Review of animal mycoses in Australia

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.

Protein A/G-based immunochromatographic test for serodiagnosis of pythiosis in human and animal subjects from Asia and Americas

Pythiosis is a life-threatening infectious disease of both humans and animals living in Asia, Americas, Africa, and parts of Australia and New Zealand. The etiologic pathogen is the fungus-like organism Pythium insidiosum The disease has high mortality and morbidity rates. Use of antifungal drugs are ineffective against P. insidiosum, leaving radical surgery the main treatment option. Prompt treatment leads to better prognosis of affected individuals, and could be achieved by early and accurate diagnosis. Since pythiosis has been increasingly reported worldwide, there is a need for a rapid, user-friendly, and efficient test that facilitates the diagnosis of the disease. This study aims to develop an immunochromatographic test (ICT), using the bacterial protein A/G, to detect anti-P. insidiosum IgGs in humans and animals, and compare its diagnostic performance with the established ELISA. Eighty-five serum samples from 28 patients, 24 dogs, 12 horses, 12 rabbits, and 9 cattle with pythiosis, and 143 serum samples from 80 human and 63 animal subjects in a healthy condition, with thalassemia, or with other fungal infections, were recruited for assay evaluation. Detection specificities of ELISA and ICT were 100.0%. While the detection sensitivity of ELISA was 98.8%, that of ICT was 90.6%. Most pythiosis sera, that were falsely read negative by ICT, were weakly positive by ELISA. In conclusion, a protein A/G-based ICT is a rapid, user-friendly, and efficient assay for serodiagnosis of pythiosis in humans and animals. Compared to ELISA, ICT has an equivalent detection specificity and a slightly lower detection sensitivity.

Antifungal susceptibility patterns of opportunistic fungi in the genera Verruconis and Ochroconis

Species of Verruconis and species of Ochroconis are dematiaceous fungi generally found in the environment but having the ability to infect humans, dogs, cats, poultry, and fish. This study presents the antifungal susceptibility patterns of these fungi at the species level. Forty strains originating from clinical and environmental sources were phylogenetically identified at the species level by using sequences of the ribosomal DNA internal transcribed spacer (rDNA ITS). In vitro antifungal susceptibility testing was performed against eight antifungals, using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. The geometric mean MICs for amphotericin B (AMB), flucytosine (5FC), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), and posaconazole (POS) and minimum effective concentrations (MECs) for caspofungin (CAS) and anidulafungin (AFG) across the Ochroconis and Verruconis species were as follows, in increasing order. For Verruconis species, the values (μg/ml) were as follows: AFG, 0.04; POS, 0.25; ITC, 0.37; AMB, 0.50; CAS, 0.65; VRC, 0.96; 5FC, 10.45; and FLC, 47.25. For Ochroconis species, the values (μg/ml) were as follows: AFG, 0.06; POS, 0.11; CAS, 0.67; VRC, 2.76; ITC, 3.94; AMB, 5.68; 5FC, 34.48; and FLC, 61.33. Antifungal susceptibility of Ochroconis and Verruconis was linked with phylogenetic distance and thermotolerance. Echinocandins and POS showed the greatest in vitro activity, providing possible treatment options for Ochroconis and Verruconis infections.

Granulomatous pododermatitis in the digits caused by Fusarium proliferatum in a cat

To the best of our knowledge, we present here the first report of a case involving granulomatous pododermatitis caused by Fusarium proliferatum in a 10-year-old female cat. A cutaneous mass developed on the foot-pad of the right hind leg. Nodular granulomatous dermatitis with numerous macrophages and multinucleated giant cells containing cytoplasmic fungal structures were revealed on histological examination. Periodic acid-Schiff reaction and Fungi-Fluor staining clearly revealed irregular, septate fungal hyphae englobed by macrophages and multinucleated giant cells. Polymerase chain reaction and sequence analysis targeting three domains of the extracted fungal DNA revealed 100% amplicon homology with F. proliferatum.

