Influenza conundrum

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Influenza conundrum by Mark Honigsbaum 21 October 2005 09:00

How scary is bird flu? Is it, as Mike , the author of The

Monster at Our Door, puts it, a " viral asteroid on a collision course

with humanity " ? Or are the " it's not if, but when " predictions

overblown?

Recently, the chief medical officer for England and Wales, Sir Liam

son, said the strain of bird flu might not hit Britain this

winter, but it would arrive some time soon.

Having stood in the same ward as a Vietnamese man with bird flu in

February, and having just visited Ceamurlia de Jos, site of the

latest outbreak in Romania, I think Sir son's cautious warning

is justified. H5N1 -- or GenZ as the current superstrain is called --

really is a monster of a virus. Chickens infected with GenZ don't

just die, they melt, leaching blood from every organ.

In people, the pathology is not so extreme. Textbooks say humans

should not be able to catch an avian virus such as GenZ -- at least,

not before it has infected an intermediary animal.

About 100 people worldwide have contracted GenZ since it first

emerged in Hong Kong in 1997, 60 of them have died -- a high

mortality rate.

That is not all. Intensive chicken farming, combined with fast-rising

South-East Asian populations and international jet travel, has

created what one epidemiologist calls a " perfect virological storm''.

What could this mean for you or me? A few weeks ago, Nabarro,

the United Nations's influenza coordinator, came up with a potential

global death toll of 150-million. The World Health Organisation (WHO)

quickly offered a rebuttal, saying a more likely figure was between

two million and 7,4-million. But as the WHO well knows, the only true

predictor is what happened in 1918. Then, as now, an avian virus

suddenly acquired the ability to latch on to and invade human lung

cells.

The difference is that the Spanish flu -- so-called because Spain was

the only country not to censor news of the illness -- was also highly

infectious between humans. Scientists now estimate that the 1918

pandemic may have killed between 40-million and 100-million people

worldwide. If you take into account the current world population, a

direct extrapolation gives you 325-million deaths.

If that's not sufficiently scary, there's more. Epidemiologists

estimate the 1918 virus killed 2,5% of those infected. But we know

that GenZ kills 70% of the people it infects. In other words, the

true worst-case scenario based on 1918 could be a billion deaths

worldwide. believes scientists, and the press, are right to

sound the alarm.

Then again, it may never happen. Flu is one of the deadliest

pathogens in nature's arsenal, but it is also one of the sloppiest.

Like all viruses, every time it replicates it makes mistakes, some of

which may render it less infective. That is the conundrum of GenZ. It

could be a huge threat to the human race or none at all.

Moreover, just as global trade now threatens to bring the virus to

Europe, so better surveillance by the WHO and World Animal Health

Organisation means we know the instant a Romanian or Turkish chicken

falls ill. It may make for lurid reading, but in the case of GenZ,

forewarned is forearmed.

So be afraid, but remember that no one understands GenZ well enough

to say what will happen. And, fingers crossed, it never may. -- ©

Guardian Newspapers 2005

Mark Honigsbaum is the author of The Fever Trail: In Search of the

Cure for Malaria

http://www.mg.co.za/articlePage.aspx?

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