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Clinicopathologic features of an unusual outbreak of cryptococcosis in dogs, cats, ferrets, and a bird: 38 cases (January to July 2003)

Sally J. Lester DVM, MVSc, DACVP1, Natalie J. Kowalewich DVM, DACVIM2, Karen H. Bartlett PhD3, Mark B. Krockenberger BVSc, PhD4, Theyne M. Fairfax MS5, and Richard Malik BVSc, PhD6
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  • 1 Central Laboratory for Veterinarians, 5645 199th St, Langley, BC V3A 1H9, Canada.
  • | 2 Central Laboratory for Veterinarians, 5645 199th St, Langley, BC V3A 1H9, Canada.
  • | 3 School of Occupational and Environmental Hygiene, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
  • | 4 Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia.
  • | 5 Central Laboratory for Veterinarians, 5645 199th St, Langley, BC V3A 1H9, Canada.
  • | 6 Post Graduate Foundation in Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia.

Abstract

Objective—To determine clinical and pathologic findings associated with an outbreak of cryptococcosis in an unusual geographic location (British Columbia, Canada).

Design—Retrospective study.

Animals—1 pink-fronted cockatoo, 2 ferrets, 20 cats, and 15 dogs.

Procedure—A presumptive diagnosis of cryptococcosis was made on the basis of serologic, histopathologic, or cytologic findings, and a definitive diagnosis was made on the basis of culture or immunohistochemical staining.

Results—No breed or sex predilections were detected in affected dogs or cats. Eleven cats had neurologic signs, 7 had skin lesions, and 5 had respiratory tract signs. None of 17 cats tested serologically for FeLV yielded positive results; 1 of 17 cats yielded positive results for FIV (western blot). Nine of 15 dogs had neurologic signs, 2 had periorbital swellings, and only 3 had respiratory tract signs initially. Microbiologic culture in 15 cases yielded 2 isolates of Cryptococcus neoformans var grubii (serotype A) and 13 isolates of C neoformans var gattii(serotype B); all organisms were susceptible to amphotericin B and ketoconazole. Serologic testing had sensitivity of 92% and specificity of 98%.

Conclusions and Clinical Relevance—Serologic titers were beneficial in identifying infection in animals with nonspecific signs, but routine serum biochemical or hematologic parameters were of little value in diagnosis. Most animals had nonspecific CNS signs and represented a diagnostic challenge. Animals that travel to or live in this region and have nonspecific malaise or unusual neurologic signs should be evaluated for cryptococcosis. (J Am Vet Med Assoc 2004;225:1716–1722)

Abstract

Objective—To determine clinical and pathologic findings associated with an outbreak of cryptococcosis in an unusual geographic location (British Columbia, Canada).

Design—Retrospective study.

Animals—1 pink-fronted cockatoo, 2 ferrets, 20 cats, and 15 dogs.

Procedure—A presumptive diagnosis of cryptococcosis was made on the basis of serologic, histopathologic, or cytologic findings, and a definitive diagnosis was made on the basis of culture or immunohistochemical staining.

Results—No breed or sex predilections were detected in affected dogs or cats. Eleven cats had neurologic signs, 7 had skin lesions, and 5 had respiratory tract signs. None of 17 cats tested serologically for FeLV yielded positive results; 1 of 17 cats yielded positive results for FIV (western blot). Nine of 15 dogs had neurologic signs, 2 had periorbital swellings, and only 3 had respiratory tract signs initially. Microbiologic culture in 15 cases yielded 2 isolates of Cryptococcus neoformans var grubii (serotype A) and 13 isolates of C neoformans var gattii(serotype B); all organisms were susceptible to amphotericin B and ketoconazole. Serologic testing had sensitivity of 92% and specificity of 98%.

Conclusions and Clinical Relevance—Serologic titers were beneficial in identifying infection in animals with nonspecific signs, but routine serum biochemical or hematologic parameters were of little value in diagnosis. Most animals had nonspecific CNS signs and represented a diagnostic challenge. Animals that travel to or live in this region and have nonspecific malaise or unusual neurologic signs should be evaluated for cryptococcosis. (J Am Vet Med Assoc 2004;225:1716–1722)