Voriconazole, a safe alternative for treating infections caused by the Chrysosporium anamorph of Nannizziopsis vriesii in bearded dragons (Pogona vitticeps)

Dermal and systemic infections caused by the Chrysosporium anamorph of Nannizziopsis vriesii (CANV) are highly prevalent in reptiles and may result in severe disease and high mortality. Due to the high incidence of therapeutic failures, optimizing treatment is required. We first determined in this study the minimal inhibitory concentrations (MIC) of itraconazole, voriconazole, amphotericin B and terbinafine against 32 CANV isolates. For voriconazole, amphotericin B and terbinafine a monomodal MIC distribution was seen, whereas a bimodal MIC distribution was present for itraconazole, indicating acquired resistance in one isolate. Fourteen naturally-infected bearded dragons (Pogona vitticeps), from the same owner, were treated orally with either itraconazole (5 mg/kg q24h) or voriconazole (10 mg/kg q24h). The clinical condition, drug plasma concentrations and the presence of CANV in skin samples were followed. The animals were treated until complete clearance of the fungus. The plasma concentrations of voriconazole and itraconazole exceeded the minimal inhibitory concentrations of the CANV isolates. Elimination of CANV was achieved on average after 27 and 47 days of treatment with itraconazole and voriconazole, respectively. Whereas only 2 out of 7 survived after itraconazole treatment, only a single animal died in the voriconazole treated group. In conclusion, based on a limited number of animals, voriconazole applied at a regimen of 10 mg/kg bodyweight (BW) q24h seems to be a safe and effective antimycotic drug to eliminate CANV infections in bearded dragons

Chrysosporium-Related Fungi and Reptiles : a Fatal Attraction

10.1371/journal.ppat.100436

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

Aspects of the pharmacokinetics of itraconazole and voriconazole in the tuatara (Sphenodon punctatus) and application in the treatment of an emerging fungal disease

Tuatara (Sphenodon punctatus) are unique, cold-adapted reptiles endemic to New Zealand. Recently, captive tuatara have been found to be affected by an emerging fungal pathogen, Paranannizziopsis australasiensis. P. australasiensis causes dermatitis in tuatara, and has caused fatal systemic mycosis in a bearded dragon (Pogona vitticeps), and in aquatic file snakes (Acrochordus spp). The discovery of P. australasiensis infections has prevented the release of tuatara from several captive institutions to offshore islands, and has negative implications for the long-term health and welfare of the animals. A review of the literature revealed that infections caused by organisms related to P. australasiensis are being recognised worldwide as emerging pathogens of reptiles. Little is known about the epidemiology of these often-fatal infections, and treatment with a range of antifungals has met with varying success. There has been little research on antifungal use in reptiles, and none on how environmental temperature affects the pharmacokinetics of antifungals. This study investigated the microbiological characteristics of P. australasiensis, primarily the growth rate of the fungus at different temperatures, and the Minimum Inhibitory Concentration (MIC) of various antifungal agents for P. australasiensis. It was determined that the optimal growth temperature for P. australasiensis encompasses the range from 20oC-30oC, with scant growth at 12oC, moderate growth at 15oC, and no growth at 37oC. The MICs of antifungals were tested at room temperature and at 37oC, and were not found to be significantly different. MICs of itraconazole and voriconazole for three isolates of P. australasiensis were found to be low, at 0.12mg/L for itraconazole and <0.008mg/L for voriconazole. The single and multiple dose pharmacokinetics of itraconazole and voriconazole in tuatara were investigated at 12 and 20oC; these are the high and low ends of the tuatara’s preferred optimal temperature zone (POTZ). Results showed statistically significant differences in antifungal elimination half-life between temperatures. With the aid of population pharmacokinetic modelling, optimal dosing regimes for both antifungals were developed for tuatara of different weights. It was established that tuatara should be treated at 20oC, at the high end of POTZ, to facilitate rapid attainment of therapeutic antifungal concentrations, improve clinical outcomes and reduce the risk of adverse effects. While itraconazole demonstrated more predictable pharmacokinetics than voriconazole in tuatara, itraconazole treatment was associated with significant adverse effects. These included elevated bile acids and uric acid concentrations, and weight loss. While voriconazole appears to be safer, its pharmacokinetics are less predictable, with high inter-individual variability in tuatara administered the same dose rate (a phenomenon also observed in humans). While voriconazole may be a useful antifungal in clinically affected tuatara where dosage can be adjusted based on the response to treatment, its use in an asymptomatic quarantine setting may be limited. The use of higher voriconazole doses may increase the likelihood of maintaining therapeutic concentrations in all treated animals, however the risk of adverse effects increases concomitantly. Furthermore, there are currently no published reports of successful treatment of P. australasiensis in tuatara with voriconazole. This study also established haematologic and biochemical reference ranges in a group of tuatara. These demonstrated variability in several parameters based on sex and season, and will be a useful tool for assessing health and disease in these and other tuatara

