High occurrence of Blastocystis sp subtypes 1-3 and Giardia intestinalis assemblage B among patients in Zanzibar, Tanzania
| Autor: | Helen Edebro, Satu Koskiniemi, Margareta Granlund, Birgitta Evengård, Joakim Forsell, Linn Samuelsson |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Giardiasis
Male 0301 basic medicine Subtype Blastocystis Infections medicine.disease_cause Tanzania Feces 0302 clinical medicine Zanzibar Intestinal Diseases Parasitic Child biology Giardia Middle Aged Infectious Diseases Child Preschool Female Adult Genotyping Adolescent 030231 tropical medicine 030106 microbiology Intestinal parasite Microbiology Microbiology in the medical area Young Adult 03 medical and health sciences parasitic diseases medicine Mikrobiologi inom det medicinska området Humans Giardia lamblia Aged Blastocystis Research Assemblage Infant biochemical phenomena metabolism and nutrition biology.organism_classification Parasitology Real-time PCR |
| Zdroj: | Parasites & Vectors |
| Popis: | Background: Blastocystis is a common intestinal parasite with worldwide distribution but the distribution of Blastocystis and its subtypes in East Africa is largely unknown. In this study, we investigate the distribution of Blastocystis subtypes in Zanzibar, Tanzania and report the prevalence of intestinal parasites using both molecular methods and microscopy. Methods: Stool samples were collected from both diarrhoeic and non-diarrhoeic outpatients in Zanzibar. In addition to microscopy, real-time PCR for Blastocystis, Entamoeba histolytica and E. dispar, Giardia intestinalis, Cryptosporidium spp., and Dientamoeba fragilis was used. Blastocystis subtypes were determined by a conventional PCR followed by partial sequencing of the SSU-rRNA gene. Genetic assemblages of Giardia were determined by PCR with assemblage specific primers. Results: Intestinal parasites were detected in 85 % of the 174 participants, with two or more parasites present in 56 %. Blastocystis sp. and Giardia intestinalis were the most common parasites, identified by PCR in 61 and 53 % of the stool samples respectively, but no correlation between carriage of Blastocystis and Giardia was found. The Blastocystis subtype distribution was ST1 34.0 %, ST2 26.4 %, ST3 25.5 %, ST7 0.9 %, and 13.2 % were positive only by qPCR (non-typable). The Giardia genetic assemblages identified were A 6.5 %, B 85 %, A + B 4.3 %, and non-typable 4.3 %. The detection rate with microscopy was substantially lower than with PCR, 20 % for Blastocystis and 13.8 % for Giardia. The prevalence of Blastocystis increased significantly with age while Giardia was most prevalent in children two to five years old. No correlation between diarrhoea and the identification of Giardia, Blastocystis, or their respective genetic subtypes could be shown and, as a possible indication of parasite load, the mean cycle threshold values in the qPCR for Giardia were equal in diarrhoeic and non-diarrhoeic patients. Conclusions: Carriage of intestinal parasites was very common in the studied population in Zanzibar. The most commonly detected parasites, Blastocystis and Giardia, had different age distributions, possibly indicating differences in transmission routes, immunity, and/or other host factors for these two species. In the Blastocystis subtype analysis ST1-3 were common, but ST4, a subtype quite common in Europe, was completely absent, corroborating the geographical differences in subtype distributions previously reported. |
| Databáze: | OpenAIRE |
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