Insect-derived environmental surveillance of lumpy skin disease virus using synanthropic flies

Lumpy skin disease (LSD) is a transboundary viral disease of cattle with substantial economic impact. Conventional surveillance strategies rely primarily on host-based sampling and clinical observation, which may be logistically constrained or insufficient during early or post-clinical phases of outbreaks. In this study, we used synanthropic flies as environmental micro-samplers to investigate temporal dynamics of LSDV under real-world outbreak conditions. Systematic fly collections were conducted at a confirmed LSDV-positive cattle farm during an active outbreak, followed by molecular screening and targeted sequencing. Both non-blood-feeding and opportunistic blood-feeding fly species, including Musca domestica and Hydrotaea spp., were analyzed to assess the presence of LSDV nucleic acids across multiple sampling periods. LSDV nucleic acids were detected in synanthropic flies, with temporal variation corresponding to the implementation of outbreak control measures. Viral signals declined over successive sampling rounds, indicating that insect-derived sampling reflects changes in environmental viral loads following intervention. Phylogenetic analysis of partial GPCR gene sequences revealed close genetic relationships between viruses detected in insect and cattle specimens, while also capturing minor sequence variation within a single outbreak setting. These findings support the concept that synanthropic flies can serve as environmental sentinels for monitoring pathogen persistence and diversity without direct animal sampling. Overall, insect-derived environmental sampling using synanthropic flies provides a non-invasive approach for capturing temporal patterns of LSDV under outbreak conditions.