Chrysosporium

25.1 Introduction 25.1.1 Classification and Morphology 25.1.2 Clinical Features 25.1.3 Diagnosis 25.2 Methods 25.2.1 Sample Preparation 25.2.2 Detection Procedures 25.3 Conclusion Reference

The epidemiology and pathology of Paranannizziopsis australasiensis in New Zealand reptiles : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science in Wildlife Health at Massey University, Palmerston North, New Zealand

Paranannizziopsis australasiensis, has recently been diagnosed in tuatara at two captive facilities in New Zealand. This newly emerging fungal pathogen, is a member of the onygenalean fungal group formally known as Chrysosporium anamorph of Nannizziopsis vriesii (CANV). Fungi of this genera are thought to be obligate primary pathogens in reptiles, and closely related species such as Ophidiomyces ophiodiicola, and Nannizziopsis guarroi have caused significant morbidity and mortalities in captive and wild reptile populations. The detection of this disease raised concerns for wild and captive population health and resulted in a temporary cessation of tuatara breed and release programmes from affected facilities. Similar lesions have been reported in tuatara at multiple other captive facilities in New Zealand, but lack of veterinary assessment and, until recently, inadequate diagnostic capabilities has led to an inability to confirm the presence or absence of P. australasiensis in these populations. This research aimed to investigate the epidemiology of P. australasiensis in New Zealand wild and captive endemic reptiles. Skin samples were collected from nine captive, six wild and two ecosanctuary populations of tuatara across New Zealand. Skin samples from in contact geckos and skinks were opportunistically collected to determine the possible cross species infection of P. australasiensis. Samples were tested for presence of P. australasiensis by fungal culture followed by PCR, and by loop-mediated isothermal amplification (LAMP). Soil samples were collected from burrows, basking areas and captive enclosures and analysed by LAMP to determine the presence of P. australasiensis within the environment. Paranannizziopsis australasiensis was found to be wide spread in New Zealand captive and wild reptile populations. In populations where the pathogen was detected prevalence varied between 6.7% and 44.4% for tuatara, 3.8% and 40% for geckos and 6.7% and 66.7% for skinks. A low virulence of disease associated with infection was seen in tuatara across New Zealand, with many LAMP positive tuatara being asymptomatic. Increased severity of disease was seen in two captive tuatara, where ii other concurrent disease was present. One fatality was reported. In other reptile hosts, no disease was identified, and it is suspected these species act as reservoirs for the transmission of this organism to tuatara. Paranannizziopsis australasiensis was detected multiple times in soil samples and may survive as an environmental saprophyte. Paranannizziopsis australasiensis appears to have a close association with New Zealand reptiles. The prevalence, distribution and pathology of P. australasiensis observed in this study suggests that this organism is not a threat to tuatara or other endemic reptile populations in New Zealand. The findings of this study have enabled restrictions placed on tuatara translocations, based on P. australasiensis status, to be removed

Ophidiomycosis in a Timber Rattlesnake, Crotalus horridus (Linnaeus 1758), with behavioral and thermal observations: A case report from Georgia, USA

N/

Phylogeny of chrysosporia infecting reptiles : proposal of the new family Nannizziopsiaceae and five new species

We have performed a phenotypic and phylogenetic study of a set of fungi, mostly of veterinary origin, morphologically similar to the Chrysosporium asexual morph of Nannizziopsis vriesii (Onygenales, Eurotiomycetidae, Eurotiomycetes, Ascomycota). The analysis of sequences of the D1-D2 domains of the 28S rDNA, including representatives of the different families of the Onygenales, revealed that N. vriesii and relatives form a distinct lineage within that order, which is proposed as the new family Nannizziopsiaceae. The members of this family show the particular characteristic of causing skin infections in reptiles and producing hyaline, thin- and smooth-walled, small, mostly sessile 1-celled conidia and colonies with a pungent skunk-like odour. The phenotypic and multigene study results, based on ribosomal ITS region, actin and β-tubulin sequences, demonstrated that some of the fungi included in this study were different from the known species of Nannizziopsis and Chrysosporium and are described here as new. They are N. chlamydospora, N. draconii, N. arthrosporioides, N. pluriseptata and Chrysosporium longisporum. Nannizziopsis chlamydospora is distinguished by producing chlamydospores and by its ability to grow at 5 °C. Nannizziopsis draconii is able to grow on bromocresol purple-milk solids-glucose (BCP-MS-G) agar alkalinizing the medium, is resistant to 0.2 % cycloheximide but does not grow on Sabouraud dextrose agar (SDA) with 3 % NaCl. Nannizziopsis arthrosporioides is characterised by the production of very long arthroconidia. Nannizziopsis pluriseptata produces 1- to 5-celled sessile conidia, alkalinizes the BCP-MS-G agar and grows on SDA supplemented with 5 % NaCl. Chrysosporium longisporum shows long sessile conidia (up to 13 μm) and does not produce lipase