In the early 2000s, a type of fungus infected hundreds of animals as well as residents in British Columbia and Washington State, USA.
Scientists discovered that this disease also killed porpoises and dolphins in the Salish Sea. The research team concluded that this fungus likely affected the whale population before it impacted humans.
C. gattii likely appeared in the Pacific Northwest in the early 1900s.
The study published in the journal Diseases of Aquatic Organisms explored the impact of human-induced changes on land on aquatic animals, specifically in the case of Cryptococcus gattii.
Led by the University of California, Davis, a group of scientists from Canada and the Pacific Northwest compiled the history of fungal outbreaks in marine mammals. They gathered and analyzed data collected over decades by veterinarians, microbiologists, and marine mammal biologists.
The C. gattii fungus can cause lung and brain infections. This fungus exists in soil and is commonly found in tropical and subtropical forests. C. gattii likely emerged in the Pacific Northwest in the early 1900s. However, the exact emergence of this fungus is still not well understood.
Since 1999, on Vancouver Island, humans, pets, and wildlife have been infected with C. gattii. Subsequently, the fungus gradually affected individuals living on the mainland of British Columbia, Washington, Oregon, and California. Researchers found that 42 porpoises and dolphins in the Salish Sea died from this fungus.
Construction, deforestation, and other land-disturbing activities may cause spores of C. gattii to be released, leading to infections in humans and animals that inhale these spores.
The lead author of the study, Sarah Teman from the Davis School of Veterinary Medicine, University of California, stated: “As the environment changes in unprecedented ways, many diseases can affect both humans and wildlife.”
Marine mammals that died from C. gattii were found in areas near the land. This indicates that fungal spores exist on the sea surface—where porpoises and dolphins inhale them when they surface for air.
Researchers also found evidence suggesting that the first case of C. gattii infection in the Pacific Northwest may have occurred in a dolphin in 1997. This was two years before the first human case of C. gattii infection in the region was identified in 1999.
