Chrysosporium guarroisp. nov. a new emerging pathogen of pet green iguanas (Iguana iguana)

A Cross-Inoculation Experiment Reveals that Ophidiomyces ophiodiicola and Nannizziopsis guarroi Can Each Infect Both Snakes and Lizards

Host range and specificity are key concepts in the study of infectious diseases. However, both concepts remain largely undefined for many influential pathogens, including many fungi within the Onygenales order. This order encompasses reptile-infecting genera (Nannizziopsis, Ophidiomyces, and Paranannizziopsis) formerly classified as the Chrysosporium anamorph of Nannizziopsis vriesii (CANV). The reported hosts of many of these fungi represent a narrow range of phylogenetically related animals, suggesting that many of these disease-causing fungi are host specific, but the true number of species affected by these pathogens is unknown. For example, to date, Nannizziopsis guarroi (the causative agent of yellow fungus disease) and Ophidiomyces ophiodiicola (the causative agent of snake fungal disease) have been documented only in lizards and snakes, respectively. In a 52-day reciprocal-infection experiment, we tested the ability of these two pathogens to infect currently unreported hosts, inoculating central bearded dragons (Pogona vitticeps) with O. ophiodiicola and corn snakes (Pantherophis guttatus) with N. guarroi. We confirmed infection by documenting both clinical signs and histopathological evidence of fungal infection. Our reciprocity experiment resulted in 100% of corn snakes and 60% of bearded dragons developing infections with N. guarroi and O. ophiodiicola, respectively, demonstrating that these fungal pathogens have a broader host range than previously thought and that hosts with cryptic infections may play a role in pathogen translocation and transmission. IMPORTANCE Our experiment using Ophidiomyces ophiodiicola and Nannizziopsis guarroi is the first to look more critically at these pathogens' host range. We are the first to identify that both fungal pathogens can infect both corn snakes and bearded dragons. Our findings illustrate that both fungal pathogens have a more general host range than previously known. Additionally, there are significant implications concerning the spread of snake fungal disease and yellow fungus disease in popular companion animals and the increased chance of disease spillover into other wild and naive populations.

Survey on Dermatophytes Isolated from Animals in Switzerland in the Context of the Prevention of Zoonotic Dermatophytosis

Most inflammatory dermatophytoses in humans are caused by zoophilic and geophilic dermatophytes. Knowledge of the epidemiology of these fungi in animals facilitates the prevention of dermatophytosis of animal origin in humans. We studied the prevalence of dermatophyte species in domestic animals in Switzerland and examined the effectiveness of direct mycological examination (DME) for their detection compared to mycological cultures. In total, 3515 hair and skin samples, collected between 2008 and 2022 by practicing veterinarians, were subjected to direct fluorescence microscopy and fungal culture. Overall, 611 dermatophytes were isolated, of which 547 (89.5%) were from DME-positive samples. Cats and dogs were the main reservoirs of Trichophyton mentagrophytes and Microsporum canis, whereas Trichophyton benhamiae was predominantly found in guinea pigs. Cultures with M. canis significantly (p < 0.001) outnumbered those with T. mentagrophytes in DME-negative samples (19.3% versus 6.8%), possibly because M. canis can be asymptomatic in cats and dogs, unlike T. mentagrophytes, which is always infectious. Our data confirm DME as a reliable, quick, and easy method to identify the presence of dermatophytes in animals. A positive DME in an animal hair or skin sample should alert people in contact with the animal to the risk of contracting dermatophytosis.