Dermatophytosis in zoo macropods: a questionnaire study

Limited published data are available on dermatophytosis in zoo macropods, despite anecdotal reports of disease occurrence and recurrent mob outbreaks. The aim of this questionnaire study was to analyze data from Australian and international zoos to evaluate estimated disease prevalence in zoos housing macropods, affected macropod species, causative organisms, predisposing factors, clinical presentations, diagnostics, treatments, and disease risk management. Two questionnaires (initial detailed and subsequent brief) were distributed via email to zoo veterinarians, with an estimated response rate of 23%. The overall estimated disease prevalence from responding zoos was 28%, with 73% of responding Australian zoos and 14% of responding non-Australian zoos reporting disease. The first cases of confirmed and suspected dermatophytosis in several macropod species and in association with Trichophyton verrucosum and Trichophyton mentagrophytes var. nodulare are reported, with young red kangaroos (Macropus rufus) appearing predisposed. Diagnosis was most commonly based on fungal culture or presumptively on typical clinical signs of minimally/nonpruritic alopecia, crusting, and scaling distributed most frequently on the tail, pinnae, and hind limbs. Both disease resolution without treatment and resolution after an average of 1 to 2 mo of treatment were reported.

Isolation and molecular identification of keratinophilic fungi from public parks soil in Shiraz, Iran

Introduction. Keratinophilic fungi are an important group of fungi that live in soil. The aim of this study was to isolate and identify keratinophilic fungi from the soil of different parks in Shiraz. Materials and Methods. A total of 196 soil samples from 43 parks were collected. Isolation of the fungi was performed by hair bait technique. The isolated colonies were identified by morphologic feature of macro- and microconidia and molecular method, using DNA sequence analysis. ITS region of ribosomal DNA was amplified and the PCR products were sequenced. Results. 411 isolates from 22 genera were identified. Fusarium (23.8%), Chrysosporium (13.13%), Acremonium (12.65%), Penicillium (12.39%), Microsporum gypseum (1.94%), Bionectria ochroleuca (1.21%), Bipolaris spicifera (1.21%), Scedosporium apiospermum (0.82%), Phialophora reptans (0.82%), Cephalosporium curtipes (0.49%), Scedosporium dehoogii (0.24%), Ochroconis constricta (0.24%), Nectria mauritiicola (0.49%), Chaetomium (0.49%), Scopulariopsis (0.24%), Malbranchea (0.24%), and Tritirachium (0.24%) were the most important isolates. Most of the fungi were isolated from the soils with the PH range of 7 to 8. Conclusion. Our study results showed that many keratinophilic fungi isolated from the parks soil are important for public health and children are an important group at a high risk of being exposed to these fungi.

Trichophyton bullosum: a new zoonotic dermatophyte species

We report the first human case of dermatophytosis caused by Trichophyton bullosum in a 21-year-old male who had a skin lesion located on his forearm. The dermatophyte was isolated in culture and further identified by sequence analysis of internal transcripted spacer regions. The species T. bullosum is a zoophilic dermatophyte rarely isolated from the coat of horses in Africa and Asia. In the present case, it was probably transmitted by contact with an infected donkey in a rural area in France. Antifungal therapy led to remission of the lesion in the patient after 2 months of treatment. T. bullosum ITS region sequences were closely related to those of the African species of Arthroderma benhamiae and grouped in a zoophilic cluster with Trichophyton verrucosum, T. erinacei and the Trichophyton anamorph of A. benhamiae (zoophilic species of the T. mentagrophytes complex). Systematic molecular identification could contribute to an accurate identification of this unusual species.

