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Genetic diversity and molecular phylogeny of Anaplasma marginale studied longitudinally under natural transmission conditions in Rio de Janeiro, Brazil.

Authors :
Silva, Jenevaldo Barbosa
Gonçalves, Luiz Ricardo
Varani, Alessandro de Mello
André, Marcos Rogério
Machado, Rosangela Zacarias
Source :
Ticks & Tick-borne Diseases; Jun2015, Vol. 6 Issue 4, p499-507, 9p
Publication Year :
2015

Abstract

Anaplasma marginale is the most prevalent tick-borne pathogen in cattle in tropical and subtropical regions of the world. Major Surface Protein 1a (MSP1a) has been found to be a stable genetic marker for identifying A. marginale isolates within geographical regions. It is conserved in cattle during infection and tick-borne transmission of the pathogen. The aim of the present longitudinal study was to determine occurrences of genetic diversity associated with high prevalence of A. marginale under natural transmission conditions. Twenty calves were evaluated every 3 months during the first year of life. Rickettsemia levels due to A. marginale , measured as the number of msp1α copies/ml in the blood of positive calves, ranged from 2.06 × 10 3 to 4.36 × 10 12 . The numbers of MSP1a tandem repeats among MSP1a tandem repeats were 3 and 6. The predominant msp1α microsatellite was E, and another MSP1a tandem repeat was found that presented genotype G. Nineteen different MSP1a tandem repeats of A. marginale were found circulating in animals. The MSP1a tandem repeats 4–63–27 (27.5%), 78–24 2 –25–31 ( n = 21.6%) and τ –10 2 –15 ( n = 17.6%) were the ones most commonly observed. Twenty-two MSP1a tandem repeats resulted in new sequences with amino acid changes, as shown in this study. Thirty sequences were found for the first time in Brazil. Glycine, glutamate, serine and alanine amino acids were found at position 20. During the study, 80% (16/20) of the animals were infected by more than one genotype. Three animals were born infected, with MSP1a tandem repeats 4–63–27, 78–24 2 –25–31 and τ –10 2 –15, thus indicating occurrence of transplacental transmission. In the phylogenetic analysis, 19 different MSP1a tandem repeats of A. marginale were found in the cattle, which suggested that many MSP1a tandem repeats and high variation in MSP1a were occurring. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
1877959X
Volume :
6
Issue :
4
Database :
Supplemental Index
Journal :
Ticks & Tick-borne Diseases
Publication Type :
Academic Journal
Accession number :
102981238
Full Text :
https://doi.org/10.1016/j.ttbdis.2015.04.002