Exploration of innate immune response during infectious bovine digital dermatitis and the evaluation of topical therapeutic treatment

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dc.contributor.advisorCobo, Eduardo R.
dc.contributor.advisorBarkema, Herman W.
dc.contributor.authorWatts, Kaitlyn
dc.contributor.committeememberDe Buck, Jeroen M.
dc.contributor.committeememberJenne, Craig N.
dc.date2018-11
dc.date.accessioned2018-10-04T16:02:56Z
dc.date.available2018-10-04T16:02:56Z
dc.date.issued2018-09-18
dc.description.abstractDigital dermatitis (DD) is a frequently occurring infectious disease amongst dairy cattle associated with ulcerative and necrotizing lesions. Due to the associated pain and lameness, DD is a recognized animal welfare problem and has economic implications associated with decreased milk production, lower reproduction rates, and premature culling. DD is of polymicrobial etiology, with the main causative agent identified as belonging to the Treponema genus. Current treatments include topical application of antibiotics such as oxytetracycline or foot baths containing caustic chemicals; however clinical cure rates remain highly variable. In this thesis cattle with DD were monitored to explore the skin innate immune response. An exhaustive description of the inflammatory response during disease progression and a novel description of bovine host defence peptides (HDPs) and their contribution to disease resolution are found herein. It was observed that active DD was characterized by necrotic tissue populated with neutrophils and elevated Cxcl-8 and Tlr4 expression. Tracheal antimicrobial peptide (Tap) was vastly increased in active lesions and key for the resolution of DD. An in vitro model utilizing human keratinocytes showed pro-inflammatory cytokines are released in the absence of living treponemes through Tlr2 signaling and that secretory treponeme products induced cathelicidins. The ability to manipulate inflammatory reactions via treatment with vitamin D3 in DD was compared to the commonly-used oxytetracycline. A cohort of cattle with M2 were topically treated with vitamin D3 against powdered oxytetracycline for 5 days. Although vitamin D3 did elevated Tap expression, lesions and inflammatory markers remained unchanged. In contrast, oxytetracycline reduced neutrophil chemoattractant Cxcl-8 while Tlr2 remained elevated. Histologic assessment evidenced scab formation. Taken together, this thesis established the skin innate response and role of host defence peptides (Tap) during DD and supported oxytetracycline as a treatment, providing lesion resolution and aiding in bacterial elimination.en_US
dc.identifier.citationWatt, K. (2018). Exploration of innate immune response during infectious bovine digital dermatitis and the evaluation of topical therapeutic treatment (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/33084en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/33084
dc.identifier.urihttp://hdl.handle.net/1880/108731
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.facultyVeterinary Medicine
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectBovine digital dermatitis
dc.subjectTreponema spp
dc.subjectCathelicidins
dc.subjectHost defense peptides
dc.subjectkeratinocytes
dc.subject.classificationMicrobiologyen_US
dc.subject.classificationVeterinary Scienceen_US
dc.subject.classificationImmunologyen_US
dc.titleExploration of innate immune response during infectious bovine digital dermatitis and the evaluation of topical therapeutic treatment
dc.typemaster thesis
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameMaster of Science (MSc)
ucalgary.item.requestcopytrue
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