Fusobacterium varium Infection In Mice as a Model for the Study of Vaccine Efficacy And Immunogenicity

Open Access
Author:
Guerra, Catherine Marie
Area of Honors:
Veterinary and Biomedical Sciences
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Jason William Brooks, Thesis Supervisor
  • Lester C Griel Jr., Honors Advisor
Keywords:
  • Fusobacterium
  • vaccine
  • white-tailed deer
Abstract:
Fusobacterium spp. are Gram-negative, obligate anaerobes, that have potentially both beneficial and pathological functions in humans and animals. Fusobacterium necrophorum has long been known as a causative agent of necrotic laryngitis, foot rot, and rumenitis-liver abscess complex in cattle, while Fusobacterium varium has been known to play a beneficial role as an integral constituent of the gut microflora. Recently, F. varium has become known as the most common pathogen to cause necrobacillosis in some white-tailed deer (Odocoileus viginianus) populations. Many deer farmers vaccinate their herds with a commercially available Fusobacterium necrophorum bacterin vaccine due to a lack of an acceptable alternative; however, many of these farms suffer from rampant cases of necrobacillosis. The objectives of this study were to investigate the effectiveness of four different vaccine preparations in preventing F. varium infection in mice. Additionally, the study explored the degree of cross-protection afforded by the vaccines prepared with F. necrophorum. Each vaccine (F. varium bacterin, F. varium toxoid, F. necrophorum bacterin, and F. necrophorum toxoid) was homogenized with an adjuvant and injected into mice on days 0 and 14. Mice were subsequently experimentally challenged with F. varium and Trueperella (Arcanobacterium) pyogenes on day 28. The F. varium toxoid vaccine induced the most protection in mice against F. varium infection, while the F. necrophorum toxoid vaccine did not induce any protective effect. This study provided information that suggests the current vaccine used by deer farmers may not be the most protective method against F. varium infection.