June 14, 2019, Morbidity and Mortality Weekly Report: Dengue and Zika virus diagnostic testing for patients with a clinically compatible illness and risk for infection with both viruses
CDC recommends Zika and dengue virus testing for:
- Anyone with possible exposure to Zika and dengue virus exposure* who has or recently experienced symptoms of Zika or dengue.
- Symptomatic pregnant women with possible Zika or dengue virus exposure
- Asymptomatic pregnant women with ongoing possible Zika or dengue virus exposure
- Pregnant women with possible Zika virus exposure who have a fetus with prenatal ultrasound findings consistent with congenital Zika virus infection
Zika testing is not routinely recommended but may be considered for
- Asymptomatic pregnant women with recent possible but no ongoing exposure to Zika or dengue virus (i.e., travelers)
Zika virus testing is not recommended for
- Non-pregnant asymptomatic people
- Preconception screening
*Possible exposure includes living in, traveling to, or having unprotected sex with someone who lives in or traveled to an area with risk of Zika.
Testing Guidance for Non-Pregnant Symptomatic Patients
For non-pregnant persons with a clinically compatible illness, dengue and Zika virus nucleic acid amplification tests (NAAT) should be performed on serum collected ≤7 days after symptom onset. Various NAATs also can be performed on plasma, whole blood, cerebrospinal fluid, or urine. For symptomatic persons with possible exposure to dengue and Zika virus, a positive NAAT result typically provides evidence of acute infection, and no antibody testing is indicated. However, patients for whom the diagnosis has epidemiologic or clinical significance (e.g., first local transmission in area, new transmission mode, patient has an unusual clinical syndrome, or diagnosis will affect clinical management), a repeat NAAT should be performed on newly extracted RNA from the same specimen to rule out false-positive test results.
Testing Guidance for Symptomatic Pregnant Women
Symptomatic pregnant women with possible Zika virus exposure should receive concurrent testing of serum and urine by NAAT and Zika virus IgM testing of serum as soon as possible, up to 12 weeks after symptom onset. In addition, for women with possible exposure to both Zika and dengue, testing of serum for dengue by NAAT and dengue virus IgM testing also should be performed.
- A positive Zika virus NAAT result, in conjunction with a positive IgM result, should be interpreted as an acute maternal Zika virus infection.
- A positive dengue virus NAAT result should be interpreted as an acute maternal dengue virus infection.
- If Zika virus NAAT is positive on a single specimen but IgM antibody tests are negative, repeat NAAT on newly extracted RNA from the same specimen.
- A positive Zika virus NAAT on either a serum or urine specimen in conjunction with a positive Zika IgM should be interpreted as confirmatory for acute Zika virus infection and repeat NAAT is not recommended.
- A negative NAAT result in conjunction with a non-negative Zika virus IgM test result should be followed by plaque reduction neutralization test (PRNT).
Testing Guidance for Asymptomatic Pregnant Women
Asymptomatic pregnant women with ongoing possible Zika virus exposure (i.e., residence in or frequent travel to an area with risk of Zika) should be tested. NAAT testing is recommended three times during pregnancy. IgM serology testing is not routinely recommended. Recommendations for the timing of NAAT testing are at the initial prenatal care visit, followed by two additional NAAT tests performed during pregnancy, coinciding with non-consecutive prenatal visits. Timing of additional NAAT testing may be informed by jurisdictional trends in Zika virus transmission, the expected length of Zika virus nucleic acid detection in serum, and the duration of exposure during pregnancy. Although not routinely recommended, after pre-test counseling and individualized risk assessment, physicians and patients, through a shared decision-making model, may collaboratively elect to have IgM testing performed concurrent with NAAT testing. For women who have a positive NAAT test during pregnancy, additional NAAT testing is not recommended. If a patient has previously been confirmed positive for Zika virus infection, no additional IgM serology testing is recommended.
Asymptomatic pregnant women with recent possible exposure to Zika virus but no ongoing exposure (i.e., travelers) may be considered for testing. Although not routinely recommended, testing may be considered on a case-by-case basis using a shared physician-patient decision-making model and in line with jurisdictional recommendations.
- Asymptomatic pregnant women with ongoing possible Zika virus exposure should be offered Zika virus NAAT testing three times during pregnancy. IgM antibody testing is no longer routinely recommended because IgM can persist for months after infection; therefore, IgM results cannot reliably determine whether an infection occurred during the current pregnancy.
- Asymptomatic pregnant women who have recent possible Zika virus exposure (i.e., through travel or sexual exposure) but without ongoing possible exposure are not routinely recommended to have Zika virus testing. Testing may be considered on a case-by-case basis using a shared physician-patient decision-making model and in line with jurisdictional recommendations.
Note: Jurisdictions may take into account local epidemiologic considerations (e.g., seasonality, geography, and mosquito surveillance and control factors) in making recommendations for Zika virus testing for this group of pregnant women; therefore, testing recommendations for this group of pregnant women may differ by jurisdiction. Please contact your state, tribal, local, or territorial health department for jurisdiction specific guidance.
Pregnant women with possible exposure to Zika virus and who have a fetus with prenatal ultrasound findings consistent with congenital Zika virus infection should be tested. NAAT and IgM testing should be performed on maternal serum and urine following the algorithm for symptomatic pregnant women. If amniocentesis is being performed as part of clinical care, NAAT testing of amniocentesis specimens should also be performed. Testing of placental and fetal tissues may also be considered.
Make sure to get your Zika test results
What You Should Know About Zika Virus Testing: For asymptomatic pregnant women with ongoing exposure to Zika
What You Should Know About Zika Virus Testing: For symptomatic pregnant women with exposure to Zika
What You Should Know About Zika Virus Testing: For asymptomatic pregnant women with recent exposure to Zika