First confirmed case of nasal pythiosis in a horse in Thailand

Abstract

IntroductionPythiosis is caused by Pythium insidiosum, a fungus-like organism in the class Oomycetes. It can infect humans and a variety of animal species in tropical, subtropical and some temperate regions. Cases of animal pythiosis have occurred predominantly in horses in the skin and subcutaneous tissue at the limbs and in the ventral portion of thoracoabdominal wall - lesions in the nasal region are rarely reported. Moreover, although many human pythiosis cases have been reported in Thailand, no cases of animal pythiosis in Thailand have been reported.Case presentationWe report a case of pythiosis in a horse infected at the nasal cavity. Diagnosis was performed by zoospore formation by bait technique, immunohistochemical stain, immunochromatography and sequence analysis.ConclusionThe sequences of rDNA were 99 % and 96 to 99 % identical to GenBank isolates of Pythium insidiosum from two Thai human patients and horses from various countries, respectively. This represents the first confirmed report of nasal equine pythiosis in Thailand.

An initial survey of 150 horses from Thailand for anti-Pythium insidiosum antibodies

“…Lower seroprevalence (0.7 vs. 11.1%) and fewer horses than in the Rio Grande do Sul State of Brazil (6,353 vs. 550,000) [25,27] explain why the number of horses with pythiosis in Thailand is minimal with just one case reported to date [28] vs. hundreds of Brazilian horses reported with the disease [29][30][31][32][33][34][35][36]. The striking difference in seroprevalences of the Thai (0.7%) and Brazilian (11.1%) horses could imply that Thai people, by comparison, might have a lower chance of having environmental exposure to P. insidiosum.…”

“…Animal pythiosis was reported in Thailand in a horse in 2018 [22] and a dog in 2020 [23]. The relative paucity of reports of animal pythiosis in Thailand may result from under-recognition and under-diagnosis of the disease.…”

Inmunoterapia y manejo quirúrgico de Pythium insidiosum en un equino: reporte de caso

“…Las lesiones cutáneas encontradas en la region periorbital de la yegua concuerdan con la descripcion de las lesiones cutáneas granulomatosas descritas en otros informes de caso en diferentes países (Bezerra-Junior et al, 2010, Mosbah et al, 2012, Cardona et al, 2014, Tartor et al, 2020, en donde se reportan lesiones cutáneas en regiones anatómicas que se encuentran en contacto directo con aguas estancadas contaminadas con zoosporas de P. insidiosum, por lo que las lesiones en regiones altas de la cabeza no son comunes. Sin embargo, en Tailandia se notificó el primer caso con lesiones de pitiosis dentro de la cavidad nasal de una yegua gestante y anticuerpos para P. insidisum en tres caballos (Tonpitak et al, 2018, Mar Htun et al, 2021.…”

History and Perspective of Immunotherapy for Pythiosis

“…Prompt and effective treatment improves the patient's prognosis [56,[85][86][87][88][89][90][91][92][93][94]. The use of conventional antifungal drugs provides limited efficacy in treating pythiosis because P. insidiosum lacks the drug-target sterol biosynthesis enzymes [95].…”