Mycopathologia 141: 123–125, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands. 123 Cutaneous Pythiosis insidiosi in calves from the Pantanal region of Brazil Janio Morais Santurio 1 , Adriana Bardemaker Monteiro 1 , Alexandre Trindade Leal 1 , Glaucia Denise Kommers 2 , Renato Silva de Sousa 2 & João Batista Catto 3 1 Departamento de Medicina Veterin´ aria Preventiva, Universidade Federal de Santa Maria – UFSM, 97105-900, Santa Maria – RS, Brazil. E-mail: santurio@ccr.ufsm.br 2 Departamento de Patologia, CCS, UFSM, Santa Maria – RS, Brazil 3 EMBRAPA – CPAP, Corumb´ a – MS, Brazil Received 7 October 1997; accepted in final form 29 April 1998 Abstract Two cases of cutaneous Pythiosis insidiosi were diagnosed in cattle from the Pantanal region, Brazil. The lesions were observed in the limbs of two 8-month-old beef calves. Close examination showed local swelling and focal ulceration of the skin. Microscopically, there was multifocal granulomatous dermatitis with intralesional Pythium insidiosum hyphae. The diagnosis was based on the morphological aspects, immunohistochemical findings and culture of the etiologic agent. Key words: Cattle disease, cutaneous pythiosis, Pythium insidiosum Introduction Cutaneous Pythiosis insidiosi is a chronic disease from tropical, subtropical and temperate regions of the world [1–3]. It is caused by Pythium insidio- sum, a member of the Chromista kingdom [3], class Oomycetes, family Pythiaceae [3–6]. In equines, P. insidiosum causes granulomatous and ulcerative cuta- neous lesions [1]. Lymphnodes [5, 7], intestines [8, 9], lungs [10] and bones [11, 12] can be also af- fected. Gastrointestinal [6, 13] and subcutaneous [14] lesions were described in dogs. There is only one report of feline Pythiosis insidiosi [15] and one of bovine Pythiosis insidiosi [16]. Human Pythiosis in- sidiosi associated with thalassemia hemoglobinopathy syndrome has been reported in Asia [17]. This report describes two cases of cutaneous Pythiosis insidiosi in beef calves from the Pantanal region of Brazil, where equine Pythiosis insidiosi is endemic [18]. Clinical and pathological findings Two 8-month-old beef calves, one male and one fe- male, from the same farm, had swollen, focally ulcer- ated dry areas in the skin of the limbs. The male calf was affected in the lateral face of the distal metatarsal portion of the right hindlimb. The affected skin area measured 5 × 3 cm. The female calf had a similar lesion, measuring 8 × 5 cm, and localized in the distal metacarpal region of the right forelimb. On the cut surface, punctiform, 1 mm in diameter yellow areas were observed in the dermis. Kunkers were absent. Biopsy samples were collected from affected areas. Histhologic findings were similar in both cases and consisted of multiple dermal granulomas, with neu- trophils in the central area surrounded by macrophages and Langhans multinucleated cells (Figure 1). Neu- trophils and eosinophils surrounded the granulomas. A small number of dark-staining hyphae, in Gomori’s metenamine silver stain, was observed in the cen- tral area of the granulomas. Some hair follicles were dilated by cellular debris and inflammatory cells. Hy- phae were also found into dilated hair follicles and sur- rounding hair shafts. These were irregular, branched, rarely septated, 5 to 9 μm in diameter. Perihyphal