Abstract: Objective To explore the tuberculosis transmission parameter under modern tuberculosis control strategy (DOTS).Methods Since 15 July 1988,the BCG vaccination for newborns in Shun Yi County of Beijing was discontinued, and a series of protective measures,mainly conducted DOTS,for children were taken at the same time.PPD tuberculin tests for the nonvaccinated 6～7 years children born in 1988～1989 of first grade of primary schools,done with international standard tuberculin (2 TU PPD Rt23+Tween 80),were conducted according to WHO/IUATLD procedures in 1995.The criterion for infection was an induration of 10mm or more according to the distribution of PPD test reaction.Results The prevalence of tuberculosis infection was 1.35%.The annual risk of TB infection (ARTI) was 0.21%. At meantime, the prevalence of smear positive pulmonary tuberculosis in Shun yi County were (21.7～39.1)/10⁵ per year.So the TB transmission parameter was about 6.Conclusion The TB transmission parameter was 6 in Shun yi County of Beijing that means an infectious tuberculosis case can infect 6 persons averagely per year.This result indicated that the modern tuberculosis control strategy (DOTS) in Shun Yi County has highly effect on controlling sources of infection,reducing infection, protecting healthy population.

Key words: Tuberculosis/Prevention and control, Tuberculosis/Transmission parameter, DOTS