Authors: Tasha Desiderio, Nicole Stacy, Robert Ossiboff, Linda Archer, Amy Alexander, Darryl Heard, Sarah Purcell, Daniel Fredholm, Kyle Donnelly, Justin Rosenberg, April Childress, James Wellehan
Faculty Mentor: James Wellehan
College: College of Veterinary Medicine
The genus Helicobacter are spiral-shaped bacteria in the phylum Proteobacteria, order Campylobacteriales. Three wild gopher tortoises (Gopherus polyphemus) presented between 2012 and 2019 with nasal discharge, lethargy, and weight loss. Cytology of nasal discharge identified heterophilic rhinitis and spiral-shaped bacteria. PCR and sequencing of the 16S rRNA gene revealed this to be a novel Helicobacter species. Two died despite treatment, the third was moribund and was euthanized. Histologic examination of the nasal mucosa showed rhinitis with variable mucosal hyperplasia, erosion, and ulceration; Warthin-Starry staining highlighted the presence of spiral bacteria in the untreated tortoise. Genus-specific primers were designed, and the gyrA and groEL genes were amplified by PCR and sequenced. Phylogenetic analysis shows that this organism and other previously characterized Helicobacter from tortoises form a clade. Development and cross-validation of two qPCR diagnostic assays for the gyrA and groEL genes showed significant correlation of the results of two assays (P<0.0001). These assays were used to survey nasal wash samples from a collection of 37 gopher tortoises. Sex, medication, nasal discharge score, blood data, and other clinical data were compared with qPCR results for this bacteria. Higher mortality of tortoises was significantly correlated to higher Helicobacter loads detected by qPCR (P=0.0128). Upper respiratory disease in tortoises appears to involve complex microbial ecology; factors beyond Mycoplasmopsis (Mycoplasma) agassizii should be taken into account.