Table 1.
Epidemiology of Nipah virus cases in India.
Table 2.
Comparative epidemiology, pathogenesis, and clinical manifestations of Nipah virus outbreaks.
Fig 1.
Epidemiological distribution of Nipah virus outbreaks and reservoirs in India (2001–2026).
The map depicts NiV epicenters in India, highlighting the eastern (West Bengal) and southern (Kerala) as high-risk zones for zoonotic spillover due to high bat density and frequent bat-human interactions. Red circles indicate locations of confirmed human outbreaks. Labels denote the year of emergence, the count of laboratory-confirmed cases, and the Case-Fatality Rate (CFR). The gray bats delineate the established geographical distribution of the primary natural reservoir. The green bats reflect regions where NiV RNA was molecularly discovered in bat tissues or anti-NiV IgG antibodies were found, indicating extensive circulation outside epidemic zones. Base map data sourced from geoBoundaries (https://www.geoboundaries.org/) licensed under CC BY 4.0. Map processed and visualized using Mapshaper (https://mapshaper.org/). The authors added outbreak data overlays, labels, and annotations.
Fig 2.
The replication cycle of the Nipah virus.
The schematic outlines the sequential stages of the NiV life cycle, such as attachment to ephrin-B2/B3 receptors through the G glycoprotein, F protein-mediated membrane fusion, release of the viral RNA, replication and transcription, translation of viral proteins (N, P, M, F, G, and L), assembly, encapsidation, and budding of progeny virions from the host cell membrane. Vaccine candidates and antiviral agents that target crucial stages of the viral life cycle are highlighted in red. Icons were used from publicly available resources including NIH/NIAID BioArt Source (https://bioart.niaid.nih.gov/), Servier Medical Art (https://smart.servier.com/; CC BY 4.0), BioIcons (https://bioicons.com/;CC0), and the Reactome Icon Library (https://reactome.org/icon-lib; CC BY 4.0). Final figure design, layout, and annotations were created by the authors.
Fig 3.
Molecular phylogenetic analysis of Nipah virus complete genome sequences.
The evolutionary history of NiV was inferred using the Maximum-Likelihood (ML) method in MEGA (Molecular Evolutionary Genetics Analysis; https://www.megasoftware.net/) using 89 complete genome sequences obtained from GenBank (National Center for Biotechnology Information; https://www.ncbi.nlm.nih.gov/genbank/). Sequence alignment and phylogenetic reconstruction utilized the General Time Reversible (GTR) nucleotide substitution model, involving a discrete Gamma distribution (+G) across 5 categories to address rate heterogeneity among sites (shape parameter = 3.7546) and a proportion of evolutionarily invariant sites (+I = 59.29%). The final dataset included 18,252 nucleotide positions post-alignment trimming. The initial heuristic search tree was chosen based on the superior log-likelihood score of Neighbor-Joining (NJ) compared to Maximum Parsimony (MP) starting trees. Statistical robustness of the inferred topology was assessed using 501 bootstrap replicates; branches that appeared in fewer than 50% of the replicates were collapsed. Internal node support values are indicated by red circles, with circle size (0.96–1) proportional to bootstrap support. The tree was visualized and annotated by the Interactive Tree of Life (iTOL) platform (https://itol.embl.de/). The outer color strips denote the geographic origin of isolates. Symbols at the branch tips indicate the host species. Labels are formatted as accession number, host, country, and year.
Table 3.
Comparative epidemiology, pathogenesis, and clinical manifestations of Nipah virus outbreaks in India.
Fig 4.
Pathophysiology of Nipah virus infection.
This diagram depicts the pathogenesis of NiV after respiratory entry. Following the initial infection of bronchial epithelial cells, the virus disseminates to lung endothelial cells, eliciting a significant inflammatory response. Viral dissemination into the bloodstream facilitates systemic spread, potentially through a “Trojan horse” mechanism involving infected leukocytes and the participation of lymphoid organs and kidneys. Neuroinvasion occurs via hematogenous dissemination across the blood-brain barrier or via retrograde transport along the olfactory nerve, leading to encephalitis, seizures, coma, and brainstem dysfunction. Pulmonary infections can lead to acute respiratory distress syndrome (ARDS) and atypical pneumonia, with systemic endothelial injury and inflammation contributing to multi-organ dysfunction. Icons were used from publicly available resources including NIH/NIAID BioArt Source (https://bioart.niaid.nih.gov/), Servier Medical Art (https://smart.servier.com/; CC BY 4.0), and the Reactome Icon Library (https://reactome.org/icon-lib; CC BY 4.0). Final figure design, layout, and annotations were created by the authors.
Fig 5.
Transmission dynamics of Nipah virus.
The schematic presents an overview of NiV transmission from reservoir hosts to humans either via consumption of contaminated raw date palm sap/fruits or through contact with intermediate amplification hosts. Icons were used from publicly available resources including NIH/NIAID BioArt Source (https://bioart.niaid.nih.gov/) and Openclipart (https://openclipart.org/). Final figure design, layout, and annotations were created by the authors.
Table 4.
Bat reservoir ecology and spillover risk of Nipah virus in India.
Table 5.
Diagnostic and surveillance for Nipah virus in India.
Table 6.
Vaccine and therapeutics.
Fig 6.
One Health framework and strategies for pandemic preparedness.
(a) The schematic depicts the process of zoonotic spillover from wildlife reservoirs, specifically fruit bats, to humans. The phenomenon is influenced by ecological disruption, habitat encroachment, agricultural intensification, and heightened human-animal interactions. (b) The One Health approach integrates surveillance of human, animal, and environmental factors to mitigate the risk of zoonotic spillover. (c) The figure presents a systematic integrated framework for the early detection and prevention of NiV outbreaks. The figure was created by the authors. The figure design, layout, and annotations were created by the authors.