Epidemiology and genetic evolution of Anaplasma species in rodents from southeastern China

Anaplasma species are globally distributed and pose significant public health threats as zoonotic pathogens. However, the epidemiological characteristics and genetic diversity of Anaplasma in rodents from Fujian Province, southeastern China, remain poorly understood. From 2015 to 2024, we systematically collected 966 rodents across 22 counties and cities in Fujian. Screening was performed using real-time PCR and nested PCR targeting the groEL and 16S rRNA genes. Positive samples were subjected to sequencing, followed by phylogenetic analysis (MEGA11) and haplotype network construction (PopART). The overall infection rate of Anaplasma was 4.35% (42/966), and all positive samples were identified as Anaplasma phagocytophilum. Infection rates showed significant differences among rodent species, cities, habitat types, and sampling years (P < 0.05). Haplotype network analysis indicated that H1 was the dominant haplotype. This study confirms the circulation of A. phagocytophilum in rodents in Fujian, reveals its association with rodent age, seasonal and habitat factors, and underscores the necessity for enhanced ongoing surveillance and control of rodent-borne Anaplasma in this region.