An Overview on the Main Assemblages and Sub-assemblages of Giardia Intestinalis in the Western Half of Iran

Context: Studies have shown that various Assemblages, sub-assemblage (subtypes) and genotypes of Giardia intestinalis have multiple hosts; therefore, their distribution reservoirs as well as pattern of epidemiological distribution are different. The present study was conducted to summarize the results of genetic studies on Giardia intestinalis in Iran. Evidence Acquisition: To investigate the articles on the sub-assemblage of Giardia intestinalis in Iran, a systematic search was conducted in Persian and English databases. The search process led to the entry of 23 articles into this systematic review. Also, in this study, to estimate the ratio of the dominant sub-assemblage of Giardia parasite in Iran, meta-analysis was used and a significant level of 0.05 was considered. Results: The results of this study showed that investigations on assemblages and sub-assemblage of Giardia intestinalis had been mostly made in the western half of Iran. The overall prevalence of A, B, and the mixed assemblages of Giardia intestinalis in these areas of Iran was estimated to be 0.56, 0.27, and 0.16, respectively. Also, the prevalence of AI and AII sub-assemblage of Giardia intestinalis in the same areas of Iran was 0.34 and 0.5, respectively. The prevalence of BIII and BIV sub-assemblage of this parasite in mentioned areas was further found to be 0.2 and 0.06, respectively. In addition, the total prevalence of all sub-assemblage (AI, AII, BIII, & BIV) was calculated to be 0.18 (P < 0.001). Conclusions: Given that assemblage A of Giardia Intestinalis has the highest prevalence in the human society of western half of Iran, in this area of the country, the main epidemiological pattern of Giardia transmission is zoonotic. However, to identify the source of this parasite spread, more studies are needed.