Babesiosis is an infectious disease caused by protozoa of the genus <i>Babesia</i> and characterized by a febrile illness and hemolytic anemia but with manifestations ranging from an asymptomatic infection to a fulminating illness that can result in death.

Inflammatory changes in the synovial membranes and articular structures with widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, as well as atrophy and rarefaction of bony structures.