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Analysis of world strains of Anaplasma marginale using major surface protein 1a repeat sequences
José de la Fuente1, Paula Ruybal, Moses S Mtshali
1Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078-2007, USA. jose_delafuente@yahoo.com
Abstract:
Anaplasma marginale is a tick-borne pathogen of cattle that causes the disease bovine anaplasmosis worldwide. Major surface proteins (MSPs) are involved in host-pathogen and tick-pathogen interactions and have been used as markers for the genetic characterization of A. marginale strains and phylogenetic studies. MSP1a is involved in the adhesion and transmission of A. marginale by ticks and varies among geographic strains in the number and sequence of amino-terminal tandem repeats. The aim of this study was to characterize the genetic diversity of A. marginale strains collected from countries in North and South America, Europe, Asia, Africa and Australia, inclusive of all continents. In this study, we characterized 131 strains of A. marginale using 79 MSP1a repeat sequences. These results corroborated the genetic heterogeneity of A. marginale strains in endemic regions worldwide. The phylogenetic analyses of MSP1a repeat sequences did not result in clusters according to the geographic origin of A. marginale strains but provided phylogeographic information. Seventy-eight percent of the MSP1a repeat sequences were present in strains from a single geographic region. Strong (> or =80%) support was found for clusters containing sequences from Italian, Spanish, Chinese, Argentinean and South American strains. The phylogenetic analyses of MSP1a repeat sequences suggested tick-pathogen co-evolution and provided evidence of multiple introductions of A. marginale strains from various geographic locations worldwide. These results contribute to the understanding of the genetic diversity and evolution of A. marginale and tick-pathogen interactions.
Insights
Anaplasma marginale, a cattle pathogen, shows significant genetic diversity globally. Analysis of its MSP1a protein reveals phylogeographic patterns, suggesting co-evolution and multiple introductions of strains worldwide.
Area of Science:
- Veterinary Microbiology
- Parasitology
- Molecular Epidemiology
Background:
- Anaplasma marginale is a significant tick-borne cattle pathogen causing bovine anaplasmosis globally.
- Major surface proteins (MSPs), particularly MSP1a, are crucial for host-pathogen interactions and serve as genetic markers for Anaplasma marginale strains.
- MSP1a exhibits variation in repeat sequences among different geographic strains, impacting adhesion and transmission.
Purpose of the Study:
- To investigate the genetic diversity of Anaplasma marginale strains across all continents.
- To analyze the phylogenetic relationships of Anaplasma marginale based on MSP1a repeat sequences.
- To understand the evolutionary dynamics and geographic dissemination of Anaplasma marginale.
Main Methods:
- Characterization of 131 Anaplasma marginale strains using 79 MSP1a repeat sequences.
- Phylogenetic analysis of MSP1a repeat sequences to determine genetic relationships.
- Assessment of sequence distribution across different geographic regions.
Main Results:
- Confirmed significant genetic heterogeneity of Anaplasma marginale strains worldwide.
- Phylogenetic analysis provided phylogeographic insights, but strains did not cluster strictly by geographic origin.
- Seventy-eight percent of MSP1a repeat sequences were unique to single geographic regions, with strong support for clusters from Italy, Spain, China, Argentina, and South America.
Conclusions:
- The genetic diversity of Anaplasma marginale is substantial, with MSP1a repeat sequences offering valuable phylogeographic information.
- Phylogenetic patterns suggest co-evolution between ticks and Anaplasma marginale, alongside evidence of multiple global introductions.
- These findings enhance understanding of Anaplasma marginale evolution, genetic diversity, and tick-pathogen interactions.
