The present study was conducted to evaluate the infection rates of Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii among asymptomatic individuals in Erbil City, northern Iraq. The research intent was to discover whether pathogenic or nonpathogenic species cause a high rate of symptomless Entamoeba infections. Stool samples were microscopically examined, and the 18S-rRNA gene was targeted utilizing the nested PCR technique in the positive specimens. Initial results based on morphological features showed that the Entamoeba prevalence rate was 7.4%. Significantly higher rates of infections were seen in females than in males and in low-income people than in moderate-income people. The incidence rates among the asymptomatic individuals, as determined by molecular analysis, were as follows: E. histolytica – 6%, E. dispar – 4.3%, and E. moshkovskii – 0.3%. Of all the Entamoeba positive samples, a single infection with E. histolytica was identified in 41.4% samples; the single infection with E. dispar in 18.6% samples, 35.7% samples had mixed infections with two Entamoeba species, and 4.3% had mixed infections with three species. The current study concluded that 7.4% of healthy people, who live in the endemic area under investigation, carry Entamoeba species asymptomatically. Additionally, the majority of asymptomatic Entamoeba infections were caused by the pathogenic E. histolytica (81.4%) compared to E. dispar (58.6%), and E. moshkovskii with the lowest rate of infection. Single and co-infections with E. histolytica and E. dispar were noted. E. moshkovskii, which was identified for the first time in the region, was only seen in mixed infections.

E. histolytica is an intestinal parasite that causes asymptomatic infection mostly; however, it may also cause amoebic dysentery and liver abscess. Molecular identification is required in epidemiological studies due to the presence of morphologically identical nonpathogenic species. Therefore, this study was conducted to first evaluate the prevalence rate of E. histolytica among symptomatic individuals of Erbil city, and to investigate the genetic diversity of the parasite in a limited geographic area. Accordingly, a total of 2026 samples were examined microscopically, and confirmed by nested PCR for 18s rRNA gene. The results showed that the prevalence rate of E. histolytica was 1.97% (40 samples) among symptomatic patients. The SREHP gene was used as a marker to show the genetic polymorphism of E. histolytica; however, to compare the genetic diversity of symptomatic with asymptomatic isolates, 57 asymptomatic samples were obtained from our previous study. The amplified products of the SREHP gene were digested by AluI endonuclease, and DNA banding patterns were analysed. Results showed 29 different DNA patterns among the 97 symptomatic and asymptomatic samples, 62 of which shared similar DNA patterns. However, 8 different DNA patterns were observed among asymptomatic samples, whereas 15 distinct patterns were observed among symptomatic isolates. In conclusion, this study found that the prevalence rate of E. histolytica was relatively low; relatively high genetic diversity was observed in a restricted endemic area; with higher rates of variability in symptomatic rather than in asymptomatic isolates, indicating a possible correlation between the genotype of E. histolytica and their clinical outcome.

Background and objective: Giardia lamblia is the intestinal flagellated protozoan parasite that infects vertebrates, including humans. Giardiasis is the major diarrheal disease found worldwide. It can be symptomatic or may be an asymptomatic carrier that led to chronic disease. This study aimed to determine the proportion of giardiasis among food handlers and evaluate the correlation between two laboratory methods for identifying the Giardia lamblia. Methods: A total of 308 stool samples were collected from food handlers that annually attend the central laboratory in Erbil City. Wetmount microscopic examination was performed for the diagnosis of cysts and trophozoites of the Giardia parasite. Molecular analysis done for positive samples, DNA extraction performed using the QIAamp Fast DNA Stool Mini Kit (Qiagen Company, Germany). Nested PCR analysis was done targeting the Glutamate dehydrogenase gene using two sets of primers for amplification of 734bp fragment. Gel electrophoresis was performed for visualizing the amplified DNA by Ultraviolet light. Results: The mean age of food handler participants was 29 years. Most (93.8%) of the food handlers were males, and the majority (98.6%) of the participants did not have any signs and symptoms. Four (7.4%) microscopy positive sample participants were highly educated. There was no association between educational level and positive rate by microscopy (P = 0.066). The majority of participants did not receive treatments, particularly most of the microscopic positive samples. The food handlers did not take any antiparasitic treatments 9 (3.4%) (P = 0.676). From 11 (3.6%) microscopically positive samples, 10 (90.9%) Giardia lamblia gdh gene 734 bp fragments were amplified by nested PCR. Conclusion: Amplification of 734bp of gdh gene by the nested PCR is the most specific and sensitive method for identifying Giardia lamblia. Food handlers were important people to care about sanitation and preparing food, particularly for avoiding diseases transmitted by food. Keywords: Giardiasis; Genetic characterization; gdh gene; Nested PCR.