The largest TB survey in the capital of the northeastern province of Heilongjiang since 1949 found almost 9 percent of under-14s tested to be infected with tuberculosis (TB).

The Harbin Daily reported on January 25 that the three-month-long check by the Harbin Center for Tuberculosis Prevention involved 310,684 people from primary schools to universities.

Of these, 193,968 were aged below 14 -- the majority of the city's children in this age group according to Jiang Zhifu, an official from the Harbin Municipal Education Bureau.

They were given skin tests that differentiated between those infected with the TB bacillus (highly positive), those who had immunity to the bacterium but no infection (positive) and those with no immunity or infection (negative).

The children found to be highly positive then had chest X-rays to see whether their latent infection had progressed to active disease.

Nearly 20,000, about 9 percent of the total age group in Harbin, were identified as being highly positive, meaning that, as long as they maintain a relatively healthy diet and lifestyle, they have a nine in ten chance of not developing the active disease in years to come.

"Although those children who tested highly positive are different from active TB patients, the bacillus in their bodies are like time-bombs and they could develop TB anytime their immunity declines," said Wang Chunhui, the center's senior physician.

Eighty-three had active TB disease, six of whom were found to be highly infectious. "If left unchecked, the number of infected will go on increasing in the future," Wang warned. It is estimated that it can spread from an infectious person to 10 to 20 others in one year, mostly through air droplets.

Wang said the number of those who tested negative was "rather small" and they have been advised to get vaccinated as soon as possible, albeit on a voluntary basis.

He rejected the idea that a breakout of TB is likely in Harbin, the rather that the number is no more than the national average.

According to Xinhua News Agency, China now has about 4.5 million people infected with TB, of whom one-third are thought to be highly infectious. This puts the country second only to India in the world.

Babies are usually given the BCG vaccine within 24 hours of birth to prevent TB.

"Unlike some infectious diseases, TB does not create as much fear," Wang said. "Early detection and proper treatment may cure it easily."

Free treatment is being provided for those children who need it.

(China Daily January 28, 2005)