The effect of antibiotic treatment on Haemophilus parasuis colonization, disease and immunity
2015-07
Loading...
Persistent link to this item
Statistics
View StatisticsJournal Title
Journal ISSN
Volume Title
Title
The effect of antibiotic treatment on Haemophilus parasuis colonization, disease and immunity
Authors
Published Date
2015-07
Publisher
Type
Thesis or Dissertation
Abstract
Glasser's disease is an important source of economic losses in commercial swine production systems. The success of controlled exposure in the field suggests that early exposure (colonization) with pathogenic H. parasuis protects pigs from Glasser's disease. However, little is known about the immune response that is generated during colonization and how antimicrobials can modulate the immune response to H. parasuis. The overall goal of this PhD dissertation was to investigate the influence of antimicrobial treatment on H. parasuis colonization and infection, and its effect on the development of immune responses against H. parasuis in swine. First, a species-specific ELISA assay and an experimental model of H. parasuis colonization were developed to study the immune response to H. parasuis colonization by a pathogenic strain in conventional pigs. Moreover, the effect of the antimicrobial enrofloxacin in reducing H. parasuis colonization in weaned pigs was assessed. It was demonstrated that enrofloxacin was able to affect H. parasuis colonization by temporarily reducing the bacterial load in the upper respiratory tract. However, enrofloxacin was unable to eradicate the organism. Then, it was demonstrated that the inoculation of pigs with a low dose of pathogenic H. parasuis protected pigs against secondary infection. Most importantly, the timing of enrofloxacin administration in relation to H. parasuis exposure was relevant to develop protection to a subsequent H. parasuis challenge. The protection observed after H. parasuis inoculation was not affected by enrofloxacin given 3 days before inoculation. In contrast, enrofloxacin given 3 days after inoculation with H. parasuis interfered with protection against challenge. Based on the lack of H. parasuis isolation after enrofloxacin treatment, it appeared that the antibiotic quickly inactivated and removed H. parasuis. For the given infectious dose of pathogenic H. parasuis used, more than 3 days of live bacteria exposure is necessary for pigs to seroconvert and be protected against reinfection. Enrofloxacin-induced abridgement of infection on day 3 post inoculation resulted in the absence of serum IgG response and protection.
Description
University of Minnesota Ph.D. dissertation. July 2015. Major: Veterinary Medicine. Advisors: Montserrat Torremorell, Albert Rovira. 1 computer file (PDF); v, 148 pages.
Related to
Replaces
License
Collections
Series/Report Number
Funding information
Isbn identifier
Doi identifier
Previously Published Citation
Suggested citation
Macedo, Nubia. (2015). The effect of antibiotic treatment on Haemophilus parasuis colonization, disease and immunity. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/175243.
Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.