Cinética da infecção experimental e desenvolvimento de PCR multiplex para o diagnóstico de infecções por Brucella ovis, Actinobacillus seminis e Histophilus somni em carneiros

Abstract

Infectious epididymitis is considered a major cause of economic losses for the sheep industry worldwide. The most common causative agents include Brucella ovis, Actinobacillus seminis and Histophilus somni. This study aimed to investigate changes associated with experimental infections with A. seminis and H. somni in rams, and to develop a direct method for differential diagnosis for these three infections. Experimental infections with A. seminis and H. somni were carried out in rams with 18 to 24 months of age. Rams were weekly examined and biological samples were collected for diagnostic purposes. A. seminis and H. somni werecapable of causing infection, colonizing several organs of the genitourinary tract, being indistinguishable only by clinical exam, necropsy or histopathology. Nevertheless, the clinical exam proved to be indispensable as a screening method. Conversely, the importance of laboratorial diagnostic techniques for direct confirmation of the etiologic agent was demonstrated in this study. Therefore, the species-specific multiplex PCR assay developed in this study can be successfully used for the diagnosis of the three most common causes of ovine infectious epididymitis. Furthermore, this technique is a practical alternative to bacteriology. Urine and preputial wash can be used as alternatives to semen samples for DNA extraction and application of the multiplex PCR described in this study.