GENEVA, Switzerland, January 26, 2004 (ENS): World Health
Organization officials are concerned that a strain of
avian influenza now spreading across Asia might exchange
genes with a human virus to create a new virus that
could spread easily among people. Over the past month,
millions of chickens in seven countries have either
died or been destroyed because of the highly infectious
bird flu strain, known as H5N1.
While the World Health Organization (WHO) says that
at present it has no evidence that person-to-person
transmission is occurring, seven human cases in Viet
Nam and two in Thailand within the past month coincide
with an historically unprecedented spread of H5N1 bird
flu in the poultry populations of Asian countries.
Since mid-December 2003, outbreaks of H5N1 disease
in poultry have been confirmed in Cambodia, Japan, Laos,
South Korea, Thailand, and Viet Nam. (Editor's Note:
It is now being reported that China has also developed
cases of the disease*).
In addition, Indonesia's agriculture minister confirmed
Sunday that 4.7 million chickens had died of disease
since November. About 40 percent were stricken with
avian flu, while the remaining 60 percent died from
Newcastle disease, which is harmless to humans.
Bird flu also was reported on a farm in Taiwan this
month, but turned out to be a different strain.
Today, Viet Nam and Thailand are the only two countries
in which human cases of H5N1 avian influenza are known
to have occurred in the current outbreak, WHO says.
The Ministry of Public Health in Thailand Friday informed
World Health Organization officials of two cases of
H5N1 avian influenza in humans. Both cases, which are
in two boys, are laboratory confirmed, and one boy has
now died (Editor's note: The second boy
has also been reported dead. Thailand confirmed its
second causality to the bird flu Tuesday*.) More
patients with respiratory symptoms that might indicate
the H5N1 infection are being tested, and results are
expected this week.
Lab tests Friday confirmed two additional human cases
of H5N1 avian influenza in Viet Nam, the first to be
confirmed in the south of the country. The cases, both
in Ho Chi Minh City, are two children, an eight year
old girl and a 13 year old boy. The boy died on January
22, WHO reports. The girl is hospitalized in stable,
but critical condition.
They bring the total number of confirmed H5N1 cases
in Viet Nam to seven, including five in Hanoi. Of the
seven cases in Viet Nam, six people have died since
December 30, 2003.
Laboratories in the WHO Global Influenza Surveillance
Network are characterizing avian and human viruses obtained
from the current outbreaks, and the agency reports that
the genome of the H5N1 bird flu strain has now been
All genes are of avian origin, indicating that the
virus that caused the deaths had not yet acquired human
genes. The acquisition of human genes increases the
likelihood that a virus of bird origin can be transmitted
from one person to another.
Preliminary lab results indicate that these viruses
are different from other H5N1 strains isolated in Asia
in the recent past, so WHO says it will be necessary
to develop a new prototype strain to manufacture a vaccine
capable of fighting the current outbreak.
The virus reservoir is wild birds and there is no method
available to control it, health officials say.
An international team led by WHO scientists is in Viet
Nam working with health authorities to assess the current
situation, conduct epidemiological investigations, and
identify the most appropriate control measures.
In Viet Nam, H5N1 infection in poultry has now been
detected in 23 of the country’s 61 provinces.
Since 23 December 2003, about 2.9 million poultry stock
have either died or been destroyed because of the disease.
In Thailand, the number of birds dead or killed by agricultural
workers and soldiers in 24 provinces has reached 9.1
million. Sunday, China and Burma joined a growing number
of countries which have banned imports of Thai chicken.
In response to claims that the government tried to
cover up the presence of bird flu, Ampon Kitti-ampon,
director of the National Bureau of Agriculture Commodities
and Food Standards, told the "Bangkok Post"
that the virus might have been in Thailand for some
time, but has gone undetected due to "technical
errors'' in ministry sampling and testing processes.
WHO scientists will be collaborating with health authorities
in Thailand in responding to the situation there.
WHO has identified the rapid culling of H5N1 infected
or exposed poultry as the most important line of defense
for preventing further human cases and possibly averting
the emergence of a new influenza virus capable of causing
an influenza pandemic.
A pandemic is a global outbreak of flu and occurs when
a new influenza virus emerges, spreads, and causes disease
worldwide. Once a new pandemic influenza virus emerges
and spreads, it typically becomes established among
people and circulates for years. Past influenza pandemics
have led to high levels of illness, death, social disruption
and economic loss.
In 1918 and 1919, the so-called Spanish flu, strain
H1N1, caused the highest number of known flu deaths.
More than 500,000 people died in the United States,
and 20 million to 50 million people may have died worldwide,
according to the U.S. federal Centers for Disease Control.
The first recorded outbreak of H5N1 infection in humans
occurred in Hong Kong in 1997, when 18 persons developed
serious disease and six died. Investigations of the
Hong Kong outbreak determined that close contact with
live infected poultry was the source of human infection
in all 18 cases.
For this reason, WHO recommends that the practice of
marketing live poultry directly to consumers should
be discouraged in areas now experiencing outbreaks of
H5N1 avian influenza among poultry.
While trade restrictions have been put in place by
some countries to protect animal health, on the basis
of presently available data, WHO does not conclude that
any processed poultry products - whole refrigerated
or frozen carcasses and products derived from them -
and eggs in or arriving from areas currently experiencing
outbreaks of avian influenza H5N1 in poultry flocks
pose a risk to public health.
Influenza viruses are killed by adequate heat, the
international health agency says, emphasizing the importance
of good hygiene practices during handling of poultry
products, including hand washing, prevention of cross-contamination,
and thorough cooking.
At this time WHO has not issued any travel alerts or
advisories for the region in response to the H5N1 outbreak.
But travelers to countries in Asia with documented H5N1
outbreaks are advised to avoid poultry farms, contact
with animals in live food markets and any surfaces that
appear to be contaminated with feces from poultry or
The Centers for Disease Control warns U.S. residents
that in Vietnam and in other tropical regions, influenza
can occur at any time during the year. People at risk
of developing influenza related complications and healthy
people who want to decrease their risk of catching bird
flu should receive the 2003-04 trivalent influenza vaccine.
The vaccine is believed to protect against three viruses
and offers some protection against variants of them
But if an H5N1 epidemic does take off globally, researchers
at St. Jude Children’s Research Hospital say the
United States is not prepared to respond rapidly. This
finding, reported in the November 28, 2003 issue of
the journal "Science," is co-authored by said
Robert G. Webster, Ph.D., a member of the Infectious
Diseases department at St. Jude's.
“If an influenza pandemic started tomorrow, we
would not be able to head it off with vaccines because
the production facilities available to produce them
are grossly inadequate,” said Webster.
In addition to the limited ability to respond to an
outbreak with vaccines, the supply of antiviral drugs
that might slow a pandemic is in “scandalously
short supply,” the St. Jude study states.
“In the face of a pandemic, the available supplies
of antiviral drugs would be used up in days,”
Webster said. “It would take up to 18 months to
make more drugs from scratch. Stockpiling is the only
The St. Jude investigators warn that while vaccine
production technology in the United States is adequate,
needed legislative and infrastructure changes have not
been made. They say intellectual property laws that
limit or slow the incorporation of new knowledge into
vaccine production are part of the problem.
Webster's team says a factor driving the evolution
of flu viruses is the ongoing mixing of human and lower-animal
influenza virus genes inside infected birds and swine
kept in close quarters in markets or farms. The animals
serve as “mixing bowls” in which influenza
viruses swap genes, Webster warns, increasing the chance
that some viruses will obtain the ability to spread
rapidly among infected humans.
Copyright Environment News Service (ENS) 2004. All Rights