Authors : Diosdado-Vargas Fernando, C. Martinez-Lara Atalo, Socci-Escatell Guadalupe, Carrera-Salas Elvira, Santiago Julio, Coba-Ayala Maria Antonia, Zapata-Salinas Laura and Pastrana-Unzuela Roxana
Abstract: The aim of this study was to determine infection frequency and genetic variability of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) in farms with suggestive clinical data located in seven states of the Mexican Republic. Sixty two farms were visited to collect blood and tissue samples, on a convenience transversal approach from animals slaughtered for decreased weight gain. Specific serum antibodies were measured by ELISA. Viruses were isolated from macerated tissues filtered and applied onto MARC-145 cells or detected by RT-PCR using specific primers to amplify 300 bp from the viral ORF7. To determine genetic variability primers amplifying 809 bp from ORF5-ORF6 were used. To differentiate between American and European strains, two sets of primers that separately amplify 337 and 241 bp from ORF7 were employed. Puebla, Veracruz, Mexico, Guanajuato, Michoacan, Queretaro and Jalisco States had PRRSV seropositive farms with 45-100% frequencies and 20-98% of positive animals. In positive farms, PRRSV was detected by RT-PCR in at least a tissue sample. Phylogenetic analysis showed high variability for PRRSV and co-existence of genetically different isolates within herds. Differential RT-PCR detected only American strains. PRRSV was isolated in three from seven sampled states. We conclude that PRRSV frequency in Mexican farms is similar to those reported for previous years and PRRSV Mexican isolated have great variability.
Diosdado-Vargas Fernando, C. Martinez-Lara Atalo, Socci-Escatell Guadalupe, Carrera-Salas Elvira, Santiago Julio, Coba-Ayala Maria Antonia, Zapata-Salinas Laura and Pastrana-Unzuela Roxana, 2015. Infection Frequency and Genetic Variability of Porcine Reproductive and Respiratory Syndrome Virus in Several States of the Mexican Republic. Journal of Animal and Veterinary Advances, 14: 130-135.