Beginning in 1999 on Vancouver Island, humans, domestic animals and terrestrial wildlife became infected with Cryptococcus gattii, progressively affecting individuals living on mainland British Columbia, Washington, Oregon and California. The researchers found that 42 dolphins and porpoises in the Salish Sea also died from the fungal pathogen, including harbor porpoises, Dall’s porpoises and Pacific white-side dolphins. The marine mammals that died from C. gattii were found near terrestrial hot spots, suggesting that the spores settled on the surface of the sea, where the porpoises and dolphins inhaled them when they surfaced to breathe.

Researchers also found evidence that the first probable case of C. gattii in the Pacific Northwest could have occurred in a Dall’s porpoise in 1997 — two years before the identification of the first human case in the region in 1999. “Often we study marine mammals because they play important roles in the ecosystem, and they are cool,” said Joe Gaydos, UC Davis wildlife veterinarian at the SeaDoc Society and co-investigator. “Too often we forget that they can also alert us to diseases that affect humans.”.