Bovine cryptococcal meningoencephalitis

Cryptococcal meningitis and encephalitis is reported in a 5-year-old bull. The clinical signs included multifocal neurological deficits manifested by hypermetria, ataxia, depression, circling, impaired vision, head pressing, low head carriage, wide-based stance, and falling to the side or backwards. At necropsy, 6 cavities with a gelatinous content were observed in the brain and brain stem, and the meninges were thickened and off white. Numerous yeasts, with a nonstaining capsule, and associated mild inflammatory reaction were observed histologically. Specimens for culture were not collected at necropsy, but the identity of the yeast in tissue sections as Cryptococcus neoformans var. grubii was supported by immunohistochemistry.

Ecology of dermatophytes and other keratinophilic fungi in swimming pools and polluted and unpolluted streams

The biodiversity and richness of keratinophilic fungal communities including dermatophytes were assessed in three stream sites and three swimming pools in the Nablus district in Palestine, using hair baiting (HBT) and surface dilution plate (SDP) techniques, over 8- and 6-month periods, respectively. The effect of wastewater effluent and selected ecological factors on these fungi in relation to species diversity and population densities were also considered. Fifty keratinophilic fungal species were recovered from the aquatic habitats studied, of which 42 were recovered from stream sites and 22 from swimming pools. Of these fungi 6 were either dermatophytes (Microsporum gypseum, and Trichophyton mentagrophytes) or dermatophyte related species (Chrysosporium merdarium, Ch. tropicum, Ch. keratinophilum and T. terrestre). The most frequently isolated species in the three pools were Acremonium strictum and Cladosporium cladosporioides, using Sabouraud dextrose agar medium (SDA). The most abundant species were Acr. strictum, and Aspergillus flavus. However, only 4 species were isolated using the SDA medium amended with 5-flurocytosine (5-FC). The most frequent and abundant species in the three stream sites using SDA medium were Geotricum candidum, and Penicillium chrysogenum. The most frequent species in the three sites using the 5-FC medium, was Paecilomyces lilacinus. Using HBT, the most abundant and frequent species in the three stream sites were G. candidum, and Pa. lilacinus, on SDA medium, and Pa. lilacinus, and Gliocladium nigrovirens on the 5-FC medium. The 5-FC medium was more suitable for the isolation of dermatophytes and closely related species than the SDA medium; 6 were recovered on 5-FC, whereas only one on the SDA medium. Variation in the levels of keratinophilic fungal populations from the three stream sites sampled 5 times over an 8-month period, followed comparable fluctuation patterns. Wastewater affected fungal population densities with the highest levels in the un-polluted stream sites, and lowest in the heavily polluted sites. Swimming pools, polluted and un-polluted stream sites were found to be rich in pathogenic and potentially pathogenic fungi.

Fungal diseases of laboratory rodents

Although fungal disease is uncommon in rodents, dermatophytosis is the most common mycosis seen in clinical practice. T. mentagrophytes is the most common etiologic agent, and the guinea pig is the most common species affected, although there are reports in all pet and laboratory rodent species except the gerbil. Despite the low incidence of clinical disease, rodents are common asymptomatic carriers of dermatophytes, and ringworm is the most common zoonotic disease transmitted from rodents to people.

Chrysosporium anamorph of Nannizziopsis vriesii associated with fatal cutaneous mycoses in the salt-water crocodile (Crocodylus porosus)

The Chrysosporium anamorph of Nannizziopsis vriesii, recently identified as the cause of cutaneous infections in chameleons and brown tree snakes, was associated with skin infections and deaths in salt-water crocodile (Crocodylus porosus) hatchlings on two separate occasions 3 years apart. In all, 48 animals died from the infection. All hatchlings came from the same farm in northern Queensland, Australia.

