Checkpoints have been set up to track suspected vehicles. Poultry markets have singled out high-risk cases. Migratory birds have been put under the microscope.

The whole nation appears geared to fight a war against avian influenza, which has already attacked humans elsewhere in the world.

The logic and motive behind the efforts is simple: bringing the bird flu epidemic under control will create a decisive defence against the fatal virus from being transmitted to humans, and escalating into a pandemic.

At a press conference in Beijing on Friday, China's health and agricultural authorities pledged to keep the country's epidemic situation at the lowest level and redouble efforts to stop it from affecting humans.

While the officials were speaking to the press, veterinary workers in Chengdu, capital of Southwest China's Sichuan Province, were examing all poultry imports from contaminated foreign countries.

Quarantine authorities in Shanghai have already closed more than 800 unqualified poultry farms, while agricultural and health inspectors made impromptu checks at livestock markets in Beijing.

Stressing China has not detected a single human case of bird flu, Chen Xianyi, director of the contingency office under the Ministry of Health, said the country's priority is to ensure no one becomes infected.

In case human infection of bird flu occurs, China will decide whether or not to close its borders in line with World Health Organization regulations and international practice, he said.

He confirmed the death of a 12-year-old girl on October 18 in Hunan Province where a bird flu outbreak occurred was caused by severe pneumonia. Her younger brother, who has been hospitalized for pneumonia, is recovering. Neither was infected with the H5N1 virus.

Chen said that so far the people who had close contact with the girl and her brother have showed no abnormal symptoms. A search of additional suspected cases is being carried out on a larger scale as well.

Chen said his ministry has been working well with other departments, including the Ministry of Agriculture, to contain bird flu virus. "It is unrealistic to completely curb highly pathogenic avian influenza from happening in China. It is bound to occur in some provinces," said Jia Youling, director of Veterinary Bureau under the Ministry of Agriculture.

"But China is well able to contain and eradicate an epidemic immediately after its outbreak."

The difficulties come from the fowl themselves: migrating birds traverse large swathes of Chinese territory, threatening to taint domestic birds during their journey, according to Jia, also China's chief veterinary officer.

In addition, at least one-fifth of the world's domestic fowl - and three-fourths of waterfowl - inhabit China. The sheer size of the population means a relatively higher bird flu infection rate in China, Jia said.

Just as important, most of China's poultry is raised in scattered, small courtyard farms with inadequate rearing conditions, making them vulnerable to a possible contagion. "The occurrence of the epidemic has lead the ministry to advocate the development of intensive farming and to optimize its stock raising method," Jia said.

As part of its efforts, the Ministry of Agriculture has required large poultry farms to keep their birds indoors to avoid contact with wild fowl, and urged individual households to vaccinate all of their domestic birds, Jia said.

The country's self-developed, government-funded vaccines, which have proven effective, have made such prevention highly feasible, he said.

Already, an integrated approach, combining massive vaccination and culling, has enabled the country to bring its three latest outbreaks - in northern Inner Mongolia, eastern Anhui and central Hunan - under effective control, he said.

Some world organizations have praised China's practice of destroying all poultry within a 3-kilometre radius of an outbreak site, according to Jia. "(By this time) last year there had been 50 cases of bird flu in China, while only six have been reported so far this year," Jia said.

(China Daily October 29, 2005)