Molecular detection and identification of spotted fever group Rickettsia in ticks infesting dairy cattle in northern...

Ticks are major vectors of pathogens affecting livestock and public health worldwide. In Algeria dairy cattle are heavily infested by ticks, but the prevalence and diversity of spotted fever group (SFG) Rickettsia, emerging human pathogens, remain poorly understood. This study aimed to detect and characterize Rickettsia species in ticks collected from dairy cattle in northern Algeria. A total of 770 ticks were manually collected from cattle in three provinces (Blida, Medea and Batna) between 2024 and 2025. From these, 128 ticks were randomly selected for molecular screening. DNA was extracted and initially screened by qPCR for Rickettsia spp. Positive samples were further characterized by conventional PCR and sequencing of the ompA gene followed by phylogenetic analysis. The overall molecular prevalence of Rickettsia spp. was 28.9% (37/128). Genetic characterization and phylogenetic analysis of 16 positive samples successfully identified three SFG Rickettsia species. Candidatus R. barbarica was detected in Rhipicephalus bursa ticks, Rickettsia aeschlimannii was identified in Hyalomma spp. ticks and Rickettsia slovaca was found in a Dermacentor marginatus tick. All sequences showed ≥ 99% identity with known pathogenic strains from the Mediterranean basin. This study provides molecular evidence and phylogenetic confirmation of multiple pathogenic SFG Rickettsia species in ticks from Algerian dairy cattle. These findings highlight the potential public health relevance of spotted fever group Rickettsia and underscore the need for further surveillance and epidemiological investigations to improve the understanding and control of tick-borne rickettsioses in Algeria.