Molecular detection and characterization of Anaplasma marginale in cattle from the Lower Shabelle Region of Somalia

Abstract Background Anaplasma marginale is a major tick-borne pathogen impacting the global cattle industry, yet its status in Somalia remains poorly understood. The present study aimed to investigate the molecular and serological occurrence and the genetic diversity of A. marginale in cattle from the Lower Shabelle region of Somalia. Methods Blood samples ( n = 131) were collected from cattle, alongside epidemiological data on location, body condition, and tick presence. Packed cell volume (PCV) was measured, and sera were screened for anti- A. marginale IgG antibodies using a commercial rMSP5-based ELISA. Molecular detection was performed by qPCR targeting the msp1β gene, and positive samples were further characterized by PCR amplification and sequencing of the msp1α and msp4 genes, followed by bioinformatic analyses. Results A total of 110/131 (83.9%) cattle presented IgG antibodies to A. marginale , while 121/131 (92.4%) tested positive by qPCR targeting the msp1β gene. A significant difference in median PCV was observed between seropositive and seronegative animals ( p = 0.026). qPCR positivity showed no significant association with tick infestation and body condition. There was a fair agreement between serology and qPCR ( κ = 0.28). Among the 32 qPCR-positive samples further analyzed, 31 (96.9%) were msp1α -positive and all were msp4 -positive. Ten new msp1α and five previously reported short-sequence repeats were identified, while msp4 analysis revealed 18 genotypes, with Somali isolates clustering alongside strains from Africa and Russia. Conclusions This study confirms the high prevalence and genetic diversity of A. marginale in Somali cattle, highlighting the need for improved surveillance and control measures.