[Epidemic Status of Echinococcosis in Gannan Tibetan Autonomous Prefecture of Gansu Province during 2007-2011].

OBJECTIVE: To investigate the prevalence of echinococcosis in Gannan Tibetan Autonomous Prefecture of Gansu Province since the implementation of the echinococcosis control project from Sepical Funds for Central Government Subsidies to Local Public Health (2007-2011).

METHODS: Eight counties of Hezuo, Lintan, Zhuoni, Luqu, Maqu, Xiahe, Zhouqu, and Diebu were selected as survey sites. The prevalence in the sampled population was investigated by B ultrasound examination. Hydatid infection in children below 12 years old was serologically investigated by ELISA. The fecal samples from dogs were determined for Echinococcus infection by double antibody sandwich ELISA method. Livestock were dissected through slaughterhouse for pathological examination. Data of echinococcosis cases of Gannan Tibetan Autonomous Prefecture from 2007 to 2011 were collected from the National Infectious Diseases Reporting System, and statistically analyzed by using SPSS 10.0 and Epi info software.

RESULTS: A total of 257 823 people received type B ultrasound examination in the 5 years. Five hundred eighty-one echinococcosis cases were found with an overall prevalence of 0.2%, including 578 cases of echinococcosis granulosus and 3 cases of echinococcosis multilocularis. The annual prevalence in the population decreased year by year, from 0.4% (97/21 938) in 2007 to 0.1% (68/63 980) in 2011 (P <0.05). Three hundred and six cases were officially reported to the National Infectious Diseases Reporting System during the period. Among those, female patients accounted for 58.2% (178/306) and male patients 41.8% (128/ 306). By occupation, more infection were found in herdsmen (82.0%, 251/306), followed by farmers (7.8%; 24/306). The cases were mainly distributed in the 20-60 year-old age group, with the highest prevalence in the group of 30-39 years (23.5%, 72/306). The sero-positive rate in children was 4.7% (1 571/33 613), which was highest in 2008 (8.4%, 413/4907), and lowest in 2010 (3.2%, 223/7 021) (P < 0.05). The mean positive rate of coproantigen in dogs was 6.3% (2 511/40 179), decreased from 11.9% (335/2 819) in 2007 to 6.3% (734/11 666) in 2011 (P < 0.05), with lowest positive rate in 2009 (3.7%, 354/9 550). The mean prevalence of livestock was 4.1% (914/22 087), decreased from 8.8% (235/2 658) in 2007 to 2.0% (144/7 347) in 2011 (P < 0.05).

CONCLUSION: Since the project implementation for echinococcosis control in 2007, the prevalence of hydatid desease in the population, the sero-positive rate in children, the positive rate of dog coproantigen, and the prevalence in livestock have been significantly decreased.