Equine pythiosis: Report of 28 cases from São Paulo State, Brazil

Abstract

Pythiosis is a granulomatous lesion of the skin and subcutaneous tissues caused by Pythium insidiosum, a microorganism belonging to the Stramenopila Kingdom and the Oomycetes Class. The pathogen is commonly found in water environments, mainly in tropical areas of the world. Twenty eight cases of equine pythiosis were presented at the Large Animal Surgery Department of the School of Veterinary Medicine and Animal Science, São Paulo State University, Brazil in six years. Among the 28 animals, 13 presented distal lesions on the limbs, with four being immediately euthanized and seven dying due to loss of body condition leading to cachexia. The horses presented with one or more wounds in the body, distributed as follows: limbs (13 distal, four proximal), abdominal region (7), thoracic region (1), pectoral region (1), lumbar region (1), nasal region (1) and prepuce (1). The diagnosis was made by the association of the macroscopic aspects of the lesions with the histopathology, isolation of the pathogen and/or nested-PCR. Treatments included surgical removal of the lesion (16), potassium iodide 67 mg kg -1 PO sid (23), intravenous regional perfusion with 50 mg of amphotericin B (6) and immunotherapy (8). Pythiosis is a disease that develops quickly, but its diagnosis is time-consuming; therefore, establishing an early treatment with special attention to the involvement of distal regions of the limbs is important. Key words: Equine, granulomatous, pythiosis, Pythium insidiosum, surgery, wound ResumoA pitiose é uma doença granulomatosa do tecido cutâneo e subcutâneo causado pelo oomiceto Pythium insidiosum, microorganismo pertencente ao reino Stramenopila, classe Oomycetes. O agente é comumente encontrado em ambientes aquáticos, principalmente nas áreas tropicais do mundo. Foram atendidos 28 casos no Serviço de Clínica Cirúrgica de Grandes Animais da Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu, São Paulo, Brasil. Dentre os 28 animais, 13 apresentaram lesões distais de membro, sendo quatro imediatamente submetidos à eutanásia e sete morreram devido à perda progressiva de condição corporal levando a caquexia. Os equinos apresentaram uma ou mais lesões, distribuídas da seguinte forma: membros (13 distais e quatro proximais), região abdominal (7), região torácica (1), região peitoral (1), região lombar (1), região nasal (1), prepúcio (1). O diagnóstico foi baseado na associação dos achados macroscópicos, histopatológicos, isolamento do patógeno e/ou nested-PCR. Os tratamentos incluíram: remoção cirúrgica (16), iodeto de potássio 67 mg kg -1 VO Sid (23), perfusão regional com 50 mg de anfotericina B (6) e imunoterapia (8 de rápido desenvolvimento, sendo imprescindível o diagnóstico rápido com especial atenção às lesões localizadas na região distal do membro.

Uso do flucozanol associado à excisão cirúrgica no tratamento da pitiose cutânea equina

“…Lesions constituted an increase in volume characterized by exuberant granular tissue with an ulcerated surface, containing serosanguineous secretion and yellowish white necrotic masses, known as kunkers. These findings are similar those previously reported (WATANABE et al, 2015).…”

“…It is important to note that in cases of ECP, time from the onset of disease is a determining factor in therapeutic success (GROOTERS, 2014) and that the inclusion of a control group might have compromised the efficacy of conventional therapy in control group animals in the period following the of the study. These data are consistent with the findings of Watanabe et al (2015) who argue that early institution of aggressive therapy is necessary for total remission of lesions. We have also noted previous studies without a control group (DÓRIA et al, 2012(DÓRIA et al, , 2015.…”

“…Equine cutaneous pythiosis is a rapidly progressing disease, and although new therapies have been tested, there is no standard treatment for chronic lesions that have developed over a period of several months, with many clinical cases presenting challenges for veterinarians (GROOTERS, 2014). Therapeutic success is based on the time since disease onset, site and size of the lesion, and speed and intensiveness of therapy (WATANABE et al, 2015). Even with the time between emergence of lesions and beginning of treatment varying from 2 to 5 months (average 3 months), a complete clinical solution was possible for all cases of ECP in this study Horses accepted oral administration of fluconazole diluted in corn glucose well, which demonstrates the practicality of this method for drug administration.…”

Immunotherapy for Fungal Infections

“…Several studies have been conducted using the culture hypha filtrate, sonicated or vortexed hypha and demonstrated some degree of protection [168][169][170][171]. PitiumVac®, a licensed immunotherapy to treat equine pythiosis in Brazil, is an example of the use of disrupted hyphae, and its use reaches a cure rate of 70-80% [172,173]. Despite the good curative properties of PitiumVac®, it does not present protective activity [174].…”

Outbreak of equine pythiosis in a southeastern region of Brazil: Environmental isolation and phylogeny

“…The wounds evolve quickly and can be characterized by the presence of necrotic yellow tissue, called ‘kunkers’, which are clusters of hyphae and inflammatory cells. Some cases of the disease may evolve to progressive loss of weight of the animal, leading to death (Santos et al., 2011; Watanabe et al., 2015).…”