Pathology of nasal infection caused by Conidiobolus lamprauges and Pythium insidiosum in sheep

Global Distribution and Clinical Features of Pythiosis in Humans and Animals

Pythiosis is a difficult-to-treat infectious disease caused by Pythium insidiosum. The condition is unfamiliar among healthcare workers. Manifestation of pythiosis is similar to other fungal infections, leading to misdiagnosis and delayed treatment. The geographical extent of pythiosis at a global scale is unclear. This study aimed to analyze the clinical information recorded in the scientific literature to comprehensively project epidemiological characteristics, clinical features, and future trends of pythiosis. From 1980 to 2021, 4203 cases of pythiosis in humans (n = 771; 18.3%) and animals (primarily horse, dog, and cow; n = 3432; 81.7%), with an average of 103 cases/year, were recruited. Pythiosis case reports significantly increased in the last decade. Pythiosis spanned 23 tropical, subtropical, and temperate countries worldwide. Some patients acquired pythiosis from a trip to an endemic country. Strikingly, 94.3% of human cases were in India and Thailand, while 79.2% of affected animals were in the U.S.A. and Brazil. Clinical features of pythiosis varied. Vascular and ocular pythiosis were only observed in humans, whereas cutaneous/subcutaneous and gastrointestinal infections were predominant in animals. Mortality depended on host species and clinical forms: for example, none in patients with ocular pythiosis, 0.7% in cows with a cutaneous lesion, 26.8% in humans with vascular disease, 86.4% in dogs with gastrointestinal pathology, and 100% in several animals with disseminated infection. In summary, this study reports up-to-date epidemiological and clinical features of pythiosis in humans and animals. It increases awareness of this life-threatening disease, as the illness or outbreak can exist in any country, not limited to the endemic areas.

Successful potassium iodide treatment for rhinofacial pythiosis in sheep

BACKGROUND

Pythiosis in sheep is an important disease in Brazil, which could cause rhinitis, dermatitis and alimentary tract inflammation. It is caused by the aquatic oomycete, Pythium insidiosum. The rhinofacial pythiosis causes facial deformity and upper respiratory tract clinical signs associated with necroproliferative masses occupying the rostral nasal cavity and hard palate. Little is known regarding the therapy, prophylaxis and pathogenesis of this disease.

METHODOLOGY

During the 6-year study, we examined 13 sheep presenting rhinofacial pythiosis. The diagnosis was performed through biopsy of the rhinofacial lesions followed by histopathology and immunohistochemistry using specific antibodies against P insidiosum, polymerase chain reaction and an indirect enzyme-linked immunosorbent assay.

RESULTS

This study presents the clinical findings of a potassium iodide treatment of rhinofacial pythiosis in sheep. All sheep were treated with 10 ml of 10% potassium iodide solution, administered orally every day during 63-120 (mean 85) days. Among treated sheep, 84.6% demonstrated complete recovery.

CONCLUSION

Potassium iodide therapy may treat rhinofacial pythiosis in sheep.

Case Report: Successful Management of Conidiobolus Lamprauges Rhinitis in a Dog

This is a case of Conidiobolus lamprauges rhinitis in a Goldendoodle, that was presented for evaluation of sneezing, coughing, lethargy, as well as right-sided epistaxis and clear ocular discharge. Computed tomography revealed a large amount of soft tissue within the right nasal passage that obscured the osseous turbinates from the right maxillary canine tooth to the right side of the choanae. Biopsies revealed eosinophilic granulomas with variable number of basophilic to negatively staining, septate, fungal hyphae with non-parallel walls and irregular branching that were subsequently determined to be Conidiobolus lamprauges via panfungal PCR and sequencing. Complete and sustained resolution of clinical disease was achieved after 75 days of systemic antifungal therapy. This report describes for the first time, important clinical features of a dog with nasal conidiobolomycosis that will facilitate its recognition, prognostication, and treatment in clinical practice.

Diseases caused by Pythium insidiosum in sheep and goats: a review

Pythiosis is characterized most commonly by ulcerative dermatitis, mainly in the limbs of sheep and occasionally of goats. In sheep, Pythium insidiosum is also responsible for necrotizing rhinitis characterized by marked enlargement and deformity of the nasal region, severe respiratory difficulty, and bloody nasal discharge. A third form of pythiosis in sheep affects the digestive tract, involving ulceration of the esophagus, forestomachs, and abomasum. Pythiosis in sheep and goats has been reported only in Brazil where it occurs mainly in the semiarid region of the country, when animals congregate and stay for longer periods of time within or around water reservoirs. However, it has been reported as well in areas of humid environments, such as the Pantanal of Mato Grosso and in the Brazilian Cerrado. The diagnosis of the different presentations of pythiosis is based on gross and microscopic findings, coupled with detection of the agent by immunohistochemical, molecular, and/or culture-based methods.

