Mere
months after the successful containment of severe acute
respiratory syndrome (SARS), the last thing the
Vietnamese government wanted was another dramatic
public-health crisis. Unfortunately, as the world now
knows, another crisis is exactly what it got.
Vietnam's struggle with H5N1
influenza, better known as bird flu, is now reaching its
climax. It should become clear in the next few weeks
whether H5N1 can be contained or will break out and
become the next great flu pandemic, as many health
authorities fear. Of course, Vietnam is only one
battlefront in the war against H5N1. But more patients
have died in Vietnam so far than in any other affected
country, and the difficulties faced by the Vietnamese
government in containing the epidemic well illustrate
the difficulties faced by other governments in the
region.
Life without chicken The
avian-flu epidemic has taken at least 15 human lives in
Vietnam and devastated the vital poultry industry.
However, not all its effects have been tragic.
To the casual visitor, the most noticeable
result is undoubtedly the eerie absence of chicken and
egg dishes from restaurant menus. KFC, which has nine
restaurants in Vietnam, was forced to close its stores
for two weeks; when they reopened on January 31, the
menus featured, bizarrely, fish and spaghetti (however,
the chain has no plans to rename itself "Kentucky Fried
Fish"). Bakeries, lacking eggs, have scrambled to import
egg flour from overseas, or simply stopped baking items
requiring eggs.
The lack of chicken is also a
serious problem for bodybuilders, who depend on white
chicken as a low-fat, low-cholesterol source of protein.
Gold-medal-winning bodybuilder Ly Duc complained to the
Vietnam News Service that "chicken is an indispensable
food for us ... if body builders lack chicken for a long
time, their muscles are adversely affected".
But
some businesses have actually benefited from the
epidemic. Prices of beef, pork and seafood soared as
consumers searched for alternatives to chicken. The
food-trading firm Vissan even sought to import 10,000
cows from Australia to meet spiraling demand for beef.
Pork consumption in Ho Chi Minh City has nearly doubled.
Supermarkets in the city saw increased business as
buyers fearful of sanitary conditions in the traditional
markets stayed away.
H5N1 has also posed a
challenge to Vietnam's zoos and circuses. The Ho Chi
Minh City Zoo, which has 178 birds of 43 types,
including extremely rare species such as the crested
argus, quarantined its birds over fears that any
infection would force a cull of the entire collection.
While the zoo's birds are safe so far, the famous
performing ducks of the Ho Chi Minh City Tourist Park
circus troupe were not so lucky. The 150 ducks, whose
act included pulling monkeys on a cart, descending a
slide into a pond, and assisting in a magic show, had to
be put down. (The circus planned to replace them with a
group of racing pigs.)
What is bird
flu? Influenza is caused by the influenza virus,
a member of the Orthomyxoviridiae family of RNA
(ribonuclein acid) viruses. Influenza virus strains are
divided into three main genera, known as influenza virus
A, B and C. Of these, influenza virus A is of primary
concern to epidemiologists because most human flu
infections are caused by type A, and it displays an
ability to infect a variety of species: it has been
reported in pigs, horses, seals, whales, and especially
birds.
In fact, scientists now believe that the
ultimate source of all influenza A infections in other
species is a population of viruses resident in aquatic
birds, such as ducks, geese, terns and gulls. The main
evidence for this is that, while only a small number of
strains of influenza A can be found in humans and swine
at any one time, every sub-type can be isolated from
aquatic birds. Furthermore, these birds are usually
asymptomatic; ie, they do not become sick because of
their infection, which shows a high level of adaptation
between the virus and the birds.
Along with
genetic evidence, this fact strongly suggests that
waterfowl are the virus's natural host. The term "bird
flu" is therefore somewhat ironic, since if one looked
back far enough into the past, all flu viruses infecting
other species may have come from birds. Equally
inappropriate is the popular association of bird flu
with chickens. In reality, the reason chickens are so
vulnerable to avian flu is precisely because they are
not its natural host: if they were, the virus would not
make them so sick.
Influenza A viruses are
further classified into various sub-types based on two
proteins on the surface of the virus particle,
hemagglutinin (H) and neuraminidase (N). H5N1, for
example, expresses hemagglutinin Type 5 and
neuraminidase Type 1. Since there are 15 known types of
H and nine types of N, and they can occur in any
combination, there are potentially 9 x 15 = 135 distinct
types of influenza A that could exist.
