Multilocus genotyping of Giardia duodenalis in Southwestern Iran. A community survey.

Giardia duodenalis is one of the main enteric pathogens associated with diarrheal disease. In developing countries, giardiasis is a major public health concern, particularly in children under five years of age. This study aimed to evaluate the occurrence and genetic diversity of G. duodenalis causing human infections in Shushtar County, Southwestern Iran. Individual faecal specimens were collected from 1,163 individuals (male/female ratio: 0.9; age range 2-75 years) with (n = 258) and without (n = 905) gastrointestinal symptoms living in rural and urban settings during the period 2017-2018. Conventional (sucrose flotation and microscopy) methods were used for the initial detection of G. duodenalis cysts in faecal specimens. Microscopy-positive samples were confirmed by PCR amplification and sequencing of the small subunit rRNA (ssu rRNA) gene of the parasite. A multilocus genotyping (MLG) scheme targeting the triose phosphate isomerase (tpi), the glutamate dehydrogenase (gdh), and the beta-giardin (bg) genes was used for genotyping purposes. Giardia duodenalis cysts were detected in 7.7% (90/1,163) of samples by microscopy, of which 82 were confirmed by ssu-PCR. Successful amplification and sequencing results were obtained for 23.2% (19/82), 9.8% (8/82), and 8.5% (7/82) of the confirmed samples at the tpi, gdh, and bg loci, respectively. MLG data for the three loci were available for two samples only. Out of the 24 samples genotyped at any loci, 50% (12/24) were identified as assemblage A and the remaining half as assemblage B. Overall, AII was the most prevalent sub-assemblage detected (41.7%, 10/24), followed by BIII (25.0%, 6/24), discordant BIII/BIV (5/24) or AII/AIII (2/24) sequences, and BIV (1/24). No significant correlation was demonstrated between a given assemblage/sub-assemblage and the occurrence of clinical symptoms. No genotypes adapted to animal hosts other than humans (e.g. assemblages C-F) were found circulating in the investigated human population, suggesting that transmission of human giardiasis in this Iranian region is primarily of anthroponotic nature. Further molecular-based studies are needed to confirm and expand these results, and to ascertain the presence and public health relevance of the parasite in environmental (e.g. drinking water) samples.

The Seroprevalence of Cystic Echinococcosis in a Rural Normal Population, Southwestern Iran.

INTRODUCTION: Cystic echinococcosis is a neglected zoonotic disease with worldwide distribution, which occurs mainly in pastoral regions. Echinococcus granulosus sensu stricto, is the main agent of human infection. Although Iran is an endemic area for CE in the Middle East, lack of data regarding the disease among rural inhabitants of Khuzestan province in recent years, persuaded us to perform the current study. METHODOLOGY: This cross-sectional study was conducted in 2016 using simple random sampling method in 15 villages of Shushtar County, southwestern Iran. Three hundred and fourteen rural inhabitants were examined using AgB- ELISA test for CE. RESULT: From 314 patients included in the study, females and males were 244 (77.7%) and 70 (22.3%), respectively. Of these, 227 (72.3%) were in close contact with dogs, out of which 173 (70.9%) of them were females and 54 (29.1%) were males. ELISA detected three (1%) seropositive cases among investigated population. All three positive cases were females and in close contact with dogs. Furthermore, the positive cases were in the age range of 21-50. None of the 70 examined males were positive. CONCLUSION: This study is the first report of CE in rural areas of Shushtar, Southwest Iran, which indicated seroprevalence of CE among rural areas with a high prevalence rate of infection among females. It seems that the rural population of the region are at the risk of exposure to E. granulosus eggs. Therefore, more studies are required to evaluate the human CE in all parts of the province using serological and ultrasound methods.