Abstract:

Objective To investigate the prevalence of echinococcosis in regions of four production types in Tibet Autonomous Region. Methods Seventy villages were selected using the stratified cluster sampling method in 7 cities/districts of four types of production (pastoral area, semi-agricultural and semi-pastoral area, agricultural area, and town), from August to October, 2016. B ultrasound examination was performed in residents aged > 1 year. Results Among the 77 049 persons receiving B ultrasound examination, 1 230 were detected to have hydatid disease (1.60%), dominated by cystic echinococcosis (87.64%, 1 078/77 049). The prevalence was highest in pastoral area (2.48%, 572/23 038), lowest in agricultural area (0.78%, 29/3 719), and 1.46%（470/32 173）and 0.94%（159/16 899）in semi-agricultural and semi-pastoral area and town, respectively, and was significantly different among the regions of four types of production (χ² = 171.670, P < 0.05). The prevalence in males and females was both highest in pastoral area (2.05%, 220/10 756 and 2.74%, 352/12 854). In females, it was higher than that in males in pastoral area (2.74%, 352/12 854 versus 2.05%, 220/10 756; χ² = 11.899, P < 0.01) as well as in semi-agricultural and semi-pastoral area (1.66%, 310/18 632 versus 1.14%, 160/14 011; χ² = 15.347, P < 0.05). Among different age groups, the prevalence was highest in the population group of > 60 years in pastoral area (5.56%, 130/2 338) and lowest in the group of < 15 year in town; the prevalence showed a trend of increase with increased age in agricultural areas, pastoral area, and semi-agricultural and semi-pastoral area, with a significant difference (χ²_trend = 39.057, 179.698, 100.914; P < 0.05). Among different educational levels, the prevalence was highest in illiteracy population in pastoral area (3.21%, 438/13 633) and no case was found in the preschool children in the town. There was a significant difference in prevalence among different education groups in regions of each type of production (χ² = 99.676, 16.683, 16.650, 11.222; P < 0.05). The prevalence was highest in populations with settlement type of summer nomads and winter settlers in semi-agricultural and semi-pastoral area (4.09%, 73/1 783) and no case was found in populations with other settlement types in pastoral area and agricultural area (χ² = 178.608, P < 0.01). There was a significant difference in prevalence among different settlement types in regions of each type of production (χ² = 503.452,P < 0.01). Conclusion The prevalence of echinococcosis in human population is highest in pastoral area in Tibet. In particular, specific attention of disease prevention should be paid to the older population, the illiteracy, and females.

Key words: Echinococcosis, Prevalence, Type of production, Tibet Autonomous Region