But the
vast majority of human flu cases at any one time tend to
be caused by only a few of these; at the moment, H1N1
and H3N2 are the most common. In 2001, H1N2 began to
circulate widely, probably due to a recombination event
in which the same individual was infected with both H1N1
and H3N2, and the two strains exchanged genetic material
to create a new type.
It is precisely such an
event that could lead to the much-feared scenario of a
global bird-flu pandemic. H5N1, the strain causing the
current crisis, is deadly to domestic fowl, but only
infects humans with difficulty - as shown by the very
small number of human cases in Asia so far. However, if
H5N1 infected a person already carrying a strain common
in humans, such as H3N2, it could pick up genes from the
human version that would allow it to spread rapidly from
person to person. And since the human population has
little or no immunity to avian strains such as H5N1, a
global pandemic would be a real possibility once the new
virus gained traction in the human population.
The word "pandemic" has been used carelessly by
many writers who seem to believe it means "an unusually
widespread and deadly epidemic". While pandemics are
indeed widespread by definition, and can be very costly
to human life, the word actually has a quite narrow and
specific meaning. According to the World Health
Organization (WHO), a "pandemic" is a global epidemic
caused by "antigenic shift" - in other words, the
appearance in the human population of a strain
containing a new combination of H and N, or an H or N
not found to infect humans previously. This is distinct
from the normal seasonal flu epidemics, which are caused
by minor genetic changes in flu strains that have
circulated before. Thus, even if a new flu strain spread
throughout the world and killed hundreds of thousands of
people, it would not qualify as a pandemic unless it
introduced a new combination of H and N to the human
population.
A true pandemic can have a
frighteningly high death toll. At least 31 have occurred
since 1580, and the notorious epidemic of 1918-20 - now
believed to have been caused by an H1N1 strain from
swine - may have killed as many as 40 million people
worldwide. The 1918 strain was particularly feared
because it struck down healthy adults, sometimes within
days of infection.
Does the current epidemic
have pandemic potential? The answer is probably yes, but
fortunately, all the preconditions for a pandemic do not
seem to be in place. The most important such
precondition is the formation of a viral strain capable
of efficient human-to-human transmission. Scientists
have not found any evidence that such a strain exists in
the current epidemic.
The number of confirmed
cases in Vietnam is now about 20, but all 20 seem to
have been infected from poultry. Two sisters in Thai
Binh province, who died in late January, caused great
concern because authorities feared that they had become
infected while caring for their brother, who died on
January 14, five days after getting married.
Unfortunately, the man was cremated before he could be
tested for H5N1. But it is now believed that the sisters
became infected while preparing a chicken for the
wedding dinner. Genetic tests performed in Hong Kong
proved that the viral strain that killed the sisters was
classical, avian H5N1, and not a hybrid containing genes
from human-adapted strains. Although this did not prove
conclusively that the sisters were infected directly by
the animal and not by their brother, the former is much
more likely.
Regrettably, while H5N1's ability
to infect humans may not be very high, its lethality
after doing so is formidable. As of mid-February, 14 of
Vietnam's 18 confirmed cases had died. But Vietnamese
physicians believe their understanding of how to treat
H5N1 has improved. Dr Tran Tinh Hien, deputy director of
the Tropical Diseases Hospital in Ho Chi Minh City, said
that patients who had been admitted to hospital within
48 hours of showing bird-flu symptoms appeared to be
recovering faster. Of the three fatal cases at this
hospital, all had waited six or seven days before
seeking medical assistance. It was not clear, however,
how many of the patients in Ho Chi Minh City actually
had H5N1, since the symptoms of H5N1 infection are very
similar to that of other flu types, and definitive tests
to identify the viral strain are time-consuming and
expensive to perform.
The most potent long-term
weapon for containing H5N1 is vaccination, and the
effectiveness of vaccination against influenza viruses
is well established. But many obstacles are combining to
prevent vaccination from becoming a short-term solution
to the bird-flu crisis. For example, flu vaccines are
normally produced with chick embryos, since the chicken
cells are suitable for growing the virus. But this
cannot be done with H5N1 because the virus is too lethal
to the cells. This technical obstacle can be overcome
with molecular methods; indeed, at least two labs, one
in the United Kingdom and one in the US state of
Tennessee, have already developed prototype vaccines
using a plasmid technology.
Unfortunately, the
patents for the technologies used are owned by various
companies, and these issues must be straightened out
before production can begin. One of the firms involved,
Medimmune of Gaithersburg, Maryland, has already
promised to waive its intellectual property rights in
the event of a pandemic. But as long as the pandemic
does not materialize, vaccine production will continue
to be held up by rights issues.
