Screening of ZIKA virus infection among dengue-like illness patients with negative RT-PCR for dengue virus in Punjab – Pakistan

OBJECTIVE: To detect ZIKV using reverse transcription-polymerase chain reaction (RT-PCR) among clinical samples tested negative for Dengue virus (DENV) by RT-PCR in Punjab, 2016. METHODS: A descriptive cross-sectional study was carried out for duration of two months. Total of 506 samples were collected within seven days from onset of illness from all over hospitals of Punjab, Pakistan of which 350 were selected simply randomly to test for presence of ZIKV by using “Trioplex Real-Time RT-PCR Assay (Trioplex)”. Cohen’s kappa coefficient (κ) and 95% confidence interval (CI) were used to assess the degree of concordance between DENV positive results of non-structural protein 1 (NS1) and IgM solid-phase enzyme immunoassay (ELISA). RESULTS: No samples were positive for any ZIKV, DENV or Chikungunya virus (CHIKV) by Trioplex. Among the 350 samples, 26 samples were positive concordant and the degree of concordance between NS1- and IgM-ELISA was 13% and κ coefficient was -0.71 (95% CI -0.79, -0.63). CONCLUSION: At study time, no samples were positive for ZIKV. Strengthening laboratory capacity to confirm arboviruses for Punjab’s laboratories is warranted. Trioplex RT-PCR has 100% sensitivity so there are nominal chances of false negative results. Establishing syndromic surveillance for Zika and conducting a sero-surveillance survey for Zika in areas with high human and Aedes mosquito density are recommended in Punjab.