Background: Pythium insidiosum is an oomycete that causes cutaneous lesions or infiltrative gastrointestinal disease in dogs, cats, humans, horses and other mammals, primarily in tropical and subtropical climates.
Hypothesis/objectives: We report the clinicopathological findings associated with cutaneous pythiosis in two dogs from a Northern temperate climate zone.
Animals: A 3-year-old intact male Chesapeake Bay retriever was presented with an ulcerated soft-tissue swelling over the left eye. A 4-year-old spayed female German shepherd dog was presented with a soft-tissue swelling overlying the right hock. Both dogs lived in northern latitudes (between 43 and 45°N) and neither had travelled outside of Wisconsin or Michigan's upper peninsula, USA.
Methods: Histopathological examination and culture of affected tissues on specialized media, serology for anti-P. insidiosum antibodies, P. insidiosum-specific PCR and ribosomal RNA gene sequencing were carried out.
Results: Histopathological examination revealed pyogranulomatous and eosinophilic inflammation associated with wide, poorly septate hyphae.
Conclusions and clinical importance: Even clinicians who practice in temperate climates should consider pythiosis as a differential diagnosis for young to middle-aged adult dogs presented with ulcerated cutaneous nodules or infiltrative gastrointestinal disease.
© 2013 ESVD and ACVD.