#19,030
Anyone who has scanned the news headlines over the past few days is likely aware of a Nipah (NiV) outbreak in Bengal State, India, which has been breathlessly reported by many media outlets (see Deadly Virus in India Sparks Asia-Wide Panic: Nipah Could Spread Like COVID).Nipah, a henipavirus carried by fruit bats in Southeast Asia and the Indian Subcontinent (see map above), was first identified in the late 1990s after a large outbreak in Malaysia spread first from bat(s) to pigs - and then from pigs to humans - eventually infecting at least 265 people, killing 105 (see Lessons from the Nipah virus outbreak in Malaysia).While official government reports are hard to find, local and international sources are reporting 5 hospital employees (see Outbreak News Today) who worked at a private hospital in Barasat have been infected.
Since then, Bangladesh has reported the most cases (see chart below), although India has - since 2018 - reported several large outbreaks.
- Nipah virus infection in humans causes a range of clinical presentations, from asymptomatic infection (subclinical) to acute respiratory infection and fatal encephalitis.
- The case fatality rate is estimated at 40% to 75%. This rate can vary by outbreak depending on local capabilities for epidemiological surveillance and clinical management.
- Nipah virus can be transmitted to humans from animals (such as bats or pigs), or contaminated foods and can also be transmitted directly from human-to-human.
- Fruit bats of the Pteropodidae family are the natural host of Nipah virus.
- There is no treatment or vaccine available for either people or animals. The primary treatment for humans is supportive care.
While we've not seen truly large outbreaks, in July of 2018, in IJID: Enhancing Preparation For Large Nipah Outbreaks Beyond Bangladesh, we looked at an open-access article that appeared in the International Journal of Infectious Diseases, that discussed the potential of the Nipah virus producing a large urban epidemic, similar to what we saw in West Africa with Ebola in 2014.
Three years ago, in EID Journal: Nipah Virus Exposure in Domestic and Peridomestic Animals Living in Human Outbreak Sites, Bangladesh, 2013–2015, we looked at a dispatch that described the detection of NiV antibodies in cattle, dogs, and cats in proximity to known outbreaks in humans.
Nipah (and its cousin Hendra) belong to the Paramyxoviridae family of viruses, and over the past 10 years have been increasingly viewed as having some pandemic potential (see OFID: Viral Families with Pandemic Potential).
Whether Nipah has - or will ever accrue - the `right stuff' to pose a genuine pandemic threat is unknowable, but in the 2013 paper The pandemic potential of Nipah virus, the author Stephen P. Luby wrote (bolding mine) argued:
Characteristics of Nipah virus that increase its risk of becoming a global pandemic include:
- humans are already susceptible; many strains are capable of limited person-to-person transmission;
- as an RNA virus, it has an exceptionally high rate of mutation
- and that if a human-adapted strain were to infect communities in South Asia, high population densities and global interconnectedness would rapidly spread the infection.
And today Taiwan's CDC issued a lengthy statement, declaring Nipah to now be a Category 5 notifiable infectious disease. A brief excerpt follows.
While the Nipah virus remains more of a regional concern than a global threat, each new human (or mammalian) infection affords the virus another opportunity to better adapt to a new host.
A reminder that the next global health crisis may already be simmering in a bat, a rat, or a cat somewhere in the world, just waiting for the right conditions to allow it to start its world tour.
For a deeper dive into the Nipah threat, the Journal of Advances in Biology & Biotechnology published a narrative review just 10 days ago:
Nipah Virus: Understanding Its Zoonotic Potential and Public Health Implications
Chandrani Goswami a* , Sophia Makdoh Gogoi b , Dimpi Choudhury c , Nayanmoni Konwar d , Karabi Phukan e and Manmi Kalita f
Journal of Advances in Biology & Biotechnology Volume 29, Issue 1, Page 476-489, 2026; Article no.JABB.151242 ISSN: 2394-1081
Abstract
Nipah virus (NiV), a paramyxovirus of the genus Henipavirus, is one of the most significant threats to the overall health of the world population because of its high mortality rate and the possibility of human-to-human transmission. NiV has resulted in repeated and frequent outbreaks in South and Southeast Asia, especially in Bangladesh and India, since its first outbreak in Malaysia in the 1998- 1999 pandemic. Pteropus fruit bats is the natural reservoir, and individuals become infected by the means of contaminated food sources, intermediate amplifying hosts, such as pigs, or through direct contact. Clinical presentation involve acute respiratory disease and fatal encephalitis and are usually accompanied by long-term neurological sequelae in survivors. Without licensed vaccine or specific antiviral drugs; early detection, surveillance, and prevention play a critical role. This review provides an overview of the existing knowledge about NiV epidemiology, transmission modes, reservoir ecology, clinical presentation, diagnostic methods and new therapeutic advances, with the need of a One Health approach in mitigating the risk of spillover and enhancing outbreak preparedness.
