Genetic Diversity of Anaplasma marginale in Argentina

PAULA RUYBAL; ROSALIA MORETTA; ROMINA PETRIGH; ANDRES PEREZ; SILVINA WILCOWSKY; PABLO NUÑEZ; KATHERINE M. KOCAN; JOSÉ DE LA FUENTE; SUSANA TORIONI DE ECHAIDE; MARISA FARBER

Merida, Yucatan , Mexico

Conferencia; 9th Biennial Conference of the Society for Tropical Veterinary Medicine; 2007

Anaplasmosis is a worldwide major constrain in cattle production caused by the intraerythrocytic rickettsia Anaplasma marginale. This study reports the first characterization of A. marginale genetic diversity based on the genotype marker msp1alpha within Argentinean soil and evaluates the influence of Boophilus microplus infestation. For this purpose, we analyzed whole blood bovine samples from anaplasmosis outbreaks from B. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different genotypes and 31 different repeat units. Twenty of these repeat units were already reported in a recently published worldwide analysis of this marker with 8 of them only present in Argentina. Moreover, 6 sequences are reported for the first time in this work. According to tick regions three groups of repeat units were found, associated to the presence of ticks (20 repeats), to the absence of ticks (6 repeats) and randomly distributed (5 repeats). Even when sequence M was detected in both regions it was not randomly distributed as it resulted statistically associated to tick absence and also presented a specific geographical distribution that empathized this association. This sequence distribution may collaborate to elucidate A. marginaleAnaplasma marginale. This study reports the first characterization of A. marginale genetic diversity based on the genotype marker msp1alpha within Argentinean soil and evaluates the influence of Boophilus microplus infestation. For this purpose, we analyzed whole blood bovine samples from anaplasmosis outbreaks from B. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different genotypes and 31 different repeat units. Twenty of these repeat units were already reported in a recently published worldwide analysis of this marker with 8 of them only present in Argentina. Moreover, 6 sequences are reported for the first time in this work. According to tick regions three groups of repeat units were found, associated to the presence of ticks (20 repeats), to the absence of ticks (6 repeats) and randomly distributed (5 repeats). Even when sequence M was detected in both regions it was not randomly distributed as it resulted statistically associated to tick absence and also presented a specific geographical distribution that empathized this association. This sequence distribution may collaborate to elucidate A. marginaleA. marginale genetic diversity based on the genotype marker msp1alpha within Argentinean soil and evaluates the influence of Boophilus microplus infestation. For this purpose, we analyzed whole blood bovine samples from anaplasmosis outbreaks from B. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different genotypes and 31 different repeat units. Twenty of these repeat units were already reported in a recently published worldwide analysis of this marker with 8 of them only present in Argentina. Moreover, 6 sequences are reported for the first time in this work. According to tick regions three groups of repeat units were found, associated to the presence of ticks (20 repeats), to the absence of ticks (6 repeats) and randomly distributed (5 repeats). Even when sequence M was detected in both regions it was not randomly distributed as it resulted statistically associated to tick absence and also presented a specific geographical distribution that empathized this association. This sequence distribution may collaborate to elucidate A. marginaleBoophilus microplus infestation. For this purpose, we analyzed whole blood bovine samples from anaplasmosis outbreaks from B. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different genotypes and 31 different repeat units. Twenty of these repeat units were already reported in a recently published worldwide analysis of this marker with 8 of them only present in Argentina. Moreover, 6 sequences are reported for the first time in this work. According to tick regions three groups of repeat units were found, associated to the presence of ticks (20 repeats), to the absence of ticks (6 repeats) and randomly distributed (5 repeats). Even when sequence M was detected in both regions it was not randomly distributed as it resulted statistically associated to tick absence and also presented a specific geographical distribution that empathized this association. This sequence distribution may collaborate to elucidate A. marginaleinfestation. For this purpose, we analyzed whole blood bovine samples from anaplasmosis outbreaks from B. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different genotypes and 31 different repeat units. Twenty of these repeat units were already reported in a recently published worldwide analysis of this marker with 8 of them only present in Argentina. Moreover, 6 sequences are reported for the first time in this work. According to tick regions three groups of repeat units were found, associated to the presence of ticks (20 repeats), to the absence of ticks (6 repeats) and randomly distributed (5 repeats). Even when sequence M was detected in both regions it was not randomly distributed as it resulted statistically associated to tick absence and also presented a specific geographical distribution that empathized this association. This sequence distribution may collaborate to elucidate A. marginaleB. microplus infested (9 samples) and eradicated/free (14 samples) regions. Sequence analysis revealed the existence of 15 different genotypes and 31 different repeat units. Twenty of these repeat units were already reported in a recently published worldwide analysis of this marker with 8 of them only present in Argentina. Moreover, 6 sequences are reported for the first time in this work. According to tick regions three groups of repeat units were found, associated to the presence of ticks (20 repeats), to the absence of ticks (6 repeats) and randomly distributed (5 repeats). Even when sequence M was detected in both regions it was not randomly distributed as it resulted statistically associated to tick absence and also presented a specific geographical distribution that empathized this association. This sequence distribution may collaborate to elucidate A. marginaleA. marginale flow within Argentinean livestock. Two and even 4 genotypes were found in samples from highly enzootic area infested with ticks. Moreover, it was previously suggested that A. marginale strains containing these repeats may have co-evolved with the tick vector. This strongly support the higher variability observed in Argentinean tick infested region compared to tick free/eradicated region and suggests an important role to tick-mediated transmission as significant factor for the generation of genetic variability of this disease. Finally, 3 of the 31 sequences showed a serine aminoacid as a new variation at position 20 within the repeat unit. This aminoacid position was suggested to be important in the rickettsia adhesion to erythrocytes and tick cells, therefore new adhesion experiments to test the function of this aminoacid in MSP1a peptides must be done. This work represents the first report of genetic variability of A. marginale strains in Argentina. Moreover, B. microplus infested and free regions were analyzed demonstrating a higher variability according to tick influence. Characterization of A. marginale strains diversity is fundamental to the design of epidemiological, virulence and vaccine development studies and control strategies for bovine anaplasmosis.A. marginale strains containing these repeats may have co-evolved with the tick vector. This strongly support the higher variability observed in Argentinean tick infested region compared to tick free/eradicated region and suggests an important role to tick-mediated transmission as significant factor for the generation of genetic variability of this disease. Finally, 3 of the 31 sequences showed a serine aminoacid as a new variation at position 20 within the repeat unit. This aminoacid position was suggested to be important in the rickettsia adhesion to erythrocytes and tick cells, therefore new adhesion experiments to test the function of this aminoacid in MSP1a peptides must be done. This work represents the first report of genetic variability of A. marginale strains in Argentina. Moreover, B. microplus infested and free regions were analyzed demonstrating a higher variability according to tick influence. Characterization of A. marginale strains diversity is fundamental to the design of epidemiological, virulence and vaccine development studies and control strategies for bovine anaplasmosis.A. marginale strains in Argentina. Moreover, B. microplus infested and free regions were analyzed demonstrating a higher variability according to tick influence. Characterization of A. marginale strains diversity is fundamental to the design of epidemiological, virulence and vaccine development studies and control strategies for bovine anaplasmosis.strains in Argentina. Moreover, B. microplus infested and free regions were analyzed demonstrating a higher variability according to tick influence. Characterization of A. marginale strains diversity is fundamental to the design of epidemiological, virulence and vaccine development studies and control strategies for bovine anaplasmosis.A. marginale strains diversity is fundamental to the design of epidemiological, virulence and vaccine development studies and control strategies for bovine anaplasmosis.