Inactivation of Highly Pathogenic Avian Influenza Viruses Using Deep Ultraviolet Radiation of at Different Wavelengths

Highly pathogenic avian influenza viruses (HPAIVs) of the H5N1 subtype have been reported to infect not only birds, but also humans, cattle, and other mammals, posing a serious public health concern and highlighting the need for effective control measures. Ultraviolet (UV) irradiation is widely known as an effective modality for virus inactivation, and recent advances in LED technology have enabled the generation of UV light of various wavelengths, each with distinct characteristics. In this study, we evaluated the efficacy of four different UV wavelengths (222 nm, 230 nm, 254 nm, and 265 nm) in inactivating HPAIVs. HPAIV at a concentration of 2.0 × 106 plaque-forming units (PFU) /mL was irradiated with UV light at doses ranging from 0 to 7.3 mJ/cm2. The UV doses required to achieve a 99.9% reduction in the viral titer were 4.2 mJ, 4.9 mJ, 5.6 mJ, and 4.3 mJ for UV light wavelengths of 222 nm, 230 nm, 254 nm, and 265 nm, respectively. All four UV light wavelengths reduced viral titers by more than 99.9%, demonstrating their effectiveness in inactivating HPAIVs. This study demonstrated that UV light at all the four tested wavelengths effectively inactivated HPAIVs to a comparable extent, suggesting the usefulness of UV light for inactivating HPAIVs in a wide range of environments.