Intestinal Parasites in Diarrheal Patients in Bandar Abbas, Southern Iran

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Data Collection and Parasitological Examination
The stool samples (watery and loose) of patients with the symptoms of gastroenteritis, who were admitted to infectious wards or referred to the laboratory, were evaluated based on the aim of the study. After obtaining written consent, the researcher administered a questionnaire to each patient, including items on sociodemographic characteristics such as age, gender, occupation and educational level (the parents caring for the patient), residency (urban or rural), type of reception (outpatient or inpatient), contact with animals, underlying diseases, addiction, and recent travel history within 3 months. The recipients of anti-parasitic drugs and diarrheic patients from bacterial infections were excluded from the study.
A single fresh stool sample was collected from each participant with a clean stool cup and immediately transferred to the laboratory of the Paramedical Faculty of Hormozgan University of Medical Sciences. The specimens were examined by the direct wet mount (normal saline and Lugol) and formalin-ether concentration method (3) which enhanced the recovery of protozoan cysts and ova of helminths. Trichrome staining was used for the better detection of protozoa. The oocysts of Cryptosporidium spp. were identified by a permanent slide after the formalin-ether concentration method and stained with the modified acid-fast staining.

Statistical Analysis
SPSS software (version 20, Chicago, IL, USA) was applied for the data analysis. In addition, the relationship between the variables and the presence of intestinal parasites was assessed by the chi-square test, and the level of significance was P < 0.05.

Results
A total of 170 diarrhea patients' stools were evaluated in this research. Of these, 57.6% and 42.4% of specimens were collected from males and females, respectively. Table 1 presents the detailed sociodemographic characteristics of the diarrheic individuals in three hospitals in Bandar Abbas. The overall prevalence of intestinal parasites was 22 (12.9%). Based on data in Table 2, the most common protozoan species were Blastocystis spp. 10 (5.9%) and G. lamblia 7 (4.1%). No statistically significant relationship was found between the infection and the variables (P > 0.05).

Discussion
In this cross-sectional study, the overall prevalence of intestinal parasites was found to be 12.9% among diarrheal patients in Bandar Abbas' hospitals; this rate was lower in our study compared to the studies conducted in the other parts of Iran and other countries, including Nahavand, western Iran (32.2%) (12) and Northwest Ethiopia (56.9%) (13). However, it is consistent with that of a study were the most common parasites in diarrheal patients (12,15). Differences in the health standards of each region, as well as the methods used to detect parasites, are the reasons for the difference in the prevalence of parasites. The role of Blastocystis spp. in the pathogenesis and pathology of the gastrointestinal tract is unclear and has always been debatable (10). The parasite appears to have many subtypes, and it is unclear which is more involved in human disease; however, the third subtype is more common in human studies (9). Unfortunately, the determination of Blastocystis subtypes was not within the scope of the study, which is one of the limitations of the present study.  (14). The prevalence of Cryptosporidium spp. using acid-fast staining was 1.8%, which matches the results of many other studies in the country (12,17), while not being in line with the findings of studies in other countries and Iran (18).
Compared to the findings of a previous study conducted in Bandar Abbas (19), the prevalence of the parasite has significantly decreased due to the differences between the subjects.
The prevalence of G. lamblia was 4.1%, which corroborates with the results of other studies (4.1%, 2.3%, and 2.75%) conducted in Mazandaran and Nahavand) in Iran (12,14) and Pakistan (20). Despite the high percentage of children under 15 years (44.7%) in this study, we expected a higher prevalence of G. lamblia, as the prevalence of this parasite in children under 5 years was 16.7% in Ethiopia (21). It should be noted that the prevalence of the parasite in primary school children was 17.23% (22) in Bandar Abbas in the past 20 years. Increasing the level of health and literacy in the community and improving the environment are effective factors in reducing this parasite. However, as mentioned earlier, bacterial or viral agents may have been involved in the diarrhea of these patients, which should be investigated in the future.
The prevalence of parasitic helminths in the present study was extremely low, only one case of Hymenolepis nana was detected, which conforms to the result of Vahedi et al in northern Iran and Kiani et al in western Iran (12,14). Intestinal helminthiases have been decreasing in recent years throughout the country (23). Only parasites with direct fecal-oral transmission were observed with a low prevalence. Sanitation and hygiene have played a role in this declining trend by increasing public awareness and improving health.
The other limitation of the research was the small number of samples due to the limited time because this article is the result of an MSc student's thesis.

Conclusion
Blastocystis spp. and G. lamblia were the predominant intestinal parasites detected in patients with diarrhea. The results revealed that intestinal parasites, especially helminth infections, have significantly decreased in recent years.