And the ancient Hebrew teachings of "pork is unclean" holds more truth
than people care to admit to and much more than "industry" will ever tell.
And much of this read tells the sad story of what not to do in an
agricultural and a settlement venue. The scavenging scourge of the
European is truly setting the stage for an "Armageddon". Whereas the
Cherokee model of farming and settlement (form of government) as often
spoken of by you, Ray, for our education would have maintained a
stability and cleanliness, based upon respect and understanding, within
our environment for our continued, healthy survival.
D.
On 15/07/2012 5:41 PM, Ray Harrell wrote:
*REH*
**
**
*THE ECOLOGY OF DISEASE*
*By **Jim Robbins*
<http://topics.nytimes.com/top/reference/timestopics/people/r/jim_robbins/index.html>**
July 14, 2012 NYTimes
**
THERE'S a term biologists and economists use these days --- ecosystem
services --- which refers to the many ways nature supports the human
endeavor. Forests filter the water we drink, for example, and birds
and bees pollinate crops, both of which have substantial economic as
well as biological value.
If we fail to understand and take care of the natural world, it can
cause a breakdown of these systems and come back to haunt us in ways
we know little about. A critical example is a developing model of
infectious disease that shows that most epidemics --- AIDS, Ebola,
West Nile, SARS, Lyme disease and hundreds more that have occurred
over the last several decades --- don't just happen. They are a result
of things people do to nature.
Disease, it turns out, is largely an environmental issue. Sixty
percent of emerging infectious diseases that affect humans are
zoonotic --- they originate in animals. And more than two-thirds of
those originate in wildlife.
Teams of veterinarians and conservation biologists are in the midst of
a global effort with medical doctors and epidemiologists to understand
the "ecology of disease." It is part of a project called Predict,
which is financed by the United States Agency for International
Development. Experts are trying to figure out, based on how people
alter the landscape --- with a new farm or road, for example --- where
the next diseases are likely to spill over into humans and how to spot
them when they do emerge, before they can spread. They are gathering
blood, saliva and other samples from high-risk wildlife species to
create a library of viruses so that if one does infect humans, it can
be more quickly identified. And they are studying ways of managing
forests, wildlife and livestock to prevent diseases from leaving the
woods and becoming the next pandemic.
It isn't only a public health issue, but an economic one. The World
Bank
<http://topics.nytimes.com/top/reference/timestopics/organizations/w/world_bank/index.html?inline=nyt-org> has
estimated that a severe influenza pandemic, for example, could cost
the world economy $3 trillion.
The problem is exacerbated by how livestock are kept in poor
countries, which can magnify diseases borne by wild animals. A study
released earlier this month
<http://www.ilri.org/ilrinews/index.php/archives/tag/dfid> by the
International Livestock Research Institute found that more than two
million people a year are killed by diseases that spread to humans
from wild and domestic animals.
The Nipah virus in South Asia, and the closely related Hendra virus in
Australia, both in the genus of henipah viruses, are the most urgent
examples of how disrupting an ecosystem can cause disease. The viruses
originated with flying foxes, Pteropus vampyrus, also known as fruit
bats. They are messy eaters, no small matter in this scenario. They
often hang upside down, looking like Dracula wrapped tightly in their
membranous wings, and eat fruit by masticating the pulp and then
spitting out the juices and seeds.
The bats have evolved with henipah over millions of years, and because
of this co-evolution, they experience little more from it than the
fruit bat equivalent of a cold. But once the virus breaks out of the
bats and into species that haven't evolved with it, a horror show can
occur, as one did in 1999 in rural Malaysia. It is likely that a bat
dropped a piece of chewed fruit into a piggery in a forest. The pigs
became infected with the virus, and amplified it, and it jumped to
humans. It was startling in its lethality. Out of 276 people infected
in Malaysia, 106 died, and many others suffered permanent and
crippling neurological disorders. There is no cure or vaccine. Since
then there have been 12 smaller outbreaks in South Asia.
In Australia, where four people and dozens of horses have died of
Hendra, the scenario was different: suburbanization lured infected
bats that were once forest-dwellers into backyards and pastures. If a
henipah virus evolves to be transmitted readily through casual
contact, the concern is that it could leave the jungle and spread
throughout Asia or the world. "Nipah is spilling over, and we are
observing these small clusters of cases --- and it's a matter of time
that the right strain will come along and efficiently spread among
people," says Jonathan Epstein
<http://www.ecohealthalliance.org/about/experts/10-epstein>, a
veterinarian with EcoHealth Alliance, a New York-based organization
that studies the ecological causes of disease.
That's why experts say it's critical to understand underlying causes.
"Any emerging disease in the last 30 or 40 years has come about as a
result of encroachment into wild lands and changes in demography,"
says Peter Daszak, a disease ecologist and the president of EcoHealth.
Emerging infectious diseases are either new types of pathogens or old
ones that have mutated to become novel, as the flu does every year.
AIDS, for example, crossed into humans from chimpanzees
<http://www.nytimes.com/2011/10/18/health/18aids.html?_r=1&pagewanted=all> in
the 1920s when bush-meat hunters in Africa killed and butchered them.
Diseases have always come out of the woods and wildlife and found
their way into human populations --- the plague and malaria are two
examples. But emerging diseases have quadrupled in the last
half-century, experts say, largely because of increasing human
encroachment into habitat, especially in disease "hot spots" around
the globe, mostly in tropical regions. And with modern air travel and
a robust market in wildlife trafficking, the potential for a serious
outbreak in large population centers is enormous.