Dermatophytes and saprobe fungi isolated from dogs and cats in the city of Fortaleza, Brazil

The possible involvement of saprobe fungi in dermatomycoses, as well as the determination of the incidence of dermatophytes in dogs and cats were studied. During a period of one year, 74 dogs and 18 cats, with cutaneous lesions suggesting mycoses were included in this study. The mycological analyses were conducted by direct microscopy and by fungal culture on Sabouraud agar, chloramphenicol Sabouraud agar and mycosel agar. Of the 92 samples, 21 resulted in positive cultures for dermatophytes. Dermatophyte fungi pure cultures were obtained from 13 samples. A simultaneous growth of dermatophytes plus saprobe fungi was observed in 8 of the samples. Of the remaining 71 samples, no fungal growth was observed in 10 samples, and at minimum the growth of one saprobe fungi in 61. One, two and three genera of saprobe fungi were isolated in 29, 30 and 2 samples, respectively. Microsporum canis was isolated in 6 (28.6 %) and 10 samples (47.6 %) from cats and dogs, respectively, and Trichophyton mentagrophytes in 2 (9.5 %) and 3 samples (14.3 %) from cats and dogs, respectively. The following genera of saprobe fungi were also isolated: Alternaria sp (1.9%), Chaetomium sp (1.9%), Rhizopus sp (2.9%), Curvularia sp (3.9%), Candida sp (6.8%), Trichoderma sp (6.8%), Fusarium sp (7.8%), Cladosporium sp (8.7%), Penicillium sp (21.4%) and Aspergillus sp (37.9%).

Human cases of cattle ringworm due to Trichophyton verrucosum in Victoria, Australia

Between 1962 and 1994, 32 isolates of Trichophyton verrucosum from cases of tinea corporis, tinea faciei and tinea capitis were referred to the Mycology Reference Laboratory of the Microbiological Diagnostic Unit at The University of Melbourne, Victoria, Australia. Patients had presented at clinics in metropolitan Melbourne and country towns in the State of Victoria, Australia. They included dairy and cattle farmers, a slaughterman who worked in an abattoir, a veterinary tutor and children who lived on farms. Many patients lived in one of the three dairy farming areas of Victoria. A few lived in the outer suburbs of Melbourne. One cattle farmer came from south-east New South Wales. Specimens were not received for examination from animal contacts of the patients. The only patient from overseas was a boy from Lebanon. The literature recording human infections due to T. verrucosum in Australia is reviewed.

Ecology of cycloheximide-resistant fungi in field soils receiving raw city wastewater or normal irrigation water

The effect of raw city wastewater irrigation on biodiversity and population densities of a cycloheximide-resistant (CH) fungal community was studied in 13 field soils receiving either raw city wastewater or normal irrigation, and in raw city wastewater in the Nablus area, using the hair baiting technique (HBT) and a surface soil dilution plating (SSDP) technique. Three of these fields [one had been receiving raw city wastewater for more than ten years and was designated a heavily polluted field, and the other 2 were cultivated for the first time and were either irrigated with raw city wastewater (newly polluted field) or normal irrigation water (nonpolluted)], were sampled 4-7 times over a 9-month period. The other ten fields, which had been under raw city wastewater irrigation for more than 10 years, were sampled only once. Fifty-seven CH-resistant species belonging to 18 genera were recovered, of which 49 species were recovered from soil habitats and 28 species from raw city wastewater. The HBT had shown to be more efficient in the isolation of pathogenic and potentially pathogenic fungi including dermatophytes. A higher percentage of this group of fungi was recovered from the three main field soils studied using HBT (70% of all isolates), than the SSDP (35.5%); no dermatophytes were recovered by the SSDP method. Two dermatophytes (Microsporum gypseum, and Trichophyton ajelloi), and five more fungi (Arthroderma cuniculi, A. curreyi, Chrysosporium keratinophilum, C. tropicum, C. pannorum), were recovered from these habitats. Wastewater irrigation seemed to have affected the fungal population densities, with the highest population densities being found in the heavily polluted field soil, while lower population densities were found in the nonpolluted field soil. Increases in organic matter were also observed as a result of sewage effluent irrigation. However, basic similarities in the biodiversity of CH-resistant fungal communities existed in nonpolluted and polluted field soils, and raw city wastewater. Comparable numbers of fungal species were recovered from the three main field soils. The species most commonly found in those habitats included: Alternaria alternata, Aspergillus candidus, Geotrichum candidum, and Paecilomyces lilacinus. Field soils receiving either raw city wastewater or normal irrigation water, were found to be rich in pathogenic and potentially pathogenic CH-resistant fungi, including dermatophytes, with raw city wastewater yielding the highest percentage (81%), followed by the newly wastewater irrigated field (77.7%), the nonpolluted field (67%), and the heavily polluted field (63.4%) Hygienic measures should therefore be taken to control the spread of these fungi in the environment of human communities, and to avoid mycotic infections among farmers.

