Cryptococcus in a Wild Loon (Gavia immer)


  • Mark A. Pokras, BS, DVM Wildlife Clinic, Tufts University Cummings School of Veterinary Medicine
  • Rose Miconi, BS Wildlife Clinic at Tufts University Cummings School of Veterinary Medicine
  • Steven Engler, BS, DVM, Dipl. AC VP Antech Diagnostics
  • Alison Hazel, BS, DVM Liverpool Animal Health Center
  • Romona Haebler, BS, PhD, Dipl. ACVP US Environmental Protection Agency



Loon, Gavia, Cryptococcus, avian, fungal infection


A debilitated adult male common loon (Gavia immer) was taken to a veterinary practice in Liverpool, NY where it later died. Subsequently it was sent to Tufts Wildlife Clinic as part of a regional mortality study. During the necropsy, pathology involving most organ systems was noted. Microbiologic and histopathologic examination revealed an overwhelming infection by the fungus Cryptococcus spp.


Download data is not yet available.

Author Biographies

Mark A. Pokras, BS, DVM, Wildlife Clinic, Tufts University Cummings School of Veterinary Medicine

Mark Pokras is Director of the Wildlife Clinic at Tufts University. He is heavily involved in conservation medicine and continues to inspire veterinary students to follow their hearts and strive to better our world.

Rose Miconi, BS, Wildlife Clinic at Tufts University Cummings School of Veterinary Medicine

Rose Miconi has a BS in wildlife biology from the University of Rhode Island and for many years worked with Dr. Pokras on loon conservation issues.

Steven Engler, BS, DVM, Dipl. AC VP, Antech Diagnostics

Steven Engler is a veterinary pathologist who taught for many years at Tufts Cummings School of Veterinary Medicine. He currently provides diagnostic pathology services for Antech Diagnostics, Inc.

Alison Hazel, BS, DVM, Liverpool Animal Health Center

Alison Hazel worked in upstate New York practicing small animal medicine and providing local rehabilitators with veterinary services. In 1998 she was voted Wildlife Veterinarian of the Year for New York State.

Romona Haebler, BS, PhD, Dipl. ACVP, US Environmental Protection Agency

Romona Haebler is a veterinary pathologist at the US EPA’s Atlantic Ecology Division, in Rhode Island. Mona has many years of experience studying disease and toxicologic threats to marine mammals, birds, and reptiles.


Aguilar, R. F., and C. D. Hilton. 1999. Clinical Challenge. Osteolysis and Cellulitis Secondary to Cryptococcus neoformans in a Barasingha (Cervus duvaucelii). Journal of Zoo and Wildlife Medicine. 30(4): 591–594.

Barry, M. T., and C. K. Stadler. 1995. Successful Treatment of Cryptococcus neoformans Infection in an Allen’s Swamp Monkey (Allenopithecus nigroviridis). Journal of Zoo and Wildlife Medicine. 26(1): 109–114.

Berry, W. L., J. E. Jardine, and I. W. Espie. 1997. Pulmonary Cryptococcoma and Cryptococcal Meningoencephalitis in a King Cheetah (Acinonyx jubatus). Journal of Zoo and Wildlife Medicine. 28(4): 485–490.

Bildfell, R. J., P. Long, and R. J. Sonn. 2002. Cryptococcosis in a Llama (Lama glama). Journal of Veterinary Diagnostic Investigation. 14(4): 337–339.

Bolton, L. A., R. G. Lobetti, D. N. Evezard, J. A. Picard, J. W. Nesbit, J. Van Heerden, and R. E. Burroughs. 1999. Cryptococcosis in Captive Cheetah (Acinonyx jubatus): Two Cases. Journal of the South African Veterinary Association. 70(1): 35–39.

Buchanan, K. L., and J. W. Murphy. 1998. What Makes Cryptococcus neoformans a Pathogen? Emerging Infectious Disease. 4(1): 71–83.

Burgess, N. M., D. C. Evers, and J. D. Kaplan. 2005. Mercury and Other Contaminants in Common Loons Breeding in Atlantic Canada. Ecotoxicology. 14: 241–252.

Casadevall, A., J. N. Steenbergen, and J. D. Nosanchuk. 2003. “Ready Made” Virulence and “Dual Use” Virulence Factors in Pathogenic Environmental Fungi—Cryptococcus neoformans Paradigm. Current Opinion in Microbiology. 6(4): 332–337.