Koch's postulates: Confirming Nannizziopsis guarroi as the cause of yellow fungal disease in Pogona vitticeps

Nannizziopsis guarroi is an ascomycete fungus associated with a necrotizing dermatitis in captive green iguanas (Iguana iguana) and bearded dragons (Pogona vitticeps) across both Europe and North America. Clinical signs of the disease include swelling and lesion formation. Lesions develop from white raised bumps on the skin and progress into crusty, yellow, discolored scales, eventually becoming necrotic. The clinical signs are the basis of a colloquial name yellow fungal disease (YFD). However, until now, N. guarroi has not been confirmed as the primary agent of the disease in bearded dragons. In this experiment, we fulfill Koch's postulates criteria of disease, demonstrating N. guarroi as the primary agent of YFD in bearded dragons.

Infection with Nannizziopsis guarroi and Ophidiomyces ophiodiicola in reptiles in Taiwan

Fungal infection is an emerging threat to reptiles. The main pathogens are fungi of the genera Nannizziopsis, Paranannizziopsis and Ophidiomyces. The clinical symptoms range from mild skin lesions to the dissemination of internal organs and even death. Most of the reported cases are from Europe, North America and Australia. In this study, we report the Nannizziopsis guarroi infection in one captive inland bearded dragon (Pogona vitticeps), one captive green iguana (Iguana iguana) and Ophidiomyces ophiodiicola infection in one wild red-banded snake (Dinodon rufozonatum) and one wild Chinese cobra (Naja atra) in Taiwan. The infections were confirmed by the presence of fungal elements in the tissue. The pathogens were identified based on their morphological and DNA sequence characteristics. The susceptibility profiles of the fungal strains to nine antifungal drugs were obtained using broth microdilution methods. The presence of both fungal species in Asia highlights the urgent need for surveillance and close monitoring of reptile infections to prevent them from spreading and to the possible collapse of reptile populations in the wild.

Cross-continental emergence of Nannizziopsis barbatae disease may threaten wild Australian lizards

Members of the genus Nannizziopsis are emerging fungal pathogens of reptiles that have been documented as the cause of fatal mycoses in a wide range of reptiles in captivity. Cases of severe, proliferative dermatitis, debility and death have been detected in multiple free-living lizard species from locations across Australia, including a substantial outbreak among Eastern water dragons (Intellagama lesueurii) in Brisbane, Queensland. We investigated this disease in a subset of severely affected lizards and identified a clinically consistent syndrome characterized by hyperkeratosis, epidermal hyperplasia, dermal inflammation, necrosis, ulceration, and emaciation. Using a novel fungal isolation method, histopathology, and molecular techniques, we identified the etiologic agent as Nannizziopsis barbatae, a species reported only once previously from captive lizards in Australia. Here we report severe dermatomycosis caused by N. barbatae in five species of Australian lizard, representing the first cases of Nannizziopsis infection among free-living reptiles, globally. Further, we evaluate key pathogen and host characteristics that indicate N. barbatae-associated dermatomycosis may pose a concerning threat to Australian lizards.

Emydomyces testavorans, a New Genus and Species of Onygenalean Fungus Isolated from Shell Lesions of Freshwater Aquatic Turtles

The fungal order Onygenales includes many pathogens of humans and animals, and recent studies have shown some onygenalean fungi to be significant emerging pathogens of reptiles. Although many of these fungi have similar morphological features in histologic tissue sections, recent molecular analyses have revealed a genetically complex and diverse group of reptile pathogens comprising several genera, most notably Nannizziopsis, Ophidiomyces, and Paranannizziopsis Infections by members of these genera have been previously reported in a variety of reptile species, including crocodilians, lizards, snakes, and tuataras, with negative impacts on conservation efforts for some reptiles. Despite the well-documented pathogenicity of these fungi in all other extant reptile lineages, infection has not yet been reported in aquatic turtles. In this study, we report the isolation of an onygenalean fungus associated with shell lesions in freshwater aquatic turtles. The morphologic and genetic characteristics of multiple isolates (n = 21) are described and illustrated. Based on these features and results of a multigene phylogenetic analysis, a new genus and species, Emydomyces testavorans, are proposed for these fungi isolated from turtle shell lesions.

