The organism is highly virulent, experts say

Apr 23, 2010 09:57 GMT  ·  By
Spores from a new strain of Cryptococcus gattii (purple) have killed six people in Oregon since 2005
   Spores from a new strain of Cryptococcus gattii (purple) have killed six people in Oregon since 2005

Six people in Oregon lost their lives after being infected with a new strain of airborne fungus. Experts investigating the new lethal agent say that the organism is highly virulent, and that it appears to be benefiting from the most suitable conditions for survival in the Pacific Northwest. The temperate climate here helps the fungus release its deadly spores, which make their way in people's airways. Once inside the body, they cause symptoms akin to those of pneumonia, as well as severe headaches. About 21 people have been discovered as infected thus far, ScienceNow reports.

The new strain, dubbed VGIIc, belongs to the Cryptococcus gattii fungus. As you may recall, another strain of the same pathogen, dubbed subtype VGIIa, was responsible for 19 deaths in Canada, back in 1999. At the time, 218 people were infected on Vancouver Island, in British Columbia, and researchers say that the new form is very similar to the old one. It's very weird that North American strains of this fungus are so virulent, given that C. gattii also exists in South America, Africa and Australia for many years, where it is commonplace, but much less dangerous.

The new study on the virulence of VGIIc was conducted by Duke University Medical Center geneticist and microbiologist, Joseph Heitman. He reveals that these two particular strains are very concerning to the scientific community on account of the fact that “they infect completely normal individuals.” The expert and his team have been tracking C. gattii since 2001, and it was only last year that the group managed to prove that VGIIc is a distinct strain of the fungus. Details of the investigation were published online yesterday, April 22, in the open-access scientific journal PLoS Pathogens.

The new strain is considered to be hypervirulent, on account of the fact that it killed 100 percent of the mice infected with the spores. Because of this, Heitman and his group are currently working on determining the precise chain of genetic mutations that VGIIa suffered in order to morph into such a virulent version of itself. Special modifications in the pathogens' mitochondria – the structures that produce energy in all living cells – allow for them to reproduce even if they are captured by the macrophage cells of the human immune system.