Features of leprosy transmission in pocket villages at low endemic situation in China.

To study the characteristics of leprosy transmission at low endemic situation and to analyze the reason why transmission still existed. A retrospective study was carried out on transmission of leprosy in thirteen leprosy high endemic villages in Wenshan district, Yunnan Province, China. A special questionnaire was designed for collecting the data. A total of 47 patients have been registered in 13 villages since 1991. Among them, 25 (53.2%) were leprosy household patients. The proportion of BI positivity was 57.4% (27). The average delay time from disease onset to diagnosis of leprosy was 12 +/- 7.9 months with a range of 1-36 months. The interval between 2 cases being detected in each village was in a range of 0.5 to 5.5 years. Many secondary patients occurred continuously after an 'index case' and they developed leprosy within the delay time of the disease of former patients. The authors here also reviewed some literature on chemoprophylaxis and discussed the importance. Most patients could not be detected at the early stage. It may be necessary of considering the chemoprophylaxis strategy among close contacts of leprosy to stop transmission in leprosy pocket areas.