infants of women infected with Zika virus during pregnancy should be evaluated for possible congenital infection and neurologic abnormalities.
- Healthcare providers are encouraged to report suspected Zika virus disease cases to their state or local health department to facilitate diagnosis and to mitigate the risk of local transmission.
- Health departments should perform surveillance for Zika virus disease in returning travelers and be aware of the risk of possible local transmission in areas where Aedes species mosquitoes are active.
- State health departments are requested to reportlaboratory-confirmed Zika virus infections to CDC.
For More Information
- General information about Zika virus and disease: http://www.cdc.gov/zika/
- Zika virus information for clinicians: http://www.cdc.gov/zika/hc-providers/index.html
- Protection against mosquitoes: http://wwwnc.cdc.gov/travel/yellowbook/2016/the-pre-travel-consultation/protection-against-mosquitoes-ticks-other-arthropods
- Travel notices related to Zika virus: http://wwwnc.cdc.gov/travel/notices
- Information about Zika virus for travelers and travel health providers: http://wwwnc.cdc.gov/travel/yellowbook/2016/infectious-diseases-related-to-travel/zika
- Pan American Health Organization (PAHO): http://www.paho.org/hq/index.php?option=com_topics&view=article&id=427&Itemid=41484&lang=en
- Information on microcephaly: http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html
- Approximate distribution of Aedes aegypti and Ae. albopictus mosquitoes in the United States: http://www.cdc.gov/chikungunya/resources/vector-control.html
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