Anaplasmosis in Animals- Advances in Molecular Epidemiology, Pathogenesis, Diagnostics and Integrated One Health Control Strategies: A Review

Abstract

Anaplasmosis is an important tick-borne disease affecting livestock, companion animals, wildlife and humans worldwide. The disease is caused by obligate intracellular bacteria of the genus Anaplasma, which infect different hematopoietic cells and produce diverse clinical manifestations depending on the host species, pathogen strain, immune status and environmental conditions. In recent years, the epidemiology of anaplasmosis has evolved considerably because of climate change, expansion of tick vectors, increasing animal movement, emergence of novel Anaplasma species and growing zoonotic concerns. Advances in molecular epidemiology, genomics and diagnostic technologies have improved understanding of pathogen diversity, host-pathogen interactions and disease transmission dynamics. This review critically synthesizes recent advances in the epidemiology, genomics, pathogenesis, diagnostics, therapeutics, vaccine development and integrated one health control strategies of anaplasmosis in animals. Recent molecular studies have revealed substantial genetic diversity among circulating Anaplasma isolates and highlighted the emergence of zoonotic species such as Anaplasma phagocytophilum and Anaplasma capra. The pathogenesis of anaplasmosis involves sophisticated immune evasion mechanisms including antigenic variation, intracellular persistence, apoptosis inhibition and modulation of host immune signaling pathways. Molecular diagnostics such as polymerase chain reaction and next-generation sequencing have improved detection sensitivity, limitations remain in field applicability and carrier-state detection. Therapeutic management continues to rely primarily on tetracyclines; however, persistent carrier states, antimicrobial resistance concerns and incomplete pathogen clearance remain major challenges. Integrated control strategies involving vector management, vaccination, surveillance, biosecurity and climate-resilient approaches are essential for sustainable disease control. Anaplasmosis remains a major constraint to livestock productivity and public health globally. Future control will depend on integrated multidisciplinary approaches combining molecular surveillance, precision diagnostics, vaccine innovation, vector ecology and One Health policy frameworks to address the evolving epidemiology of this economically and zoonotically important disease.