NEW DELHI: As the Chandipura virus outbreak continues in Gujarat and Rajasthan, the Centre has deployed a National Joint Outbreak Response Team (NJORT) to strengthen the response in the affected states.
The team comprises experts from the National Centre for Disease Control (NCDC), the Indian Council of Medical Research (ICMR), and the Department of Animal Husbandry and Dairying (DAHD).
According to Union Health Ministry officials, the team will supplement the efforts of the two state governments in outbreak investigation, epidemiological assessment, clinical management, laboratory coordination, vector surveillance, and implementation of public health measures.
The team will work closely with the state health departments to review the on-ground response and submit recommendations to the ministry after completing its field assessment, officials said.
Gujarat has reported 35 confirmed Chandipura virus cases out of 184 suspected patients tested, along with 22 deaths among children below the age of 15.
Rajasthan has also confirmed three Chandipura virus cases from the border districts of Dungarpur and Sirohi.
The Chandipura virus causes Acute Encephalitis Syndrome (AES), characterised by rapid inflammation of the brain. The disease primarily affects children under 15 years of age, especially during the monsoon season.
Officials said the deployment comes against the backdrop of sustained and intensified scientific investigations by a nationwide network of premier research institutions, alongside continuous disease surveillance under the Integrated Disease Surveillance Programme (IDSP), coordinated by the NCDC in close collaboration with State Surveillance Units.
"These coordinated efforts are aimed at advancing the understanding of the virus, including its transmission dynamics, clinical spectrum, epidemiology and potential treatment approaches, while guiding evidence-based public health interventions," officials said.
The NCDC's Public Health Emergency Operations Centre (PHEOC) has also been activated to support the joint response team.
Officials said experts from ICMR-National Institute of Epidemiology (ICMR-NIE), Chennai; ICMR-National Institute of Vector Control Research (ICMR-NIVCR), Puducherry; ICMR-National Institute of Virology (ICMR-NIV), Pune; ICMR-National Institute for Pre-Clinical Research (ICMR-NIPCR), Hyderabad; and ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (ICAR-NIVEDI), Bengaluru, are working closely with the Gujarat State Health Department to investigate the outbreak.
The collaborative exercise brings together specialists in epidemiology, virology, entomology, veterinary sciences and laboratory diagnostics to understand the full clinical spectrum of Chandipura virus infection, from mild febrile illness to AES, and generate evidence to strengthen public health interventions.
As part of the investigation, active surveillance has been intensified among patients presenting with Acute Febrile Illness (AFI) and AES in the affected districts. Community-based serosurveys are also being conducted to estimate asymptomatic infections and assess the true extent of virus transmission.
Laboratory teams are simultaneously working to strengthen diagnostic assays and develop improved animal models to better understand the disease's pathogenesis.
A key focus of the investigation is to unravel the virus's transmission cycle. While sandflies are the established vectors of the Chandipura virus, scientists are also examining whether other arthropods, including mosquitoes, ticks and mites, may play a role in transmission.
Large numbers of vector samples collected from affected areas are currently undergoing laboratory analysis.
Officials emphasised that it is premature to identify the vector responsible for the current outbreak until scientific investigations are completed.
Animal surveillance has also been expanded to determine whether the virus is circulating among domestic animals that could potentially act as reservoirs.
Blood samples from cattle, buffaloes and goats, along with milk samples, have been collected for testing.
Around 70 animal blood samples have been collected so far and are being analysed for the Chandipura virus and other relevant pathogens.
Authorities have clarified that no conclusions can be drawn until laboratory investigations are completed.
The ongoing investigations are also drawing on lessons from the 2024 Chandipura virus outbreak in Gujarat. During that outbreak, several vector species, including sandflies, were collected and tested. However, all samples were negative for the Chandipura virus (CHPV), and no specific vector could be conclusively implicated.
Scientists are also closely examining whether the virus has undergone genetic changes.
Whole-genome sequencing of virus samples from the current outbreak is being carried out at the Gujarat Biotechnology Research Centre (GBRC) in Gandhinagar.
Preliminary analysis has identified minor genetic variations. However, experts said detailed comparative genomic studies are required before determining whether the currently circulating virus has evolved from strains associated with previous outbreaks.
Adding to the growing body of scientific evidence, researchers from ICMR-NIV, Pune, in collaboration with ICMR-Rajendra Memorial National Institute of Health Research (ICMR-RMNIHR), Patna; BJ Medical College (BJMC), Ahmedabad; the Department of Animal Husbandry and Dairying; and the Health and Family Welfare Department, Government of Gujarat, have recently published a research paper titled "Investigations into the Outbreak of Chandipura Virus Encephalitis, Gujarat, India, 2024," documenting the multidisciplinary investigations carried out during last year's outbreak.
The current investigations are further supported by India's Hospital-based Acute Encephalitis Syndrome (AES) Surveillance Network, a multicentric prospective surveillance programme spanning 15 tertiary care hospitals across the country.
Using standardised clinical protocols, serological and molecular diagnostics, and selective next-generation sequencing, the network is generating critical epidemiological and laboratory evidence to strengthen outbreak detection, improve understanding of the aetiology of AES, and support timely public health action.
"With the deployment of the joint response team and parallel investigations by multiple national institutions, the Centre has significantly expanded scientific and field support to Gujarat and Rajasthan, reflecting a coordinated 'One Health' approach that integrates human, animal and vector surveillance to better understand and contain the Chandipura virus outbreak," officials added.