Conidiobolomycosis, cryptococcosis, and aspergillosis in sheep and goats: a review

We review herein infections by Conidiobolus spp., Cryptococcus spp., and Aspergillus spp. in sheep and goats. Conidiobolus spp. are common causes of rhinitis in sheep and are less frequent in goats, in which Conidiobolus spp. also cause skin lesions. Cryptococcus spp. cause rhinitis, meningitis, encephalitis, and pneumonia in goats, and are rarely observed in sheep. Aspergillus spp. may cause rhinitis in goats, and pneumonia and mastitis in sheep and goats. Gross and microscopic lesions caused by these 3 fungal infections may be similar to each other. The diagnosis of these diseases must be based on gross and microscopic lesions, coupled with detection of the agent by immunohistochemical, molecular, and/or culture-based methods.

GASTRIC PYTHIOSIS IN A BACTRIAN CAMEL ( BACTRIANUS CAMELUS)

Pythium insidiosum, an aquatic oomycete, causes chronic lesions in the skin and digestive tract of multiple species. A captive-bred Bactrian camel ( Camelus bactrianus) showed clinical signs of lethargy and weight loss in a clinical course of 30 days, with no response to treatment. At necropsy, the abdominal cavity had approximately 32 L of a yellow, turbid fluid with fibrin. The third compartment of the stomach (C-3) showed a focal area of rupture covered with fibrin. Close to this area, the C-3 wall was thickened and firm, demonstrating irregular, yellow, and friable areas on cut surface (kunkers). Microscopically, these corresponded to necrosis, characterized by a central amorphous eosinophilic material, surrounded by a pyogranulomatous inflammatory infiltrate and fibrosis. Negatively stained hyphae were observed at the periphery of the necrotic areas, which showed marked immunostaining for P. insidiosum. Pythiosis in camelids may involve the stomach, resulting in peritonitis and death.

First confirmed case of nasal pythiosis in a horse in Thailand

Introduction

Pythiosis 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 presentation

We 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.

Conclusion

The 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.

Pythiosis in the Nasal Cavity of Horses

Two cases of nasal pythiosis are reported in horses from the semi-arid region of northeastern Brazil. From January 1986 to December 2015, the Laboratory of Animal Pathology, Federal University of Campina Grande received 830 equine samples, 156 (18.79%) of which were diagnosed with pythiosis. Of these, two horses (1.28%), a male and a female adult cross-breed, had lesions in the nasal cavity. Both horses had access to water reservoirs. Clinically, they had swelling in the rhinofacial region and a serosanguineous nasal discharge. Macroscopically, in case 1, the lesion affected the nasal vestibule, extending to the alar cartilage and nasal septum. In case 2, the lesion extended through the turbinates and the meatuses of the nasal cavity, as well as the ethmoid region. In both cases, the lesions were characterized by having a yellow-grey granular surface with cavitations of different sizes containing coral-like masses of necrotic tissue (kunkers). Histologically, multifocal necrotizing eosinophilic rhinitis associated with hyphae (2-8 μm) similar to Pythium insidiosum were observed. In case 2, the lesions extended to the muscle, cartilage and bone adjacent to the nasal cavity and lungs. The diagnosis was confirmed by immunohistochemistry. It is concluded that nasal pythiosis occurs sporadically in horses in the semi-arid region of northeastern Brazil where cutaneous pythiosis is prevalent.

Diagnostic pathology in microbial diseases of sheep or goats

Post-mortem examination is a key step in the diagnostic process of infectious diseases in sheep and goats. Diagnostic pathology deals with identification and study of lesions, at the same time providing also significant clues regarding pathogenesis of the diseases. This article reviews the salient pathological findings associated with the most significant infectious diseases of sheep and goats present in countries where small ruminants are a relevant agricultural industry. Lesions are reviewed according to the different organ systems where they occur. Emphasis has been given in the description of the salient lesional patterns than can be identified in each organ and which can be of help in the differential diagnosis of the lesions caused by bacteria, viruses, fungi or prions. Finally, a review of the usefulness of ancillary tests that may be used on various tissue samples for performing an aetiological diagnosis, is included; the application of various techniques, from immunohistochemistry to molecular biology-based tests, is described.

