MSNBC/Associated Press 2/2/04: Asia is traditional cradle of influenza; most flu strains start in China

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Asia is traditional cradle of influenza

But flu can originate anywhere, experts warn

 

The Associated Press

Updated: 1:15 p.m. ET Feb. 02, 2004

 

BANGKOK - For much of the past century, Asia has

been the cradle of influenza, including two of

the three major human flu pandemics.

 

Experts say that given the right conditions,

influenza can emerge anywhere, but they say Asia

has all the ingredients for spawning flu, such as

the outbreak of bird flu now afflicting 10 Asian

countries.

 

All flu viruses probably originate in birds, and

the best environment for making the jump to

humans is one where densely packed people live

closely with birds and animals.

 

" In Asia we have a huge animal population, a huge

bird population and two-thirds of the world's

people living there, " said Klaus Stohr, chief

influenza scientist at the World Health

Organization.

 

Most flu strains start in China

The population of China alone is bigger than that

of the whole of Africa, and 80 percent of the new

human flu strains the last few decades appeared

in China first. With health officers already

leery about a return of SARS, experts are keeping

watch on the bird flu in Asia, where the virus

has killed millions of chickens, and millions

more have been slaughtered in an effort to

prevent its spread. Eight people have died in

Vietnam and two in Thailand.

 

Asia's traditional situation of peasant farmers

keeping ducks, chickens and pigs together with

the family has long created opportunities for

influenza to jump the species barrier.

 

And now industrial-scale commercial chicken

farming is exacerbating the problem, said Robin

Weiss, a professor of virology at University

College in London.

 

" We've had nothing like this gigantic chicken

breeding in the world before, " he said.

 

As Asia has become not only more populous but

also richer and more urbanized, its wealthy

citizens demand a more diversified diet, favoring

more meat, eggs and dairy products. To meet that

demand, agriculture has undergone a fundamental

change, so that even backyard farms have turned

almost industrial, filling every square inch with

chickens.

 

" As soon as you have that many animals in one

spot you are likely to get into trouble with

disease, " said Dr. Samuel Jutzi, director of

animal production and health at the U.N. Food and

Agriculture Organization.

 

Fast growth in poultry, pigs

From the early 1970s to the early 1990s, per

capita consumption of meat, eggs and milk grew

about 50 percent in developing countries, leading

to big increases in animal herds. Over the last

25 years, the fastest growth has been in the

numbers of chickens and pigs, the FAO says.

 

Asians' fondness for shopping at live animal

markets also adds to the chances for flu jumping

species, experts say.

 

And climate may play a role. " Respiratory

viruses, like orchids, do seem to like the Asian

climate, because they have influenza viruses

nearly all year round. It's not so seasonal as it

is in the rest of the world, " said John Oxford, a

flu expert from Queen Mary School of Medicine in

London.

 

Many scientists believe a major bird migratory

pathway from Siberia across Asia could keep the

continent's poultry seeded with the flu virus,

which lives naturally in the gut of waterfowl.

 

Despite Asia's prominent role in spawning flu

outbreaks, experts say strains do crop up in

other parts of the world.

 

Scientists are convinced the 1957 Asian flu and

1968 Hong Kong flu pandemics originated in Asia,

but there is much debate about where the biggest

killer of them all - the 1918-19 Spanish flu

pandemic - came from.

 

Crowded conditions

That flu, which killed an estimated 40 million to

50 million people, was so named because the king

of Spain got it, not because it originated in

Spain.

 

" We've got a huge amount of information which

tells us this virus arose in Europe, not Asia, "

Oxford said. " If it is the case that it started

in Europe, that tells us that these new outbreaks

could happen anywhere in the world where the

circumstances are right. "

 

The Europe theory holds that the Spanish flu

began in the crowded World War I army camps

around Etaples in northern France.

 

There were 100,000 soldiers on any one day there,

and they raised chickens, geese and possibly pigs

for food, Oxford said. Those conditions mimic

what naturally occurs in Asia.

 

A bird flu strain also arose in the Netherlands

last year, albeit of a milder strain. The Dutch

may have averted an epidemic by slaughtering

their entire chicken population within one week.

 

" I don't think anyone should always assume that

these new outbreaks are exclusive to Asia, "

Oxford said.

 

He also warned against judging the seriousness of

the Asia's current outbreak too quickly. While

the World Health Organization said Friday that

testing indicates the strain so far has not been

very successful at jumping to humans, Oxford said

flu strains may take a year before they really

take off.

 

On Sunday, the WHO said two Vietnamese sisters

who died may have caught the disease through

contact with their brother in what would be the

first cases of human-to-human transmission of

confirmed.

 

" We think these outbreaks in these army camps

started in 1917, then it took another year of an

extra few mutations before it really exploded

into the great wide world, " he said. " That's what

could happen in Asia. It could be another year

before it really gets moving. "

 

© 2004 The Associated Press. All rights reserved.

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