SEVEN-YEAR-OLD Jian Song hid behind his mother and cried when journalists swarmed into his village house 40 kilometres from Guiyang, capital of one of the poorest provinces in China. Local medical officials accompanying the journalists asked the boy to walk to show how he had improved from poliomyelitis, which attacked him more than three years ago. The Primary One student has recovered to a large extent from the disease which ravaged China in the 1980s and still poses a serious threat to children despite efforts to eradicate it. According to statistics released by the Ministry of Public Health, there were more than 5,000 polio cases in China in 1990. In 1992, another 1,000 new cases were added, and more than 500 cases were reported last year. Guizhou ranks fifth as the most polio affected province, after Fujian, Guangdong, Yuannan, and Qinghai, medical officials said. Its poverty and mountainous terrain have hindered efforts to eradicate the disease, which not only paralyses but can also kill. Polio eradication work started in the mid-1980s in Guizhou, said Deputy Governor Zhang Yuqin. She said governments at all levels in the province had spent more than 10 million yuan (HK$9.09 million) to eradicate the disease and had covered 85 per cent of the province. But, Ms Zhang said she was worried that some areas remained uncovered because of a lack of transport, adding that the biggest problem was a lack of funds. Since 1982, UNICEF (the United Nations Children's Fund) has worked with the Ministry of Public Health on the eradication of polio. Up to 1989, UNICEF had provided $150 million towards equipment and transport. From 1985 to 1989 it made a further contribution of $117 million for the purchase of polio vaccines. Guizhou medical officials said the effectiveness of vaccines had been affected by poor transport. Wen Qi, director of the Guiyang Sanitary and Anti-Epidemic Station, said three to four per cent of the province's children had a polio attack even after they took all the required doses. Jian Song was among the unlucky ones. He had at least four doses of polio vaccine before symptoms appeared in March 1991. Why he had the polio attack still remains a mystery. Dr Mac Otten, a medical officer with the World Health Organisation in China, said to study cases like Jian's was too expensive. '[We'd] rather spend money on the eradication of the wild polio virus because we know we can get rid of that disease,' he said. 'Some other paralytic conditions of children in China are certainly more difficult, or even impossible, to treat.'