Epidemiology of Human and Animal Anthrax in India, 1990-2022: A Comprehensive Analysis of Literature and National Surveillance Data.

Background: Anthrax, a neglected zoonotic disease caused by Bacillus anthracis, exerts considerable health consequences in resource-limited regions and is notably prevalent in India, causing persistent outbreaks that pose major animal and public health challenges. This study reviews the spatiotemporal patterns of human and animal anthrax outbreaks in India to identify high-risk areas and assess the correlation with environmental factors. Methods: A comprehensive literature search covering the period from 1990 to 2022 was conducted across various databases including CAB Direct, PubMed, Scopus, and Web of Science, alongside Indian government databases like the Integrated Disease Surveillance Programme (IDSP) and the National Animal Disease Referral Expert System (NADRES). We extracted data from studies published in English, using predefined keywords, and evaluated them using the Joanna Briggs Institute checklists. Data analysis was carried out using Microsoft Excel and EpiInfo, with spatial mapping in ArcGIS Pro. Results: Out of the 423 studies reviewed, 44 fulfilled our inclusion criteria, providing data on 174 human outbreaks (1778 cases, 130 fatalities) and 1775 animal outbreaks (7818 deaths). We identified key hotspots for human anthrax in West Bengal, Odisha, and Andhra Pradesh, and significant hotspots for animal anthrax in Karnataka, Andhra Pradesh, Tamil Nadu, and West Bengal. Majority of human outbreaks were reported between March and June, whereas the majority of animal outbreaks were reported between June and September. A strong correlation was observed between rainfall and animal outbreaks in the eastern region (correlation coefficient of 0.94). Conclusion: The study highlights key hotspots for human and animal anthrax and discrepancies in human and animal anthrax reporting and gaps in surveillance. There is a critical need for enhanced One Health surveillance and animal anthrax vaccination programs for effective management and mitigate the disease. These strategies are essential not only for public health and livestock welfare in India but also for global health security.