Chute, H. L. 1991. Miscellaneous fungal infections. Pp. 338–339 in Diseases of Poultry, 9th edition. (B. W. Calnek, H. J. Barnes, C. W. Beard, W. M. Read, and H. J. Yoder, eds.). Iowa State University Press: Ames, IA.

Decostere, A., K. Hermans, T. De Baere, F. Pasmans, and F. Haesebrouck. 2003. First Report on Cryptococcus laurentii Associated with Feather Loss in a Glossy Starling (Lamprotornis chalybaeus). Avian Pathology. 32(3): 309–311.

Emmons, C. W. 1951. Isolation of Cryptococcus neoformans from Soil. Journal of Bacteriology. 62: 685–690.

Feldmesser, M., S. Tucker, and A. Casadevall. 2001. Cryptococcus neoformans: Intracellular or Extracellular? Trends in Microbiology. 9(9): 418.

Gales, N., G. Wallace, and J. Dickson. 1985. Pulmonary Cryptococcosis in a Striped Dolphin (Stenella coeruleoalba). Journal of Wildlife Diseases. 21(4): 443–446.

Hamir, A. N., J. M. Miller, and R. J. Sonn. 2002. Meningoencephalitis and Pneumonia Associated with Cryptococcus neoformans Infection in a Free–ranging Elk in the U.S.A. Veterinary Record. 151(11): 332–334.

Howard, D. 2003. Pathogenic Fungi in Humans and Animals. Marcel Dekker: New York, NY.

Hull, T. G. 1963. Diseases Transmitted from Animals to Man, 5th edition. Pp. 468–470. Charles C. Thomas: Springfield, IL.

Irokanulo, E. O. A., A. Makinde, C. O. Akuesgi, and M. Ekwonu. 1997. Cryptococcus neoformans var. neoformans Isolated from Droppings of Captive Birds in Nigeria. Journal of Wildlife Diseases. 32(2): 343–345.

Jungermann, P. F., and R. M. Schwarzmann. 1972. Veterinary Medical Mycology. Lea & Febiger: Philadelphia, PA.

Kidd, S. E., P. J. Bach, A. O. Hingston, S. Mak, Y. Chow, L. MacDougall, J. W. Kronstad, and K. H. Bartlett. 2007. Cryptococcus gattii Dispersal Mechanisms, British Columbia, Canada. Emerging Infectious Disease. 13(1): 51–57.

Kielstein, P., H. Hotzel, A. Schmarlreck, D. Khaschabi, and W. Glawischnig. 2000. Occurrence of Cryptococcus spp. in Excreta of Pigeons and Pet Birds. Mycoses. 43(1–2): 7–15.

Krockenberger, M. B., P. J. Canfield, and R. Malik. 2003. Cryptococcus neoformans var. gattii in the Koala (Phasolarctos cinereus): A Review of 43 Cases of Cryptococcosis. Medical Mycology. 41(3): 225–234.

Luberto, C., B. Martinez–Mariño, D. Taraskiewicz, B. Bolaños, P. Chitano, D. L. Toffaletti, G. M. Cox, J. R. Perfect, Y. A. Hannun, E. Balish and M. Del Poeta. 2003. Identification of App. 1 as a Regulator of Phagocytosis and Virulence of Cryptococcus neoformans. Journal of Clinical Investigations. 112: 1080–1094.

McIntyre, J. W. 1988. The Common Loon: Spirit of Northern Lakes. University of Minnesota Press: Minneapolis, MN.

McNamara, T. S., R. A. Cook, J. L. Behler, L. Ajello and A. A. Pachye. 1994. Cryptococcosis in a Common Anaconda (Eunectes murinus). Journal of Zoo and Wildlife Medicine. 25(1): 128–132.

Malik, R., M. B. Krockenberger, G. Cross, R. Doneley, D. N. Madill, D. Black, P. McWhirter, A. Rozenwax, K. Rose, M. Alley, D. Forshaw, I. Russell–Brown, A. C. Johnstone, P. Martin, C. R. O’Brien, and D. N. Love. 2003. Avian Cryptococcosis. Medical Mycology. 41(2): 115–124.

Malik, R., B. Nalderton, D. Finaison, M. B. Krockenberger, H. Karaoglu, W. Meyer, P. Martin, M. P. France, J. McGill, S. J. Lester, C. R. O’Brien, and D. N. Love. 2002. Cryptococcosis in Ferrets: A Diverse Spectrum of Clinical Disease. Australian Veterinary Journal. 80(12): 749–755.