Because the
development of a flu virus capable of causing a pandemic
would require an individual, or animal, to be infected
with a human-type flu strain and H5N1 at the same time,
the quick-and-dirty way to avert a pandemic may be
simply to immunize people against human-type flu strains
in H5N1-affected countries. Such people could still get
H5N1, but would be much less likely to develop a second
infection simultaneously, and thus could not become an
incubator for a pandemic-causing virus. Unfortunately,
the global production capacity for flu vaccines is
limited, and at the moment, that capacity is already
committed to customers outside of H5N1-affected
countries. For example, Solvay (Belgium) and
pharmaceutical giant GlaxoSmithKline, both major vaccine
producers, told New Scientist that they would not have
any production capacity to spare for countries such as
Vietnam.
Another complication is that, because
flu viruses evolve from year to year, and different
strains become common at different times, vaccine
producers must make calculated guesses regarding which
strains will become common in order to produce an
effective vaccine. These guesses are sometimes
incorrect, and as it turned out, Solvay guessed wrong
this year when it supplied the WHO with a vaccine that
is ineffective against the "Fujian" strain that has been
most common during the current flu season.
Humans are not the only species that can act as
a mixing bowl for creating new flu viruses. Pigs also
get flu, and one great concern for health authorities is
the possibility that a pig simultaneously infected with
H5N1 and a typical human strain could be the source of a
pandemic-causing virus. Many contradictory reports have
appeared regarding the infection of pigs in Vietnam. On
February 6, the Associated Press reported that a Food
and Agriculture Organization (FAO) representative in
Vietnam had found two pigs near Hanoi that tested
positive for H5N1 by nasal swab. But the same story
quoted Vietnamese officials as saying that samples from
179 pigs in two northern Vietnamese provinces tested in
Hong Kong all came back negative for the virus. Later in
the week, an FAO official in Rome told Reuters that the
nasal-swab tests were experimental, and played down the
significance of the positive results. In the third week
of February, another cross-species scare occurred when
Thai authorities found H5N1 infection in cats, including
several house cats that had eaten infected chickens from
a nearby farm, and at least one leopard at a zoo near
Bangkok. Vietnam began testing cats after the Thai cases
were reported.
The possibility of
pandemic-capable flu viruses being created in pigs, or
in cats, is just a small example of a much larger
problem, namely, the threat posed by interspecific
transmission of pathogens. The bird-flu crisis raises
major questions about whether Asian societies can afford
to risk the continuation of traditional animal
husbandry, especially the practice of keeping different
animal species in close proximity. In many parts of
Asia, especially southern China, chickens and ducks are
raised at very high density in wire enclosures with the
two species next to each other, and pigs or other
animals nearby. Many farmers allow their ducks to swim
in streams or ponds, from which the ducks are exposed to
a constant barrage of new viral strains originating with
wildfowl that use the same body of water. The risks are
obvious and terrifying, even to a non-expert: infected
ducks can infect nearby chickens, which can then infect
pigs and humans. And every infection of a non-avian
rolls the dice for the creation of a new
pandemic-causing supervirus.
A final mystery for
scientists investigating the Vietnamese epidemic was why
the human cases have been clustered in northern Vietnam,
while in the south, mostly chickens have been affected.
Regional differences in weather - the north is colder
during the dry season, and cold, dry air is thought to
facilitate the spread of airborne viruses - are
considered a possible explanation. But experts are
concerned about another possibility: that human cases in
the south may have been under-diagnosed.
The
government response The Vietnamese regime
received great praise in the global press for its open,
appropriate and vigorous response to the SARS crisis,
faring well mostly by comparison with the inept denials
and cover-ups that characterized China's initial
measures. Officially, the story is the same this time
around; Hanoi has generally cooperated well with
international health organizations, and the state media
are full of Sovietesque feel-good stories with such
titles as "Young volunteers rally to help poultry
farmers" and "Dedicated team treats sufferers of bird
flu".
However, there have been strong signs that
the government's image may not escape damage in this
crisis. Serious allegations have been made about the
timeliness of Hanoi's response to H5N1. A recent Time
story (January 26) reported that signs of avian flu were
found in northern Vietnam as early as last July, in Vinh
Phuc province just northwest of Hanoi. Blood samples
from the dead chickens were sent to the Ministry of
Agriculture and Rural Development (MARD), which was
apparently unable to identify the cause. A MARD
veterinarian confirmed this, and speculated that the
government did not want to announce the mysterious
epidemic in the run-up to the 22nd Southeast Asia Games,
held last December. Anton Rychener, the FAO
representative in Vietnam, also said that reports of a
poultry epidemic had been received in the summer.
