Molecular prevalence of Giardia duodenalis in domestic pig (Sus domesticus) and captive wild boar (Sus scrofa) in China: A systematic review and meta-analysis

Giardia duodenalis is a typical enteric protozoan pathogen that causes diarrhea in humans and various animals, including domestic pigs (Sus domesticus) and wild boars (Sus scrofa). A healthy livestock would help maintain a hygienic environment, which is crucial for human health. This review has summarized the molecular prevalence of G. duodenalis among various types of pigs (domestic pigs and captive wild boars) in China on the basis of relevant data. A random-effects model of meta-analysis was used to estimate the overall and subgroup-based pooled prevalence of G. duodenalis, and the I² index was used for the evaluation of the heterogeneity. Altogether, 23 datasets from 20 studies reporting G. duodenalis in 8282 pigs and captive wild boars across 12 regions in China revealed a 6.5 % (95 % CI, 6.0–7.0) pooled molecular prevalence of the parasite. Sensitivity analysis demonstrated that the data included in this study were stable. Meta-regression analysis showed that regions, type of pigs, age, and gender were not notably associated with the prevalence of G. duodenalis in the swine population in China. It was found that five G. duodenalis assemblages (A-E) are capable of infecting pigs in China, and assemblage E was found to be significantly dominant genotype (i.e., 73.2 % for the positive samples). G. duodenalis assemblages A and B were of major zoonotic concern with regard to humans; however, some reports have also documented assemblages C, D, and E from humans. Until now, information on the occurrence and distribution of G. duodenalis assemblages in Chinese pigs is limited, and therefore requires a rigorous and in-depth research.