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

Abstract

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.

Giardia duodenalis in colony stray cats from Italy

“…Giardia duodenalis genotyping at the sub-assemblage level allowed us to better identify zoonotic isolates and to define the potential risk of zoonotic transmission in the study area. Previous data showed that AII sub-Assemblage is predominantly found in humans, thus considered zoonotic (Ballweber et al, 2010;Cacciò et al, 2002;Skhal et al, 2017;Sprong et al, 2009), whereas while AIII has been detected in humans only occasionally, also in Italy (Cacciò et al, 2002), infecting preferentially wild hoofed animals (De Liberato et al, 2015;Rafiei et al, 2020;Sprong et al, 2009) and sometimes cats (Lebbad et al, 2010). In our data, a potential risk of zoonotic transmission could be deduced from the clusters obtained in the phylogenetic analysis, which grouped human and cat isolates TA B L E 1 Descriptive analysis and association between direct immunofluorescence assay outcome for Giardia duodenalis and individual and colony variables in cats from central Italy Abbreviation: SD, standard deviation.…”

Detection of enteric parasites and molecular characterization of Giardia duodenalis and Blastocystis sp. in patients admitted to hospital in Ankara, Turkey

“…Our sequence data revealed that assemblage A was more prevalent than assemblage B (53.3 vs 43.3%) in the clinical population investigated. Similar assemblage frequencies have been documented in neighbouring Iran (Hooshyar et al ., 2017; Kasaei et al ., 2018; Rafiei et al ., 2020). These results are in sharp contrast with the European scenario, where assemblage B is the predominant assemblage reported in most countries (Feng and Xiao, 2011).…”

Prevalence and Clinical Manifestations of Giardia intestinalis and Other Intestinal Parasites in Children and Adults in Algeria

“…Giardia lamblia and Giardia duodenalis) is a protozoan intestinal parasite, which can infect various mammalian hosts, including humans, wildlife, livestock, and companion animals. 2 The prevalence of Giardia infection varies from approximately 2-5% in the industrialized world 3 to 20-30% in low-and middle-income countries, 4,5 with children typically being more frequently infected than adults. 6 Owing to the elevated burden of G. intestinalis-related illnesses in developing countries, its impact on developmental and socioeconomic improvements, and its close connection with poverty, this parasite has been included in the WHO's Neglected Diseases Initiative since 2004.…”