The Vietnamese Ministry of Foreign Affairs has
denied this version of events. However, judging by the
subsequent extent of affected areas (57 of the country's
64 provinces have reported cases), it is hard to believe
that the virus did not begin spreading long before
January, when the crisis broke. And it is also
questionable whether MARD officials were acting
appropriately when they claimed as late as January 7
that "there has been no sign the disease will affect
human health" - by that time, 12 patients were already
in hospital with unusual symptoms.
Contrary to
conventional wisdom, therefore, it appears that Vietnam
fumbled its initial response to avian flu just as badly
as Thailand and Indonesia, which have received a great
deal more international criticism.
The Hanoi
bureaucracy, however, is characteristically as decisive
in dire emergencies as it is passive and obstructionist
under normal circumstances. Once the seriousness of the
epidemic became apparent, the government went into
wartime-crisis mode and the situation rapidly began to
improve. General Secretary Nong Duc Manh (best known
outside Vietnam for allegedly being Ho Chi Minh's
illegitimate son) released a statement in the official
media describing the control of bird flu "as an
emergency and key task of the [Communist] Party, the
government and the people". And Prime Minister Pham Van
Khai, on a visit to hard-hit Nam Dinh province early in
the epidemic, warned officials hyperbolically that if a
pandemic happens "it will be the most terrible
catastrophe that Vietnam has ever had".
The main
features of Vietnam's response to the epidemic, in a
public-policy sense, were contained in a MARD document
released last month. Most of the document consists of
guidelines for the protection of breeding stock and
hygienic distribution of chicken feed, which suggests,
curiously, that the government may have been concerned
that the epidemic had spread through contaminated feed.
The most significant section, however, pertained to
measures for containing the outbreak and listed the
following four recommendations:
Prevent the spread of bird flu by promptly culling
all sick birds in affected areas and strengthening the
surveillance of bird shipments.
Workers culling birds should protect themselves with
masks, gloves and other biological-safety gear to
prevent infections.
The protection of birds in parks from the epidemic
must be strictly observed.
Affected areas should be disinfected to protect the
environment from pollution.
Considering that
more than 250 million chickens were being raised in
nearly every corner of the country at the time of the
outbreak, achieving the first goal was a monumental
task. To achieve it, the government mobilized health
officials, student groups, farmers' cooperatives, and
even the army. Originally, the policy called for
slaughtering all birds within three kilometers of an
affected area. But this draconian approach was reversed
in early February in favor of sacrificing only sick
birds, as it became clear that the
three-kilometer-radius policy would have devastating
economic effects. Unfortunately, the reversal also
increased the risk of a recurrence of the disease; the
government in effect gambled that it could get by with a
more relaxed policy. Hanoi also balked at sacrificing
ornamental birds and rare poultry breeds, such as the
locally famous Ho chickens of Bac Ninh province, which
weigh as much as 10 kilograms. One hopes that this
program of half-measures will prove successful, but
then, in the Hong Kong outbreak of 1997, the government
had to sacrifice every chicken, duck and goose in the
territory to win its war with H5N1.
The amount
of compensation to poultry farmers for lost fowl was a
critical factor in determining the effectiveness of the
cull. Compensation at below-market rates, for obvious
reasons, tempts farmers to conceal their birds or sell
them illegally, and coercive measures cannot catch every
individual who might attempt such actions. So it is a
cause for concern that the government, for whatever
reason, clearly did not pay market rates to farmers.
Compensation rates were usually set around
VND15,000 (about US$1) per bird, although the rate
varied from region to region. However, even less was
promised in some cases, and the rates were apparently
always well under the market price of $2. Usually,
farmers were prepared to accept the compensation and
cooperate with the cull in spite of this. But they were
also told that actual payments would not be made until
the end of the epidemic, so they have typically received
nothing to date. Consequently, many poultry farmers and
dealers are facing not a mere financial setback, but
instant pauperization, if not starvation. The situation
has been exacerbated because local officials in many
provinces lent farmers money to build up poultry farms,
in pursuit of economic-development targets. The media
have cited many cases of farmers who owe the state more
than $10,000 - a staggering sum in a country where the
per capita gross domestic product (GDP) is well under
$1,000 a year. If the effort to contain H5N1 fails, it
is likely that insufficient compensation to farmers will
be a major reason. Still, in at least some cases,
officials displayed a more astute understanding of human
nature. For example, in Soc Trang province, the
provincial veterinary service proposed reducing the
level of compensation severely if farmers with sick
birds delayed reporting the problem to local authorities
by even a few hours.
