World Health Organization (WHO): interim case definition
An interim case definition has been published by the WHO for the purpose of global standardisation of classification and reporting.
A person presenting with rash and/or fever and at least one of the following signs or symptoms:
A suspected case with the presence of IgM antibodies against Zika virus and no evidence of infection with other flaviviruses, plus an epidemiological link (i.e., contact with a confirmed case, or a history of residence in or travelling to an area with local transmission of Zika virus within 2 weeks prior to onset of symptoms).
A person with laboratory confirmation of recent Zika virus infection:
Presence of Zika virus RNA or antigen in serum or other samples (e.g., saliva, tissues, urine, whole blood)
IgM antibody against Zika virus is positive and plaque reduction neutralisation test (PRNT) for Zika virus with titre ≥20 and Zika virus PRNT titre ratio ≥4 compared with other flaviviruses.
Pan American Health Organization (PAHO): interim Zika virus case definition
An interim case definition has been published by the PAHO.
Patient with rash (usually pruritic and maculopapular) plus 2 or more of the following:
Fever (usually <38.5°C [<101.3°F])
In geographical areas without autochthonous transmission and where there are no vectors present, patients who meet the criteria above and who:
in the 2 weeks prior to onset, travelled to/resided in a geographical area where there is known local transmission of the Zika virus or there is known vector presence; or
had unprotected sex in the 2 weeks prior to onset with a person who travelled in the previous 8 weeks to a geographical area with known local transmission of the Zika virus or an area with known vector presence.
Patient who meets the criteria of a suspected case and has Zika IgM antibodies with no evidence of infection with other flaviviruses.
Patient who meets the criteria of a suspected case and has laboratory confirmation of recent Zika virus infection:
RNA or Zika virus antigen in any specimen (i.e., serum, urine, saliva, tissue, or whole blood); or
Positive Zika IgM antibodies and PRNT for Zika virus titres ≥20 and 4 or more times greater than the titres for other flaviviruses, as well as exclusion of other flaviruses; or
Detection of viral genome (in fresh or paraffin tissue) in autopsy specimens by molecular techniques, or detection by immunochemistry.
PAHO have also published case definitions for Guillain-Barre syndrome or a congenital syndrome associated with Zika virus, as well as definitions for Zika virus-associated abortion or still birth and vertical transmission (without congenital syndrome).
Centers for Disease Control and Prevention (CDC): Zika virus disease and Zika virus infection case definition
The CDC previously included Zika virus infection in their arboviral diseases (neuroinvasive and non-neuroinvasive) case definition; however, they now have separate case definitions for congenital and non-congenital subtypes:
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