Cystic Echinococcosis: An Impact Assessment of Prevention Programs in Endemic Developing Countries in Africa, Central Asia, and South America
Table 6
Appraisal summary of Article Meeting Inclusion Criteria [43].
Population:
(i) Location: Emin County, Xinjiang Uygur Autonomous Region, China (Xinjiang 1/5 major pastoral areas). Comprised of 11 administrative townships, with five pastures and one farm, covering 1,050 acres of natural grassland (ii) All sheep raised locally outdoors: 73.5% (12,649/17,215) males; 42.8% (7,363/17,215) aged <1 year; 91.4% (15,735/17,215) aged <3 and 1.6% >4 years old. Thus, majority male sheep (0-3 years old) (iii) Domestic and stray dogs
Sample size:
(i) 17,215 slaughtered sheep (ii) Total human population 220, 000 (iii) All domestic dogs and stray dogs in the county
Program outputs:
National control program launched 2006, study commenced October 2007: (i) De-worming dogs with Praziquantel (PZQ): dose 200 mg/<15 kg and 400 mg >15 kg. Each village appointed one resident to de-worm owned dogs (ii) Stray dogs de-wormed by auto-feeding PZQ-mixed in food and left at assigned sites (iii) Dog feces buried to prevent transmission The County Department of Quarantine implemented: (i) Strict management and inspection of slaughterhouses (ii) Quarantine of livestock from dogs (iii) Restrictions on feeding dogs infected offal (iv) Prohibited sale of infected meat or “sick animals” (v) Community health education to promote positive behavioral change. Village appointed one resident to de-worm dogs and deliver health education (e.g., washing hands before meals and drinking boiled water) (vi) Treatment of human patients
Study design:
Non-randomized prospective cross-sectional study
Program outcomes and/or impact:
(i) Cystic Echinococcosis (CE) prevalence in slaughtered sheep from during peak slaughter (October 2007 to November 2013) at one authorized slaughterhouse in Emin County (ii) Prevalence calculated by subjective visual inspection and palpation of hydatid cysts across multiple organs: liver, lungs, spleen, heart, and kidneys
Main findings:
(i) Prevalence/infection rate: Statistically significant (Xtrend2=59.79, ) decreased 27% (1.8/6.6) (2007-2010) (ii) 2007 (6.6%); 2008 (3.9%); 2009 (2.0%); 2010 (1.8%); 2011 (1.9%); 2012 (1.7%); 2013 (2.0%); 2010-2013 not statistically significant () (iii) Prevalence increased as sheep aged: 4.5% at the age <1, 6.7% at age 2~, and 17.9% ≥4 years. Decline in sheep response to control measures attributed to issues of program sustainability (e.g., missed PZQ dosing increasing dog-sheep transmission) (iv) Domestic dogs living in large populations in Northwest China (2-4 shepherding dogs per household) were primary definitive host (v) Dogs played important cultural and productive roles as shepherds of livestock. In ethnic communities in Western China, Buddhist religion forbids the killing of any animals (vi) Dogs’ proximity to humans and water sources increased transmission (vii) Barriers to testing roaming stray dogs due to inaccessibility of remote and widely distributed terrain
Limitations:
(i) No sample size calculation for sheep (ii) No sample size calculation or population size for owned or stray dogs (iii) No detail about sample collection methods (iv) Mentioned community public health education, but no measures of program outcomes or correlation to significant differences in prevalence (v) PZQ administration method not standardized for domestic vs. stray dogs (vi) Each village appointed one resident to de-worm dogs and deliver health education. No mention of how resident was selected or trained (vii) Post-mortem: visual assessment could introduce subjective bias if variations in assessor skill or method (viii) The finding of increased incidence as sheep age was not clearly supported by the study’s cited reference [44]
