UBC Reports | Vol. 48 | No. 12 | Oct.
UBC Research Unlocking the Key to Mystery Killer Fungus
No one knows yet how it got here
By Hilary Thomson
How did a potentially lethal fungus spread by koala bears
end up on Vancouver Island? Thats the mystery that UBC
researcher Karen Bartlett is trying to unravel.
Bartlett, an assistant professor in the School of Occupational
and Environmental Hygiene, has been traveling since March
to Vancouver Island tracking down Cryptococcus neoformans
var. gattii. It is a microscopic yeast typically found in
eucalyptus and other tropical and sub-tropical trees. It started
showing up on the Island in 1999 -- the first time ever the
tropical fungus has been found in a temperate climate.
When fungal spores are inhaled, they can produce a rare infection
called cryptococcosis. Affecting the lungs and nervous system,
symptoms include prolonged cough and weight loss and the infection
can sometimes lead to potentially fatal meningitis or swelling
of the brain.
About 59 cases, including two fatalities, have been diagnosed
on the Island since 1999 -- an incidence higher than anywhere
else in the world. More than 35 cases in pets and wildlife
have been diagnosed since 2000.
Although health risks associated with the fungus are low,
physicians were educated about the disease that is complicated
by patients in northern climates having no antibodies to fight
This is a fascinating puzzle for a researcher,
says Bartlett, who is an expert on fungi and building materials.
Its exciting to be so directly involved in finding
out how this disease is spread and to be working in a natural
lab out in the forest.
The mystery started in late 1999 when Island veterinarians
identified an unusual airborne infection in llamas, ferrets
and other animals. Samples were sent to the B.C. Centre for
Disease Control (BCCDC) in Vancouver. UBC, BCCDC and the Vancouver
Island Health Authority have been working together to deal
with the problem.
Reports of illness originated on the east side of the Island
and Bartlett has tested trees from Parksville and Rathtrevor
Beach to Victoria. She is examining samples of tree pulp taken
from holes created by birds and insects and also testing bark
and the air around the trees.
Eucalyptus did not show evidence of the organism but some
Douglas Fir, arbutus, Garry Oak, big-leaf maple, cedar, alder
and bitter cherry have tested positive for the fungus. While
the yeast has actually colonized in some of the trees, nearby
trees may also have tested positive simply due to wind-blown
spores landing there. Bartlett has tested trees in North Vancouver
and the Sunshine Coast, all of which have been negative.
She suspects birds may carry fungal spores from tree to tree.
She has also found that the yeast survives well in salt water,
which suggests other methods of transmission.
Future investigations will look at the range of the fungal
spores; determine if the fungus is always present or seasonal;
and gauge exposure risks for people working with infected
trees, lumber or wood products.
Were going to see more unusual infectious diseases
because of climate change, increased mobility and other factors,
says Bartlett, who is the recipient of a 2003 Scholar Award
from the Michael Smith Foundation for Health Research. We
need to take the environment seriously, allocate resources
and make changes to keep the next generation safe.
For more information check the B.C. Centre for Disease Control
Web Site at www.bccdc.org.