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Evaluation of risk factors for Cryptococcus gattii infection in dogs and cats

Colleen G. Duncan DVM, MSc1, Craig Stephen DVM, PhD2, and John Campbell DVM, DVSc3
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  • 1 Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
  • | 2 Center for Coastal Health, Nanaimo, BC V9R 5S5, Canada.
  • | 3 Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.

Abstract

Objective—To determine risk factors associated with Cryptococcus gattii infection in dogs and cats residing on Vancouver Island in British Columbia, Canada.

Design—Matched case-control study.

Animals—20 dogs and 29 cats with C gattii infection and matched controls.

Procedure—Dogs and cats with a confirmed or probable diagnosis of cryptococcosis resulting from infection with C gattii were enrolled by veterinarians, and owners completed a questionnaire designed to obtain information pertaining to potential risk factors for the disease. Owners of matched control animals were also interviewed. Odds ratios and 95% confidence intervals or paired t tests were calculated to determine significant associations.

Results—Animals were enrolled during 2 noncontiguous periods in August 2001 to February 2002 (8 dogs and 9 cats enrolled) and May to December 2003 (12 dogs and 20 cats enrolled). Risk factors significantly associated with development of cryptococcosis included residing within 10 km of a logging site or other area of commercial soil disturbance, above-average level of activity of the animal, travelling of the animal on Vancouver Island, hunting by the animal, and owners hiking or visiting a botanic garden.

Conclusions and Clinical Relevance—Results indicated that dogs and cats that were active or that lived near a site of commercial environmental disturbance had a significantly increased risk of developing C gattii infection. Veterinarians should communicate these risks to owners in context because cryptococcosis was an uncommon disease in this population.

Contributor Notes

Dr. Duncan.

Supported by the Companion Animal Health Fund, Western College of Veterinary Medicine.