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Guardian Weekend – Flu on the Wing

Our car rumbles besides glistening rice paddy and through Vietnamese villages one-house-deep. We pass a duck-filled pond, chicken-soup shacks crammed with diners entangled in bowls of rice noodles, egg sellers, goose-down plumpers and makeshift poultry slaughterhouses snicking and chopping. Improvised electric plucking machines thrum, their stiffened rubber fingers snatching the feathers from broken-necked fowl. Unwanted butchers’ ooze mingles with rainwater and sluices along a communal sewer.

Drums and symbols crash all around us. Tambourines jangle and horns squawk. Small processions of children crowned in red rooster feathers press their faces against the car windows. Tomorrow will be the 15th day of the 8th lunar month, Tet-Trung-Thu, the Mid-Autumn Festival, when farmers celebrate gathering in the harvest with sweet Moon Cakes and fables. This year is especially auspicious as Tet-Trung-Thu falls in the Year of the Rooster, a sign of the zodiac that is resonant in a country founded on poultry.

The chicken is king in Vietnam and in this village, in the northern province of Thai Binh, there is nothing that visibly contradicts the bucolic scene or explains why foreigners might be rooting around in a place where Western faces are rarely seen. The casual visitor, passing through, would never guess that countless villages like this one in the flood plains of the Red River, east of Hanoi, the Vietnamese capital, are on the frontline of a titanic micro-biological war. At least three quarters of all ducks and one quarter of chickens here are now host to a mutable and deadly form of Avian Influenza that Dr David Nabarro, the UN’s newly-appointed co-ordinator for avian and human influenza, warned in September was capable of killing 150 million people in a pandemic that ‘could happen at any time’.

Nabarro was accused of alarmism but his fear is rooted in critical new evidence emerging from the north of Vietnam that has become a breeding ground for the bird flu virus that relishes its traditional farming techniques – fenceless, free-range rearing, communal live markets, and backyard slaughterhouses – that place people close to the flock and expose birds to everthying that flies by.

Since it was first detected here in December 2003, H5N1, to use the scientific shorthand, quickly proliferated, spreading to South Korea (December 2003), emerged in Japan and China (January 2004), infected Thailand (at the end of January 2004), was detected in Indonesia (July 2004), Cambodia (in February 2005) and then landed in North Korea (in March 2005). By the time bird flu researchers were called to Laos last summer the virus was in the Philippines (in July 2005) and spanned the entire of Asia.

Earlier this year it spilled towards Europe, spreading along migratory superhighways after H5N1 infected 184 species of wild birds that nest in the remote lake-land of Qinghai, in northwestern China. Russia and Kazakhstan reported bird flu in late July 2005. Mongolia and Tibet followed suit in early August. That month, following fears that the virus had crossed the Urals, the Dutch and German governments ordered all poultry be brought indoors while ornithologists advised the British government that infected wild birds could land in Norfolk. H5N1 shot up the UK risk assessment table to the highest priority alongside chemical, biological and nuclear terror attacks.

However, for all of these apocalyptic stories, as long as bird flu remains in poultry, in its current form, it represents a threat primarily to those who farm or slaughter fowl. The critical phase that presages a pandemic is when the virus mutates becoming readily transmissible between humans. This is what experts believe happened 87 years ago when a similar strain of bird flu – known by the misnomer Spanish Influenza – engulfed the world with catastrophic consequences. Tissue samples from that period, rediscovered in the Royal London Hospital, by John Oxford, Professor of virology at the London School of Medicine, showed that the 1918 pandemic was probably caused by Avian Influenza that leapt from poultry kept in British army camps on the Western Front in the winter of 1916. Within two years the bird virus had mutated enabling it to pass, as easily as the common cold, between soldiers, killing more than 40 million people.

The current bout of bird flu in northern Vietnam has begun to mutate in a similar fashion and the critical phase of human-to-human transmission of H5N1 may have started. Weekend has learned that this year at least eight human clusters of bird flu have been discovered in northern Vietnam, where a number of the victims are likely to have been infected with the virus by sick siblings, friends or in hospital as they had no contact with diseased poultry. As this new human-friendly strain becomes more efficient it will spread around the world as quickly as the strain now endemic in waterfowl.

The first sign that the virus strain present in northern Vietnam had mutated came when international investigators discovered that it had leapt the species barrier. The majority of viruses are unable to adapt to the cellular structure of species other than the one in which they first evolve. However, bird flu quickly learned to reconfigure its hemagglutinin gene, the H in H5N1, so that it could attach itself to the receptors on the cell walls of many different species.

