Canis ISSN: 2398-2942
Cryptococcus neoformans
Synonym(s): C. neoformans
Contributor(s): Rosanna Marsella
Introduction
Classification
Taxonomy
- Genus: Cryptococcus - a genus of yeast-like fungi. (Strains have been experimentally converted to a mycelial, sexually reproducing phase and given the name Filobasidiella neoformans.)
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Clinical Effects
Epidemiology
Habitat
Lifecycle
- Can affect any mammal, but cats are at higher risk for it.
- No immunosuppression is usually detected in cats with cryptococcosis, eg FeLV, FIV.
- Pigeons often carry the agent but are rarely affected clinically - temperature too high for growth of agent.
Transmission
- Respiratory, occasionally percutaneous by direct inoculation of the organism.
- Non-contagious.
Pathological effects
- Human infection often associated with pre-existing immunosuppression.
- Virulence is largely associated with the antiphagocytic and immunosuppressive capsule.
- Route of infection: usually respiratory, resulting in lesions in nasal cavity or sinuses with possible extension to the brain (involvement of the optic nerve causing blindness), and meninges.
- Cattle: mastitis, with severe swelling and rarely may spread to lungs. Infection may be introduced during intramammary medication.
- Horses: nasal passage granulomata.
- Dogs: granulomata of subcutaneous tissue, with possible central nervous system (CNS) and ocular signs including.
- Cats: granulomata of subcutaneous tissue, with respiratory signs.
- Human beings: respiratory disease and meningitis.
Control
Control via chemotherapies
- Amphotericin B Amphotericin B (used initially for rapid efficacy combined later on with aerodes, eg flucytosine (orally) Flucytosine ).
- Fluconazole Fluconazole - drug of choice if neurological involvement is present due to excellent penetration in the brain. Used orally at 2.5-5 mg/kg once daily for several months. Dosage should be reduced in patients with compromised renal function.
Control via environment
- Avoid areas contaminated with pigeon droppings.
Vaccination
Diagnosis
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Further Reading
Publications
Refereed papers
- Recent references from VetMed Resource and PubMed.
- Malik R, Speed B R, Kaldor J, Cairns B, Pegorer M, Wigney D I & Love D N (1999) Serum antibody response to Cryptococcus neoformans in cats, dogs and koalas with and without active infection. Med Mycol 37(1), 43051.
- Malik R, Hunt G B, Bellenger C R, Allan G S, Martin P, Canfield P J & Love D N (1999) Intra-abdominal cryptococcosis in two dogs. JSAP 40(8), 387-391.
- Tiches D, Vite C H, Dayrell-Hart B, Steinbery S A, Gross S & Lexa F (1998) A case of canine central nervous system cryptococcosis - management with fluconazole. JAAHA 34(2), 145-151.
- Malik R, McPetrie R, Wigney D I, Craig A J & Love D N (1996) A latex cryptococcal antigen agglutination test for diagnosis and monitoring of therapy for cryptococcosis. Aust Vet J 74(5), 358-365.
- Malik R, Craig A J, Wigney D I, Martin P & Love D N (1996) Combination chemotherapy of canine and feline cryptococcosis using subcutaneously administered amphotericin B. Aust Vet J 73(4), 124-128.
- Malik R, Dill-Macky E, Martin P, Wigney D I, Muir D B & Love D N (1995) Cryptococcosis in dogs - a retrospective study of 20 consecutive cases. J Med Vet Mycol 33(5), 291-297.
- Cook J R et al (1991) Successful chemotherapy for canine cryptococcal meningoencephalitis. JAAHA 27, 61.
- Mason G D et al (1989) Ketaconazole therapy in a dog with systemic cryptococcosis. JAVMA 195, 954.
- Hodgin E C et al (1987) Cryptococcosis in a pup. JAVMA 191, 697.
- Noxon J O et al (1986) Ketoconazole treatment in canine and feline cryptococcosis. JAAHA 22, 179.