The second MARD guideline
stipulated the protection of workers with bio-safety
gear, but it is now clear that the protection was often
inadequate. Even the state-controlled media have
acknowledged this; a February 9 Vietnam News story
described how Dao Thi Hoa, a Ha Tay province
veterinarian, had no choice but to wear the same set of
disposable coveralls over and over. For many poultry
farmers, protective equipment was a distant dream; the
same Vietnam News story described how farmer Nguyen Dinh
Thao, who lost his entire flock to H5N1, was protected
by nothing more than boots and a cloth mask as he
disposed of germ-laden chickens. In Le Minh Xuan
Commune, in Ho Chi Minh City's Binh Chanh district,
students, farmers and veterinarians culled birds with no
protective equipment whatsoever.
As laudable as
the patriotic zeal of these volunteers may be, one would
like to ask why more protective equipment was not in
place ahead of time - especially given that SARS also
originated with animals. Still, considering that cullers
in some provinces were paid as little as $1 a day, the
underlying cause of the lack of equipment seems clear:
the government could not afford it. Much of the
equipment that was available apparently came from
international donors, who have assisted Vietnam
generously. Both individual countries, including Japan,
China, Germany, the United States and New Zealand, and
international organizations such as WHO, FAO and the
Asia Development Bank have made significant donations of
equipment and supplies, or provided advisory assistance.
Although the fourth guideline regarding
disinfection was justified, it arguably should have been
accompanied by a recommendation to separate chickens and
ducks from other animals in the future. Another obvious
omission from the MARD guidelines was a recommendation
to prevent contact between domestic fowl and wild
waterfowl, which are believed to be the ultimate source
of bird-flu epidemics.
In addition to mass culls
at the farm level, extreme efforts have been made to
prevent the transport or sale of poultry. Transport of
chickens has been banned in southern provinces since
mid-January; the ban was extended to the entire country
in early February. Roadblocks were set up outside Ho Chi
Minh City and Hanoi to enforce the no-transport policy.
In Ho Chi Minh City, authorities checked households for
live birds (many homes had kept a small number of
chickens, especially in outlying districts). Officials
also patrolled markets throughout the country to prevent
illicit poultry sales.
Finally, spreading
information about the epidemic required another massive
effort. In addition to heavy coverage in the state print
and television media, the government set up a bird-flu
hotline with four separate numbers, and distributed
leaflets to residents in Ho Chi Minh City and elsewhere
giving information about bird-flu control measures.
Also, an archive of bird-flu-related information,
including official documents, has been maintained on the
Vietnam News Service's website.
Conclusion As February drew to a
close, the Vietnamese government was officially
optimistic about achieving its goal of quelling the
epidemic by this month. There were, indeed, some reasons
for optimism: new outbreaks appear to have waned, with
13 of the affected provinces reporting no new cases for
15 days. The government has said it will consider areas
free of H5N1 if no new cases are reported for 25 days.
Preliminary measures have already been taken to
reapprove the slaughter and transport of poultry early
this month.
This decision, however, may be
premature; elsewhere in Asia, bird flu has proved to be
a resilient foe. Both Japan and Thailand had been on the
verge of declaring the outbreak contained in late
February when new cases suddenly emerged. In both cases,
valuable fowl protected by their owners from the cullers
may have been to blame: fighting cocks in Thailand, and
bantams kept as pets in the Japanese case. Vietnamese
government officials, including the prime minister, have
urged health authorities to maintain vigilance; but this
may not be an easy task with legions of desperate
poultry farmers eager to return to business as usual.
For its part, the WHO warned governments in late
February not to relax their surveillance and detection
efforts, and noted that experience had shown that it was
difficult to eradicate the virus from bird populations,
and previous efforts to control the contagion had taken
years. Scientists are also concerned that infected
migratory birds now in Southeast Asia could spread the
infection to northern Asia as they begin flying north
over the next few weeks.
Clearly, the H5N1
crisis is not yet over.
John Parker
(BS, MS) is a freelance writer based in Vietnam.
Vietnam's struggle with H5N1
influenza, better known as bird flu, is now reaching its
climax. It should become clear in the next few weeks
whether H5N1 can be contained or will break out and
become the next great flu pandemic, as many health
authorities fear. Of course, Vietnam is only one
battlefront in the war against H5N1. But more patients
have died in Vietnam so far than in any other affected
country, and the difficulties faced by the Vietnamese
government in containing the epidemic well illustrate
the difficulties faced by other governments in the
region. 
