Wednesday, July 10, 2019

Diagnostic testing of concurrent suspected dengue or Zika in symptomatic patients

Dr KK Aggarwal

The United States Centers for Disease Control and Prevention (CDC) has issued updated guidance for diagnostic evaluation of Zika and dengue virus infection in symptomatic patients. According to the guideline, nucleic acid amplification tests (NAATs) are the preferred method of diagnosis for patients with suspected dengue or Zika virus disease. 

The key recommendations are:

·         For symptomatic nonpregnant persons, dengue and Zika virus NAATs should be done on serum collected ≤7 days after symptom onset. A positive NAAT in symptomatic persons with possible exposure to dengue and Zika virus typically provides evidence of acute infection, and no antibody testing is indicated.
·         If NAAT is negative or serum is collected >7 days after symptom onset, dengue and Zika virus IgM antibody tests should be done.
·         Positive IgM antibody test results with negative NAAT results should be confirmed by neutralizing antibody tests when clinically or epidemiologically indicated, including for all pregnant women.
·         Pregnant women with a clinically compatible illness and recent possible exposure to dengue and Zika virus should have concurrent diagnostic testing for dengue and Zika virus infection performed by NAAT and IgM antibody testing on a serum specimen and NAAT on a urine specimen to diagnose Zika virus infection 
·         If either dengue or Zika virus IgM antibody testing is positive without a positive NAAT or NS1 antigen test, and definitive diagnosis is needed for clinical or epidemiologic purposes, confirmatory Plaque reduction neutralization tests (PRNTs) should be performed against dengue, Zika, and other flaviviruses endemic to the region where exposure occurred.

(Source: MMWR Recomm Rep. 2019 Jun 14; 68(1): 1–10).

Dr KK Aggarwal
Padma Shri Awardee
President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)
Group Editor-in-Chief IJCP Publications
President Heart Care Foundation of India
Past National President IMA

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