Anaplasmosis in the Amazon: Diagnostic Challenges, Persistence, and Control of A. marginale and A. phagocytophilum

Jhorsan David Mauri Pablo ¹ Jakson Jacob Chuquimia del Solar ¹ Elthon Thomas Hinojosa Enciso ¹ Richard Costa Polveiro ² Dielson da Silva Vieira ^3,4 Eduardo Milton Ramos Sanchez ⁵ William Bardales Escalante ⁶ Jorge Luis Maicelo Quintana ⁶ Rainer Marco Lopez Lapa ^1*

• ¹ Laboratorio de Fisiología Molecular, Facultad de Ingeniería Zootecnista, Agronegocios y Biotecnología, Instituto de Investigación en Ganadería y Biotecnología, UNTRM, Chachapoyas, Peru
• ² Laboratory of Bacterial Diseases, Sector of Preventive Veterinary Medicine and Public Health, Department of Veterinary, Universidade Federal de Viçosa, Viçosa, MG, Brazil
• ³ Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, United States
• ⁴ Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana, United States
• ⁵ Faculty of Medicine, Toribio Rodríguez National University of Mendoza of Amazonas, Chachapoyas, Amazonas, Peru
• ⁶ Facultad de Ingeniería Zootecnista, Agronegocios y Biotecnología, Instituto de Investigación en Ganadería y Biotecnología, Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas, Chachapoyas, Peru

Anaplasmosis remains a significant threat to livestock production in tropical regions, particularly in the Amazon basin, where ecological complexity and limited veterinary infrastructure challenge effective disease management. This review focuses on Anaplasma marginale and A. phagocytophilum, the primary species associated with bovine and granulocytic anaplasmosis, respectively. We examine the current state of diagnostic tools, highlighting the limited accessibility of molecular techniques in rural settings and the emerging but underutilized potential of technologies. Persistent infection and antigenic variation are explored as major obstacles for disease eradication and vaccine development. Although live attenuated and inactivated vaccines are in use for A. marginale, none provide sterilizing immunity, and no commercial vaccines exist for A. phagocytophilum. The review evaluates recent advances in recombinant antigens, chimeric constructs, and genetically attenuated strains, as well as future directions involving multiepitope design, novel adjuvants, and nextgeneration vaccine platforms. Additionally, we assess the role of tick control in disease prevention and emphasize the importance of integrated strategies in regions like the Amazon.Together, these findings underscore the need for context-specific solutions that address the ecological and epidemiological complexity of anaplasmosis in the Amazon basin.