Morbidity and Mortality in the Koala (Phascolarctos cinereus).

Backhouse, T. C.; Bolliger, Adolph

doi:10.1071/zo9610024

Cited by 44 publications

(30 citation statements)

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“…Cryptococcosis was first reported in koalas in 1960 (186) and is almost always due to C. gattii (174,187). The koala habitat in the wild is the same as that of the species of eucalypt that has been identified as the environmental niche of C. gattii.…”

Section: Gattii Infection In Animalsmentioning

confidence: 86%

Cryptococcus gattii Infections

2014

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SUMMARY Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans , although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended.

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Section: Gattii Infection In Animalsmentioning

confidence: 86%

Cryptococcus gattii Infections

2014

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“…Since cryptococcosis was first described in the koala in 1960 [24], 10 cases have been reported [25–30]. Three were male, five were female, and in two the sex was not recorded.…”

Section: Introductionmentioning

confidence: 99%

Asymptomatic carriage of Cryptococcus neoformans in the nasal cavity of the koala (Phascolarctos cinereus)

Connolly¹,

Krockenberger²,

Malík

et al. 2008

Med Mycol

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Over a 22‐month period, sequential nasal and skin swabs were obtained from 52 healthy captive koalas (Phascolarctos cinereus) from the Sydney region. Cryptococcus neoformans was isolated in 17 koalas from 64 of 262 (24%) nasal swabs and from nine of 262 (3%) skin swabs. Prevalence of nasal colonization varied seasonally from 12% (3/25) to 38% (10/26). Cryptococcus neoformans var. gattii alone was cultured from 37, var. neoformans alone from 22 and both varieties from five nasal swabs. Of 33 koalas sampled on three or more occasions, organisms were isolated persistently from six, occasionally from eight and never from 19. Two koalas were persistently and heavily (≥100 colonies/plate) colonized by C. neoformans var. gattii and two with var. neoformans. Isolation of C. neoformans var. gattii from the skin was low grade and sporadic. No koalas from which C. neoformans was persistently isolated showed clinical signs of cryptococcosis and all except one had a negative latex cryptococcal antigen test, therefore the nasal cavity was presumed to be colonized by, rather than infected with, C. neoformans. Preliminary observations of koalas from Coffs Harbour indicated a much higher prevalence of colonization by C. neoformans, suggesting that environmental factors influenced the extent of carriage by C. neoformans.

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“…ymphoid neoplasia is reported to be the most common form of neoplasia in the koala (Phascolarctos cinereus) L (Canfield 1990). It was first reported in koalas in 1961 (Backhouse and Bolliger 1961;Heuschele and Hayes 1961) and since then has been recorded in both captive and freeliving koalas from Victoria, New South Wales and Queensland (Mckenzie 1981: Canfield et a1 1987Canfield 1990). Viral particles associated with cases of lymphoid neoplasia were reported by Canfield et a1 (1988), and more recently, a viral aetiology has been proposed for lymphosarcoma and other conditions in the koala (Worley et a1 1993).…”

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confidence: 95%