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Review
. 2014:2014:476142.
doi: 10.1155/2014/476142. Epub 2014 Apr 1.

Individual subject meta-analysis of parameters for Giardia duodenalis shedding in animal experimental models

A D Adell  1 , W A Miller  2 , D J Harvey  3 , E Van Wormer  4 , S Wuertz  5 , P A Conrad  2
Affiliations
Review

Individual subject meta-analysis of parameters for Giardia duodenalis shedding in animal experimental models

A D Adell et al. Biomed Res Int. 2014.

Abstract

Giardia duodenalis is a zoonotic protozoan parasite with public health importance worldwide. While articles about animal model infectivity have been published for G. duodenalis, the studies have used diverse protocols and parameters to evaluate the infectivity of this protozoan parasite. Hence, the objectives of this study were to (1) conduct a meta-analysis of published literature for cyst shedding and diarrhea outcomes in animal models and (2) develop recommendations to help standardize experimental dose response studies. Results showed that, for the outcome of cyst shedding in faeces, the covariates of infective stage (cyst versus trophozoite), Giardia dose, and the interactions between doses and infective stage, as well as dose and species of experimental host, were all significant (P value ≤ 0.05). This study suggests inoculation of the experimental host with cysts rather than trophozoites and administration of higher doses of Giardia will most likely result in cyst shedding. Based on the results of this meta-analysis, the infective stage (cyst versus trophozoite), parasite dose, and the interactions between dose and infective stage, as well as dose and species of experimental host, should be considered when designing experimental dose response studies that will assist in the study of zoonotic neglected tropical diseases globally.

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Figures

Figure 1
Figure 1
Flow of information through the different phases of a systematic literature review for the Giardia duodenalis meta-analysis.
Figure 2
Figure 2
Range of Giardia dosages captured in the articles included in this meta-analysis by the odds of the cyst shedding outcome for the categories “Age” and “Experimental Species.” (a) Range of Giardia dosages (log scale) by odds of cyst shedding by Experimental Species. (b) Range of Giardia dosages (log scale) by odds of cyst shedding by Age.
Figure 3
Figure 3
Funnel plot of standard error by logit event rate for cyst shedding outcome after Giardia infection showing possible publication bias as evidenced by a higher concentration of studies to the right of the mean.
See this image and copyright information in PMC

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