Abstract

As with the recently reported epidemic of cryptococcosis in humans and companion animals on Vancouver Island, British Columbia, Canada, over the course of the last 4 years there has been an increased incidence of Cryptococcus neoformans gatti infection in wild Dall's porpoises (Phocoenoides dalli) and harbor porpoises (Phocoena phocoena) stranded along southeast coast of Vancouver island, lower mainland of British Columbia, and more recently Washington state. Since 2000, 7 harbor and 4 Dall's porpoises consisting of 5 females and 6 males have stranded. Based on total body length, there were 9 adult and 2 sub adult animals. Porpoises generally presented in good body condition and the most significant lesions were localized to the respiratory and hemolymphatic systems. Within all 11 animals, nodular to diffuse granulomatous pneumonia and mediastinal lymphadenitis were consistently observed with massive accumulations of yeast. In more severely affected animals, prescapular, retropharyngeal and mesenteric lymph node involvement was also noted. Yeast morphologically consistent with Cryptococcus spp has sporadically been reported in captive bottlenose dolphins (Tursiops truncatus) in the United States with a solitary case involving a wild stranded stripped dolphin (Stenella coeruleoalba) in western Australia. In 2003, C neoformans gatti was identified in a semi captive bottlenose dolphin at a naval research facility in California. Fungal culture of lung and mediastinal lymph nodes consistently isolated Cryptococcus neoformans gatti type B from all 9 of 9 sampled animals. PCR fingerprinting, RFLP and AFLP of human, companion animal, porpoise, and environmental isolates consistently identified genotype VGII. Two exceptions included a 2002 human fatality and 2001 stranded Dall's porpoise, which were typed as VGI. Historically, this fungus has been associated with eucalyptus trees. However, Intensive environmental cultures in British Columbia have identified Douglas fir, alder and cedar trees as environmental sources. The human, companion animal and marine mammal cases are believed to be the first multispecies outbreak of C neoformans gatti.