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Recent studies on the characterization of Anaplasma marginale isolated from North American bison
Katherine M Kocan1, José De La Fuente, Elizabeth J Golsteyn Thomas
1Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078-2007, USA. kmk285@cvm.okstate.edu
Abstract:
Anaplasma marginale (Rickettsiales: Anaplasmataceae), a tick-borne pathogen of cattle, is endemic in tropical and subtropical regions of the world. Many geographic isolates of A. marginale occur worldwide that have been identified by major surface protein (MSP) 1a, which varies in sequence and molecular weight owing to different numbers of tandem 28-29 amino acid repeats. Although serologic tests have identified American bison, Bison bison, as being infected with A. marginale, the present studies were undertaken to confirm A. marginale infection in bison, to characterize bison isolates, and to compare the phylogenetic relationship of the bison isolates with other A. marginale isolates from North America. Nine A. marginale isolates derived from Canadian bison possessed identical msp4 sequences with one characteristic silent nucleotide change. The sequence of MSP1a was determined for one Canadian and two U.S. bison isolates of A. marginale, and these isolates contained 4 and 5 tandem repeats, respectively. One U.S. bison isolate tested for infectivity proved to be infective for cattle and transmitted by Dermacentor variabilis ticks. the results of this study demonstrated that these A. marginale isolates obtained from bison were similar to ones derived from naturally infected cattle.
Insights
Anaplasma marginale, a cattle pathogen, was confirmed in bison. Bison isolates showed similarities to cattle strains, highlighting potential transmission dynamics of this tick-borne disease.
Area of Science:
- Veterinary Microbiology
- Tick-borne Diseases
- Bovine Pathogens
Background:
- Anaplasma marginale is a significant tick-borne pathogen affecting cattle globally.
- Geographic isolates of A. marginale are often distinguished by variations in the major surface protein (MSP) 1a.
- Previous serologic studies suggested American bison may harbor A. marginale.
Purpose of the Study:
- To confirm and characterize Anaplasma marginale infection in bison populations.
- To determine the phylogenetic relationship of bison-derived A. marginale isolates with North American isolates.
- To assess the infectivity and transmission potential of bison isolates in cattle.
Main Methods:
- Analysis of msp4 gene sequences from Canadian bison isolates.
- Sequencing of the MSP1a gene from Canadian and U.S. bison isolates.
- Infectivity and transmission studies of a U.S. bison isolate in cattle using Dermacentor variabilis ticks.
Main Results:
- Nine Canadian bison isolates shared identical msp4 sequences with a single silent nucleotide variation.
- Bison isolates exhibited variations in MSP1a tandem repeats (4 and 5 repeats).
- One U.S. bison isolate was infective to cattle and transmitted by Dermacentor variabilis ticks.
Conclusions:
- Anaplasma marginale isolates from bison are genetically similar to those found in cattle.
- Bison can serve as a reservoir for Anaplasma marginale, with implications for cattle health.
- The findings underscore the importance of monitoring wildlife for tick-borne pathogens impacting livestock.
