Pythium insidiosum is an aquatic oomycete that causes severe segmental thickening of the canine gastrointestinal (GI) tract, resulting in weight loss, vomiting, diarrhea, and death. Infection in dogs previously has been observed primarily in the southeastern United States.
To describe the clinicopathologic and epidemiologic findings associated with GI pythiosis in 10 dogs from California.
Dogs were initially identified on the basis of supportive clinical findings and routine histology. Pythiosis was confirmed in each dog with at least one of the following: immunoblot serology, enzyme-linked immunosorbent assay serology, immunohistochemistry, and culture followed by species-specific polymerase chain reaction, rRNA gene sequencing, or both.
Between September 2003 and December 2006, GI pythiosis was confirmed in 1 dog from central California and 9 dogs that lived within a 30-mile radius of Davis, CA. Seven of 8 dogs for which environmental data were available had frequent access to flooded rice fields or other water sources. Esophageal lesions were present in 2 of 10 dogs. Common laboratory findings included eosinophilia (7/9), hypoalbuminemia (9/9), and hyperglobulinemia (8/9). Median survival time was 26.5 days (range, 0-122 days), and the disease was ultimately fatal in all 10 dogs.
The geographic distribution of pythiosis has widened in recent years to include the western United States. Factors that may have contributed to this change include altered rice-farming practices and landscape irrigation. Veterinarians in California should be familiar with the clinicopathologic features associated with GI pythiosis to aid in early diagnosis and effective treatment.
"s the diagnostic efficiency of the molecular-based assay. Alternatively, several investigators have developed immunoperoxidase staining assays (IPS) to facilitate histodiagnosis of pythiosis, using antiserum raised against P. insidiosum antigens. (Brown et. al, 1988; Howerth et. al, 1989; Reis et. al, 2003; Camus et. al, 2004; Rakich et. al, 2005; Berryessa et. al, 2008; White et. al, 2008; Martins et. al, 2012; Pessoa et. al, 2012; Ubiali et. al, 2013). These IPS assays show good detection sensitivity, but some of them have limited detection specificity (Keeratijarut et. al, 2009). Cross reactivity of IPS with some fungi, i.e., Fusarium species, may due to endogenous activity of fungal peroxidase. An "
[Show abstract][Hide abstract] ABSTRACT: Pythiosis is an infectious disease of humans and animals living in tropical and subtropical countries. The etiologic agent is the pathogenic oomycete Pythium insidiosum. The disease has a high rate of morbidity and mortality. Patients usually presented with symptoms associated with arterial or ocular infection. Most patients underwent surgical removal of an infected organs (i.e., legs and eyes) to control the infection. Early and accurate diagnosis is important because it leads to prompt treatment and better prognosis for patients with pythiosis. Here, we developed and evaluated an immunofluorescent staining assay (IFA) for histodiagnosis of pythiosis. Rabbit anti-P. insidiosum antibodies were generated for direct detection of P. insidiosum in paraffin-embedded samples. Sixteen P. insidiosum isolates and 16 other fungi were used to prepare paraffin-embedded culture blocks for diagnostic performance evaluation of IFA. As a result, all culture blocks prepared from P. insidiosum were stained positive, while those prepared from the other fungi (control) were stained negative. IFA was further evaluated using paraffin-embedded tissue blocks prepared from infected tissues of patients with vascular pythiosis (n=3) and other fungal infections (2 Candida albicans, 1 Aspergillus flavus, and 1 Fusarium sp). All infected-tissue blocks from pythiosis patients were tested positive, while those from patients with other mycoses were tested negative. Taken together, the developed IFA provided high diagnostic performance (100% sensitivity and specificity), and could be used to facilitate diagnosis of pythiosis.
The 6th National Science Research Conference, Faculty of Science, Burapha University; 03/2014
"The epidemiology and distribution of the genus Pythium was described in soil and aquatic environments around the world and the life cycle of P. insidiosum occurs necessarily in flooded environment. This organism affects several species of animals including horses, cats, dogs, cattle, sheep, camels, bears, and birds resulting in various pathological conditions (Pier et al. 2000, Wellehan et al. 2004, Berryessa et al. 2008, Pesavento et al. 2008). In Brazil, the disease in horses was described in northern state of Rio de Janeiro, Brazil (Reis Jr. et al. 2003), in cattle in flooded areas of the states of Mato Grosso do Sul, and Rio Grande do Sul (Santurio et al. 2004, Gabriel et al. 2008, Grecco et al. 2009), and in flocks of sheep, in the state of Paraíba, northeastern Brazil (Tabosa et al. 2004). "
[Show abstract][Hide abstract] ABSTRACT: Pythiosis is caused by Pythium insidiosum and the occurrence of disease in horses was described in the North and Northwest State of Rio de Janeiro, Brazil. The disease was described in cattle, sheep, humans, and horses in different states and regions across the country. This paper describes the development of IgY and IgG polyclonal antibodies, in chicken and rabbits, respectively against proteins extracted from kunkers and hyphae of P. insidiosum from affected horses. The proteins were recognized by chicken, rabbit and horse antibodies by immunodiffusion and Western blot against majority bands of 27 and 43 KDa, and titrated by ELISA. The antibodies IgY developed by the first time against Brazilian strains of P. insidiosum may represent a valuable tool in the detection of antigens of the pathogen and contribute to further studies aimed at immunotherapy and knowledge about this disease in endemic areas in Rio de Janeiro and in Brazil.
[Show abstract][Hide abstract] ABSTRACT: An 18-year-old Arabian mare was examined with a large mass on the left hind pastern and fetlock. The mare was located in the Central Valley of northern California, and had never been out of the state. Routine histopathological processing and examination of biopsy samples from the mass showed several hyphal organisms that were delineated with a silver stain. Using immunohistochemistry the organism was diagnosed as Pythium insidiosum. The owner declined debulking surgery, and despite treatment with an immunotherapeutic vaccine, the horse's condition deteriorated leading to euthanasia.
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