Segmental enteritis associated with Pythium insidiosum infection in a horse
Silva, Taiara Müller daFlores, Mariana MartinsLamego, Eryca CeolinLorenzetti, Douglas MiottoRamos, Cristina PradeKommers, Glaucia Denise
Background: Pythiosis is an infectious disease caused by the oomycete Pythium insidiosum, with higher occurrence in wetlands and hot climate regions. This microorganism develops its cycle in aquatic plants, and most cases happen because of the contact of animals or people with water containing the motile zoospores (infectious form). Horses are the principal species affected and develop principally cutaneous and subcutaneous lesions, but the gastrointestinal tract is seldom affected. Humans develop various forms of pythiosis, such as a vascular form. The objectives of the current study are to describe an unusual case of intestinal pythiosis, its clinical signs, aspects of pathogenesis, and diagnosis. Case: A 13-year-old Crioula mare, from Santa Maria, RS, Brazil, presented with reduced food and water intake, apathy, restlessness, rolling, nasal reflux, firm abdomen upon palpation, and tachypnea during 2 days. The horses of this farm were fed native pasture and horse feed, and they had access to a nearby pond. Two days following the start of the clinical signs, the horse died and was necropsied on the farm. During necropsy, there was around 400 mL of reddish effusion in the abdominal cavity (modified transudate). A 15 cm segment of jejunum was firm upon palpation and had a severe transmural thickening. The wall of the affected area was up to 3 cm in thickness and firm, with small yellowish and irregular masses that stood out and looked friable, interpreted as kunkers. Microscopically, the yellowish masses (kunkers) were characterized by dense accumulations of intact and degenerate eosinophils (eosinophilic necrosis). Within these kunkers, and also on their periphery, there were multiple negatively stained hyphal profiles. Hyphae were also seen on the wall of small arteries inside the kunkers. These hyphae had nearly parallel walls and were occasionally...(AU)
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