Novel Paranannizziopsis species in a Wagler's viper (Tropidolaemus wagleri), tentacled snakes (Erpeton tentaculatum), and a rhinoceros snake (Rhynchophis boulengeri) in a zoological collection

We report several cases of fungal infections in snakes associated with a new species within the genus Paranannizziopsis. Three juvenile Wagler's vipers (Tropidolaemus wagleri) presented with skin abnormalities or ulcerative dermatitis, and two snakes died. Histologic examination of skin from the living viper revealed hyperplastic, hyperkeratotic, and crusting epidermitis with intralesional fungal elements. The terrestrial Wagler's vipers were housed in a room with fully aquatic tentacled snakes (Erpeton tentaculatum), among which there had been a history of intermittent skin lesions. Approximately 2 months after the biopsy of the viper, a skin sample was collected from one tentacled snake (TS1) with skin abnormalities and revealed a fungal infection with a similar histologic appearance. Fungal isolates were obtained via culture from the Wagler's viper and TS1 and revealed a novel species, Paranannizziopsis tardicrescens, based on phenotypic characterization and molecular analysis. P. tardicrescens was cultured and identified by DNA sequence analysis 8 months later from a dead tentacled snake in an exhibit in an adjacent hallway and 13 months later from a living rhinoceros snake (Rhynchophis boulengeri) with two focal skin lesions. Antifungal susceptibility testing on three of four cultured isolates demonstrated potent in vitro activity for terbinafine and voriconazole.

Characterization of Metarhizium viride Mycosis in Veiled Chameleons (Chamaeleo calyptratus), Panther Chameleons (Furcifer pardalis), and Inland Bearded Dragons (Pogona vitticeps)

Metarhizium viride has been associated with fatal systemic mycoses in chameleons, but subsequent data on mycoses caused by this fungus in reptiles are lacking. The aim of this investigation was therefore to obtain information on the presence of M. viride in reptiles kept as pets in captivity and its association with clinical signs and pathological findings as well as improvement of diagnostic procedures. Beside 18S ribosomal DNA (rDNA) (small subunit [SSU]) and internal transcribed spacer region 1 (ITS-1), a fragment of the large subunit (LSU) of 28S rDNA, including domain 1 (D1) and D2, was sequenced for the identification of the fungus and phylogenetic analysis. Cultural isolation and histopathological examinations as well as the pattern of antifungal drug resistance, determined by using agar diffusion testing, were additionally used for comparison of the isolates. In total, 20 isolates from eight inland bearded dragons (Pogona vitticeps), six veiled chameleons (Chamaeleo calyptratus), and six panther chameleons (Furcifer pardalis) were examined. Most of the lizards suffered from fungal glossitis, stomatitis, and pharyngitis or died due to visceral mycosis. Treatment with different antifungal drugs according to resistance patterns in all three different lizard species was unsuccessful. Sequence analysis resulted in four different genotypes of M. viride based on differences in the LSU fragment, whereas the SSU and ITS-1 were identical in all isolates. Sequence analysis of the SSU fragment revealed the first presentation of a valid large fragment of the SSU of M. viride According to statistical analysis, genotypes did not correlate with differences in pathogenicity, antifungal susceptibility, or species specificity.

Nannizziopsis guarroi infection in 2 Inland Bearded Dragons (Pogona vitticeps): clinical, cytologic, histologic, and ultrastructural aspects

Chrysosporium-related infections have been increasingly reported in reptiles over the last 2 decades. In this report, we describe clinical, cytologic, histopathologic, and ultrastructural aspects of Chrysosporium-related infection in 2 Inland Bearded Dragons (Pogona vitticeps). Case 1 was presented for an enlarging raised lesion over the left eye and multiple additional masses over the dorsum. Case 2 was submitted to necropsy by the referring veterinarian for suspected yellow fungus disease. Impression smears of the nodules in case 1 revealed granulomatous to pyogranulomatous inflammation and many septate, variably long, 4-10 μm wide, often undulated hyphae, and very rare conidia. Postmortem impression smears of the superficial lesions of case 2 contained large numbers of solitary conidia and arthroconidia and low numbers of hyphae with similar morphology to case 1. Histopathology of the 2 cases revealed severe, multifocal, chronic, ulcerative, nodular pyogranulomatous dermatitis, with myriad intralesional septate hyphae, and arthroconidia. Fungal culture and molecular sequencing in both cases indicated infection with Nannizziopsis guarroi.

