Zika Virus Outbreak Investigation - Kanpur Nagar, Uttar Pradesh, India, December 2021
Zika virus (ZIKV) disease is a flavivirus disease transmitted primarily through mosquito bites. Other modes including sexual and transplacental have also been documented. ZIKV infection is associated with microcephaly in newborns. In October 2021, Uttar Pradesh (UP) reported its first case of ZIKV from Kanpur Nagar district. Authorities initiated containment activities, house searches, sample collection, vector control, fogging activities and entomological investigations. On November 28, two AEP officers joined the investigation in Kanpur Nagar to describe the epidemiological characteristics and provide evidence-based recommendations.
We confirmed the outbreak by reviewing district reports from 2018-2021. We identified line listed RT-PCR positive cases for either in-person or telephonic interviews. We collected and analyzed information on sociodemographic characteristics, clinical presentation, laboratory, and entomological investigation.
We contacted 141 positive cases; 138 were interviewed. Cases were distributed equally by sex and nearly half of cases (45%) were adults aged 20-41 years. Half (51%) of cases were symptomatic with mild illness. Of 13 pregnancies among the 70 female cases, four resulted in a live birth (two were hospitalized – one for prematurity, one for a congenital heart problem), one pregnancy was medically terminated, and eight women were still pregnant. No microcephaly was reported. Nearly all cases (99%) reported presence of mosquitoes and only 4% reported recent travel. One of 246 mosquitos tested positive for ZIKV; 1330/93198 houses and 1503/698520 containers in the area had mosquito larvae breeding.
The first reported ZIKV outbreak in UP occurred in an urban area with a high presence of mosquitos and reported ZIKV in a mosquito. Given the likely mosquito-bite transmission, we recommend measures to prevent mosquito bites. Additional recommendations included screening of pregnant females, use of contraceptives by at-risk couples, and inclusion of ZIKV laboratory testing in existing fever rash surveillance to identify future outbreaks.