Upper respiratory tract disease in European hedgehogs ( <i>Erinaceus europaeus</i> ): Histopathological, microbiological, and clinical aspects

Respiratory disease is a common cause for morbidity and mortality in European hedgehogs ( Erinaceus europaeus ) presented for rehabilitation. Despite frequent suspicions of underlying pulmonary disease, upper respiratory tract disease (URTD) investigations rarely occur. Fifty rehabilitating European hedgehogs that died after exhibiting respiratory clinical signs were necropsied with histological and microbiological investigations of the respiratory tract. Fifty-six percent (n = 28) of these hedgehogs had substantial URTD based on histological assessment of 3 transverse nasal cavity sections. URTD cases presented with moderate to marked lethargy (82%), dyspnea and/or tachypnea (79%), abnormal breathing sounds (75%), nasal discharge (64%), and sneezing (54%). Most hedgehogs with URTD were euthanized, 13 (48%) within 24 hours of admission due to the severity of clinical signs, the others (52%) after a period ranging from 3 to 240 days whilst receiving various treatments. Histologically, substantial URTD cases presented as moderate-to-severe rhinitis (40%), epithelial damage ranging from widespread attenuation to multifocal ulceration (40%) and/or maxilloturbinate atrophy (22%) of the nasal chamber proper, and/or inflammation of the vestibule (20%) or caudal nasal cavity (43%). Rhinitis cases were often bilateral (80%), exudative, and neutrophilic with intraluminal gram-negative bacterial colonies. Bacterial culture yielded Morganella morganii (n = 6) and Pasteurella spp. (n = 5) from cases with URTD but not from histologically unremarkable noses. Potentially underlying triggers for URTD included trauma, foreign bodies, periodontal disease, oronasal fistula, and nasal fluke. As respiratory clinical signs in hedgehogs are commonly associated with URTD, routine antemortem and postmortem assessments of the nasal and oral cavities are warranted.