Veterinary Insights into Cryptococcosis Caused byCryptococcus neoformansandCryptococcus gattii

Computed tomographic anatomy of the nasal cavity, paranasal sinuses and tympanic cavity of the koala

“…The current study used cross‐sectional imaging (helical computed tomography (CT)) complemented by conventional anatomical dissection to gain more detailed information about the normal anatomy of the nasal cavity and bony cavitations of the head of the koala. The intention was to provide not only a basis for future functional and comparative anatomical studies, but also to establish a reference point for investigation of sinonasal disease, which is of particular clinical relevance because koalas appear to be at greater risk of developing cryptococcosis than other species, with the sinonasal cavity frequently the primary site of infection and the meninges and brain commonly involved …”

“…CT has begun to be used to define the extent of disease in individual koalas suspected of having cryptococcosis, although the absence of a formal description of the species' normal cross‐sectional anatomy has limited interpretation of the findings. Cryptococcal lesions can be expected to occur in sinonasal, facial and nasopharyngeal locations in the koala and, potentially, the middle ear and cribriform plate of the ethmoid bone . Compared with conventional radiographic imaging, CT is particularly suited to imaging all these sites because there is no superimposition by normal anatomical structures .…”

“…The nasal cavity of the koala is the likely portal of entry for the infectious propagules of Cryptococcus gattii , leading initially to colonisation and subsequently to tissue invasion in many cases . The architecture of the nasal passages influences the passage and deposition of inspired particulate matter, so a species' nasal anatomy has a potential role in determining susceptibility to colonisation by infectious agents . In addition, central nervous system involvement is the most significant sequela of cryptococcosis in koalas and could potentially result from local extension from nasal or paranasal sinus disease as is hypothesised to occur in domestic carnivores .…”

Rising to the challenge of multiple Cryptococcus species and the diseases they cause

“…Cryptococcus spp. have a broad host range, in that many animals other than humans are also affected naturally (Malik et al, 2011). This provides research advantages in terms of using these as models for the disease.…”

“…From the fungal side this has resulted in the separation of strains into different serotypes, varieties, groups based on molecular markers, and establishing two species C. neoformans and C. gattii (Kwon-Chung, 1976; Kwon-Chung et al, 2002). Hosts include diverse animal species (Malik et al, 2011), and for the human host a separation into immune status such as HIV+, otherwise immunosuppressed, and other unknown susceptibilities. However, there is now greater realization of the different fungal subtypes and their biology and the underlying immune status of the patient population, and consequences in clinical outcome.…”