Abstract:

Objective To understand the endemic situation and distribution of echinococcosis in Qinghai Province. Methods Stratified random sampling was performed in 43 counties/cities/districts in Qinghai Province from March to September in 2012, according to pastoral area, pastoral-agricultural area, agricultural area, and township area. The numbers of individuals and villages for survey in each kind of area were determined based on the proportions of total number of residents in each area to the total number in the county/city/district. B ultrasound examination was performed on residents aged over 3. B ultrasound was performed among students of 6-13 years in one primary school selected from each kind of area, or in all the primary schools from the school-enriched counties. Venous blood was also collected to detect serum level of anti-echinococcus IgG by ELISA. The results were statistically analyzed using SPSS17.0 software. The detection rate of echinococcosis and positive rate of serum IgG were calculated and analyzed with chi-square test using SPSS17.0 software. Results A total of 683 villages/communities were selected from the 43 counties/cities/districts. B ultrasound was performed on 121 683 participants, of whom 1 333 were positive for echinococcosis (morbidity rate, 1.10%). The morbidity rates in the pastoral area, pastoral-agricultural area, agricultural area, and township area were 2.51% (1 101/43 822), 0.84% (111/13 228), 0.08% (30/38 882) and 0.35% (91/25 751), respectively. There was a significant difference of the morbidity rate between males（0.90%, 526/58 348） and females（1.27%, 807/63 335）（χ² = 38.93, P < 0.01）. There was also a significant difference in the morbidity rate among different age groups（χ² = 80.84, P < 0.01）, with the highest rate being in the 30-39 years（1.51%, 387/25 682). The participants were of 14 ethnicities. Of them 1 333 were positive for echinococcosis, mainly from five ethnicities, the Tibetan （morbidity rate, 2.25%, 1 277/56 752), Han （0.07%, 32/44 420）, Hui （0.01%, 1/8 229）, Mogol （0.25%, 17/6 806） and Sala ethnicity（0.04%, 1/2 558). There was a significant difference in the morbidity rate among the ethnicities（χ² = 1 354.77, P < 0.01）. Among occupations, the religious people had the highest morbidity rate (5.08%, 52/1 024), followed by herdsmen（2.42%, 1 089/44 981）. A total of 191 primary schools, all from the county towns, were selected, and 47 747 students aged 6-13 years were examined by ultrasonography, of whom 253 were detected to be positive for echinococcosis, with a morbidity rate of 0.53% （253/47 747）. ELISA results showed that 2 693 of 45 507 students were positive for serum anti-echinococcus IgG, with a positive rate of 5.92%. Conclusion There is a serious endemic situation of echinococcosis in counties of southern Qinghai.

Key words: Echinococcosis, Epidemiology, Qinghai