title: Cyclic rickettsemia during persistent Anaplasma marginale infection of cattle.
abstract: Submicroscopic levels of Anaplasma marginale rickettsemia in persistently infected cattle were determined by using nucleic acid hybridization. Within individuals, the rickettsemia levels steadily increased from less than 10(4) infected erythrocytes per ml to a peak of more than 10(6) infected erythrocytes per ml and then rapidly declined. This logarithmic variation parallels the variation of the rickettsemia level seen in acute infection and suggests that cyclic emergence of antigenic variants is a mechanism of rickettsial persistence.
authors.affiliation: Department of Veterinary Microbiology and Pathology, U.S. Department of Agriculture, Pullman, Washington.
authors.forename: S T
authors.initials: ST
authors.lastname: Kieser
authors.forename: I S
authors.initials: IS
authors.lastname: Eriks
authors.forename: G H
authors.initials: GH
authors.lastname: Palmer
mesh_terms: D000709:Anaplasma / Q000302:isolation & purification; D000712:Anaplasmosis / Q000382:microbiology*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D008297:Male; D009693:Nucleic Acid Hybridization; D018805:Sepsis / Q000382:microbiology / Q000662:veterinary*
chemical_list: D004269:DNA, Bacterial