Pulmonary adiaspiromycosis in critically endangered northern hairy-nosed wombats (Lasiorhinus krefftii)

Adiaspiromycoses in Wild Rodents from the Pyrenees, Northeastern Spain

Adiaspiromycosis is a nontransmissible infectious pulmonary disease caused by the inhalation of propagules from fungal species belonging to the family Ajellomicetaceae, especially Emergomyces crescens. Adiaspiromycosis caused by E. crescens has been recorded in a broad number of species worldwide, with small burrowing mammals being considered the main hosts for this environmental pathogen. Only a handful of studies on adiaspiromycosis in European wildlife has been published to date. We assessed the occurrence of adiaspiromycosis in wild rodents (Murinae and Arvicolinae) from the central Spanish Pyrenees (NE Spain). The lungs of 302 mice and 46 voles were screened for the presence of adiaspores through histopathologic examination. Pulmonary adiaspiromycosis was recorded in 21.6% of all individuals (75/348), corresponding to 63/299 wood mice (Apodemus sylvaticus) and 12/40 bank voles (Myodes glareolus). Adiaspore burden varied highly between animals, with a mean of 0.19 spores/mm2 and a percentage of affected lung tissue ranging from <0.01% to >8%. These results show that the infection is present in wild rodents from the central Spanish Pyrenees. Although the impact of this infection on nonendangered species is potentially mild, it might contribute to genetic diversity loss in endangered species.

Ecology and conservation of the critically endangered northern hairy-nosed wombat (Lasiorhinus krefftii): past, present and future

The northern hairy-nosed wombat (Lasiorhinus krefftii) is an iconic marsupial endemic to Australia, recognised globally for its status as the largest, herbivorous burrowing mammal. Owing to historical challenges, including anthropogenic conflict and environmental threats, the species was pushed to near extinction and was officially classified as Critically Endangered in 1996. Establishing an effective conservation plan is complicated by ongoing and novel threats as well as by aspects of the species’ ecology that remain unstudied due to its neophobic and nocturnal behaviour. To identify areas where additional research is needed, we conducted a comprehensive search of the literature published on the northern hairy-nosed wombat from 1980 to 2019 to identify where knowledge gaps exist and to suggest where future efforts may be focussed. We found that the breeding ecology, in particular, of the northern hairy-nosed wombat is largely unstudied but could be vital in conservation efforts. Further, there is a need to establish additional populations, and several threats – including disease, invasive species, and climate change – may require ongoing management action to ensure the species’ longevity.

Adiaspore development and morphological characteristics in a mouse adiaspiromycosis model

Lesions of adiaspiromycosis, a respiratory disease affecting wild animals, have been found mainly in dead mammals and free-living mammals captured for surveillance. No report has described an investigation of adiaspore formation progress in the lung. After establishing an experimental mouse model of intratracheal adiaspiromycosis infection with the causative agent Emmonsia crescens, we observed adiaspore development. The spores grew and reached a plateau of growth at 70 days post-infection. The median adiaspore diameter showed a plateau of around 40 μm. The characteristic three-layer cell-wall structure of adiaspores was observed in the lung at 70 days post-infection. We examined infection with a few spores, which revealed that adiaspores in the mouse lung progressed from intratracheal infection of at least 400 spores. Moreover, we developed adiaspores in vitro by culture in fetal bovine serum. Although most spores broke, some large spores were intact. They reached about 50 μm diameter. Thick cell walls and dense granules were found as common points between in vitro adiaspores and in vivo adiaspores. These models are expected to be useful for additional investigations of E. crescens adiaspores and adiaspiromycosis.

Rhinosinusitis in an Australian mare caused by Flavodon flavus, a recently recognized invasive fungal pathogen of the horse

We describe herein the clinical, endoscopic, computed tomography (CT), pathologic, and microbiologic features of an infection caused by an under-recognized fungal pathogen, Flavodon flavus, in a 25-y-old Australian Quarter Horse. The horse had a unilateral obstructive nasal mass, resulting in stertor and dyspnea. On endoscopy, the mass was tan, multinodular, and completely obstructed the nasal passage. CT analysis revealed a large, soft tissue-attenuating and partially mineralized mass in the right nasal passage and dorsal-conchofrontal sinus, expanding into adjacent paranasal sinuses with associated bone lysis and rhinosinusitis. Histopathology of the mass on 2 occasions revealed suppurative inflammation initially, and pyogranulomatous inflammation subsequently. The inflammatory reaction surrounded numerous spherical fungal structures (~60-80 µm diameter) that stained positively on periodic acid-Schiff and Grocott methenamine silver stains. PCR for the fungal internal transcribed spacer 1 and 2 regions followed by Sanger sequencing on a cultured isolate identified the agent as F. flavus, which has only been reported previously as pathogenic in one horse in the United States, to our knowledge. Previous reports described this fungus as a nonpathogenic, environmental commensal fungus associated with insects and plants.

Disseminated Sporotrichosis in a Bilby (Macrotis lagotis)

A male bilby (Macrotis lagotis) was presented to the Murdoch University Veterinary Anatomical Pathology Service following humane destruction due to severe lethargy. The bilby was emaciated with a focal ulcerated skin lesion on the dorsal tail base. Multifocal to coalescing foci of pyogranulomatous and often necrotizing inflammation was present within multiple organs, including the tail wound, adrenal glands, kidneys, lungs, brain, testes, lymph nodes, heart, liver, spleen and salivary glands. Admixed were abundant intrahistiocytic and extracellular pleomorphic yeast (round, oval and cigar-shaped) up to 6 μm diameter, often with a thin clear halo and occasional narrow-based budding. The diagnosis of disseminated sporotrichosis was confirmed via culture and sequencing of the internal transcribed spacer region of the causative agent, Sporothrix schenckii sensu lato. The route of entry of infection was considered most likely to have been via cutaneous inoculation of the tail base wound. To the authors' knowledge, this report describes the first known case of sporotrichosis in a native Australian animal.

Molecular Diagnosis of Emmonsia-Like Fungi Occurring in Wild Animals

Using specific primers based on the ribosomal operon, positive DNA amplification was obtained from lungs of 11/215 tested small burrowing animals, both terrestrial and aquatic, and including frozen (n = 4) and formalin-fixed paraffin-embedded (n = 7) samples. The main species detected in Europe in mice, otters and river rats was Emmonsia crescens. Two strains from otters and weasels were Blastomyces parvus. Two Australian wombats revealed the presence of a hitherto unknown species of the geophilic genus Emmonsiellopsis.