Doenças da cavidade nasal em pequenos ruminantes no Distrito Federal e no Estado de Goiás

Resumo As enfermidades que acometem a cavidade nasal de pequenos ruminantes podem causar prejuízos aos rebanhos de ovinos e caprinos na região central do Brasil. Foi realizado estudo retrospectivo dos laudos de necropsia do Laboratório de Patologia Veterinária da Universidade de Brasília (LPV-UnB) nos anos de 2003 a 2014 para verificar a ocorrência das doenças que acometeram a cavidade nasal de pequenos ruminantes. Foram analisados 463 protocolos de ovinos e 75 de caprinos totalizando 538 casos. Seis ovinos (6/463 1,29%) foram necropsiados com rinite granulomatosa micótica ou oomicótica e 22 animais do estudo (22/538; 4,08%) tiveram o diagnóstico de oestrose, sendo 86,36% ovinos e 13,64% caprinos. As rinites piogranulomatosas em ovinos ocorreram em áreas alagadas, com abundante material vegetal em decomposição. Os ovinos com pitiose rinofacial apresentaram como principais alterações aumento de volume na região nasal devido a extensas lesões granulomatosas associadas a necrose tecidual, caracterizadas por inúmeros macrófagos e polimorfonucleares circundando centros necróticos contendo o agente envolto por reação de Splendore-Hoeppli. Os ovinos com conidiobolomicose exibiram extensas áreas de necrose e inflamação piogranulomatosa, associadas à presença de hifas fúngicas na nasofaringe e também na região peribulbar e exoftalmia. A maioria dos animais com oestrose não apresentou alterações clínico-patológicas significativas, apesar de serem encontradas larvas principalmente nos seios e conchas nasais, traqueia e seio paranasal. A importância dessas enfermidades ainda é pouco conhecida na região, sendo de grande relevância que as condições clínico-patológicas e epidemiológicas sejam elucidadas para o diagnóstico, o controle e a prevenção, para evitar a expansão e prejuízos para os rebanhos.

Disseminated Conidiobolus incongruus in a dog: A case report and literature review

Conidiobolomycosis is a rare fungal disease of both humans and animals, occurring mainly in tropical and subtropical climates. We describe a disseminated fungal infection in a young, apparently immunocompetent dog who initially presented for antibiotic resistant pneumonia. Histopathology and mycology identified a Conidiobolus sp., further confirmed as Conidiobolus incongruus through DNA sequencing of D1/D2 regions. This is the first report of this species causing disease in dogs and the fifth reported infection in animals.

Development and application of polymerase chain reaction test for detection of Conidiobolus lamprauges

Conidiobolomycosis is a granulomatous disease caused by the fungus Conidiobolus spp. in humans and animals. Traditional technique for diagnosis of the disease is isolation of the agent associated with the presence of typical clinical signs and pathological conditions. The aim of this study was to describe the development of a specific polymerase chain reaction (PCR) test for Conidiobolus lamprauges to detect the fungus in clinical samples. Samples from suspected animals were collected and submitted to isolation, histopathological analysis and amplification by PCR. DNA from tissues was subjected to PCR with fungi universal primers 18S rDNA gene, and specific primers were designed based on the same gene in C. lamprauges that generated products of about 540 bp and 222 bp respectively. The culture was positive in 26.6% of clinical samples. The PCR technique for C. lamprauges showed amplification of DNA from fresh tissues (80%) and paraffin sections (44.4%). In conclusion, the PCR technique described here demonstrated a high sensitivity and specificity for detection of fungal DNA in tissue samples, providing a tool for the rapid diagnosis of C. lamprauges.

Nasal and cutaneous aspergillosis in a goat

Nasal and cutaneous aspergillosis is reported in an adult goat. The clinical signs were severe respiratory distress due to partial nasal obstruction, bilateral mucopurulent nasal discharge, skin nodules on the ears and dorsal nasal region and focal depigmentation of the ventral commissure of the right nostril. At necropsy examination, sagittal sectioning of the head revealed a yellow irregular mass extending from the nasal vestibule to the frontal portion of the nasal cavity. Microscopically, there was pyogranulomatous rhinitis and dermatitis, with numerous intralesional periodic acid-Schiff-positive fungal hyphae morphologically suggestive of Aspergillus spp. Aspergillus niger was isolated by microbiological examination.