title: Assessment of a low virulence Australian isolate of Anaplasma marginale for pathogenicity, immunogenicity and transmissibility by Boophilus microplus.
abstract: A 14-year-old cow (Dawn) born and kept in a Boophilus microplus-free region gave birth to a calf, which showed the presence of an Anaplasma marginale infection after splenectomy. The calf's grand dam was from a B. microplus infected area and we assume the infection originated via the transplacental route over two generations. An isolate, prepared from the calf, had similar or lower pathogenicity as Anaplasma centrale, and previously exposed steers were resistant to challenge by four A. marginale field isolates. Two attempts to transmit the isolate using B. microplus were unsuccessful. Our results indicate that Dawn A. marginale may be a useful vaccine in Australia and warrants larger scale validation of its safety and potency locally as well as of the protection it affords against African and New World isolates.
authors.affiliation: Tick Fever Research Centre, Department of Primary Industries, Queensland, 280 Grindle Road, Wacol, Queensland 4076, Australia. russell.bock@dpi.qld.gov.au
authors.forename: Russell E
authors.initials: RE
authors.lastname: Bock
authors.forename: Albertus J
authors.initials: AJ
authors.lastname: deVos
authors.forename: Terry G
authors.initials: TG
authors.lastname: Kingston
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Carter
mesh_terms: D042322:Anaplasma marginale / Q000276:immunology / Q000472:pathogenicity*; D000712:Anaplasmosis / Q000276:immunology* / Q000469:parasitology / Q000635:transmission; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology*; D001428:Bacterial Vaccines; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000469:parasitology / Q000635:transmission; D005260:Female; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary; D026863:Ixodidae / Q000382:microbiology*; D008297:Male; D011897:Random Allocation; D013156:Splenectomy / Q000662:veterinary; D014774:Virulence
chemical_list: D001428:Bacterial Vaccines