Killer fungus from Oregon could spread across the West Coast
ConsumerReports.org 30 April 2010, 2:27 pm
Researchers have identified a highly fatal emerging disease caused by the spores of a fungus known as Cryptococcus gattii, or C. gattii. Because the fungus may spread in lumber, wind, water, and animals— including those as disparate as birds, dogs, farm animals, and even dolphins—researchers expect that the fungus will eventually spread to Northern California, where the climate is similar, but will be stopped from eastward expansion by freezing winters.
The researchers involved in the study began looking at animal deaths caused by the fungus, and noticed they were dealing with a new, more virulent strain closely related to another—and still quite dangerous— C. gattii species found in nearby British Columbia.
“This novel fungus is worrisome because it appears to be a threat to otherwise healthy people,” said co-author Edmond Byrnes III, in a release from PLoS Pathogens, the journal that published the study. “We more often see this fungal disease associated with transplant recipients and HIV-infected patients, but that is not what we are seeing yet.”
The fungus cannot spread from person to person, or from animal to person. A recent paper from the Centers for Disease Control and Prevention reported that people appear mostly likely to become infected near their homes, and that the disease is most prevalent in forested, rural, or semi-urban areas where older trees are common, but it has also been found in urban areas. Mature trees, especially eucalyptus, are thought to provide a breeding ground for the fungus.
While the new strain of the disease has killed one in four people who have been known to come down with it, so far it has affected very few Americans. The researchers analyzed 21 cases and found 5 deaths, though there are almost certainly more cases.
While the study sample is small, an analysis of the pathogen in mice confirmed that the new species of C. gattii was more virulent than the British Columbia strain. Still, no special precautions or travel restrictions have yet been recommended, likely due to the low risk of acquiring C. gattii—even for people living in the endemic areas, according to the Oregon state health authorities.*
Most people who do encounter the fungus never develop symptoms, but those who do usually develop pneumonia—an infection of the lungs—two months to about a year after the initial exposure. The signs of pneumonia include, a cough lasting weeks, sharp chest pains, shortness of breath, headache, fever, nighttime sweats, and weight loss, among others.
Approximately 20 percent of C. gattii cases result in meningitis—an inflammation of the brain and spinal cord. The symptoms of meningitis may also include fever, headache, a stiff neck, nausea, vomiting, sensitivity to light, confusion, sleepiness and seizures, among others.
Both meningitis and pneumonia can be serious, whatever the cause, so see a doctor if you have symptoms for either. If your physician is having trouble treating your condition and you live in the Pacific Northwest or have visited there within the previous year, it may be worthwhile to raise the possibility of a fungal infection. Your doctor may have several screening options and medical treatments, including antifungal drugs.
The researchers said that further study of the disease is necessary to fully understand where it spreads and how to treat it most effectively. Environmental factors are thought to be behind the emergence of the tropical fungus into temperate regions. Whatever the cause, the disease does not seem widespread enough to cause you to alter your travel plans. But know the symptoms, and see a doctor if you develop signs of pneumonia or meningitis.
For more, see the CDC's page on cryptococcus.
—Kevin McCarthy, associate editor