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article imageDeadly fungus causes fears for US as it travels south from BC

By Stephanie Dearing     Apr 24, 2010 in Health
Vancouver - With a scientific name that holds little meaning for the general public, Cryptococcus gattii is a relatively new fungal pathogen in North America that is completely capable of killing those it infects.
The name doesn't sound particularly horrifying, but the insidious fungus is causing alarm because not only is it not understood how people and animals get infected; the organism has adapted quite well to temperate areas of North America's west coast. But worse than that, the organism is spreading south from Vancouver Island to Washington and Oregon. California might soon be home to the fungus. But as if that was not enough, the most frightening aspect of the fungus is its proclivity to take up residence in otherwise healthy hosts, causing severe illness and even death. Those who contract the fungus can show symptoms as soon as two weeks after exposure and up to one year later.
An international team of researchers has recently released a study of the organism, demonstrating through genetic analysis that cases of illness caused by Cryptococcus glattii in Oregon came from Vancouver, British Columbia.
Once considered to be a tropical fungus only, Cyrptococcus glattii has readily adapted to life in temperate areas of the North American west coast. The fungus is causing consternation and even fear on the west coast because it "... causes life-threatening disease in otherwise healthy hosts and to a lesser extent in immunocompromised hosts." In fact, the researchers found that the fungus caused mortality in 25% of the cases attributed to the fungus. In 2007, this meant there was an average of one death a year attributed to the fungus.
Dr. Edmond J. Brynes, who led the research team, and his colleagues wrote in their recently published report, Emergence and Pathogenicity of Highly Virulent Cryptococcus gattii Genotypes in the Northwest United States "The appearance of C. gattii in North America is alarming because this is the first major emergence in a temperate climate, indicating a possible expansion in the endemic ecology of this pathogen."
The team of eleven researchers, from the United States, United Kingdom and Australia said the new strain of Cryptococcus gattii is "highly virulent." They warn "...further expansion into neighboring regions is likely to occur ..."
The team used sequence barcoding to track the fungus, and found that cases of illness in Washington and Oregon were caused by the fungus found on Vancouver Island. That fungus has spread and the scientists noted "... The continued expansion of C. gattii in the United States is ongoing, and the diversity of hosts increasing. Cases have been observed in urban and rural areas, and have occurred in a range of mammals." As noted, the fungus does not discriminate, and has been found in humans, dogs, porpoises, sheep and other mammals.
The first anyone knew of the fungus in North America was an outbreak that arose in Vancouver, 1999. The cause of the outbreak was not identified until some years later, however. Since identification, the fungus has been found living on tree surfaces and in the soil on Vancouver Island.
Symptoms of infection can be vague, consisting of a "prolonged cough (lasting weeks or months); sharp chest pain; unexplained shortness of breath; severe headache; fever; night sweats; and weight loss." People with these symptoms should consult their doctor, because infection with the fungus can result in death. There is a test which can determine if the fungus is causing the illness.
While the researchers are certain the North Amercian version of the fungus is genetically different from the species found in tropical regions of the world, they are not sure where the North American fungus originated. Scientists are interested in determining the origin of the fungus, but they emphasize "... the major concern is and continues to be the inexorable expansion throughout the region. From 1999 through 2003, the cases were largely restricted to Vancouver Island. Between 2003 and 2006, the outbreak expanded into neighboring mainland British Columbia and then into Washington and Oregon from 2005 to 2009. Based on this historical trajectory of expansion, the outbreak may continue to expand into the neighboring region of Northern California, and possibly further."
Treatment can save lives, if the fungus is detected in time. Anyone can become infected with the fungus, and the researchers noted that travellers to the West Coast have picked up the organism.
More about Deadly fungus, Pathogen, Cryptococcus gattii, North carolina duke university, Doctor edmond brynes
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