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Category: Research Summary / Infectious Disease Explainer
Comprehensive review of Nipah virus epidemiology, transmission pathways, clinical features, and research progress based on peer-reviewed literature.

Nipah virus (NiV) is a zoonotic, enveloped RNA virus in the genus Henipavirus (family Paramyxoviridae) with a single-stranded, negative-sense genome. Its structural proteins include glycoproteins that mediate attachment and fusion, enabling entry into host cells expressing ephrin-B2 and ephrin-B3 receptors (relevant to respiratory and neurological tissue tropism) [1, 2].

Nipah virus has emerged as a serious public health concern due to its high lethality and recurrent outbreaks across South and Southeast Asia [3]. 

Global Epidemiology and Outbreak History

NiV was first identified during an outbreak in Malaysia in 1998–1999, where transmission occurred via infected pigs to humans, causing encephalitis and respiratory disease [3]. Subsequent outbreaks have been reported in:

• Bangladesh, often linked to consumption of raw date palm sap contaminated by fruit bat secretions;
• India, including outbreaks in West Bengal and Kerala;
• Philippines, with evidence of pig-to-human and human-to-human transmission.
  

Fruit bats (family Pteropodidae) are considered the natural reservoir, and intermediate hosts such as pigs can amplify virus spread to humans [3]. 

Transmission Pathways

Transmission of NiV to humans occurs via:

1. Zoonotic spillover — direct contact with infected bats or contaminated food products (e.g., date palm sap).
2. Intermediate hosts — pigs and other mammals can amplify the virus and facilitate human infection.
3. Human-to-human transmission — documented in several outbreaks, particularly among close contacts and in healthcare settings, though it is generally less efficient than for highly transmissible respiratory viruses [3].
   

The wide bat reservoir range and ecological changes, including habitat disruption and increased human–wildlife interfaces, are thought to elevate the risk of spillovers [4]. 

Clinical Features and Pathogenesis

NiV infection presents a spectrum of disease from asymptomatic or mild febrile illness to severe encephalitis and acute respiratory disease. Common symptoms reported in clinical series include fever, headache, myalgia, and respiratory distress, progressing in some patients to neurological signs such as seizures and altered consciousness [1].

NiV infection is characterized by:

• Encephalitis, due to infection of neural tissue;
• Systemic vasculitis, contributing to multi-organ pathology;
• Respiratory involvement, especially in some outbreaks.

These diverse clinical manifestations reflect the virus’s ability to infect multiple cell types and tissues [5].

Fatality rates vary substantially across outbreaks and settings, with documented case fatality ratios from roughly 40% up to over 90%, influenced by viral strain, clinical management, and surveillance sensitivity [6].

Diagnosis and Clinical Management

Diagnosis of Nipah virus infection relies on laboratory methods such as real-time reverse transcription polymerase chain reaction (RT-PCR) and serological tests for antibodies. These tests are generally performed under high biosafety (BSL-4) conditions due to the virus’s pathogenicity [7].

There are no licensed antiviral treatments or vaccines for NiV infection. Clinical management focuses on supportive care, including respiratory support and intensive care for severe disease. The absence of specific therapies underscores the challenge posed by NiV and similar emerging pathogens [7]. 

Research Progress and Challenges

Vaccine Development

Progress toward Nipah vaccines has been incremental and remains an active area of research. Several platforms, including viral vectors and protein subunit vaccines, are in preclinical or early clinical stages. However, sporadic and unpredictable outbreak patterns complicate large-scale efficacy trials and licensure.

Therapeutics and Countermeasures

Experimental approaches investigated in laboratory and animal models include monoclonal antibodies targeting viral glycoproteins, antiviral compounds, and fusion inhibitors, but none have yet been approved for routine clinical use. Continued research is aimed at identifying broadly protective agents with potential to mitigate severe disease [8]. 

Public Health Significance and Preparedness

Nipah virus is included in international research and development priority lists due to its combination of high lethality, zoonotic potential, and lack of medical countermeasures. Strengthening surveillance, biosafety infrastructure, and rapid outbreak response protocols are key for reducing the impact of future NiV events [3].

Collaborative One Health approaches — integrating human, animal, and environmental health — are recommended to anticipate spillovers and enhance early detection. 

Key Takeaways

• Nipah virus is a highly pathogenic zoonotic RNA virus with a wide bat reservoir and potential for human outbreaks [3].
  
• Transmission occurs via animal-to-human spillover and, in some settings, human-to-human spread [3].
  
• Clinical illness ranges from febrile disease to fatal encephalitis [5].
  
• No licensed vaccines or antiviral therapies exist yet, making research and preparedness priorities.

References 

1. Ganguly A, Mahapatra S, Ray S, et al. The rising threat of Nipah virus: a highly contagious and deadly zoonotic pathogen. Virol J. 2025;22(1):139. Published 2025 May 10. doi:10.1186/s12985-025-02728-4

2. Brown B, Gravier T, Fricke I, Al-Sheboul SA, Carp T-N, Leow CY, Imarogbe C, Arabpour J. Immunopathogenesis of Nipah Virus Infection and Associated Immune Responses. Immuno. 2023; 3(2):160-181. 

3. Tan FH, Sukri A, Idris N, et al. A systematic review on Nipah virus: global molecular epidemiology and medical countermeasures development. Virus Evol. 2024;10(1):veae048. Published 2024 Jul 25. doi:10.1093/ve/veae048

4. Kiran V, Girigoswami K, Girigoswami A. Nipah Virus: Transmission Dynamics of a Zoonotic Outbreak and Therapeutic Challenges. Biomed. Res. Ther. 2025;12(5):7350-7371.

5. Devnath P, Wajed S, Chandra Das R, Kar S, Islam I, Masud HMAA. The pathogenesis of Nipah virus: A review. Microb Pathog. 2022;170:105693. doi:10.1016/j.micpath.2022.105693

6. Asokan S, Luke MS, Atiyah HM, et al. Nipah virus as a pandemic threat: Current knowledge, diagnostic gaps, and future research priorities. Diagn Microbiol Infect Dis. 2026;114(2):117141.

7. Ambat AS, Zubair SM, Prasad N, et al. Nipah virus: A review on epidemiological characteristics and outbreaks to inform public health decision making. J Infect Public Health. 2019;12(5):634-639. doi:10.1016/j.jiph.2019.02.0138. Gazal S, Sharma N, Gazal S, Tikoo M, Shikha D, Badroo GA, Rashid M, Lee S-J. Nipah and Hendra Viruses: Deadly Zoonotic Paramyxoviruses with the Potential to Cause the Next Pandemic. Pathogens. 2022; 11(12):1419.

Ana Correia-Branco, PhD is a placenta biologist specializing in glycomics, proteomics, placental biology, and imaging. Her work focuses on translating complex biomedical research into clear, evidence-based content across pregnancy, microbiome science, and disease mechanisms.

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