Molecular genetic variation in Emmonsia crescens and Emmonsia parva, etiologic agents of adiaspiromycosis, and their phylogenetic relationship to Blastomyces dermatitidis (Ajellomyces dermatitidis) and other systemic fungal pathogens

Emmonsia crescens, an agent of adiaspiromycosis, Blastomyces dermatitidis, the agent of blastomycosis, and Histoplasma capsulatum, the agent of histoplasmosis, are known to form meiotic (sexual) stages in the ascomycete genus Ajellomyces (Onygenaceae, Onygenales), but no sexual stage is known for E. parva, the type species of the genus Emmonsia. To evaluate relationships among members of the putative Ajellomyces clade, large-subunit ribosomal and internal transcribed spacer region DNA sequences were determined from PCR-amplified DNA fragments. Sequences were analyzed phylogenetically to evaluate the genetic variation within the genus Emmonsia and evolutionary relationships to other taxa. E. crescens and E. parva are distinct species. E. crescens isolates are placed into two groups that correlate with their continents of origin. Considerable variation occurred among isolates previously classified as E. parva. Most isolates are placed into two closely related groups, but the remaining isolates, including some from human sources, are phylogenetically distinct and represent undescribed species. Strains of B. dermatitidis are a sister species of E. parva. Paracoccidioides brasiliensis and Histoplasma capsulatum are ancestral to most Emmonsia isolates, and P. brasiliensis, which has no known teleomorph, falls within the Ajellomyces clade.

Natural pathogens of laboratory mice, rats, and rabbits and their effects on research

Laboratory mice, rats, and rabbits may harbor a variety of viral, bacterial, parasitic, and fungal agents. Frequently, these organisms cause no overt signs of disease. However, many of the natural pathogens of these laboratory animals may alter host physiology, rendering the host unsuitable for many experimental uses. While the number and prevalence of these pathogens have declined considerably, many still turn up in laboratory animals and represent unwanted variables in research. Investigators using mice, rats, and rabbits in biomedical experimentation should be aware of the profound effects that many of these agents can have on research.

Dermatophytes from cases of skin disease in cats and dogs in Turin, Italy

In urban environments, pet animals such as dogs and cats may be largely responsible for the progressive increase of zoophilic over anthropophilic dermatophytes in the aetiology of human dermatophytoses. Mapping, in each city, of the natural foci of zoophilic dermatophytes may thus be important for understanding the epidemiology of human dermatophytoses, and for planning preventive measures. We have surveyed dogs and cats suspected of carrying dermatophytic lesions in the Turin area. Hairs, skin scrapings and the contents of pustules or vesicles were inoculated on Dermasel agar supplemented with choramphenicol and cycloheximide. The mating type of the isolates was checked, testing their compatibility with the two mating types of Arthroderma simii Stockdale, Mackenzie and Austwick. We isolated dermatophytes from about 40% of the cases examined. Microsporum canis Bodin was the only dermatophyte found in the lesions. In the cats the lesions were more frequent, in the dogs more severe. Animals less than a year old and male dogs were most often affected. Some cases of transmission of the infection between animals and from animals to man are described. All the isolates of M. canis, tested for mating behaviour, were non-reactive.