A DisseminatedCryptococcus gattiiVGIIa Infection in a Citron-Crested Cockatoo (Cacatua sulphurea citrinocristata) in Québec, Canada

Abstract

Cryptococcus gattii infection in mammals and birds has been confined historically to tropical and subtropical regions in Australia, Southeast Asia, Africa, and South America. Since the early 2000s, numerous reports describe the emergence of C. gattii on the Pacific Coast of North America. We report on a C. gattii infection in an 8-year-old male citron-crested cockatoo (Cacatua sulphurea citrinocristata) hatched on the Canadian Pacific Coast and raised in the province of Québec, Canada. The bird developed a slow growing ulcerated, fleshy, crusty, and hemorrhagic mass infiltrating the left lower rhamphotheca. Cryptococcus gattii infection was confirmed by cytologic examination of a fine needle aspirate of the mass, and results of fungal culture and sequencing. The genotype of the strain was determined to be VGIIa sequence type 20, the strongly overrepresented subgroup found on the Canadian Pacific coast. Minimum inhibitory concentrations for multiple antifungal drugs were determined. The bird received fluconazole but died acutely 55 days after initial presentation. Postmortem examination revealed a disseminated infection, with involvement of the beak, lungs, spleen, and brain.

Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest

“…Dispersal in the last 100 years would strongly suggest anthropogenic causes, directly or indirectly, rather than movement by natural animal migrations, as suggested with Cryptococcus populations ( 48 ) and other environmental pathogenic fungi ( 32 ). The identification of VGIIa in a pet store bird (sample number B11566) and a separate, unrelated case in pet store worker (sample number B11569), both in Québec, are unexpected occurrences ( 29 ), and it is of interest to note that the bird reportedly originated from British Columbia and the infecting C. gattii strain clearly evolved from the PNW VGIIa population, suggesting a linkage to human transport of animals as the cause. Conversely, the appearance of a PNW-derived strain of VGIIb (sample number B11567) in a Nova Scotia yearling white-tailed deer ( Odocoileus virginianus ) ( 17 ) is less explainable.…”

“…Given the commonality of just under 100 years for the PNW arrival of the VGIIa, -b, and -c subtypes and given their lack of known presence elsewhere on the North American continent (with three notable exceptions: a single Florida VGIIb isolate [ 28 ], the recently discovered Québec cluster of VGIIa [ 16 , 29 ], which seems to have derived from the PNW VGIIa population, and the single VGIIb isolate from a deer in Nova Scotia [ 17 ], likely derived from the PNW VGIIb population), it is logical to hypothesize that these C. gattii subtypes arrived in the PNW region shortly into the 20th century. It is possible that populations arrived elsewhere on the continent and failed to become established; a similar scenario was seen with the concurrent spread of Yersinia pestis by boats from Asia to multiple U.S. ports around the turn of the 20th century that only became enzootic through the ports in California ( 30 ).…”

Clinical Management of Avian Renal Disease

“…75 and Cryptococcus spp. 78 Of note, the dose should be decreased in cases of impaired renal function. 57 Studies have documented dose-and species-dependent variability, suggesting that different dosage regimens of antifungals may be required for different species of birds ( Table 3).…”

“…75 Cryptococcosis Systemic cryptococcosis may also affect companion psittacine birds. 78,96 Partial response to treatment with fluconazole (15 mg/kg by mouth every 12 hours) and terbinafine (15-20 mg/kg by mouth every 12 hours) was described in an African gray parrot (Psittacus erithacus) with renal cryptococcosis. 96…”

“…Data from Refs. 57,69,71,72,75,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95] Succimer (meso 2,3-dimercaptosuccinic acid or DMA) is an oral chelator, derived from British Anti-Lewisite capable of chelating lead from soft tissues, but not from bone. 107 Succimer is less efficient in cases of zinc intoxication.…”