Background Kyasanur Forest Disease (KFD) is a zoonotic viral disease caused by the Kyasanur Forest Disease Virus (KFDV), belongs to the family Flaviviridae, and is transmitted to humans through the bites of infected ticks, primarily in forested regions. Thirthahalli taluk from Shivamogga district of Karnataka has been reporting a consistently high burden of KFD. We describe the epidemiology of KFD cases in Thirthahalli taluk including their temporal and spatial distribution, correlate KFD hot spots with the number of cases, and identify high-risk groups. Methods We conducted a retrospective analysis of KFD surveillance data obtained from the district surveillance unit, Shivamogga, on human, tick, and monkey data, of Thirthahalli taluk from November 2017 to May 2022, described epidemiology, calculated the annual and seasonal time-trend of cases and correlated number of cases with number of tick pools and/ or monkey carcass positive for KFDV. We report Pearson correlation coefficient. We performed spatial analysis to identify clustering patterns and describe the PHC-wise disease burden. Results Thirthahalli taluk reported 326 cases, all were lab-confirmed using either RT-PCR (93%) or IgM-ELISA (7%); with an annual incidence rate of 45.9 per 100,000 population, 58% in males and median age 40 (IQR 28-51) years. Most (71,5%) cases occurred from February to April, case fatality rate was 1.8%. The maximum number of cases occurred in the years 2019 (38%) and 2020 (44%) crossing the outbreak threshold. The populations coming under six Primary Health Centre (PHCs) reported 84% of all cases and reported all deaths. There was correlation between the number of human cases in a PHC and tick pool positivity (r=0.62); and positive tick pools and positive monkey carcasses (r=0.71). Age groups with the highest average annual incidence were 45 to 49 years (8.4 per 100,000 population) and 50-54 years (8.1 per 100,000 population). Conclusion Thirthahalli taluk had an ongoing endemic transmission of KFD during the study period including two outbreaks in consecutive years. All deaths occurred in PHCs with a high case burden; occurrence of human cases per year was moderately correlated with tick pool positivity. Age groups most at risk for both the occurrence of the disease and mortality were middle-aged adult males. We recommend continued tick surveillance and monkey carcass testing to map disease hot-spots; and targeted interventions in high-burden PHCs and at-risk age groups for effective disease control. Keywords: Flaviviridae, Tick surveillance, Animal mortality surveillance, Zoonoses, One-health

The authors have declared no competing interest.

This study did not receive any funding

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