First Molecular Characterization of Theileria equi from Northeastern Algeria

Equine piroplasmosis (EP) is a tick-borne disease that affects equids and is caused by the parasites Theileria equi, Theileria haneyi and Babesia caballi. This disease leads to significant economic losses for the global equine industry. The current study aimed to evaluate the prevalence of Piroplasmida infections in equines from El Tarf, located in northeastern Algeria, and investigate the phylogenetic diversity within isolates obtained from infected equines in this study and between those from previous studies.

A total of 120 blood samples were collected from equines in three municipalities of El Tarf. The small subunit of the 18 S rRNA gene, commonly used for genotyping and phylogenetic analysis, was amplified from the positive samples and subsequently sequenced for further analysis.

The study found that 40% of equines were infected with T. equi, while no cases of B. caballi infection were detected. The positivity rate was almost identical across all three municipalities. Four distinct T. equi 18 S rRNA gene sequences were identified in equines from El Tarf. Phylogenetic analysis revealed that these T. equi sequences could be categorized into three distinct clades. The isolates identified in this study grouped into clades A and C, indicating the presence of two genotypes of T. equi 18S rRNA sequences in El Tarf, Northeastern Algeria.

The results confirmed a high prevalence of equine piroplasmosis in three municipalities of El Tarf. They also demonstrated that different isolates of T. equi can coexist within the same geographic region, offering additional insight into T. equi sequences. This finding emphasizes the significant implications for the surveillance of Apicomplexan parasites.