Ophidiomyces ophiodiicola dermatitis in eight free-ranging timber rattlesnakes (Crotalus horridus) from Massachusetts

Eight free-ranging timber rattlesnakes (Crotalus horridus) from two geographically isolated Massachusetts populations were observed with skin lesions located primarily on the head but occasionally also on the lateral and ventral surfaces of the body. The snakes underwent health assessments that included physical examination, clinical pathology, full body radiographs, and full thickness biopsies of skin lesions. Each snake had fungal elements present histologically in tissue sections from skin lesions. Ophidiomyces ophiodiicola was identified from skin lesions using polymerase chain reaction in all eight snakes.

Microsporum aenigmaticum sp. nov. from M. gypseum complex, isolated as a cause of tinea corporis

An undescribed Microsporum species was isolated from skin scales recovered from a 40-mm large, annular, scaling lesion on the wrist of a 46-year-old woman. The risk factors for dermatophyte infection in the patient were frequent work in the garden, hunting, and contact with dogs and horses. Direct microscopic examination of the scales revealed the presence of dermatophyte hyphae; when the samples were cultured, a morphologically similar fungus grew on all slants in pure culture. Both of these findings strongly suggested that the isolate was the true causal agent of infection. The possible geophilic nature of the species was based on phylogenetic analysis (internal transcribed spacer region of rDNA and β-tubulin gene) that placed it in between species of the M. gypseum complex. However, its divergencies from all other Microsporum species exceeded 4% base pairs. Based on β-tubulin phylogeny, the isolated species is a sister to M. gypseum. The species produces abundant chlamydospores and clumps of hyphae similar to those of ascomatal primordia but no conidia and ascospores. The species was unable to grow at 37°C and does not grow on T6 basal medium, which is unlike other Microsporum species; hair perforation and urease tests were positive. The addition of histidine to the T6 medium resulted in rapid growth of the fungus. The phylogenetic evidence, morphology, growth parameters, and physiology justified the proposal that the isolate is a new species, M. aenigmaticum, sp. nov.

Molecular characterization of reptile pathogens currently known as members of the chrysosporium anamorph of Nannizziopsis vriesii complex and relationship with some human-associated isolates

In recent years, the Chrysosporium anamorph of Nannizziopsis vriesii (CANV), Chrysosporium guarroi, Chrysosporium ophiodiicola, and Chrysosporium species have been reported as the causes of dermal or deep lesions in reptiles. These infections are contagious and often fatal and affect both captive and wild animals. Forty-nine CANV isolates from reptiles and six isolates from human sources were compared with N. vriesii based on their cultural characteristics and DNA sequence data. Analyses of the sequences of the internal transcribed spacer and small subunit of the nuclear ribosomal gene revealed that the reptile pathogens and human isolates belong in well-supported clades corresponding to three lineages that are distinct from all other taxa within the family Onygenaceae of the order Onygenales. One lineage represents the genus Nannizziopsis and comprises N. vriesii, N. guarroi, and six additional species encompassing isolates from chameleons and geckos, crocodiles, agamid and iguanid lizards, and humans. Two other lineages comprise the genus Ophidiomyces, with the species Ophidiomyces ophiodiicola occurring only in snakes, and Paranannizziopsis gen. nov., with three new species infecting squamates and tuataras. The newly described species are Nannizziopsis dermatitidis, Nannizziopsis crocodili, Nannizziopsis barbata, Nannizziopsis infrequens, Nannizziopsis hominis, Nannizziopsis obscura, Paranannizziopsis australasiensis, Paranannizziopsis californiensis, and Paranannizziopsis crustacea. Chrysosporium longisporum has been reclassified as Paranannizziopsis longispora. N. guarroi causes yellow fungus disease, a common infection in bearded dragons and green iguanas, and O. ophiodiicola is an emerging pathogen of captive and wild snakes. Human-associated species were not recovered from reptiles, and reptile-associated species were recovered only from reptiles, thereby mitigating concerns related to zoonosis.

