Anaplasma marginale

Anaplasma marginale is an obligate intracellular Gram-negative bacterium of the family Anaplasmataceae that parasitizes the erythrocytes of cattle and other ruminants. It is the etiologic agent of bovine anaplasmosis, a disease characterized by severe hemolytic anemia, fever, weight loss, and potential death, resulting in substantial economic losses in tropical and subtropical regions worldwide. It is transmitted predominantly by ticks, but also by other blood-feeding arthropods or iatrogenic means. The bacterium demonstrates extensive antigenic variation driven by its major surface proteins (MSP1a, MSP4, MSP5), which are critical both for host cell invasion and immune evasion. Diagnostic procedures include PCR assays targeting MSP1a/MSP5 and blood smear analysis. The principal treatments are tetracycline-class antibiotics, and vaccination strategies (attenuated, inactivated, or subunit vaccines targeting specific adhesins) are under development, although vaccine efficacy has limitations.

Antibiotics act by inhibiting bacterial protein synthesis (oxytetracycline). Vaccine approaches use inactivated or attenuated organisms, or surface protein subunits to stimulate immune response.