First molecular and phylogenetic study of the bovine lumpy skin disease virus declared in Algeria in 2024

Lumpy skin disease (LSD) is a re-emerging transboundary viral disease of major economic importance affecting cattle worldwide. In Algeria, LSD was reported for the first time in June 2024, based on clinical observations and serological evidence. This study aimed to perform molecular detection and phylogenetic characterization of the first LSD virus (LSDV) strains circulating in Algeria. From June to August 2024, blood samples were collected from clinically affected cattle in eastern Algeria, a region characterized by active outbreaks and environmental conditions favorable to vector-borne transmission. Animals exhibited typical clinical signs of LSD, including fever, generalized skin nodules, ocular and nasal discharge, and lymphadenopathy. Blood samples were selected to detect LSDV during the viremic phase of infection and enable molecular confirmation under field conditions. Molecular detection was performed using PCR targeting the P32 gene for specific identification of Capripoxvirus. Selected samples were further analyzed using a multi-target PCR approach targeting partial P32 and F genes, as well as complete GPCR and RPO30 genes, followed by sequencing and phylogenetic analysis. LSDV was successfully detected, and sequence analysis revealed genetically homogeneous strains belonging to the pathogenic clade. The Algerian isolates showed close genetic relationships with strains circulating across Africa, the Middle East, Asia, and Europe, suggesting a shared epidemiological origin. A characteristic deletion in the GPCR gene further distinguished field strains from vaccine-related strains. This study provides the first molecular and phylogenetic characterization of LSDV associated with the initial outbreak in Algeria, highlighting transboundary spread patterns and emphasizing the need for enhanced surveillance to monitor virus circulation and evolution and evolution.