Selected emerging infectious diseases of squamata

It is important that reptile clinicians have an appreciation for the epidemiology, clinical signs, pathology, diagnostic options, and prognostic parameters for novel and emerging infectious diseases in squamates. This article provides an update on emerging squamate diseases reported in the primary literature within the past decade. Updates on adenovirus, iridovirus, rhabdovirus, arenavirus, and paramyxovirus epidemiology, divergence, and host fidelity are presented. A new emerging bacterial disease of Uromastyx species, Devriesea agamarum, is reviewed. Chrysosporium ophiodiicola-associated mortality in North American snakes is discussed. Cryptosporidium and pentastomid infections in squamates are highlighted among emerging parasitic infections.

Dermatitis and cellulitis in leopard geckos (Eublepharis macularius) caused by the Chrysosporium anamorph of Nannizziopsis vriesii

An epizootic of ulcerative to nodular ventral dermatitis was observed in a large breeding colony of 8-month to 5-year-old leopard geckos (Eublepharis macularius) of both sexes. Two representative mature male geckos were euthanized for diagnostic necropsy. The Chrysosporium anamorph of Nannizziopsis vriesii (CANV) was isolated from the skin lesions, and identification was confirmed by sequencing of the internal transcribed spacer region of the rRNA gene. Histopathology revealed multifocal to coalescing dermal and subcutaneous heterophilic granulomas that contained septate fungal hyphae. There was also multifocal epidermal hyperplasia with hyperkeratosis, and similar hyphae were present within the stratum corneum, occasionally with terminal chains of arthroconidia consistent with the CANV. In one case, there was focal extension of granulomatous inflammation into the underlying masseter muscle. This is the first report of dermatitis and cellulitis due to the CANV in leopard geckos.

Reptiles with dermatological lesions: a retrospective study of 301 cases at two university veterinary teaching hospitals (1992-2008)

This retrospective study reviews the medical records of 301 reptiles with dermatological lesions that were examined at the Veterinary Medical Teaching Hospital, University of California at Davis (VMTH-UCD) and the Unité de Dermatologie-Parasitologie-Mycologie, Ecole Nationale Vétérinaire de Nantes (UDPM-ENVN) from 1 January 1992 to 1 July 2008. The most common reptile groups differed between the two hospitals, with lizards being the most common at the VMTH-UCD and chelonians at the UDPM-ENVN. At the VMTH-UCD, boa constrictors (Boa constrictor), ball pythons (Python regius) and other Python species were over-represented, and box turtles (Terrapene carolina) were under-represented in the dermatological lesion caseload. When institutional data were combined, 47% of all reptiles at both institutions with confirmed or suspected cases of sepsis had petechiae, with the highest association seen in chelonians at 82%. Dependent on institution and reptile group, from 29% to 64% of the cases had underlying husbandry issues. Sixty-two per cent of all cases were alive at final status. Veterinarians treating reptiles with skin disease should be aware of the following: (i) that boa constrictors and Python species may be predisposed to dermatological lesions; (ii) that client education is important for proper husbandry; and (iii) that there is a possible association between petechiae and sepsis, especially in chelonians. The conjectural association between certain skin lesions and sepsis remains to be confirmed by systematically derived data that demonstrate a causal relationship between the two.