Epidemiological Survey And Long-term Follow-up Of Curative Effect And Nature History For Cystic Echinococcosis

Objective:This study aimed to investigate the prevalence and possible risk factors of human cystic echinococcosis (CE) in Hobukesar, Xingjiang Uygur autonomous Region. To understand the natural history of the disease through long term follow-up of curative effect and nature history of CE patients in Xingjiang. To understand the cause of re-infection through long-term follow-up of cured CE cases. Methods:1) Studies were carried out between 1995 and 2000 to investigate the prevalence of human cystic echinococcosis in traditional Mongolian communities in western Mongolia and Xinjiang (northwest China).2) Fifty-five cases including confirmed CE patients, ultrasound query cases, isolated calcification cases, previous CE surgery cases, as well as ultrasound normal but seropositive persons were resurvey using ultrasound and serology in Hobukesar, Xingjiang Uygur autonomous Region during the period 1995 to 2003.3) From August 2005 to October 2008, follow-up studies about cystic echinococcosis were carried out twice in Hobukesar, Xingjiang Uygur autonomous Region, ultrasonography as primary diagnostic method. Results:1) The prevalence of human hepatic CE in the two communities was significantly different. In Hobukesar human CE prevalence by ultrasound was 2.7% (49/1844), while in Bulgan it was 0.2% (4/1609) (P<0.001). Dog surveys showed that coproantigen positive rates or dog necropsy positives were similar in both communities, i.e.35.0% in Hobukesar and 35.7% in Bulgan. Comparing possible risk factors, there appeared to be some significant differences between the two communities, which might contribute to the observed difference in CE prevalence. These included, the proportion of herdsman or farmers recorded in Hobukesar (48.5%) was significantly higher than that in Bulgan (9.6%); the proportions of dog ownership and livestock ownership in Hobukesar (56%) were both higher than those in Bulgan (25-27%); and the proportion of families practicing home slaughter in Hobukesar (78.9%) was also significantly higher than that in Bulgan (28.1%).2) In the untreated patients, one case exhibited a spontaneous cure, another case changed form a hepatic hydatid cyst that contained a floating laminated membrane (type T3) to a cyst that contained daughter cysts (type T2). In the 20 surgically treated cases, two recurrent CE cases occurred, and five cases had residual cavities. Of the 4 PAIR treated cases, two recurrent. Serological follow-up date showed that specific IgG antibody levels were persistently positive in most CE casesbut exhibited a decreasing tendency in cases that were effectively treated by surgery. In contrast, serum IgG levels in the PAIR group or in the recurrent CE cases after surgery exhibited an increasing tendency.3) Among 24 patients comfirmed CE by ultrasonography,22 patients were primary CE (including surgery in 18 cases, no treat-ment in two cases, chemotherapy in two cases) and two patients were recurrence CE (one case underwent surgery, the other case received chemotherapy), two cases with surgical complications were found. Conclusion:1) In Hobukesar human CE prevalence was higher than that of Bulgan.2) The long-term follow-up studies demonstrated CE cases either treated nor untreated exhibited various pathologies. Serum IgG antibody levels has by and large not been very useful.3) Ultrasonography was required to differentiate residual effusion, recurrence and re-infection during epidemiological investigation and follow-up of CE. To control the main factors of re-infection has a profound impact on managing the prevalence of CE.