Cystic Echinococcosis: An Impact Assessment of Prevention Programs in Endemic Developing Countries in Africa, Central Asia, and South America
Table 5
Appraisal summary of Article Meeting Inclusion Criteria [42].
Population:
Northwest Kenya, Turkana County (mainly migratory pastoral population): Five age groups (i) (0-5 years): 15.4% (1985), 22.9% (2010-2011), and 25.7% (2011-2012) (ii) (6–11 years): 26.6% (1985), 24.6% (2010–2011), and 23.9% (2011-2012) (iii) (16–25 years): 23.2% (1985), 10.8% (2010–2011), and 11.9% (2011-2012) (iv) 26–50 years: 32.0% (1985), 29.0% (2010–2011), and 29.0% (2011-2012) (v) (>50 years): 2.8% (1985), 11.8% (2010–2011), and 9.4% (2011-2012) Gender: (i) Males: 38.2% (1985), 39.5% (2010-2011), and 39.9% (2011-2012) (ii) Females: 61.8% (1985), 60.5% (2010-2011), and 60.1% (2011-2012) Program target areas: (i) Highest surgical incidence of CE in the district (40 per 100,000); highest prevalence in dogs (63.5%); highest dog-to-human ratio; presence of wild animal reservoirs (golden and silver-backed jackals)
Sample size:
(i) No sample size reported (ii) Non-randomized convenience sampling
Program outputs:
Cystic echinococcosis control program (Kenyan Ministry of Health; African Medical and Research Foundation (AMREF) Health Africa; Kenya Medical and Research Institute; Ministry of Agriculture; and local non-governmental organizations): (i) Health education campaigns: reducing contact with dogs, not feeding infected offal, large stray dog population transmission, and anthelmintic administration. Education delivered verbally, via video and images of surgical treatments and canine CE infections (ii) Targeted women (high risk population). Initially delivered by program education officers. Subsequently, community members trained Human ultrasound (US) screening in Lopiding, Kakuma, and Lodwar hospitals: (i) Total scanned: 3,553 (1985), 3,179 (2010-2011), and 4,188 (2011-2012) (ii) World Health Organization CE cyst classification: standardized screening of the liver, spleen, and kidneys. Screening at the same time of year and same location. Video display of suspected CE lesions recorded digitally or on thermal paper (iii) Positive cases referred to closest health facility for follow-up (funding permitted) and counseled on stage of infection (iv) Positive cases treated: smaller cysts with albendazole and puncture-aspiration-injection. Larger, complex cysts (e.g., CE2-3 stages) treated surgically Dogs: (i) Arecoline (ii) Praziquantel (PZQ) de-wormer every 6 weeks (iii) Female dogs spayed
Study design:
Non-randomized cross-sectional study
Program outcomes and/or impact:
(i) Prevalence in patients who tested positive between 1985-2012 and 2010-2012
Main findings:
CE prevalence: (i) US diagnosed: 961 patients with 2,182 cysts (1983–2012). Overall decrease: 5.6% (1985) to 1.9% (2010-2011), and 3.8% (2011-2012) (ii) Early prevalence reductions mostly attributed to reductions in dog population and regular PZQ treatment (iii) Age: Statistically significant differences (,) in age groups (0–5, 16–25, and <50 years) between 1985 and 2012. Continuing trend of higher prevalence in females, across multiple age groups. Although a relatively smaller sample size, prevalence (>50 years) has not changed significantly when compared to other age groups. Attributed to persistent infection and lower life expectancy before program (iv) Gender: CE prevalence per 1000 males or females between 1985 and 2010-2011 or 2011-2012, statistically significant , (v) Behavioral outcomes: appropriate disposal of offal and dog population control. Health education programs targeted to women, who spent most time at home with dogs, linked to behavioral changes and decreased CE prevalence. Effects of health education conclusively slow and rarely effective alone (vi) Infrastructure: construction of abattoirs (vii) Statistically significant changes to prevalence linked to both gender and age, using Pearson χ2 () and ordinal Somers’ tests () (viii) US proved superior results (higher sensitivity) compared to serology ELISA. CE cysts detected in 198 patients using US vs. 76 using serology ELISA Barriers: (i) Large, young, immunologically naive dog population (ii) Human behavior facilitating transmission (iii) Limited Infrastructure and Services: no abattoirs; and limited access to medical and veterinary care (iv) Test positive patients hesitant to undergo surgical treatment (v) Low education and literacy rates (vi) Transmission-supportive customs or behaviors (vii) Environmental factors, such as open grazing or herding dogs near cattle, can reduce the impact of health education
Limitations:
(i) No research question (ii) No sample size reported. Due to transient nature and remoteness of the Turkana population, actual population numbers not obtained, only representative estimates (iii) Unclear when serology testing ceased (may be 1980s) (iv) Analysis of data between (1983-2010) obtained from secondary source (v) Missing serology data for 5-year-old patients (vi) Reliability: some dogs administered arecoline, and some PZQ (vii) Information bias: US screening times not standardized. Study did not control for multiple presentations (duplicate results) or specify skill set of US screeners (viii) US is not sensitive to detecting pulmonary or osseous lesions (ix) No details of ethics approval for female dogs spayed Confounding variables: (i) The introduction of unvaccinated sheep into study area (ii) Community behavioral changes not tested for correlation to health education or prevalence (iii) Did not distinguish between stray and owned dogs. Not clear if stray dogs were tested or treated. Used general term: “local dog population”