The key to forecasting and preventing the next pandemic, experts say,
is understanding what they call the "protective effects" of nature
intact. In the Amazon, for example, one study showed an increase in
deforestation by some 4 percent increased the incidence of malaria by
nearly 50 percent, because mosquitoes, which transmit the disease,
thrive in the right mix of sunlight and water in recently deforested
areas. Developing the forest in the wrong way can be like opening
Pandora's box. These are the kinds of connections the new teams are
unraveling.
Public health experts have begun to factor ecology into their models.
Australia, for example, has just announced a multimillion-dollar
effort to understand the ecology of the Hendra virus and bats.
IT'S not just the invasion of intact tropical landscapes that can
cause disease. The West Nile virus came to the United States from
Africa but spread here because one of its favored hosts is the
American robin, which thrives in a world of lawns and agricultural
fields. And mosquitoes, which spread the disease, find robins
especially appealing. "The virus has had an important impact on human
health in the United States because it took advantage of species that
do well around people," says Marm Kilpatrick, a biologist at the
University of California, Santa Cruz. The pivotal role of the robin in
West Nile <http://news.ucsc.edu/2011/10/west-nile-virus.html> has
earned it the title "super spreader."
And Lyme disease, the East Coast scourge, is very much a product of
human changes to the environment: the reduction and fragmentation of
large contiguous forests. Development chased off predators --- wolves,
foxes, owls and hawks. That has resulted in a fivefold increase in
white-footed mice, which are great "reservoirs" for the Lyme bacteria,
probably because they have poor immune systems. And they are terrible
groomers. When possums or gray squirrels groom, they remove 90 percent
of the larval ticks that spread the disease, while mice kill just
half. "So mice are producing huge numbers of infected nymphs," says
the Lyme disease researcher Richard Ostfeld.
"When we do things in an ecosystem that erode biodiversity --- we chop
forests into bits or replace habitat with agricultural fields --- we
tend to get rid of species that serve a protective role," Dr. Ostfeld
told me. "There are a few species that are reservoirs and a lot of
species that are not. The ones we encourage are the ones that play
reservoir roles."
Dr. Ostfeld has seen two emerging diseases --- babesiosis and
anaplasmosis --- that affect humans in the ticks he studies, and he
has raised the alarm about the possibility of their spread.
The best way to prevent the next outbreak in humans, specialists say,
is with what they call the One Health Initiative
<http://www.onehealthinitiative.com/> --- a worldwide program,
involving more than 600 scientists and other professionals, that
advances the idea that human, animal and ecological health are
inextricably linked and need to be studied and managed holistically.
"It's not about keeping pristine forest pristine and free of people,"
says Simon Anthony, a molecular virologist at EcoHealth. "It's
learning how to do things sustainably. If you can get a handle on what
it is that drives the emergence of a disease, then you can learn to
modify environments sustainably."
The scope of the problem is huge and complex. Just an estimated 1
percent of wildlife viruses are known. Another major factor is the
immunology of wildlife, a science in its infancy. Raina K. Plowright,
a biologist at Pennsylvania State University who studies the ecology
of disease, found that outbreaks of the Hendra virus in flying foxes
in rural areas were rare but were much higher in urban and suburban
animals. She hypothesizes that urbanized bats are sedentary and miss
the frequent exposure to the virus they used to get in the wild, which
kept the infection at low levels. That means more bats --- whether
from poor nutrition, loss of habitat or other factors --- become
infected and shed more of the virus into backyards.
THE fate of the next pandemic may be riding on the work of Predict.
EcoHealth and its partners --- the University of California at Davis,
the Wildlife Conservation Society, the Smithsonian Institution and
Global Viral Forecasting --- are looking at wildlife-borne viruses
across the tropics, building a virus library. Most of the work focuses
on primates, rats and bats, which are most likely to carry diseases
that affect people.
Most critically, Predict researchers are watching the interface where
deadly viruses are known to exist and where people are breaking open
the forest, as they are along the new highway from the Atlantic to the
Pacific across the Andes in Brazil and Peru. "By mapping encroachment
into the forest you can predict where the next disease could emerge,"
Dr. Daszak, EcoHealth's president, says. "So we're going to the edge
of villages, we're going to places where mines have just opened up,
areas where new roads are being built. We are going to talk to people
who live within these zones and saying, 'what you are doing is
potentially a risk.' "
It might mean talking to people about how they butcher and eat bush
meat or to those who are building a feed lot in bat habitat. In
Bangladesh, where Nipah broke out several times, the disease was
traced to bats that were raiding containers that collected date palm
sap, which people drank. The disease source was eliminated by placing
bamboo screens (which cost 8 cents each) over the collectors.
EcoHealth also scans luggage and packages at airports, looking for
imported wildlife likely to be carrying deadly viruses. And they have
a program called PetWatch <http://www.petwatch.net/about/> to warn
consumers about exotic pets that are pulled out of the forest in
disease hot spots and shipped to market.
All in all, the knowledge gained in the last couple of years about
emerging diseases should allow us to sleep a little easier, says Dr.
Epstein, the EcoHealth veterinarian. "For the first time," he said,
"there is a coordinated effort in 20 countries to develop an early
warning system for emerging zoonotic outbreaks."
/Jim Robbins is a frequent contributor to the Science section of The
New York Times./
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