Pythiosis is a disease affecting horses, caused by the aquatic oomycete pathogen Pythium insidiosum. This organism is found in warm, wet environments and infects horses through open wounds or abrasions, leading to the development of granulomatous lesions, often referred to as "kunkers." These lesions typically appear on the limbs, abdomen, or chest and can cause significant tissue damage. Clinical signs of pythiosis in horses include pruritus, lameness, and the presence of ulcerative lesions with necrotic tissue. Diagnosis is generally based on clinical presentation, histopathology, and culture or molecular identification of the organism. Treatment options are limited and can include surgical excision of lesions, antifungal therapy, and immunotherapy. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, diagnostic methods, and treatment strategies for pythiosis in equine populations.
Rodrigues VS, Trevisan LAC, Cintra BS, Pires RH, Ribeiro AB, Tavares DC, Oberhaus E, Ferreira JC.Cutaneous pythiosis is a life-threatening infectious disease. Low-level laser therapy (LLLT) and ozone (O3) have been used individually in the treatment of infected wounds. The goals of the study were a) to characterize the antimicrobial action of the photo-ozone therapy (LLLT-O3) against equine Pythium insidiosum, and b) to assess the cytotoxic potential of the LLLT-O3 in keratinocytes. Specimens of pathogen were isolated from 10 horses. After culturing, 120 hyphae plugs were distributed among four groups (n=30 hyphae plugs/group): LLLT (laser irradiation for 160 sec;), O3 (exposition to O3 f...
Dos Santos CEP, Loreto ES, Zanette RA, Santurio JM, Marques LC.Horse pythiosis is considered an endemic disease in the Brazilian Pantanal region, causing devastating health and economic losses. This study aimed to enhance the understanding of pythiosis epidemiology, map the distribution of horse body lesions, and investigate the correlation between these lesions and warm body surface areas, potentially implicating hematophagous vectors in the disease's transmission. A prospective study was conducted on equids in the Pantanal Mato-grossense and adjacent areas from 2012 to 2022, with 112 horses and three mules diagnosed with pythiosis. Clinical and epidemio...
de Souto EPF, Kommers GD, Souza AP, Miranda Neto EG, Assis DM, Riet-Correa F, Galiza GJN, Dantas AFM.Pythiosis is an endemic disease in northeastern Brazil and we now report the epidemiological, clinical and pathological findings in a retrospective study of naturally occurring cases in domestic animals. From January 1985 to December 2020, the Laboratory of Animal Pathology of the Federal University of Campina Grande examined 13,542 tissue samples from necropsies and biopsies. Among these samples, 306 were diagnosed as pythiosis: 195 cases in horses, 75 in sheep, 19 in dogs, six in mules, four in cattle, three in cats, two in goats, one in a donkey and one in an ostrich. Affected equids had le...
Rotchanapreeda T, Sae-Chew P, Lohnoo T, Yingyong W, Rujirawat T, Kumsang Y, Payattikul P, Jaturapaktrarak C, Intaramat A, Pathomsakulwong W....Pythiosis, a life-threatening disease caused by , has been increasingly diagnosed worldwide. A recently developed immunochromatographic test (ICT) enables the rapid diagnosis of pythiosis. During the 3-year clinical implementation of ICT in Thailand, we collected the laboratory reports of 38 animals with suspected pythiosis and detected ICT false-positive results in three horses and a dog with basidiobolomycosis. and cause infections with indistinguishable clinical and microscopic features. This study investigated cross-reactive antibodies by probing and crude extracts and cell-free synthe...
Krajaejun T, Kittichotirat W, Patumcharoenpol P, Rujirawat T, Lohnoo T, Yingyong W.Genome sequences are a vital resource for accelerating the biological exploration of an organism of interest. Pythium destruens (a synonym of Pythium insidiosum) causes a difficult-to-treat infectious disease called pythiosis worldwide. Detection and management of pythiosis are challenging. Basic knowledge of the disease is lacking. Genomes of this organism isolated from different continents (i.e., Asia and the Americas) have been sequenced and publicly available. Here, we sequenced the genome of an Australian isolate of P. destruens. Genome data will facilitate the comparative analysis of thi...
