posted on Jul, 23 2014 @ 05:06 PM
Viruses, toxic chemicals, and bacteria get all of the disease glory, but after posting
concerning White Nose Syndrome in bats, I was stunned to learn
nature's little fungi are the true menace and deserve much more attention than they seem to be getting.
So is this really a growing problem?
A Rise in Fungal Diseases is Taking Growing Toll
“Fungi have driven more animal species extinct than any other class of pathogens by quite a long way,” says Matthew Fisher, an
epidemiologist at Imperial College in London. Fisher and his colleagues calculate that fungi have caused more than 80 percent of known
disease-driven animal extinctions. (Viruses, by comparison, are responsible for only 1 percent.) The vast majority of these fungi-driven
extinctions have happened in the past 20 years. The first proven victim, Fisher says, was a captive population of Polynesian tree snails, wiped out by
fungal disease in a London zoo in the 1990s.
This lethal pattern is partly explained by the independence and flexibility of fungal species: Unlike viruses, they don’t usually depend on their
hosts for survival, and unlike both viruses and bacteria, which tend to be more specialized, they can quickly switch to new hosts.
The article, which is nearly three years old, cites some pretty big examples:
Batrachochytrium dendrobatidis, which attacks the outer skin layers of amphibians, disrupting their water and electrolyte intake so severely
that infected animals can die of cardiac arrest. The fungus, known familiarly as Bd, has been found in more than 500 species of amphibians in 54
countries to date, most recently in Asia. Some areas of Central America have lost more than 40 percent of their amphibian species to Bd
Karen Lips, a University of Maryland herpetologist who has watched Bd march through Central American amphibian populations for almost 20 years, says
no amphibian is safe: “We live in a Bd world now,” she says.
The article continues:
Bd is just one of several modern-day eruptions of fungal disease. White-nose syndrome, first observed in North American bats in New York State
in early 2007, is thought to be caused by the fungus Geomyces destructans, and the disease is estimated to have killed well over a million
cave-dwelling bats and has now spread to 19 states and four Canadian provinces. Biologists describe the epidemic as the most dramatic decline of North
American wildlife in living memory.
Of course, the numbers have gotten far worse for bats in the past two and half years, jumping to nearly 7 million dead bats and infections at the end
of the 2013-2014 hibernating season confirmed in 25 states and five Canadian provinces.
The article cites other examples:
Fungal disease also appears to play a key role in colony-collapse disorder, the recent and sudden dieoff of North American bees: Scientists
posit that the bees are weakened and killed by multiple factors, including a one-two punch from a virus and a fungal parasite. In the Caribbean, a
fungus called Aspergillus sydowii has contributed to the precipitous decline of coral reefs, sweeping through populations of sea fans weakened
by rising ocean temperatures.
And in the Pacific Northwest and British Columbia over the past decade, a new and virulent strain of the fungus Cryptococcus gattii, which attacks the
lungs and nervous system, has killed more than 30 people, and infected dogs as well.
Many researchers have noticed the number and severity of these emerging fungal diseases. “I think there’s absolutely no question
that there’s been a huge increase in fungal infections,” says Joseph Heitman, a microbiologist at Duke University Medical Center who
studies Cryptococcus gattii.
Well, that's a bit discomforting. But why haven't we seen more articles aggregating examples and supporting the notion of an increase in fungal
So looking further, this is what I could find in a brief afternoon of searching...
In 2012, this article appeared:
Emerging fungal threats to animal, plant and ecosystem health
The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes. In
both animals and plants, an unprecedented number of fungal and fungal-like diseases have recently caused some of the most severe die-offs and
extinctions ever witnessed in wild species, and are jeopardizing food security.
The following article was published two days ago:
Fungus likely to take a hit on banana crops worldwide
If a banana is part of your daily breakfast fare, you may want to brace yourself for this news: A fungus is making its way across the globe,
destroying banana crops and threatening to deplete the world's supply of the popular fruit.
"It's expected to devastate banana plantations all through South America. It would take two, three or four years for it to get all
across Latin America, and it could make bananas a very expensive, exotic, holiday treat instead of an everyday shelf item,"
And another from earlier this year:
An Unprecedented Plague Has Hit
Citrus greening disease has been a steadily growing problem that has reached epidemic levels this year. Because of this disease, the
U.S. Department of Agriculture is projecting that orange production in the U.S. this year will be down 18 percent compared to last year.... the worst
in nearly 30 years
edit on 23-7-2014 by loam because: (no reason given)