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Bird flu: An ill wind
from the East
By David Isenberg
The US foreign policy
establishment has pinpointed the newest Asian
threat to the world - birds. More specifically, it
is the  probability - some
say the inevitability - of a deadly avian
influenza virus spreading across the world. As the
old cliche goes, it is not a question of if, but
when.
That avian flu is dangerous is no
longer in doubt. Since the virus, known as H5N1 (a
strain of avian influenza A virus), first emerged
in Hong Kong in 1997, it has been responsible for
the deaths of more than 60 people and millions of
chickens, ducks and other poultry and fowl in
Southeast Asia. In fact, more than 100 million
birds in the affected countries either died from
the disease or were killed in order to try to
control the outbreak.
The danger now is
that the virus may mutate to become easily
transmissible among humans and spread in a global
pandemic in poor and rich countries alike.
According to a June 15 World Health
Organization (WHO) report, Vietnam's Ministry of
Health has confirmed a number of human cases of
H5N1 virus infection. And on Thursday, a
73-year-old Vietnamese man died from bird flu,
taking the country's toll to 39, 19 of them since
the virus returned in December, state-run media
reported.
It is thought that a few cases
of person-to-person spread of H5N1 viruses have
occurred. For example, one instance of probable
person-to-person transmission associated with
close contact between an ill child and her mother
is thought to have occurred in Thailand in
September 2004. More recently, possible
person-to-person transmission of H5N1 viruses is
being investigated in several clusters of human
cases in Vietnam.
This week, the WHO
repeated its warning that the H5N1 virus could
mutate into a form which could pass easily between
people and cause a global pandemic. "Because
influenza viruses are inclined to change
frequently, WHO advises Vietnam and the rest of
the world to remain vigilant in its influenza
control efforts," the WHO said in a statement.
"The risk of a pandemic remains, but with
further research and international collaboration,
the possibility of lessening its impact is a goal
that may ultimately be realized," Hans Troedsson,
WHO representative in Vietnam, said in the
statement.
Just last week, China reported
a new outbreak of deadly bird flu. The outbreak,
the third revealed by China in the past two
months, occurred at a farm in northwest China's
Xinjiang region. At least 128 geese and ducks were
infected and 63 of them were by the H5N1 strain of
the virus, according to the United Nation's Food
and Agriculture Organization
And last
Friday, the WHO announced that a team of
international experts was in Vietnam studying
whether the H5N1 bird flu virus may be evolving
into a form that might trigger a human pandemic.
The WHO says that an H5N1 pandemic could
kill up to 7.4 million people globally, because
people lack immunity to it. And half a million
Americans could die and more than 2 million could
end up in the hospital with serious complications
if an even moderately severe strain of a pandemic
flu hit, a report by the Trust for America's
Health says.
In addition to Vietnam,
outbreaks of H5N1 among poultry have been
confirmed in Cambodia, China, Indonesia and
Thailand during 2005, and in Malaysia and Laos
during 2004.
This week, a Japanese farm is
expected to cull most of its 25,000 chickens to
prevent the spread of bird flu, identified as A
H5N2, which has killed about 800 chickens. The
H5N2 strain has not been known to cause any human
illness cases, unlike H5N1. The Japanese
government ordered another 16 nearby farms in
Ibaraki prefecture to suspend transportation of
chickens and eggs. Japan had four outbreaks of
avian flu in 2004, all involving the H5N1 virus.
The H5N2 strain of avian flu has been
responsible for highly pathogenic outbreaks in
Pennsylvania (1983-85), Mexico (1994-95), Italy
(1997), Texas (2004), and South Africa (2004),
according to the WHO report, "Assessing the
Pandemic Threat".
The H5N1 strain is seen
as such a danger that US-based Foreign Affairs
journal, the preeminent status quo journal, has a
special set of four articles on the subject in its
newly published issue.
In the lead article
author Laurie Garrett writes, "The havoc such a
disease could wreak is commonly compared to the
devastation of the 1918-19 Spanish flu, which
killed 50 million people in 18 months. But avian
flu is far more dangerous. It kills 100% of the
domesticated chickens it infects, and among humans
the disease is also lethal: as of May 1, about 109
people were known to have contracted it, and it
killed 54%."
Garrett also wrote that the
H5N1 virus developed in ways unprecedented in
influenza research. It is not only incredibly
deadly, but also very difficult to contain. The
virus apparently now has the ability to survive in
chicken feces and the meat of dead animals,
despite the lack of blood flow and living cells;
raw chicken meat fed to tigers in Thailand zoos
resulted in the deaths of 147 out of a total of
418.