Medleau, L., and J. A. Barsanti. 1998. Cryptococcus. Pp. 383–390 in Infectious Diseases of the Dog and Cat, 2nd edition. (C. E. Greene, ed.). W. B. Saunders Co: Philadelphia, PA.

Migaki, G., R. D. Gunnels, and H. W. Casey. 1978. Pulmonary Cryptococcosis in an Atlantic Bottlenosed Dolphin (Tursiops truncatus). Laboratory Animal Science. 28(5): 603–606.

Miller, W. G., A. A. Padhye, W. Van Bonn, L. Jensen, M. E. Brandt, and S. H. Ridgway. 2002. Cryptococcosis in a Bottlenose Dolphin (Tursiops truncatus) Caused by Cryptococcus neoformans var. gattii. Journal of Clinical Microbiology. 40(2): 721–724.

Nosanchuk, J. D., S. Shoham, B. C. Fries, D.S. Shapiro, S. M. Levitz, and A. Casadevall. 2000. Evidence of Zoonotic Transmission of Cryptococcus neoformans from a Pet Cockatoo to an Immunocompromised Patient. Annals of Internal Medicine. 132(3): 205–208.

Peachey, P. R., P. O. Gubbins, and R. E. Martin.1998. The Association Between Cryptococcal Variety and Immunocompetent and Immunocompromised Hosts. Pharmacotherapy. 18(2): 255–264.

Simmer, M., and D. M. Secko. 2008. A Peach of a Pathogen: Cryptococcus neoformans. Available at: <–peach–of–a–pathogen–cryptococcus–neoformans/> [cited 2008 October 15].

Sorrell, T. C., A. G. Brownlee, P. Ruma, P. Malik, T. J. Pfeiffer, and D. H. Ellis. 1996. Natural Environmental Sources of Cryptococcus neoformans var. gattii. Journal of Clinical Microbiology. 34(5): 1261–1263.

Staib, F., W. Weller, S. Brem, R. Schindlmayer, and E. Schmittdiel. 1985. A Cryptococcus neoformans Strain from the Brain of a Wildlife Fox (Vulpes vulpes) Suspected of Rabies: Mycological Observations and Comments. Zentralblatt Fuer Bakteriologie Mikrobiologie Und Hygiene (Reihe A). 260(4): 566–571.

Stephen, C., L. Lester, W. Black, M. Fyfe, and S. Raverty. 2002. Multispecies Outbreak of Cryptococcosis on Southern Vancouver Island, British Columbia. Canadian Veterinary Journal. 43(10): 792–794.

Tell, L. A., D. K. Nichols, W. P. Flemming, and M. Bush. 1997. Cryptococcosis in Tree Shrews (Tupaia tana and Tupaia minor) and Elephant Shrews (Macroscelides proboscides). Journal of Zoo and Wildlife Medicine. 28(2): 175–181.

Tucker, S. C., and A. Casadevall. 2002. Replication of Cryptococcus neoformans in Macrophages is Accompanied by Phagosomal Permeabilization and Accumulation of Vesicles Containing Polysaccharide in the Cytoplasm. Proceedings of the National Academy of Sciences. 99(5): 3165–3170.

Walter, J. E., and R. W. Atchinson. 1966. Epidemiological and Immunological Studies of Cryptococcus neoformans. Journal of Bacteriology. 92(1): 82–87.

Warren, N. G., and K. C. Hazen. 1999. Candida, Cryptococcus and Morphology of the Fungi. Pp. 1167–1183 in Manual of Clinical Microbiology, 4th edition. (E. J. Baron, M. A. Pfaller, F. C. Tenover, and R. H. Yolken, eds.). American Society for Microbiology: Washington, D.C.

Wright, L., W. Bubb, J. Davidson, R. Santangelo, M. Krockenberger, U. Himmelreich, and T. Sorrell. 2002. Metabolites Released by Cryptococcus neoformans var. neoformans and var. gattii Differentially Affect Human Neutrophil Function. Microbes and Infections. 4(14): 1427–1438




How to Cite

Pokras, M., Miconi, R., Engler, S., Hazel, A., & Haebler, R. (2009). Cryptococcus in a Wild Loon (Gavia immer). Wildlife Rehabilitation Bulletin, 27(1), 18–23.



Case Studies