First it struck down pigs in neighbouring China, an animal whose immune system is closely related to humans (in August 2004). It moved on to tigers and leopards (in October 2004), killing 23 of them in Sriracha Zoo in central Thailand, and then (in June 2005) domesticated cats and rare civets in Vietnam, the mammals that in 2003 spread the human outbreak of Sudden Acute Respiratory Syndrome (SARS), another virus that originated in poultry. ‘Every species leap [by H5N1] represents a new virus mutation, increasing the chance that one of these mutations will become highly infectious to humans,’ Dr Peter Horby, an epidemiologist at the WHO, in Hanoi, told Weekend.

In northern Vietnam H5N1 jumped to humans in January 2004. The virus triggered an explosive cytokine storm within the body as the immune system was induced into attacking human tissue, causing massive haemorrhaging in the lungs. Vietnamese doctors struggled to insert multiple drainage pumps into patients through the trachea such was the flow of blood and mucus into the lungs. Respirators, instead of assisting patients to breath, ruptured their lungs. The chest x-rays of one patient in the grip of this strain of H5N1 make for chilling study – on Day Five the bottom left of her lung is partially fogged; on Day Seven both lungs have filled completely with matter, as the patient drowned in her own body fluids.

Within 18 months 87 people in Vietnam had been infected of whom 38 died excruciating deaths. What worried doctors most was that with each new case, the H5N1 virus advanced, affecting a wider age range, infecting larger clusters of patients, remaining for weeks in one community before re-emerging in another without visible links. Unlike other Asian countries, including Thailand and Hong Kong, where outbreaks of H5N1 among humans were quickly brought under control, in Vietnam the virus lingered and proved quixotic, the symptoms for it ever-changing, making it harder to diagnose and treat. ‘We are at a critical situation in Vietnam,’ said Peter Horby, of the WHO in Hanoi. ‘There are little alarm bells ringing everywhere in Vietnam. The pandemic is inevitable and probably soon.’

However, rather then allow epidemiologists free access to its H5N1 hotspots, the government in Hanoi balked at sharing biological samples with foreign scientists, hoarded critical data and withheld evidence about human-to-human transmission. Hanoi kept the world’s epidemiologists at arms length and instead of issuing warnings went on a propaganda offensive. This autumn it announced that it had launched an £18 million poultry vaccination programme that it claimed would protect all birds from the flu virus. It said it had recruited 10,000 animal health workers to patrol the countryside on the look out for diseased birds. The Vietnamese daily paper Labour reassured readers that no new cases of human infection had been registered. State radio announced that a new treatment regime, using oseltamivir, an anti-viral drug that is currently being stockpiled across Europe and the United States, had enabled doctors to ‘cure’ dozens of Vietnam’s bird flu victims. According to one recent government statement, Vietnam had succeeded in reducing the bird flu death rate in humans from 70 per cent in 2004 to 20 per cent this year. Last month, government scientists in Hanoi also revealed that they were on the verge of going into clinical trials with a radical human vaccine against H5N1. The country was working hard and winning the war without foreign intervention, Hanoi said. The threat of a pandemic had subsided. The countryside settled down to an ordinary life – unaware of the real threat that was rising.

Our car lollops beside the Mid Autumn revellers and scores of chickens crammed into coops ready for market as Vietnamese consumers return to eating poultry after two years of fear. We have a farmer sitting besides us who we picked up, 60 miles back, at Counter A145 of Hanoi’s Hang Da market where he had just sold a cage-full of live birds. He readily agreed to show us his farm and now he motions for us to take a right. The car launches itself over the wall of a dyke and skims across the paddy. We abandon our vehicle in the mud and wade with him into a large pond of reddish water filled with geese and ducks. ‘More than 600 I think,’ the farmer says, throwing his hands up into the air releasing fistfuls of seed.

He pulls a plump duck out of the water, inspecting it carefully and signalling that it is a perfect specimen, unaware that many of these birds are likely to be H5N1 carriers, shedding the virus into the water they paddle in and on the ground they defecate on – silently passing it to humans who share their environment. The highest risk of all is at the moment of slaughter, when fine particles of poultry blood, mucous and faeces are sprayed through the air.

The farmer wades with his trophy over to a platform where a fire is fizzing. We realise that he is going to slaughter the bird to mark our visit. He folds back the duck’s neck. He slits its throat and blood fountains into a bucket. Should we have brought protective gloves, hats and masks? We had worried about being seen to be pessimistic, dressed for death while everyone around us was wearing their everyday shirts and shorts. He sees our concern: ‘Don’t worry,’ he says. ‘Vietnamese birds are now safe. It’s the imported Chinese ones, pumped full of chemicals that carry disease. Vietnam has won the war. Our doctors have beaten bird flu.’

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