Why Nipah virus outbreaks are occurring only in Kerala

Subject :Science and technology

Section: Health

Introduction

Kerala experienced four Nipah outbreaks since May 2018: three in Kozhikode and one in Ernakulam in 2019.

Presence of Nipah Virus in Fruit Bats

A 2021 study confirmed Nipah virus in Pteropusfruit bats across Kerala districts.
NIV Pune found Nipah virus antibodies in Pteropusmediusbats in nine states, including Kerala.

Kerala’s Proactive Healthcare System

Kerala’s virologist-led teams quickly identified the Nipah virus in undiagnosed fever cases.
Advanced healthcare infrastructure and suspicion enhance rapid diagnosis.

Nipah Virus Infectivity

Nipah has lower infectivity than SARS-CoV-2 (R₀ of 0.2-0.3 compared with R₀ of over 1.5 in the case of SARS-CoV-2 virus), with index cases posing higher transmission risk.
Not all index cases become superspreaders, and secondary cases may be limited, depending on symptoms.
Basic Reproduction Number:
- R₀ (pronounced “R naught”) is a basic reproduction number used in epidemiology to measure the contagiousness or transmission potential of an infectious disease.
- It represents the average number of secondary infections that one infected individual can produce in a completely susceptible population.

About Nipah Virus

Nipah virus is a highly contagious and often deadly virus that can infect both humans and animals.
It belongs to the family Paramyxoviridae, genusHenipavirus.
Nipah virus was first identified in Malaysia in 1998 when it caused an outbreak of severe respiratory and neurological illness in pigs and a subsequent outbreak in humans.
Transmission: It spreads through contact with infected animals, contaminated food, or direct human-to-human contact.
Symptoms: It causes fever, headache, and vomiting, and can lead to severe encephalitis with a high mortality rate.
Geographic Distribution: Nipah virus outbreaks have occurred in South and Southeast Asia, primarily in Malaysia, Singapore, Bangladesh, and India.
Animal Reservoir: Fruit bats, especially flying foxes, are natural carriers of the virus.