Abstract:

Objective To understand the prevalence of human and animal hydatid disease/echinococcosis in Guoluo Tibetan Autonomous Prefecture of Qinghai Province. Methods Sampling was made in counties of Banma, Dari, Gande, Jiuzhi, Maduo and Maqin in Guoluo Prefecture of Qinghai Province, 2-3 villages from each County. B ultrasonography was performed in residents at the age of > 1 year to calculate the prevalence of hydatid disease. ELISA was performed to detect serum anti-echinococcus antibody in humans, and visceral anatomy was used to detect hydatid cyst in murines and livestock. Canine fecal samples were collected in field to detect antigens with ELISA. Results A total of 15 890 residents received B ultrasonography, of whom 826 (5.20%) were positive for hydatid cysts. ELISA in 1 200 residents revealed a positive rate of 16.75% (201/1 200) for anti-echinococcus antibody. The prevalence of hydatid disease was highest in Dari County (11.93%, 430/3 605). The positive rate of serum antibody was highest in Gande County (48.15%, 65/135), followed by Banma County (12.77%, 136/1 065). The prevalence of hydatid disease and positive rate of serum antibody in females were 6.37% (499/7 839) and 26.01% (142/546) respectively, which were both significantly higher than those in males (4.06% and 9.02%). There was a relatively higher prevalence of hydatid disease in herdsmen, religious people, students and houseworkers (5.24%, 700/13 370; 6.46%, 41/635; 8.39%, 25/298; 5.68%, 18/317; respectively) among the occupations, and in age ranges of 60- years (6.91%, 76/1 100), 30- years (6.25%, 255/4 078) and ≥ 70 years (8.08%, 37/458). The serum positive rate was higher in age group of ≥ 70 years (48.28%, 14/29), 60- years (28.57%, 20/70), and 40- years (23.12%, 40/173). Among different educational levels, the prevalence of hydatid disease and positive rate of serum antibody were the highest in the illiterate population (5.85%, 431/7 365 and 62.61%, 72/115, respectively). Among populations with different living styles, the prevalence of hydatid disease and positive rate of serum antibody were the highest in those who settled in winter and move about in summer (6.36%, 642/10 087; 60.49%, 147/243). There were significant differences in different regions, genders, occupations, age groups, education levels and living styles (P<0.05). The positive rate of echinococcus infection in rodents was 2.41% (98/4 058) in Guoluo Prefecture; more specifically, it was highest in Jiuzhi County (4.82%, 49/1 016). The antigen positive rate in dog feces was 14.90% (303/2 034), and was the highest in Maqin County (18.76%, 160/753). The positive detection rate of hydatid cysts in yaks and sheep was 28.37% (570/2 009), and was the highest in Dari County (62.80%, 314/500). These were also significant differences among the regions in positive rates of yaks, sheep, murines and dogs (P<0.05). Conclusion The echinococcosis epidemicity is still serious in Guoluo. Dogs remain a major source of transmission.

Key words: Qinghai, Guluo, Hydatid disease, Fecal antigen, Epidemiology, Investigation