Molecular epidemiology and phylogeny of Anaplasma species in goats from Pakistan

Abstract

Despite a goat population of approximately 80 million in Pakistan during 2020−2021, the prevalence of vector-borne pathogens in goats remains largely underexplored. This study aimed to assess the molecular prevalence and phylogenetic characteristics of Anaplasma ovis, Anaplasma marginale and Anaplasma phagocytophilum in goat blood samples (N = 239) collected from three districts (Muzaffargarh, Rajanpur, and Dera Ghazi Khan) in Punjab between September 2023 and October 2024. Blood samples were first screened with generic and then with species specific primers. Molecular analyses revealed a prevalence of 39% for Anaplasma spp. and 14% for A. ovis. A. marginale and A. phagocytophilum were not detected. DNA sequencing, by targeting 16S rRNA and msp4 genes, and BLAST analysis confirmed the presence of Anaplasma spp. and A. ovis, respectively. For both screening, bacterial prevalence rates varied significantly across sampling sites (P = 0.01 for Anaplasma spp. and P = 0.04 for A. ovis). Additionally, the prevalence of Anaplasma spp. significantly differed among goat breeds (P = 0.004), while no association was found between goat sex and bacterial infections (P > 0.05 for both screening). Notably, Anaplasma spp. infection was associated with a significant decrease in red blood cell count and hemoglobin concentration, while A. ovis infection did not affect the complete blood count profile. Phylogenetic analysis revealed that our Anaplasma spp. isolates clustered with those from Iran, Cyprus and China while our A. ovis isolates clustered with those from Pakistan, China, and Sudan. In conclusion, this study reports the presence of Anaplasma spp. and A. ovis in Pakistani goats and recommends large-scale studies across diverse geo-climatic regions to further investigate the epidemiology, genetic diversity and host-parasite interactions for effective control of these infections in local goat populations.