Abstract:

Objective To understand the prevalence of echinococcosis in Shigatse City in Tibet Autonomous Region. Methods A stratified cluster sampling method was used to select villages in 17 counties(district) in Shigatse City from August to October, 2016. B ultrasound examination was performed in residents aged > 1 year, accompanied by a serological test for those suspected, to calculate the prevalence of hydatid disease. The prevalence and the number of cases in the population of the city were estimated. Ten pigs/sheeps or 5 cattle were randomly selected in each village, to examine the status of echinococcosis disease in livestock by visceral dissection. In counties found with cases of echinococcosis, no less than 300 adult rodents were captured in places of patient residence and with frequent activity of humans and dogs, to calculate the prevalence of echinococcosis in rodents. In each village, 20 households raising dogs were randomly selected to collect dog feces. Echinococcus antigen in fecal samples was determined by ELISA. Knowledge on echinococcosis prevention and control was surveyed in 20 residents randomly selected in each village, and in grade 4-6 students in a primary school of each county questionnairing. Results A total of 21 497 residents in 96 villages of 18 counties(district) received B ultrasound, of whom 289 were detected with echinococcosis (1.34%). The prevalence in population was estimated to be 1.10%, and the number of cases was estimated to be 7 792. The cases were dominated by cystic echinococcosis (90.31%, 261/289). The 18 counties(district) were all found with cystic echinococcosis cases, and 13 were also found with alveolar echinococcosis. The estimated prevalence was highest in Zhongba County (4.03%, 33/819), and lowest in Renbu County (0.24%, 2/833), with significant difference among the counties (χ² = 39.963,P < 0.05). The prevalence in females was 1.50% (191/12 737), significantly higher than that in males (1.12%, 98/8 760) (χ² = 5.676, P < 0.05). Among different age groups, the prevalence was highest in the age group of ≥ 70 years (2.75%, 22/799), and lowest in the age group of 1-9 years (0.34%, 12/3 479), showing a trend of increase with age (χ² = 61.390, P < 0.05). As to the education levels, the prevalence was highest in the illiterates (1.56%, 190/12 214), and lower in those with a primary school level (1.04%, 74/7 086) and college and above (1.08%, 4/372) (χ² = 61.502,P < 0.05, among different education levels). The prevalence showed a trend of decrease with increased education level (χ² = 5.704, P < 0.05). The prevalence was highest in herdsmen (2.68%, 76/2831) (χ² = 75.110, P < 0.05, among different occupations). The prevalence was highest in pastoral area (1.83%, 85/4 654) and lowest in agricultural area (0.91%, 75/8 285) (χ² = 24.450, P < 0.05, among different production types). The positive rate of Echinococcus antigen in dog fecal samples of the terminal host dogs was 4.73% (92/1946), showing no significant difference (χ² = 3.155, P > 0.05) between domestic dogs (5.42%, 66/1 218) and stray dogs (3.57%, 26/728). The infection rate in rodents was 1.02% (3/293), and that in livestock (cattle, and sheep) was 11.61% (67/577). The populational qualified rate on knowledge of echinococcosis prevention was 33.08% (1 500/4 534), being higher in pupils (39.57%, 1 064/2 689) than in residents (23.63%, 436/1 845) (χ² = 125.541, P < 0.05). Conclusion Echinococcosis both in human populations and animals are widely prevalent in Shigatse. More attention should be paid to females, herdsmen and populations with older age and less education.

Key words: Echinococcosis, Prevalence, Tibet Autonomous Region, Shigatse City