Kyasanur Forest Disease: An Epidemiological Investigation and Case-Control Study in Shivamogga, Karnataka, India-2022

Objective: Kyasanur Forest Disease (KFD) is a viral zoonosis reported from Karnataka, India. We investigated cases in the Shivamogga district, Karnataka, to describe the epidemiology and identify risk factors in the affected block in 2022.

Methods: A case was defined as a laboratory-confirmed KFD-positive resident of Shivamogga from 1 January-31 May 2022. We extracted the records of KFD cases from district surveillance. We conducted a 1:3 case-control study in the Thirthahalli block. We enrolled laboratory-confirmed KFD-positive Thirthahalli residents from January to May 2022 as cases, and residents without "fever with myalgia" as controls. We reported adjusted odds ratios (aOR) with 95% confidence intervals (CI).

Results: Shivamogga reported 35 cases, with a median age of 46 (4-75) years, of which 51% were men, and one death. Among 25 cases and 90 controls, knowledge of avoiding recent monkey death sites was low (cases = 0%, controls = 11%). Monkey death sites within 500 m [aOR = 8.6 (1.8-41.9)] and household tick exposure [aOR = 3.7 (1.3-10.7)] were independent risk factors.

Conclusion: This was a laboratory-confirmed cluster of KFD cases in Thirthahalli, with residence near a monkey death site and household tick exposure considered significant risk factors. We recommend evaluating monkey carcass disposal procedures and increasing awareness of tick protective measures.