A fungus making its way down the western US from Canada may not pose a serious threat to horses, according to researchers familiar with the situation. A report from Duke University Medical Center on Cryptococcus gattii and its movement from Canada into Washington, Oregon, and Idaho made headlines recently as a "potentially lethal fungus," but not only is it rare, horses do not often appear to be affected.

Edmond J. Byrnes III, a microbiologist at Duke University, is the lead author of a report on C. gattii movement that appeared in the online journal PLoS Pathogens. The fungus has killed people in the US, often because its emergence in the US is new and physicians haven't known to look for it. The spores are inhaled and take root in the lungs before spreading through the body.

"This fungus has been considered a tropical fungus, but emerged to cause an outbreak in the temperate climes of Vancouver Island in 1999 that is now causing disease in humans and animals in the United States," said the researchers in the report.

However, Byrnes noted that the fungus "is still very rare