Sero-prevalence of Nipah antibodies among close contacts of the index case during 2019 Ernakulam outbreak

INTRODUCTION: Nipah virus (NiV) infection is a fatal emerging zoonotic disease. Infection with NiV has a wide range of clinical spectrum which can range from asymptomatic cases to acute respiratory distress syndrome (ARDS). The index case of NiV infection of 2019 outbreak in Ernakulam district was a 23-year-old male who presented with features of encephalitis. This study was undertaken to address the subclinical or asymptomatic NiV infection amongst the close contacts of this index case by using NiV-specific Immunoglobulin IgM and IgG antibodies. The index case was first treated in a primary care center. He survived the infection and was discharged after a period of 108 days from the tertiary care facility where he was treated eventually. METHODS: Serum samples from 49 close contacts of the index case were collected and tested for anti-NiVIgM and anti-NiVIgG antibodies. The contacts included health care workers including those from the primary care facility, family members, and his friends. RESULTS: Most common type of exposure included physical contact (59.2%), followed by exposure to body fluids (22.4%). CONCLUSION: None of the 49 contacts tested positive for anti-NiV human IgM and anti-NiVIgG antibodies. There were no subclinical cases amongst the close contacts of Nipah index case during the 2019 Kerala outbreak.