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NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

CSTE Position Statement(s)

  • 23-ID-10

Subtype(s)

  • Congenital Zika Virus Disease
  • Non-congenital Zika Virus Disease

Background

Zika virus is a flavivirus that is primarily transmitted through the bite of an infected Aedes species mosquito. Intrauterine, perinatal, sexual, laboratory, and transfusion-associated transmission have also been reported (1, 2).

Most people infected with Zika virus have asymptomatic infections or mild clinical disease characterized by acute onset of fever, maculopapular rash, arthralgia, and nonpurulent conjunctivitis. Other common symptoms can include myalgia, headache, edema, vomiting, retroorbital pain, or lymphadenopathy. Hospitalization and death are uncommon. Guillain-Barré syndrome, encephalopathy, meningoencephalitis, myelitis, uveitis, and severe thrombocytopenia rarely occur. Transmission of the virus to the unborn child during pregnancy can lead to congenital Zika virus infection and may cause serious birth defects of the brain and eyes, including severe microcephaly, intracranial calcifications, cerebral or cortical atrophy, chorioretinal abnormalities, and optic nerve abnormalities (3-8).

Development of surveillance case definitions for Zika virus infection and disease (16-ID-01) occurred in 2016 during a rapidly evolving Zika virus disease outbreak in the Western Hemisphere. Since that time, levels of Zika virus transmission in the Americas have declined considerably (9-11). The 23-ID-10 position statement revises the standardized case definition for Zika virus disease to address the changing epidemiology and current knowledge of the laboratory and clinical findings associated with Zika virus disease. It also removes non-congenital and congenital Zika virus infection without disease from the case definition, thus removing these subtypes from the Nationally Notifiable Conditions list.

Epidemiologic Linkage

  • Resided in or traveled to an area with a risk* of Zika virus transmission in the 14 days before the onset of symptoms, in the 28 days before the onset of Guillain-Barré syndrome, or during pregnancy; OR
  • Laboratory exposure to Zika virus before onset of symptoms or during pregnancy; OR
  • Receipt of blood, blood products, organ transplant, or tissue transplant within 30 days of symptom onset or during pregnancy from a person who has either been diagnosed with Zika virus infection or returned from traveling to an area with risk of Zika virus transmission; OR
  • Sexual contact, within 14 days of symptom onset or during pregnancy, with a person who in the last 90 days has either been diagnosed with Zika virus infection or has returned from traveling to an area with a risk of Zika virus transmission.

*Consult with CDC as needed for assistance with geographic risk determinations.

Criteria to Distinguish a New Case from an Existing Case

A person not previously enumerated as a case that meets the confirmed or probable case classification.

Note: Infection with Zika virus is expected to provide lifelong immunity. However, in persons who are severely immunocompromised, viral persistence following infection may occur, which can lead to persistent disease. Immunocompromised individuals may also be vulnerable to reinfection with Zika virus.

Subtype(s) Case Definition

References

  1. Major, C. G., Paz-Bailey, G., Hills, S. L., Rodriguez, D. M., Biggerstaff, B. J., & Johansson, M. (2021). Risk Estimation of Sexual Transmission of Zika Virus-United States, 2016-2017. The Journal of infectious diseases224(10), 1756–1764. https://doi.org/10.1093/infdis/jiab173
  2. Barjas-Castro ML, Angerami RN, Cunha MS, et al. Probable transfusion-transmitted Zika virus in Brazil. Transfusion. Jul 2016;56(7):1684-8. https://doi.org/10.1111/trf.13681
  3. Roth NM, Reynolds MR, Lewis EL, et al. Zika-Associated Birth Defects Reported in Pregnancies with Laboratory Evidence of Confirmed or Possible Zika Virus Infection — U.S. Zika Pregnancy and Infant Registry, December 1, 2015–March 31, 2018. MMWR Morb Mortal Wkly Rep 2022;71:73–79. DOI: http://dx.doi.org/10.15585/mmwr.mm7103a1external icon.
  4. Delaney A, Olson SM, Roth NM, Cragan JD, Godfred-Cato S, Smoots AN, et al. Prevalence of individual brain and eye defects potentially related to Zika virus in pregnancy in 22 U.S. states and territories, January 2016 to June 2017. Birth Defects Res. 2022;114:805-11. https://doi.org/10.1002/bdr2.2067
  5. Honein MA, Woodworth KR, Gregory CJ. Neurodevelopmental abnormalities associated with in utero Zika virus infection in infants and children-the unfolding story. JAMA Pediatr. Mar 1 2020;174(3):237-238. https://doi.org/10.1001/jamapediatrics.2019.5257
  6. Rice ME, Galang RR, Roth NM, et al. Vital Signs: Zika-associated birth defects and neurodevelopmental abnormalities possibly associated with congenital Zika virus infection — U.S. Territories and Freely Associated States, 2018. MMWR Morb Mortal Wkly Rep 2018;67:858-867. DOI: http://dx.doi.org/10.15585/mmwr.mm6731e1.
  7. van der Linden V, Lins OG, de Lima Petribu NC, et al. Diaphragmatic paralysis: Evaluation in infants with congenital Zika syndrome. Birth Defects Res. Nov 15 2019;111(19):1577-1583. https://doi.org/10.1002/bdr2.1597
  8. Moore CA, Staples JE, Dobyns WB, Pessoa A, Ventura CV, Fonseca EB, et al. Characterizing the pattern of anomalies in congenital Zika syndrome for pediatric clinicians. JAMA Pediatr. 2017;171:288-95. https://doi.org/10.1001/jamapediatrics.2016.3982
  9. CSTE. Zika virus disease and Zika virus infection without disease, including congenital infections case definitions and addition to the Nationally Notifiable Diseases List. https://cdn.ymaws.com/www.cste.org/resource/resmgr/2016PS/16_ID_01_edited7.29.pdf
  10. CDC. Zika cases in the United States. https://www.cdc.gov/zika/reporting/index.html
  11. PAHO. Health Information Platform for the Americas (PLISA). Data reported by Health Ministries of the countries. PAHO/WHO Data - ZIKA.

Related Case Definition(s)