Pythiosis

Abstract

Pythiosis is a granulomatous disease that affects subcutaneous, vascular, ocular, and gastrointestinal tissues of many humans and animals. The disease is caused by the fungus-like pathogen Pythium insidiosum, an oomycete found predominantly in tropical and subtropical areas of the world. Pythiosis in animals (horses and dogs) has been more prevalent in the American continent, while the disease in humans has been mostly reported from Thailand. Susceptibility according to age, sex, and breed of the animals is not considered as determinants for infection. Continuous stay in stagnant water with the presence of abundant plant material is the most important factor responsible for the infection, since the disease is acquired in aquatic environment due to the penetration of motile biflagellate zoospores into injured skin. Diagnosis of pythiosis is often difficult, delayed, and time-consuming due to the lack of clinical experience and diagnostic techniques. Treatment of choice is frequently relied upon extensive surgery, which, however, is not always possible due to the great extension of the lesions. Frequently, the disease has a poor prognosis, leading animals to death or euthanasia. In humans, removal of the infected organ or death is the common outcome. Therefore, new diagnosis methodologies and treatment approaches against pythiosis and its etiological agent would be among the most studied fields in the near future.