Fungal meningitis spreads in Pacific Northwest

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Fungal meningitis spreads in Pacific Northwest

Science News*

By Seppa

Web edition : Monday, October 27th, 2008

http://www.sciencenews.org/view/generic/id/38123/title/Fungal_meningi

tis_spreads_in_Pacific_Northwest

Rare infection slowly making its way down Washington-Oregon coast

WASHINGTON — A fungus that causes meningitis has sickened 19 people,

four of whom died, in Oregon and Washington over the past four

years, researchers report at a meeting of microbiologists and

infectious disease experts.

The new findings indicate that the culprit, a yeast-like fungus

called Cryptococcus gattii, is spreading gradually down the West

Coast. Before 1999, the fungus was rarely encountered in North

America. But that year a case cropped up on Vancouver Island in

British Columbia, Canada. Since then, more than 200 people in

British Columbia have been diagnosed with illness stemming from the

fungus.

C. gattii naturally lives in foliage, particularly eucalyptus and

rubber trees. Once airborne and inhaled, the fungus can infect

people and animals. It doesn't spread from person to person or

between people and animals.

A related fungus called Cryptococcus neoformans causes lethal

infections in immune-comprised people, such as those with HIV. While

none of the 19 patients in Oregon and Washington had HIV, 11 were

immune-comprised by other ailments or medications, says West,

an infectious disease physician at the Oregon Health Science

University in Portland. She reported the findings at a joint meeting

of the Infectious Diseases Society of America and the American

Society for Microbiology.

Like C. neoformans, C. gattii can be dangerous. Apart from the four

deaths, 13 of the 19 patients required hospitalization longer than

11 days, West says. Ten of the patients had lung infections, five

had meningitis and four had both, she says. Doctors treated the

patients with antifungal drugs.

The Centers for Disease Control and Prevention in Atlanta is now

monitoring these two states, as well as Montana, Alaska, Idaho and

California, for C. gattii infections.

C. gattii normally shows up in subtropical parts of Australia, New

Guinea, India and South America. Scientists speculate that the

fungus made its way to North America from one of those regions,

resulting in the Vancouver Island outbreak. West says some evidence

suggests the fungus might have found a home in fir trees.

, a physician at the University of Texas Health

Sciences Center at San , says the key to controlling C.

gattii will be to raise the level of suspicion surrounding the

fungus. In North America, he says, " I think people just don't look

for it " as a possible explanation for troubling symptoms.

C. gattii can cause a prolonged cough, headache, fever, chest pain

and other nondescript symptoms. Of the 19 Washington and Oregon

patients, 12 went more than a week before being properly diagnosed.

C. gattii causes disease in people only sporadically. Most of those

who come into contact with either form of cryptococcus don't become

ill, says Farrar, an Oxford University physician based in Ho

Chi Minh City, Vietnam. An HIV infection and other forms of immune

suppression clearly place people at risk. But other people who get

lung infections or meningitis from either form of cryptococcus might

just be unlucky, he says.

" My guess is that in some very tiny way, these people have some

defect in their immune system that makes them susceptible to

crypto, " he says. That flaw is likely to be hardwired into a

person's innate immunity and not in the immune cells and proteins

that make antibodies in response to specific pathogens, he says.

Since no such specific immune flaw has been identified, predicting

who might be naturally susceptible remains a puzzle, he says.

How the fungus moves from place to place is equally mysterious, and

existing antifungal drugs are sometimes inefficient in stopping an

infection, says . He has developed a mouse model of the

disease and is testing drugs against C. gattii in the animals.

" I think we may have seen only the tip of the iceberg with C. gattii-

caused infections in the United States, " he says