Phylogenetic and Biologic Evidence That Babesia divergens Is Not Endemic in the United States
The causative agent of human babesiosis in a Kentucky case, which was first identified asBabesia divergens, is identical to a parasite of eastern cottontail rabbits on Nantucket Island, Massachusetts based on piroplasm size, morphology, and ribosomal RNA sequence analysis. Studies showing differential infectivity for cattle, host erythrocyte specificityin vitro, parasite size and morphologyin vitro, and ribosomal RNA sequences clearly demonstrate that the parasite from the rabbit (conspecific with the human Kentucky agent) is not the same organism as B. divergens
human babesiosis eastern cottontail rabbit b. divergens small subunit ribosomal rna gene intervening transcribed spacer