A strain of toxic fungus has begun to spread from Vancouver BC into Oregon and other areas of the Northwest. The Cryptococcus gattii fungus can cause serious respiratory illness and death.
Over the past several years a toxic fungus in the woods of the Pacific Northwest drifting into peoples' lungs, causing illness and death. Cryptococcus gattii has affected a handful of people in Oregon, most recently a Junction City woman hospitalized for more than four months this fall.
In the Northwest it was first detected on Vancouver island in 1999, where it has sickened about 180 residents and killed eight, yet the disease is still considered rare. The fungus was associated with tropical and subtropical climates, but it has apparently mutated and has begun to thrive in the wet climate of the Pacific Northwest.
The fungus is spreading rapidly in Oregon and is expected to reach Washington, Idaho and California very soon. Some reports state that nearly a quarter of people which were infected with this fungus have died. The tropical fungus was previously only infecting those whose immune systems was weak or they were already sick but now its getting stronger and is also infecting healthy individuals. C. gattii has also infected animals, including dogs, cats and dolphins swimming as far south as San Diego.
The fungus may have arrived on an imported plant or bird or it may have been there for a long time, unnoticed until changes in climate or land-use patterns allowed it to grow in high enough concentrations to become airborne.
Once the fungus is established in soil or in trees, it can float in the air in dry weather and cause an infection in the lungs, or more seriously, in the central nervous system, causing fungal meningitis.
Until 2004, the only human cases in Canada were found among people who lived on or had traveled to Vancouver Island. In 2004, when the first case was found in someone who had never been to the island, researchers began looking elsewhere and found other cases including two in Oregon. One, an 87-year-old Portland man, died from fungal meningitis in December 2005. Scientists in Oregon took 197 samples of air, soil, water, trees and other structures but found nothing.
Initial symptoms resemble flu and a general malaise. Only after symptoms continue for several weeks or worsen with a cough that doesn't go away, unexplained weight loss and night sweats do physicians realize they're dealing with something else.
Illness occurs six to nine months after exposure. Once diagnosed, it is very treatable unless it gets to the central nervous system, as happened to the Junction City woman.
This woman was treated for bacterial meningitis, but wasn't getting better. It wasn't until lab tests came back that doctors in Eugene figured out she had fungal meningitis.
The symptoms include chest pain, a persistent cough, shortness of breath, fever, and weight loss. The vast majority of people exposed to the fungus never develop symptoms. Doctors suspect most people have some form of natural protection, but it remains unclear why others are susceptible. In animals, symptoms can vary by species but generally include a runny nose, lumps under the skin, and infections of the lungs and central nervous system.
Because in many cases exact dates were unavailable, the incubation periods are estimates only. Rounding errors may have over- or underestimated the true incubation period by as much as 1 month.
The incidence of C. gattii infection among the people of Vancouver Island from 1999 to 2003 was between 8.5 and 37 cases per million residents per year. This incidence is significantly greater than that of C. gattii infection typically observed in Australia which is less than 1 case per million residents per year, where C. gattii is endemic. A public advisory was issued by the British Columbia Centre for Disease Control on June 6, 2002 (www.bccdc.org) advising the public, medical practitioners, and veterinarians of the potential health risk and telling them to be alert for symptoms and to seek early diagnosis. Because the majority of patients were in good health, cryptococcal infection was listed as a disease that must be reported to the BC health department.
Cryptococcal infection was diagnosed in 35 animals during 2000 and 2001, including 13 dogs, 17 cats, 2 ferrets, and 3 wild Dall's porpoises.
Thirty-five of the 38 (92.1%) human cases and 28 terrestrial animals of the 35 (80.0%) animal cases resided on the east coast of Vancouver Island, designated the Coastal Douglas Fir biogeoclimatic zone (CDF). The remaining three human cases and four terrestrial animal cases resided on the BC mainland but had visited Vancouver Island within a year before diagnosis. The corpses of three porpoises were found on the shores of some Gulf Islands in the Strait of Georgia, located between Vancouver Island and the BC mainland. The geographical distribution of the human and animal cases is illustrated below.
Cryptococcosis can be treated effectively with antifungal medication. A more serious infection, such as meningitis, usually requires treatment in hospital. Diagnosing the disease early is important to curing it. There is no known vaccine to prevent cryptococcosis.