Epidemiological characteristics of echinococcosis in Zhuoni County Gansu Province

Objective To understand the epidemic trend and characteristics of echinococcosis in Zhuoni County, and to provide evidence for formulating prevention and control strategies. Methods From 2008 to 2016, according to the "Monitoring Program for Prevention and Control of Echinococcosis in Gansu", a cluster sampling method was adopted to examine the prevalence of echinococcosis in the villages and towns of Zhuoni County with the administrative village as a unit; B ultrasonic examination was used to study the prevalence of echinococcosis in the population. According to "the Diagnostic Criteria of Echinococcosis"(WS 257-2006), epidemiological history and clinical manifestations, the detection rate of echinococcosis was calculated; children under 12 years of age in one rural primary school were surveyed every year in each of the disease affected county; venous blood was collected, serum was separated, enzyme linked immunosorbent assay (ELISA) was used to detect the IgG antibody of echinococcosis, and the positive rate of IgG antibody of echinococcosis in children was calculated; 50 - 100 households were sellected every year in each of the disease affected village and town, one sample of canine feces was collected from each household, the fecal antigen of echinococcus canis was detected via the double antibody sandwich ELISA method, and the positive rate of dog fecal antigen was calculated; every year 700 sheep or 300 cattle were randomly dissected at the slaughterhouse of Zhuoni County, and their organs such as liver and lungs of slaughtered cattle and sheep were examined, the infection rate of echinococcosis in the year was calculated. Results From 2008 to 2016, echinococcus detection rate in Zhuoni County was 0.18% (200/108 522), and all of the cases were cystic; the detection rate of female (0.23%, 123/53 556) was higher than that of male (0.14%, 77/54 966), and the difference was statistically significant (χ2 = 11.83, P < 0.05); the number of farmer cases was the highest (58.00%, 116/200) , followed by herdsmen (39.50%, 79/200) ; 96.94% (95/98) of the administrative villages in Zhuoni County had echinococcus; the disease was most severe in pure pastoral areas (0.44%, 15/3 423), followed by semi pastoral areas (0.37%, 29/7 756), and cities and towns the least (0.06%, 16/25 923). The positive rate of IgG in children with echinococcus was 2.13% (235/11 048), the infection rate of echinococcus canis was 1.71% (183/10 711), and the infection rate of echinococcus in livestock was 1.36% (100/7 348). The detection rate of echinococcus decreased from 1.02% (106/10 350) in 2009 to 0.03% (3/11 804) in 2016, the IgG positive rate of echinococcus in children dropped from 7.50% (9/120) in 2008 to 0.71% in 2016 (9/1 264), the infection rate of echinococcus canis decreased from 3.13% (47/1 500) in 2009 to 0.30% (3/1 000) in 2016, and the rate of echinococcus in livestock infection decreased from 4.21% (34/807) in 2010 to 0.30% (3/1 000) in 2016. Conclusions County wide epidemic of echinococcus is found in Zhuoni with serious damage; after 9 years of comprehensive prevention and control, the detection rate of echinococcosis, IgG positive rate of echinococcus in children, positive rate of echinococcus granulosus antigen in domestic dogs and infection rate of echinococcosis in livestock are all decreased significantly. It shows that comprehensive prevention and control strategy has achieved remarkable results. Key words: Echinococcosis; Epidemiology; Situation analysis