Resumen

SALAS, Yaritza J; MARQUEZ, Adelys A; CORRO, Ana C  y  COLMENAREZ, Victoria. Macroscopic and microscopic characterization of dog gastrointestinal Pythiosis in Venezuela. Rev. Fac. Cienc. Vet. [online]. 2009, vol.50, n.1, pp.23-31. ISSN 0258-6576.

The pythiosis is a fungal, chronic, granulomatous disease that affects humans and several animal species. The pythiosis is caused by the oomycete Pythium insidiosum . In Venezuela, dog pythiosis has been reported in its gastrointestinal form, showing a marked frequency of gastrointestinal diagnosis, compatible with that seen in patients with chronic hemorrhagic diarrhea. The purpose of this investigation was to characterize from the macroscopic and microscopic standpoint, gastrointestinal pythiosis in dogs of the State of Lara, Venezuela. A descriptive field research was conducted. A total of 46 dogs with a histological diagnosis compatible with gastrointestinal pythiosis were chosen. The dogs had been referred to the Pathological Diagnostic Service of the Veterinary Hospital “Dr. Humberto Ramírez Daza”, from January 2001 to July 2007. Gastrointestinal samples were submitted for macroscopic evaluation of tumorous lesions located in the stomach and intestine of dogs under study. For the microscopic assessment, samples were taken and fixed in 10% buffered formaldehyde. The samples were subsequently subjected to histological processing and stained with Hematoxilin and Eosin and Grocott Methenamine Silver. Then, cuts of tissues were obtained and observed in its entire extension under a light microscope. The results of the present investigation show that gastrointestinal pythiosis is macroscopically characterized by a tumor-like moltinodular lesion that involves both the stomach and intestine. Histopathologically, the lesions showed multifocal gastritis and extensive pyogranulomatous enteritis where the etiological agent forms mycelia with long hyphae, few septa, branched in 90º angles, and a diameter of 3 to 5 µm.

Palabras clave : Dog; Pythium; digestive system; lesion; Venezuela.

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