Molecular Survey of Selected Vector-Borne Pathogens in Algerian Horses

Vector-borne pathogens (VBPs) can affect equine health, welfare, and productivity, with potential implications for animal management and trade. However, data on their occurrence in North Africa remain limited. The present study aimed to estimate the molecular occurrence of selected equine VBPs in clinically healthy horses from Algeria. Specifically, a cross-sectional molecular survey was conducted between May and November 2024 on 241 clinically healthy horses selected using convenience sampling from three ecologically distinct regions of Algeria (Tiaret, Laghouat, and Tlemcen). Demographic and management data were collected at sampling, and blood samples were spotted onto filter paper for DNA preservation. Genomic DNA was extracted using a modified Chelex/InstaGene Matrix protocol, followed by conventional and nested PCR assays targeting piroplasms, Anaplasmataceae, filarioid helminths, Rickettsia spp., Trypanosomatidae, haemotropic Mycoplasma spp., and Bartonella spp. Positive amplicons were subjected to sequence and phylogenetic analysis. Theileria equi (T. equi) DNA was detected in 4.98% (12/241) of examined horses, and one animal (0.41%; 1/241) tested positive for Theileria capreoli (T. capreoli). T. equi genotypes A and B were identified via molecular characterisation, but no amplification was obtained for Anaplasmataceae, Babesia caballi, Rickettsia spp., haemotropic Mycoplasma spp., Bartonella spp., Trypanosomatidae, or filarioid helminths. These findings should be interpreted cautiously, given the convenience sampling design, the clinically healthy status of the sampled animals, and the known limitations of PCR-based detection in low-parasitaemia infections. Nevertheless, this study provides preliminary molecular data on equine VBPs in Algeria and supports the need for broader epidemiological investigations using complementary molecular and serological approaches.