Zika virus disease is a nationally notifiable condition:

Healthcare providers should report suspected Zika virus disease cases to their state, local, or territorial health department to facilitate diagnosis and mitigate risk of local transmission. State, local, and territorial health departments should report laboratory-confirmed and probable cases to CDC.

CLINICAL ACTIONS:

The following is a summary of CDC testing protocols.  For detailed protocols and information, the CDC resource pages can be found in the Learn More – Primary Sources section below

Testing Guidance for Non-Pregnant patients

Symptomatic individuals with possible exposure to Zika virus

• CDC defines ‘exposure’ to Zika virus as travel or residency in an area of active Zika virus transmission or sexual intercourse without a condom with a parter who has lived in or traveled to such an area
• Concurrent testing of serum and urine by Zika virus ribonucleic acid (RNA) nucleic acid testing (NAT) and Zika virus and dengue virus IgM testing of serum is recommended
• NAT testing is dependent on the timing of specimen collection
  • NAT testing should be performed on specimens collected <14 days after symptom onset
    • NAT testing is not recommended on specimens collected ≥ 14 days after symptom onset
  • Zika virus and dengue virus IgM serology testing should be performed on NAT negative samples collected <14 days after onset of symptoms or on samples collected ≥14 days after onset of symptoms

SYNOPSIS:

Testing for Zika virus is available using molecular and serological assays. Typical symptoms include acute onset of fever, with maculopapular rash, arthralgia, myalgia, headache, conjunctivitis. Differential diagnosis of such symptoms is broad and include group A strep, rubella, measles and other viral diseases. Therefore, to identify those at risk for Zika virus, it is essential to take a travel and sexual history of all patients presenting with the above symptoms and to stay current with CDC updates as to high Zika virus transmission areas.

KEY POINTS:

Tests for Zika virus include the following

Molecular Testing: Triplex Real-time RT-PCR Assay (rRT-PCR)

• A molecular test designed to detect Zika virus, Dengue virus and Chikungunya virus RNA
• FDA is currently allowing its use under an Emergency Use Athoriziation
• RNA can be detected in the acute phase, and up to 14 days post symptoms in urine
• If clinically indicated, amniocentesis and CSF specimens may be tested alongside patient-matched serum sample

Antibody Detection Methods: Zika virus IgM

• Antibody testing not required if there is a a positive rRT-PCR result
• Due to cross reactivity, symptomatic individuals should be tested for anti-Zika and anti-Dengue IgM and where clinically relevant, anti-chikungunya IgM

PRNT (Plaque Reduction Neutralization Test) to confirm antibodies

• Works by quantifying the antibodies that neutralize the virus
• Positive or equivocal IgM results must be confirmed with an antibody neutralization assay to rule out false positives (previous and not recent infection)
• Not necessary with positive rRT-PCR which is definitive
• Test is performed by the CDC or CDC approved lab
• PRNT may not be able to provide definitive determination of the specific virus causing the recent infection

Learn More – Primary Sources:

CDC: Zika Virus

CDC: Areas with Risk of  Zika

Related ObG Topics:

New CDC Interim Guidance on Infants with Possible Zika & Perinatal Review (Oct 2017)

Microcephaly – Definitions and Key Points

Zika virus: transmission, symptoms and management

CDC Guidance on Zika and Pregnancy