Nipah virus outbreaks in India refer to multiple episodes of infection caused by the Nipah virus (NiV), a zoonotic virus of the genus Henipavirus. India has reported several outbreaks and isolated cases since 2001, primarily in the states of West Bengal and Kerala. The virus has a high case-fatality rate and is transmitted through contact with infected fruit bats (Pteropus species), contaminated food, or human-to-human transmission.[1]
Background[edit | edit source]
Nipah virus was first identified during an outbreak in Malaysia in 1998. Fruit bats are the natural reservoir of the virus, and sporadic spillover events have occurred in South and Southeast Asia. Human infections often present with acute encephalitis or severe respiratory illness, with case fatality rates ranging from 40% to 75%.[2]
Outbreaks in India[edit | edit source]
2001: Siliguri, West Bengal[edit | edit source]
The first recognized Nipah virus outbreak in India occurred in Siliguri, West Bengal, between January and February 2001. A total of 66 cases of acute encephalitis syndrome were reported, with 45 deaths. Most infections occurred in hospital settings, indicating nosocomial transmission.[3]
The outbreak was controlled through improved infection control practices, patient isolation, and surveillance.
2007: Nadia district, West Bengal[edit | edit source]
In April 2007, a cluster of encephalitis cases was reported in Nadia district, West Bengal. Five cases were confirmed, all of whom died. Epidemiological investigation suggested transmission from an index case who likely acquired the infection from bats, followed by person-to-person spread.[4]
2018: Kozhikode and Malappuram, Kerala[edit | edit source]
In May 2018, Kerala experienced its first Nipah virus outbreak. Nineteen cases were reported, including 17 deaths. The outbreak was centered in Kozhikode and Malappuram districts. Human-to-human transmission was documented, particularly among caregivers and healthcare workers.[5]
The Government of India and Kerala implemented extensive contact tracing, quarantine, and public health measures, successfully containing the outbreak.
2019: Ernakulam, Kerala[edit | edit source]
In June 2019, a single confirmed case of Nipah virus infection was reported in Ernakulam district, Kerala. The patient survived, and no secondary cases were detected due to rapid containment and surveillance measures.[6]
2021: Kozhikode, Kerala[edit | edit source]
In September 2021, a 12-year-old boy from Kozhikode district died after being infected with Nipah virus. Over 240 contacts were traced and monitored, and no additional cases were reported.[7]
2023: Kozhikode, Kerala[edit | edit source]
In September 2023, Kerala reported six confirmed Nipah virus cases in Kozhikode district, resulting in two deaths. More than 1,200 contacts were traced. Genome sequencing confirmed the virus belonged to the Indian genotype closely related to Bangladesh strains.[8]
2024: Malappuram, Kerala[edit | edit source]
In July 2024, a 14-year-old boy from Malappuram district died due to Nipah virus infection. Health authorities traced over 200 contacts, and no secondary transmission was reported.[9]
2025: Kerala[edit | edit source]
In 2025, Kerala reported four Nipah virus cases across Malappuram and Palakkad districts, including two fatalities. Investigations suggested independent zoonotic spillover events rather than a single transmission chain.[10]
2026: North 24 Parganas, West Bengal[edit | edit source]
In January 2026, two healthcare workers in Barasat, North 24 Parganas district, tested positive for Nipah virus. Both survived. Extensive contact tracing found no additional cases.[11]
Year-wise summary[edit | edit source]
| Year | Location | Cases | Deaths |
|---|---|---|---|
| 2001 | Siliguri, West Bengal | 66 | 45 |
| 2007 | Nadia, West Bengal | 5 | 5 |
| 2018 | Kozhikode–Malappuram, Kerala | 19 | 17 |
| 2019 | Ernakulam, Kerala | 1 | 0 |
| 2021 | Kozhikode, Kerala | 1 | 1 |
| 2023 | Kozhikode, Kerala | 6 | 2 |
| 2024 | Malappuram, Kerala | 1 | 1 |
| 2025 | Kerala | 4 | 2 |
| 2026 | North 24 Parganas, West Bengal | 2 | 0 |
See also[edit | edit source]
References[edit | edit source]
- ↑ "Nipah virus". World Health Organization. Retrieved 30 January 2026.
- ↑ Chadha, M. S. (2006). "Nipah virus-associated encephalitis outbreak, Siliguri, India". Emerging Infectious Diseases. 12 (2): 235–240.
- ↑ Chadha, M. S. (2006). "Nipah virus-associated encephalitis outbreak, Siliguri, India". Emerging Infectious Diseases. 12 (2): 235–240.
- ↑ Arankalle, V. A. (2011). "Nipah virus infection in India". Emerging Infectious Diseases. 17 (5): 822–824.
- ↑ "Nipah virus – India". World Health Organization. 7 August 2018.
- ↑ "Kerala reports Nipah case, patient stable". The Hindu. 4 June 2019.
- ↑ "A case of Nipah Virus detected in Kozhikode district of Kerala". Press Information Bureau. 5 September 2021.
- ↑ "Nipah virus infection – India". World Health Organization. 3 October 2023.
- ↑ "One dead from Nipah virus in India's Kerala". Reuters. 21 July 2024.
- ↑ "Nipah virus infection – India". World Health Organization. 6 August 2025.
- ↑ "Nipah virus infection – India". World Health Organization. 30 January 2026.