[An Epidemiological Survey on Echinococcosis in Yushu Prefecture of Qinghai Province].

Objective: To investigate the prevalence of echinococcosis in Yushu Prefecture of Qinghai Province in 2012. Methods: Two to three towns were selected in each of Chengduo, Nangqian, Qu malai, Yushu, Zaduo and Zhiduo Counties from June to August in 2012. Ultrasound examination was conducted for residents aged over 1 year, and ELISA was performed to detect serum antibody against Echinococcus. Visceral dissection was performed to detect hydatid infection in rodents and livestock. ELISA was used to detect Echinococcus antigen in collected dog feces. Results: A total of 7 025 residents received ultrasound examination, of whom 319 showed hydatid cysts with a morbidity rate of 4.54%. ELISA showed a serum antibody positive rate of 16.38% （457/2 790）. The mobidity of hydatid disease was highest in Chengduo County （7.41%, 181/2 444）, and the rate of serum antibody was highest in Yushu County （23.18%, 127/548）. The morbidity and serum antibody in males were 3.91% （118/3 018） and 13.93% （172/1 235） respectively, and those in females were 5.02% （201/4 007） and 18.33% （285/1 555）. In terms of age distribution, the morbidity was relatively higher in residents of 60- （8.39%, 38/453） and 40- years （6.61%, 67/1 014）; and the rate of serum antibody was highest in residents over 70 years （33.93%, 19/56）. In terms of occupation, the morbidity was relatively higher in herdsmen （5.28%, 252/4 777）, Herdsmen-peasants （6.52%, 24/368）, and religious workers（3.37%, 11/326）, while the rate of serum antibody was relatively higher in children（24%, 6/25）, religious workers （18.79%, 31/165） and herdsmen（18.34%, 328/1 788）. In terms of education level, the morbidity and the rate of serum antibody were both highest in the uneducated（5.04%, 41/4 779; 18.34%, 359/1 958, respectively）. In terms of residential pattern, the morbidity and the rate of serum antibody were both highest in those who were settled in winter and nomadic in summer （8.25%, 227/2 753; 19.48%, 158/811, respectively）. There were significant differences in the morbidity and the rate of serum antibody in aspects of residential region, sex, age, occupation, education level and residential pattern (P<0.05 or P<0.01). In 872 rodents detected, the Echinococcus hydatid rate was 0.46% （4/872）, while in 809 cattle and sheep detected, the Echinococcus hydatid rate was 10.14% （82/809）. The fecal antigen positive rate in 838 samples of dog feces was 10.74%（90/838）. Conclusion: It shows a high morbidity of hydatid diesease and serum antibody positive rate in residents, a high Echinococcus hydatid rate in cattle and sheep, and a high fecal antigen positive rate in dogs in Yushu Prefecture.

Cystic and alveolar echinococcosis: an epidemiological survey in a Tibetan population in southeast Qinghai, China.

An epidemiological investigation on echinococcosis was made in Jiuzhi County of Qinghai Province, western China. Ultrasonography and an indirect hemagglutination test revealed a morbidity of 8.0% (124/1,549) and a seroprevalence of 25.8% (287/1,113), respectively, in the Tibetan population. The morbidity in herdsmen (16.6%) and Buddhist priests (15%) was significantly higher than that in other occupation groups (3.2%), and it was higher in females (9.8%) than in males (6.2%). The ultrasound images showed a coexistence of cystic echinococcosis (CE) and alveolar echinococcosis (AE), occupying 69 and 31% of the cases, respectively. An Echinococcus Western blot assay was performed as a serological backup test for differentiating CE and AE. The assay revealed that serum samples from most cases with a positive AE image showed a specific antibody against antigen bands at 16/18 kDa. Autopsy proved that 9 out of 12 stray dogs were infected with Echinococcus granulosus (n = 8) and E. multilocularis (n = 1). Inspection at the abattoirs demonstrated a hydatid rate of 78.5% in yaks and 82.6% in sheep. The data indicate that Jiuzhi County is an important endemic area for both CE and AE, in both human and animal populations.

[An epidemiological survey on hydatid disease in Yushu Prefecture of Qinghai Province].

Local inhabitants in 8 towns/townships of the counties Yushu, Zhiduo and Chengduo were examined with serology and ultrasound in 2006. Among 2 251 people tested by indirect hemagglutination (IHA), 207 showed anti-hydatid IgG positive (9.2%). Ultrasound examination found 106 cases out of 2581 people, with a morbidity of 4.1%. Females showed higher sero-positive rate (11.3%) and morbidity rate (5.0%) than males (6.6% and 3.0% respectively). The highest sero-positive rate was in the group of 40-49 years old (16.4%). The morbidity rate increased with age, with the highest rate (15.5%) in the group of 60 years old and above. Occupationally, those involved in semi-agriculture and semi-animal husbandry showed highest sero-positive rate and morbidity rate, 21.5% and 11.4% respectively. The survey demonstrated that the prevalence of hydatid disease in human population is at a high level in Yushu Tibetan Autonomous Prefecture.

[An epidemiological survey on echinococcosis in Zhiduo County of Qinghai Province].

The survey was carried out in July, 2006 in Zhiduo County. The IHA and ELISA positive rate in human population was 4.5% (42/933) and 8.2% (76/931) respectively. Ultrasonography revealed a morbidity of 3.4% (33/979) with 3.2% Echinococcus granulosus and 0.2% of E. multilocularis respectively. Animal dissection showed an infection rate of 15.1% (14/93) in pikas with one infected by E. shiquicus proved by molecular biology. Coproantigen rate by ELISA was 62% (12/193) in dogs and 35.7% (5/14) in wolves. The results indicated that Zhiduo County is a mixed endemic area for echinococcosis.