# Validated Methods for Inactivation of Tick-Borne Encephalitis Virus Compatible with Immune-Based and Enzymatic Downstream Analyses

## TL;DR

This study identifies safe methods to inactivate Tick-Borne Encephalitis Virus for research outside high-containment labs.

## Contribution

Validated UV and detergent-based inactivation methods for TBEV that preserve sample integrity for downstream assays.

## Key findings

- 45 seconds of UV irradiation effectively inactivates TBEV.
- Triton-X100 at 0.05%-0.1% concentration inactivates TBEV while preserving sample integrity.
- Inactivated samples remain compatible with immuno- and enzymatic assays.

## Abstract

Tick-Borne Encephalitis Virus (TBEV) is impacting public health in the Eurasian region, with increasing case numbers. There is, therefore, a need to expand research efforts and the corresponding infrastructure capacity. Since TBEV is classified as a risk group 3 organism in Switzerland, handling infectious material containing the virus is restricted to biosafety level 3 laboratories. In some instances, downstream analyses may need to be performed outside of the containment facility. It is, therefore, essential to validate effective inactivation protocols compatible with the safe and accurate processing of samples. This study evaluated UV irradiation, chemical treatment with detergents, and mechanical filtration as candidate methods to inactivate TBEV infectious samples, including culture supernatants and tissue homogenates, while preserving their compatibility for different assays. Among the methods tested, 45 s of UV irradiation or Triton-X100 at concentrations between 0.05% and 0.1% effectively inactivated TBEV while mostly preserving the integrity of the processed samples for immuno- or enzymatic assays. These findings establish safe and reliable procedures for advancing TBEV research beyond high-containment settings.