Indonesia this week announced that it
was changing tactics in its fight against the H5N1
virus. Minister for Agriculture Anton Apriyantono
is reported as saying that the country will shift
from its controversial approach of killing only
visibly ill birds and vaccinating others, to
culling all poultry in outbreak zones. Indonesia's
policy change comes soon after the country found
its first human case of H5N1, in a poultry worker
who was not sick but carried antibodies of the
virus.
Among other morbidly fascinating
facts one of the Foreign Affairs articles notes
that in early 2004 the virus became supervirulent
and capable of killing a broad range of species,
including rodents and humans. That permutation of
the virus was dubbed "Z+". In the first three
weeks of January 2004, Z+ killed 11 million
chickens in Vietnam and Thailand.
The
economic impact of a pandemic would be staggering.
In another Foreign Affairs article author Michael
Osterholm notes that its arrival would trigger a
reaction that would change the world overnight.
A vaccine would not be available for a
number of months after the pandemic started, and
there are very limited stockpiles of antiviral
drugs. Plus, only a few privileged areas of the
world have access to vaccine-production
facilities. Foreign trade and travel would be
reduced or even ended in an attempt to stop the
virus from entering new countries - even though
such efforts would probably fail given the
infectiousness of influenza and the volume of
illegal crossings that occur at most borders.
It is likely that transportation would
also be significantly curtailed domestically, as
smaller communities sought to keep the disease
out. The world relies on the speedy distribution
of products such as food and replacement parts for
equipment. Global, regional and national economies
would come to an abrupt halt - something that has
never happened due to HIV, malaria or TB, despite
their dramatic impact on the developing world.
Is the world prepared? Not
really
First, the H5N1 flu strain
and several of its cousins are ones to which
humans have no immunity. This is because the H5N1
virus does not usually infect humans; thus there
is little or no immune protection against them in
the human population.
Second, as Nature journal
pointed out in May, extinguishing avian flu in
poultry and pigs, the population from which a
pandemic strain would probably emerge, is the job
of national agriculture and veterinary
departments, the United Nations' Food and
Agriculture Organization, and the World
Organization for Animal Health. The public-health
aspects are the responsibility of health
departments and the WHO. This international
coalition is shaky and far from united or sure in
its purpose. Its efforts are grossly underfunded,
and undermined at every turn by conflicts between
global public health, sovereignty and the stakes
of trade and economics.
Third, if the next pandemic
were to arise in the near term, say the next two
years, there would be no vaccine and few drugs to
treat the virus. Currently, a vaccine against a
pandemic flu would not be ready until at least six
months after a pandemic starts. Too late: by then
the worst of the pandemic would already have
happened.
Fourth, although a
pandemic would be global, defense plans are so far
strictly national. So far, due to prodding by the
WHO, about 50 countries have drawn up preparedness
plans. Most are still very sketchy, but include
strategies for stockpiling antiviral drugs. Only a
handful of nations, including Britain and Canada -
but notably not the United States - have given
their plans legal status. Distressingly, the list
of relatively well-prepared nations includes few
of those countries in Asia where a pandemic strain
is most likely to emerge.
Finally, it is
also notable that the H5N1 virus has continued to
evolve. In late 2002 it acquired the ability to
kill its natural host, wild waterfowl, and spread
across 10 countries in Southeast Asia. The virus
has also found ways to vastly increase the range
of species it can infect and kill. Its host range
now includes tigers and domestic cats. The concern
is now whether it will acquire consistent
human-to-human transmission.
Most strains
of influenza are not lethal in lab mice, but Z+ is
lethal in 100% of them. It even kills the very
types of wild migratory birds that normally host
influenza strains harmlessly. Yet domestic ducks,
for unknown reasons, carry the virus without a
problem, which may explain where Z+ hides between
outbreaks among chickens.
Influenza
reproduces messily: its genes easily fall apart,
and it can absorb different genetic material and
get mixed up in a process called reassortment.
When influenza successfully infects a new species
- say, pigs, as happened with the emergence of the
Nipah virus in Malaysia in 1999 - it can reassort,
and may switch from being an avian virus to a
mammalian one. When that occurs, a human epidemic
can result.
The WHO highlights the need
for the world to take action well before "there is
unmistakable evidence that the virus has become
sufficiently transmissible among people to allow a
pandemic to develop".
David
Isenberg, a senior analyst with the
Washington-based British American Security
Information Council (BASIC), has a wide background
in arms control and national security issues. The
views expressed are his own.
(Copyright 2005 Asia Times Online Ltd. All
rights reserved. Please contact us for information
on sales, syndication and republishing.) |
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