We report here a Nipah virus (NiV) outbreak in Kozhikode district of Kerala state, India, which had caused fatal encephalitis in a 12-year-old boy and the outbreak response, which led to the successful containment of the disease and the related investigations. Quantitative real-time reverse transcription (RT)-PCR, ELISA-based antibody detection, and whole genome sequencing (WGS) were performed to confirm the NiV infection. Contacts of the index case were traced and isolated based on risk categorization. Bats from the areas near the epicenter of the outbreak were sampled for throat swabs, rectal swabs, and blood samples for NiV screening by real-time RT-PCR and anti-NiV bat immunoglobulin G (IgG) ELISA. A plaque reduction neutralization test was performed for the detection of neutralizing antibodies. Nipah viral RNA could be detected from blood, bronchial wash, endotracheal (ET) secretion, and cerebrospinal fluid (CSF) and anti-NiV immunoglobulin M (IgM) antibodies from the serum sample of the index case. Rapid establishment of an onsite NiV diagnostic facility and contact tracing helped in quick containment of the outbreak. NiV sequences retrieved from the clinical specimen of the index case formed a sub-cluster with the earlier reported Nipah I genotype sequences from India with more than 95% similarity. Anti-NiV IgG positivity could be detected in 21% of <i>Pteropus medius</i> (<i>P. medius</i>) and 37.73% of <i>Rousettus leschenaultia</i> (<i>R. leschenaultia</i>). Neutralizing antibodies against NiV could be detected in <i>P. medius</i>. Stringent surveillance and awareness campaigns need to be implemented in the area to reduce human-bat interactions and minimize spillover events, which can lead to sporadic outbreaks of NiV.
Anti-Nipah virus immunoglobulin G antibodies and neutralizing antibodies were detected in Pteropus medius and Rousettus leschenaultia bats near the outbreak area, indicating prior viral exposure.
Anti-NiV IgG positivity could be detected in 21% of Pteropus medius (P. medius) and 37.73% of Rousettus leschenaultia (R. leschenaultia). Neutralizing antibodies against NiV could be detected in P. medius.
Method
ELISA; plaque reduction neutralization test
Sample type
blood; serum
Serological EvidenceExtraction confidence 0.90
Key finding
Anti-Nipah virus immunoglobulin G antibodies were detected in 37.73% of Rousettus leschenaultia bats, showing evidence of Nipah virus exposure.
Anti-NiV IgG positivity could be detected in 21% of Pteropus medius (P. medius) and 37.73% of Rousettus leschenaultia (R. leschenaultia).
Method
ELISA
Sample type
blood; serum
Zoonotic Surveillance2 records
Zoonotic SurveillanceExtraction confidence 0.95
Key finding
Nipah virus surveillance in bats near the Kerala outbreak detected anti-NiV antibodies and neutralizing antibodies in Pteropus medius and seropositivity in Rousettus leschenaultia, indicating bat involvement in Nipah virus ecology.
Bats from the areas near the epicenter of the outbreak were sampled for throat swabs, rectal swabs, and blood samples for NiV screening by real-time RT-PCR and anti-NiV bat immunoglobulin G (IgG) ELISA. Anti-NiV IgG positivity could be detected in 21% of Pteropus medius and 37.73% of Rousettus leschenaultia. Neutralizing antibodies against NiV could be detected in P. medius.
Method
real-time RT-PCR; ELISA; plaque reduction neutralization test
Sample type
throat swab; rectal swab; blood
Geographic raw
Kerala
Country inferred
India
Zoonotic SurveillanceExtraction confidence 0.90
Key finding
Serological surveillance found anti-NiV IgG antibodies in Rousettus leschenaultia bats near the Kerala outbreak, supporting their role as potential Nipah virus hosts.
Anti-NiV IgG positivity could be detected in 37.73% of Rousettus leschenaultia using ELISA in bats sampled near the epicenter in Kerala.
Method
ELISA
Sample type
blood
Geographic raw
Kerala
Country inferred
India
Genomic Evolution1 records
Genomic EvolutionExtraction confidence 0.80
Key finding
Genomic sequencing of Nipah virus from the Kerala outbreak showed that the virus clustered with the Nipah I genotype previously identified in India, demonstrating high sequence similarity.
Whole genome sequencing (WGS) were performed to confirm the NiV infection. NiV sequences retrieved from the clinical specimen of the index case formed a sub-cluster with the earlier reported Nipah I genotype sequences from India with more than 95% similarity.
Genes or proteins
whole genome
Analysis methods
whole genome sequencing; phylogenetic analysis
Outbreak Investigation1 records
Outbreak InvestigationExtraction confidence 0.95
Key finding
A Nipah virus outbreak in Kozhikode district, Kerala, India resulted in a fatal human case and triggered outbreak investigations and containment measures.
We report here a Nipah virus (NiV) outbreak in Kozhikode district of Kerala state, India, which had caused fatal encephalitis in a 12-year-old boy and the outbreak response, which led to the successful containment of the disease and the related investigations.
We report here a Nipah virus (NiV) outbreak in Kozhikode district of Kerala state, India, which had caused fatal encephalitis in a 12-year-old boy ... Bats from the areas near the epicenter of the outbreak were sampled ... Anti-NiV IgG positivity could be detected in 21% of Pteropus medius and 37.73% of Rousettus leschenaultia ... surveillance and awareness campaigns need to be implemented in the area to reduce human-bat interactions and minimize spillover events.
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