Evaluation of the efficacy of two different tulathromycin treatments in weaned piglets infected intratracheally with Haemophilus parasuis serovar 5
Once viewed as an infrequent disease of young pigs, Glässer's disease has emerged as a major pathogen affecting naïve swine herds. Current trends recognize Haemophilus parasuis (HPS)serovar 5 as one of the most virulent and most prevalent serovars capable of eliciting sudden death and systemic Glässer's disease in swine. The prudent use of antimicrobials is considered to be an important component in the control of the septicemic spread of a HPS infection within a pig. Tulathromycin, a
... omycin, a triamilide antibiotica, is an approved antimicrobial in many countries however its efficacy against HPS has not been completely examined. The objective of this study was to evaluate the efficacy of two different tulathromycin treatments in commercially weaned piglets challenged intratracheally with HPS serovar 5. A total of 27 piglets were infected with 5 x 10 (8) CFU HPS serovar 5. Eighteen of these piglets were administed two tulathromycin treatments at different times (7 days, 4 days)prior to infection and nine piglets served as controls. After challenge, severe clinical signs, pathological and histopathological lesions indicative of Glässer's disease were seen in all pigs infected with HPS. Furthermore, pyelitis was observed in seven challenged pigs. This is the first study which reports the findings of these lesions in HPS infected pigs and further studies are required to confirm these findings. Based on the results of the clinical examinations, gross and histopathological lesions, the administration of the two tulathromycin treatments 4 and 7 days prior to the experimental HPS infection did not appear to have a significant antimicrobial effect against the infection dose and serovar used in this study. Factors such as unsuitable application times or the high challenge inoculum dose may have contributed to these findings. Further studies examining the efficacy of tulathromycin taking these changes into consideration are necessary.