Valente JSS, Brasil CL, Braga CQ, Zamboni R, Sallis ESV, Albano APN, Zambrano CG, Franz HC, Pötter L, Panagio LA, Reis GF, Botton SA, Pereira DIB.Pythiosis is a rapidly progressing disease that can be lethal to affected individuals due to resistance to available therapeutic protocols. The disease affects mammals, with the largest number of reports in horses and humans. The present study investigated the activity of biogenic silver nanoparticles (bioAgNP) in the treatment of experimental pythiosis. The disease was reproduced in nine female 90-day-old New Zealand rabbits. Animals were divided into three groups: group1 (control, n = 3) daily and topically treated with a nonionized gel-based formulation and 1 ml of sterile distilled wate...
Dória RG, Freitas SH, Linardi RL, Mendonça Fde S, Arruda LP, Boabaid FM, Valadão CA.To evaluate the effects of intravenous regional limb perfusion (IRLP) administration of amphotericin B in horses to treat pythiosis after surgical excision and thermocautery. Methods: Case series. Methods: Horses (n = 12) with Pythium insidiosum infection of the distal aspect of the thoracic or pelvic limbs. Methods: After surgical excision of granulation tissue and thermocautery, 50 mg amphotericin B was administered by IRLP through a catheter placed in a superficial vein of the affected limb next to the lesion after placing a tourniquet above the injection site. The lesions and locomotor sys...
Martins TB, Kommers GD, Trost ME, Inkelmann MA, Fighera RA, Schild AL.Twenty-one cases of pythiosis in horses (n = 10), dogs (n = 9) and cattle (n = 2) were investigated. The aetiology in all cases was confirmed by immunohistochemistry. Data related to the clinical course and outcome and localization of the lesions were obtained from pathology reports. The equine lesions consisted of fibrotic tissue with multiple, often coalescing, areas of immature granulation tissue encircling eosinophilic cores. Affected dogs had gastrointestinal and/or cutaneous lesions with either or both of a granulomatous/pyogranulomatous or necrotizing eosinophilic inflammatory reaction....
Bach BC, Leal DB, Ruchel JB, Souza Vdo C, Maboni G, Dal Pozzo M, Schlemmer KB, Alves SH, Santurio JM.NTPDase (EC 3.6.1.5) occurs in lymphocytes and plays an important role in immune function, in that hydrolyzes extracellular nucleoside tri- and/or diphosphates to form AMP. Pythium insidiosum causes the disease pythiosis, a pyogranulomatous disease of horses, dogs, cattle, cats and humans. Most antifungal drugs are ineffective against this pathogen, and immunotherapy, a treatment approach that relies on the injection of P. insidiosum antigen, has been successfully used in humans and horses to manage this disease. In this study, we investigated NTPDase activity in lymphocytes from rabbits inocu...
Mendoza L, Mandy W, Glass R.The immunotherapeutic properties of a new Pythium insidiosum-vaccine formulation (PIV), was evaluated in 18 horses and 6 dogs with proven pythiosis from different enzootic areas in the United States. All injected horses but one responded with a weak (=29 mm, n=3), a mild (30-90 mm, n=7) or a strong (=100 mm, n=7) inflammatory reactions at the site of injection. Three equines with weak or negative reactions at the injection site were not cured. Seven equines with strong reactions at their injection sites, however, were cured. Six of the eight horses with mild reactions were also cured. The rema...
Worster AA, Lillich JD, Cox JH, Rush BR.A 9-year-old pregnant mare was referred for evaluation of a nonhealing wound of 8 weeks' duration on the lateral aspect of the left forelimb. A soft tissue mass encircled the proximal two thirds of the metacarpus; radiography revealed a moderate periosteal reaction affecting metacarpal bone i.v. Histologic and immunohistochemical examinations revealed eosinophilic granulomatous inflammation and Pythium sp in the soft tissues. The mare was treated for 12 days with antimicrobials, medicated wound dressings, debridement, and i.v. administration of sodium iodide; radiography revealed progression o...
