Abstract:

Objective To investigate the prevalence of echinococcosis in Shannan City of Tibet Autonomous Region. Methods Villages were selected using stratified cluster sampling method from the counties of Langkazi, Longzi, Cuona, Zhanang, Gonggar, Qiongjie, Gacha, Sangri, Qusong, Luozha and Naidong District in Shannan City, from August to October, 2016. In each village, 200 residents aged > 1 year were selected for B ultrasound examination to calculate the prevalence of hydatid disease among the populations. Visceral necropsy was performed in livestock to investigate the status of hydatid infection. Feces from home-raised dogs were collected to examine Echinococcus antigen using ELISA method. Knowledge on echinococcosis control was surveyed in 20 randomly-selected residents in each village and no less than 50 students of each grade of grades 4-6 in a selected primary school in each county. Results Among the 10 287 persons receiving B ultrasound examination, 103 were detected to have hydatid cysts (1.00%), dominated by Echinococcus granulosus (97.09%). The 11 counties(districts) were all found with cases of hydatid disease, of which Langkazi County, Longzi County, and Cuona County had a high prevalence of 2.03% (17/836), 1.81% (15/830), and 1.43% (12/839), respectively, while Luozha County had the lowest prevalence of 0.11% (1/931). There was a significant difference in prevalence among the 11 counties/districts. There was no significant difference between males (0.84%, 31/3 683) and females (1.09%, 72/6 604) (χ² = 1.47, P > 0.05). The detection rate elevated with increased age (χ²_trend = 25.64, P < 0.01), being highest in the population groups of ≥ 60 years (1.76%, 30/1 708) and 45-59 years (1.32%, 44/3 333), and was significantly different among occupations (χ² = 20.73, P < 0.05), being highest in herdsmen (1.81%, 17/937), farmers (1.04%, 64/6 155), and semi-herdsman-and-farmers (1.03%, 18/1 740). The prevalence showed a trend of decrease with higher educational level (χ²_trend = 7.63, P < 0.05), being highest in those illiterates (1.26%, 63/5 009). The prevalence of hydatid disease was highest in pastoral area (1.19%, 20/1 682); there was no significant difference in the prevalence of hydatid disease among populations with different types of production (χ² = 0.85, P > 0.05). Among the 307 livestock examined, the prevalence of hydatid disease was 11.40% (35/307). There was a significant difference in livestock prevalence among the 11 counties(districts) (χ² = 175.409, P < 0.01), with Qusong County having the highest prevalence. Among the 932 fecal samples collected, the positive rate of Echinococcus antigen was 6.87% (64/932), with Langkazi County having the highest positive rate (27.50%, 22/80), followed by Cuona County (13.75%, 11/80)and Longzi County (7.50%, 6/80)[χ² = 61.41, P < 0.01, among the 11 counties(districts)]. The overall qualified rate on knowledge of echinococcosis control was 51.63% (1 343/2 601) in the residents. It was better in Sangri County (97.83%, 225/230) and Qusong County (91.34%, 211/231), and poor in Cuona County (10.24%, 17/166) and Langkazi County (18.55%, 41/221) [χ² = 605.52, P < 0.05, among the 11 counties(districts)]. Conclusion There is a high prevalence of hydatid disease in human populations, a high positive rate of Echinococcus antigen in dog feces, and poor knowledge on echinococcosis control in some counties of Shannan City, Tibet.

Key words: Echinococcosis, Dog feces, Antigen detection, Knowledge on control, Endemic situation, Shannan City, Tibet Autonomous Region