Abstract
Aim: To determine the common genotypes of Giardia duodenalis causing diarrhea in the study region and to assess the extent of genetic polymorphism among them. Study Design: Stool samples were collected from the patients attending IDBG Hospital, Kolkata with diarrheal complaints through a systemic sampling technique and were screened for Giardia duodenalis. The G. duodenalis positive samples were subjected to molecular genotyping through ‘PCR - Direct DNA sequencing’ procedure. All the sequence data obtained were incorporated into MEGA 4 software for multiple alignment and validation followed by phylogenetic analysis. The genotyping data obtained are stored in Excel spreadsheets and incorporated into EpiInfo 3.1 for analyzing possible association of genotype outcome with common physical factors such as age, sex etc. Place and Duration of Study: Department of parasitology, National Institute of Cholera and Enteric Diseases, Kolkata, India from July 2009 to November 2011. Methodology: A total of 68 Giardia duodenalis positive stool samples were identified from the diarrhea patients attending IDBG hospital in the city and were subjected to multi-locus genotyping. Fragments of s-giardin, Glutamate-dehydrogenase and Triosephosphate-isomerase genes of Giardia were amplified from those samples with specific primers and sequenced. All the sequences were analyzed using MEGA 4 software for obtaining the genotyping results. Results: Multi-locus genotyping identified 13 isolates as assemblage A and 41 as assemblage B, whereas 14 of them could not be assigned in a particular group. Detailed phylogenetic analysis revealed that multiple genotypes were observed in those 14 isolates depending upon the marker loci. Conclusion: The study could produce a preliminary idea about the G. duodenalis genotypes found in Kolkata city. High percentage of mixed assemblages in the study population also revealed the presence of genetic diversity among a small population of diarrheal patient within a limited geographical boundary. It has also hypothesized the possibility of inter-assemblage genetic exchange among Giardia.
Highlights
Giardia is a genus of intestinal flagellates that infects a wide range of vertebrate hosts
Single stool samples were taken from 700 subjects attending IDBG hospital who had previously tested for Giardia duodenalis via microscopy, PCR and ELISA following published protocols [9], and were kept at -80°C
Based on the cumulative sequence data of all three loci, 41 samples could be assigned as assemblage ‘B’ (60.2%) and as assemblage ‘A’ (19.1%), while (20.5%) isolates showed multiple assemblages depending on the marker loci (Supplementary Table 1)
Summary
Giardia is a genus of intestinal flagellates that infects a wide range of vertebrate hosts. Intestinalis) infecting amphibians, birds, rodents and mammals [1]. These species can be distinguished based on the morphology and ultrastructure of their trophozoites. According to the previous reports, the members of species G. duodenalis have negligible morphological variations but great genetic diversity. They are regarded as a species complex [3] with eight distinct genetic groups or assemblages (A-H) [4]. Assemblage A and B can infect and multiply in humans and other mammals whereas the remaining assemblages show a much restricted host range. Likewise C and D mostly infect the canids, whereas E, F, G and H infect livestock, cats, rodents and marine vertebrates respectively [4,5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