Sedrish SA, Moore RM, Valdes-Vasquez MA, Haynes PF, Vicek T.Pythiosis, caused by Pythium insidiosum, is a common cutaneous granulomatous disease in horses. Surgical removal is the most common treatment; however, high rates of recurrence have been reported. Results of examination of 2 horses with pythiosis granulomas in which a neodymium:yttrium-aluminum-garnet laser was used to photoablate the bed after removal are reported. The mass had not recurred in either horse 1 year after surgery. Photoablation results in collateral thermal necrosis and may kill organisms that have infiltrated surrounding tissues, thus reducing the risk of recurrence.
Mendoza L, Mandy W, Glass R.The immunotherapeutic properties of a new Pythium insidiosum-vaccine formulation (PIV), was evaluated in 18 horses and 6 dogs with proven pythiosis from different enzootic areas in the United States. All injected horses but one responded with a weak (=29 mm, n=3), a mild (30-90 mm, n=7) or a strong (=100 mm, n=7) inflammatory reactions at the site of injection. Three equines with weak or negative reactions at the injection site were not cured. Seven equines with strong reactions at their injection sites, however, were cured. Six of the eight horses with mild reactions were also cured. The rema...
Martins TB, Kommers GD, Trost ME, Inkelmann MA, Fighera RA, Schild AL.Twenty-one cases of pythiosis in horses (n = 10), dogs (n = 9) and cattle (n = 2) were investigated. The aetiology in all cases was confirmed by immunohistochemistry. Data related to the clinical course and outcome and localization of the lesions were obtained from pathology reports. The equine lesions consisted of fibrotic tissue with multiple, often coalescing, areas of immature granulation tissue encircling eosinophilic cores. Affected dogs had gastrointestinal and/or cutaneous lesions with either or both of a granulomatous/pyogranulomatous or necrotizing eosinophilic inflammatory reaction....
Dória RG, Freitas SH, Linardi RL, Mendonça Fde S, Arruda LP, Boabaid FM, Valadão CA.To evaluate the effects of intravenous regional limb perfusion (IRLP) administration of amphotericin B in horses to treat pythiosis after surgical excision and thermocautery. Methods: Case series. Methods: Horses (n = 12) with Pythium insidiosum infection of the distal aspect of the thoracic or pelvic limbs. Methods: After surgical excision of granulation tissue and thermocautery, 50 mg amphotericin B was administered by IRLP through a catheter placed in a superficial vein of the affected limb next to the lesion after placing a tourniquet above the injection site. The lesions and locomotor sys...
Krajaejun T, Kittichotirat W, Patumcharoenpol P, Rujirawat T, Lohnoo T, Yingyong W.Genome sequences are a vital resource for accelerating the biological exploration of an organism of interest. Pythium destruens (a synonym of Pythium insidiosum) causes a difficult-to-treat infectious disease called pythiosis worldwide. Detection and management of pythiosis are challenging. Basic knowledge of the disease is lacking. Genomes of this organism isolated from different continents (i.e., Asia and the Americas) have been sequenced and publicly available. Here, we sequenced the genome of an Australian isolate of P. destruens. Genome data will facilitate the comparative analysis of thi...
Sedrish SA, Moore RM, Valdes-Vasquez MA, Haynes PF, Vicek T.Pythiosis, caused by Pythium insidiosum, is a common cutaneous granulomatous disease in horses. Surgical removal is the most common treatment; however, high rates of recurrence have been reported. Results of examination of 2 horses with pythiosis granulomas in which a neodymium:yttrium-aluminum-garnet laser was used to photoablate the bed after removal are reported. The mass had not recurred in either horse 1 year after surgery. Photoablation results in collateral thermal necrosis and may kill organisms that have infiltrated surrounding tissues, thus reducing the risk of recurrence.
Bach BC, Leal DB, Ruchel JB, Souza Vdo C, Maboni G, Dal Pozzo M, Schlemmer KB, Alves SH, Santurio JM.NTPDase (EC 3.6.1.5) occurs in lymphocytes and plays an important role in immune function, in that hydrolyzes extracellular nucleoside tri- and/or diphosphates to form AMP. Pythium insidiosum causes the disease pythiosis, a pyogranulomatous disease of horses, dogs, cattle, cats and humans. Most antifungal drugs are ineffective against this pathogen, and immunotherapy, a treatment approach that relies on the injection of P. insidiosum antigen, has been successfully used in humans and horses to manage this disease. In this study, we investigated NTPDase activity in lymphocytes from rabbits inocu...
