Identification of risk areas and practices for Taenia saginata taeniosis/cysticercosis in Ethiopia: a systematic review and meta-analysis

Abstract

Background: Bovine cysticercosis (BCC) is an infection of cattle with the metacestode stage of Taenia saginata, the beef tapeworm, which causes taeniosis in humans. BCC is responsible for considerable economic losses in the meat sector worldwide. This systematic review and meta-analysis summarizes the prevalence, risk factors and treatment efforts made so far on T. saginata infections in Ethiopia, providing a detailed analysis of different factors influencing the varying prevalence estimates in Ethiopia to gain more insight into the occurrence and risk factors of T. saginata taeniosis and cysticercosis to date.

Methods: A systematic review and meta-analysis was conducted on data collected from published and grey literature accessed through an electronic database and manual search.

Results: The literature search resulted in 776 outputs of which 132 conformed to the predefined criteria. The average zonal prevalence of meat inspection-based BCC ranged from 2% in Buno-Bedele to 24.6% in Sidama zone. The pooled prevalence of BCC was influenced by the number of muscle/organs inspected, ranging from 3.4% (95% CI: 1.7-5.1%) using fewer predilection sites to 19.4% (95% CI: 13.3-25.4%) using inspection of a maximum number of predilection sites. None of the tested variables were significantly associated with BCC. Questionnaire-based taeniosis ranged between 19.0% in Halaba special woreda to 70.0% in Gedeo zone and stool test-based taeniosis varied from 0.6% in central Tigray to 10.7% in Gurage zone. Questionnaire-based prevalence of taeniosis was higher in people with a frequent raw beef consumption habit (pooled OR, pOR: 10.5, 95% CI: 6.0-17.9), adults (pOR: 2.5, 95% CI: 1.7-3.6), men (pOR: 2.8, 95% CI: 2.1-3.6), and Christians (pOR: 2.0, 95% CI: 1.4-2.8) compared to less frequent raw beef consumers, younger people, women and Muslims, respectively.

Conclusions: This review revealed a widespread but variable occurrence of BCC and taeniosis in Ethiopian regions and zones, urging for harmonized and enhanced detection for improved control of the parasite. Accurate prevalence estimates using more sensitive tests, detailed risk factor analysis, as well as data on financial losses are needed to develop effective control strategies for the Ethiopian epidemiologic condition.

Keywords: Bovine cysticercosis; Ethiopia; Prevalence; Review; Risk factors; Taenia saginata; Taeniosis.

Fig. 1

Flow chart describing the output of the literature search and selection of articles

Fig. 2

Map of Ethiopia showing regions and zones where a bovine cysticercosis (BCC), taeniosis (questionnaire-based (QB)), and taeniosis (stool test-based (STB)) is reported. b Cattle population density in Ethiopia (expressed as the number of cattle per km²). c The open defecation status in Ethiopia (expressed as the proportion of people without a latrine). Copyright: Creative Commons Attribution license (CC BY 3.0 IGO). Citation: World Bank. 2018. Maintaining the Momentum while Addressing Service Quality and Equity: A Diagnostic of Water Supply, Sanitation, Hygiene, and Poverty in Ethiopia. WASH Poverty Diagnostic. World Bank, Washington, DC [28]

Fig. 3

Map of Ethiopia displaying the zonal prevalence of a bovine cysticercosis (BCC), b taeniosis (questionnaire-based) and c taeniosis (stool test-based)

Fig. 4

Forest plot showing an overview of studies reporting bovine cysticercosis (BCC) in Ethiopia, grouped by the number of organs/muscles that were inspected during post-mortem meat inspection. The box size shows the weight of the study and the middle of the box (dot) represents the point estimate of the study, the length of the horizontal lines indicates the 95% CI; the vertical broken line indicates the pooled estimate; the diamond-shaped box at the bottom represents the 95% CI; the solid line indicates the point of null assumption

Fig. 5

Overview of the meta-analyses results for different risk factors for bovine cysticercosis (BCC) in Ethiopia. Abbreviations: OR, pooled odds ratio; n, number of studies that are included in the analysis; I², inverse variance index representing the percentage of the variation in the estimates attributable to heterogeneity; Q, Cochrans Q test value representing heterogeneities of the study level estimates

Fig. 6

Forest plot showing an overview of studies reporting stool test-based human taeniosis prevalence in Ethiopia, grouped per study population. The box size shows the weight of the study and the middle of the box (dot) represents the point estimate of the study, the length of the horizontal lines indicates the 95% CI; the vertical broken line indicates the pooled estimate; the diamond-shaped box at the bottom represents the 95% CI; the solid line indicates the point of null assumption

Fig. 7

Overview of the random effects meta-analyses results for different risk factors for questionnaire based taeniosis in Ethiopia. Abbreviations: OR, pooled odds ratio; n, number of studies that are included in the analysis; I², inverse variance index representing the percentage of the variation in the estimates attributable to heterogeneity; Q, Cochrans Q test value representing heterogeneities of the study level estimates