ROME, Italy, July 12,
2004 (ENS): New outbreaks of the avian influenza virus
H5N1 in China, Thailand and Vietnam confirm that the virus is still
spreading in the region, the United Nations agency responsible for
food and agriculture said Friday. This viral strain caused the deaths
of more than 100 million chickens and ducks in Asian countries earlier
this year. Some birds died from the flu, but the vast majority were
culled in an attempt to control the virus.
"The new cases do not come as a surprise," said Joseph
Domenech, chief of the UN Food and Agriculture Organization's Animal
China reported a new outbreak of bird flu last Tuesday. It was
China's first report of the H5N1 virus since the government declared
it had stamped out the disease nearly four months ago. Tests at
a farm in the southeastern province of Anhui have confirmed that
chickens died of bird flu, the government said on state-run television.
In Thailand, authorities said they suspect a new outbreak of bird
flu at a farm in the central province of Ayutthaya. Thousands of
chickens at the farm have died.
Bird flu has also been confirmed on farms in Vietnam in recent
days, and about 4,700 chickens have died.
"After the major outbreaks of a few months ago, affected countries
succeeded in bringing the disease under control. But the new outbreaks
clearly demonstrate that the virus continues to circulate in parts
of the region and new cases might flare up in future, posing a continuing
threat to human health," Domenech said.
"In designing their control strategies governments need to
acknowledge that the virus will continue to circulate and that different
flu viruses could also be introduced. Eradication of the avian flu
virus should be considered, at best, as a long-term task,"
The World Health Organization (WHO) said Thursday that these outbreaks
could either be new outbreaks of the highly pathogenic avian influenza
A H5N1 virus, or, a continuation of the outbreaks first reported
earlier this year.
"These events, in addition to two new research reports about
the virus becoming increasingly pathogenic and becoming more widespread
in birds in the region, fuel the World Health Organization's concern
about the threat the virus poses to human health," the agency
Several countries in Asia have documented this virus crossing the
species barrier - moving from infected chickens or ducks directly
into humans - three times since 1997 with severe, and sometimes
fatal, outcomes. "The virus has the potential to acquire the
ability to spread easily from human to human, and, thus, trigger
a global influenza pandemic," WHO said.
The two research resports that worry WHO officials were both published
this month. First, members of China's Ministry of Agriculture, and
colleagues, reported, in a paper published in the "Proceedings
of the National Academy of Sciences," that the virus appears
to be widespread in domestic ducks in southern China. The scientists
found that the virus is causing increasingly severe disease, but
these tests were done in mice and "may not have a direct implication
for humans," WHO said.
Last week, the journal "Nature" published a report which
indicates domestic and wild birds in the region may have contributed
to the increasing spread of the virus, and, suggests that the virus
is gaining a stronger foothold in the region. These observations
suggest that control of the virus may be even more difficult than
thought in the spring.
K.S. Li and 21 others from universities in China, Indonesia, Thailand,
Vietnam and the United States are coauthors of the "Nature"
article. "Our results suggest that H5N1 viruses with pandemic
potential have become endemic in the region and are not easily eradicable,"
they write. "These developments pose a threat to public and
veterinary health in the region, and, potentially, the world, and
suggest that long-term control measures are required."
It is probably unreasonable to expect that the disease can be totally
excluded from the region in the near future, Domenech said. In his
view, managing the risk that the viruses pose to human health and
animal productivity is the challenge. "The presence of highly
pathogenic strains of the virus in wild birds makes control of the
disease particularly complex and difficult," he said.
It is very encouraging that governments have reacted immediately
on recent outbreaks and have officially informed international organizations,
the FAO said. This demonstrates that country surveillance systems
are becoming operative.
But the UN agency warned that surveillance and immediate reaction
to outbreaks need to be strengthened and applied in all countries
of the region. "In some countries the extent of infection is
still not precisely known and further investigation is urgently
needed," Domenech said.
"Countries should apply surveillance and control measures nationwide
and should consider the fight against bird flu as a long-term commitment.
There is no easy solution to the problem," he said.
Currently, there are indications that the virus is still present
at least in Cambodia, China, Indonesia, Thailand and Vietnam providing
the potential for renewed epidemics as poultry production systems
are re-stocked with vulnerable birds.
Pandemic preparedness activities started by WHO in the wake of
the outbreaks reported earlier this year are continuing.
At the end of June, WHO hosted a meeting in Kuala Lumpur, Malaysia
with experts from 13 countries and areas of the Asia-Pacific region.
Participants were provided with a WHO preparedness self-assessment
WHO is collaborating with scientists, and the pharmaceutical community,
on a global surveillance system to monitor changes in the virus's
susceptibility to known antivirals.
And vaccine development continues. Two vaccine manufacturers, both
based in the United States, have produced a supply of trial vaccine
which will be tested for safety and efficacy in humans.
Key elements of a successful control strategy are surveillance
operative in all production systems, strengthened biosecurity of
commercial enterprises and an immediate response to outbreaks including
stamping-out in affected areas, plus disinfection, restriction of
movements of animals and goods, and public awareness campaigns.
Copyright Environment News Service (ENS) 2004. All Rights Reserved.