Valente JSS, Brasil CL, Braga CQ, Zamboni R, Sallis ESV, Albano APN, Zambrano CG, Franz HC, Pötter L, Panagio LA, Reis GF, Botton SA, Pereira DIB.Pythiosis is a rapidly progressing disease that can be lethal to affected individuals due to resistance to available therapeutic protocols. The disease affects mammals, with the largest number of reports in horses and humans. The present study investigated the activity of biogenic silver nanoparticles (bioAgNP) in the treatment of experimental pythiosis. The disease was reproduced in nine female 90-day-old New Zealand rabbits. Animals were divided into three groups: group1 (control, n = 3) daily and topically treated with a nonionized gel-based formulation and 1 ml of sterile distilled wate...
de Souto EPF, Kommers GD, Souza AP, Miranda Neto EG, Assis DM, Riet-Correa F, Galiza GJN, Dantas AFM.Pythiosis is an endemic disease in northeastern Brazil and we now report the epidemiological, clinical and pathological findings in a retrospective study of naturally occurring cases in domestic animals. From January 1985 to December 2020, the Laboratory of Animal Pathology of the Federal University of Campina Grande examined 13,542 tissue samples from necropsies and biopsies. Among these samples, 306 were diagnosed as pythiosis: 195 cases in horses, 75 in sheep, 19 in dogs, six in mules, four in cattle, three in cats, two in goats, one in a donkey and one in an ostrich. Affected equids had le...
Rotchanapreeda T, Sae-Chew P, Lohnoo T, Yingyong W, Rujirawat T, Kumsang Y, Payattikul P, Jaturapaktrarak C, Intaramat A, Pathomsakulwong W....Pythiosis, a life-threatening disease caused by , has been increasingly diagnosed worldwide. A recently developed immunochromatographic test (ICT) enables the rapid diagnosis of pythiosis. During the 3-year clinical implementation of ICT in Thailand, we collected the laboratory reports of 38 animals with suspected pythiosis and detected ICT false-positive results in three horses and a dog with basidiobolomycosis. and cause infections with indistinguishable clinical and microscopic features. This study investigated cross-reactive antibodies by probing and crude extracts and cell-free synthe...
Worster AA, Lillich JD, Cox JH, Rush BR.A 9-year-old pregnant mare was referred for evaluation of a nonhealing wound of 8 weeks' duration on the lateral aspect of the left forelimb. A soft tissue mass encircled the proximal two thirds of the metacarpus; radiography revealed a moderate periosteal reaction affecting metacarpal bone i.v. Histologic and immunohistochemical examinations revealed eosinophilic granulomatous inflammation and Pythium sp in the soft tissues. The mare was treated for 12 days with antimicrobials, medicated wound dressings, debridement, and i.v. administration of sodium iodide; radiography revealed progression o...
Dos Santos CEP, Loreto ES, Zanette RA, Santurio JM, Marques LC.Horse pythiosis is considered an endemic disease in the Brazilian Pantanal region, causing devastating health and economic losses. This study aimed to enhance the understanding of pythiosis epidemiology, map the distribution of horse body lesions, and investigate the correlation between these lesions and warm body surface areas, potentially implicating hematophagous vectors in the disease's transmission. A prospective study was conducted on equids in the Pantanal Mato-grossense and adjacent areas from 2012 to 2022, with 112 horses and three mules diagnosed with pythiosis. Clinical and epidemio...
Rodrigues VS, Trevisan LAC, Cintra BS, Pires RH, Ribeiro AB, Tavares DC, Oberhaus E, Ferreira JC.Cutaneous pythiosis is a life-threatening infectious disease. Low-level laser therapy (LLLT) and ozone (O3) have been used individually in the treatment of infected wounds. The goals of the study were a) to characterize the antimicrobial action of the photo-ozone therapy (LLLT-O3) against equine Pythium insidiosum, and b) to assess the cytotoxic potential of the LLLT-O3 in keratinocytes. Specimens of pathogen were isolated from 10 horses. After culturing, 120 hyphae plugs were distributed among four groups (n=30 hyphae plugs/group): LLLT (laser irradiation for 160 sec;), O3 (exposition to O3 f...
