Here’s one that should keep pessimists and hypochondriacs awake at night for months to come. It seems that a new strain of airborne fungus has emerged in the state of Oregon. It’s deadly, and it’s heading south to California and beyond. The fungus, known as VGIIc of the fungus Cryptococcus gattii — or C. gattii for short — has killed one out of four people known to be infected. If that’s not enough, the fungus not only targets humans, it also affects other mammals including dogs, cats, sheep, alpacas and elk. Other strains have been known to affect porpoises.
Even worse, the fungus does not spread from animal to animal. Instead, the fungus infects trees and releases spores into the air that people and animals inhale. It can take several months for symptoms to appear. These include a cough lasting weeks, sharp chest pain, shortness of breath, fever, nighttime sweats, weight loss, and meningitis symptoms including headache. Symptoms in animals may include a runny nose, breathing problems, nervous system problems, and raised bumps under the skin.
A related fungus, C. neoformans, is common among people with compromised immune systems such as those who received organ transplants and HIV-infected patients. In contrast, C. gattii seems to be much more virulent and indiscriminate. “This novel fungus is worrisome because it appears to be a threat to otherwise healthy people,” said Edmond Byrnes III, a graduate student in the Duke Department of Molecular Genetics and Microbiology. The mortality rate for C. gatti in the U.S. is about 25% out of 21 cases analyzed. Clearly, C. gattii is a very virulent strain,
But hold the panic. Karen Bartlett, an environmental health scientist at the University of British Columbia in Vancouver says that although C. gattii can be dangerous, infections are relatively rare. For example, on Vancouver Island, where the fungus is ubiquitous, most of the population has remained unaffected despite multiple exposures. Scientists don’t yet know what makes a person susceptible to infection.
Researchers at Duke University Medical Center have been tracking the fungus to try to figure out its evolution. If you thought the man-eating plant in Little Shop of Horrors was farfetched, the researcher’s findings may give you pause. They think C. gattii arose from a fungus associated with Eucalyptus trees in the tropics and sub-tropics. The first known outbreak in temperate climates occurred on Vancouver Island, British Columbia, Canada, in 1999 and has now spread to Washington and Oregon. According to Duke researcher Wenjun Li, because the fungus had been confined to tropical areas until recently, it may be that environmental changes are responsible for the evolution and development of these new strains. As to the virulence of these strains, Dr. Byrnes speculates that the fact that this fungus can reproduce sexually may lead to the emergence of new, hyper-virulent combinations of genes. He also says that no matter how it arose, it is likely to stick around “at least for the foreseeable future.”
So what can you do to protect yourself? Not much, at least according to the British Columbia Center for Disease Control. “There are no particular precautions that can be taken to avoid Cryptococcosis [C. gattii], You can, however, be alert for long lasting or severe symptoms and consult a physician (or veterinarian for animals) for early diagnosis and treatment.”
A presentation by epidemiologist Dr. Julie Harris delivered to the U.S Department of Heath this year may ease any concerns you have — if you live in the city. After studying the information about those who succumbed to infection by C. gattii and those who died from it, Dr. Harris says the greatest risk factor was participating in activities that disturb the soil (like construction). This makes sense since the fungus is found in trees, soil, and decaying organic matter, and most of the people affected lived within a mile of wooded areas, farms, or soil disturbance of some kind. So much for getting “back to the garden.” Also, Dr. Harris says that incidence of the disease in animals usually precedes incidence of the disease in humans, making animals a kind of early warning system.
At the moment, C. gattii is stuck in Oregon, but it is on the move. Your best bet is to stay alert for news of C. gattii and to keep your immune system strong. Also, you might want to keep a supply of a good antipathogen formula on hand — not just for C. gattii, but also for MRSA, rogue flus, and a whole range of other pathogens that go bump in the night. In the meantime, Dr. Harris recommends that health departments spread the word to create greater awareness among doctors, veterinarians, and the public.