Hatam-Nahavandi Kareem, Ahmadpour Ehsan, Badri Milad, Eslahi Aida Vafae, Anvari Davood, Carmena David, Xiao Lihua
Tropical and Communicable Diseases Research Center, Iranshahr University of Medical Sciences, Iranshahr, Iran.
Infectious and Tropical Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
PLoS Negl Trop Dis. 2025 Apr 24;19(4):e0013021. doi: 10.1371/journal.pntd.0013021. eCollection 2025 Apr.
Members of the Giardia genus are zoonotic protozoan parasites that cause giardiasis, a diarrheal disease of public and veterinary health concern, in a wide range of mammal hosts, including humans.
We conducted a systematic review and meta-analysis to provide evidence-based data on the worldwide prevalence of Giardia infection in nonhuman mammals that can be used as scientific foundation for further studies. We searched public databases using specific keywords to identify relevant publications from 1980 to 2023. We computed the pooled prevalence estimates utilizing a random-effects meta-analysis model. Animals were stratified according to their taxonomic hierarchy, as well as ecological and biological factors. We investigated the influence of predetermined variables on prevalence estimates and heterogeneity through subgroup and meta-regression analyses. We conducted phylogenetic analysis to examine the evolutionary relationships among different assemblages of G. duodenalis.
The study included 861 studies (1,632 datasets) involving 4,917,663 animals from 327 species, 203 genera, 67 families, and 14 orders from 89 countries. The global pooled prevalence of Giardia infection in nonhuman mammals was estimated at 13.6% (95% CI: 13.4-13.8), with the highest rates observed in Rodentia (28.0%) and Artiodactyla (17.0%). Herbivorous (17.0%), semiaquatic (29.0%), and wild (19.0%) animals showed higher prevalence rates. A decreasing prevalence trend was observed over time (β = -0.1036477, 95% CI -0.1557359 to -0.0515595, p < 0.000). Among 16,479 G. duodenalis isolates, 15,999 mono-infections belonging to eight (A-H) assemblages were identified. Assemblage E was the predominant genotype (53.7%), followed by assemblages A (18.1%), B (14.1%), D (6.4%), C (5.6%), F (1.4%), G (0.6%), and H (0.1%). The highest G. duodenalis genetic diversity was found in cattle (n = 7,651, where six assemblages including A (13.6%), B (3.1%), C (0.2%), D (0.1%), E (81.7%), and mixed infections (1.2%) were identified.
CONCLUSIONS/SIGNIFICANCE: Domestic mammals are significant contributors to the environmental contamination with Giardia cysts, emphasizing the importance of implementing good management practices and appropriate control measures. The widespread presence of Giardia in wildlife suggests that free-living animals can potentially act as sources of the infection to livestock and even humans through overlapping of sylvatic and domestic transmission cycles of the parasite.
贾第虫属的成员是人畜共患的原生动物寄生虫，可在包括人类在内的多种哺乳动物宿主中引起贾第虫病，这是一种涉及公共卫生和兽医卫生的腹泻病。
我们进行了一项系统综述和荟萃分析，以提供关于非人类哺乳动物中贾第虫感染全球流行率的循证数据，可作为进一步研究的科学基础。我们使用特定关键词搜索公共数据库，以确定1980年至2023年的相关出版物。我们使用随机效应荟萃分析模型计算合并患病率估计值。动物根据其分类层次以及生态和生物学因素进行分层。我们通过亚组分析和荟萃回归分析研究预定变量对患病率估计值和异质性的影响。我们进行了系统发育分析，以检查十二指肠贾第虫不同组合之间的进化关系。
该研究包括861项研究（1632个数据集），涉及来自89个国家的327个物种、203个属、67个科和14个目的4917663只动物。非人类哺乳动物中贾第虫感染的全球合并患病率估计为13.6%（95%CI：13.4-13.8），在啮齿目（28.0%）和偶蹄目（17.0%）中观察到的患病率最高。食草动物（17.0%）、半水生动物（29.0%）和野生动物（19.0%）的患病率较高。随着时间的推移，患病率呈下降趋势（β=-0.1036477，95%CI -0.1557359至-0.0515595，p<0.000）。在16479株十二指肠贾第虫分离株中，鉴定出15999株属于八个（A-H）组合的单一感染。组合E是主要基因型（53.7%），其次是组合A（18.1%）、B（14.1%）、D（6.4%）、C（5.6%）、F（1.4%）、G（0.6%）和H（0.1%）。在牛中发现了最高的十二指肠贾第虫遗传多样性（n=7651，其中鉴定出包括A（13.6%）、B（3.1%）、C（0.2%）、D（0.1%）、E（81.7%）和混合感染（1.2%）在内的六个组合）。
结论/意义：家养哺乳动物是贾第虫囊肿环境污染的重要贡献者，强调了实施良好管理实践和适当控制措施的重要性。贾第虫在野生动物中的广泛存在表明，通过寄生虫的野生和家养传播周期的重叠，自由生活的动物可能成为家畜甚至人类感染的来源。
