Fasciolopsis buski (Digenea: Fasciolidae) from China and India may represent distinct taxa based on mitochondrial and nuclear ribosomal DNA sequences.
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ABSTRACT: Fasciolopsis buski is a zoonotic intestinal fluke infecting humans and pigs, but it has been seriously neglected. It is yet to know whether there is any genetic diversity among F. buski from different geographical locations, particularly in sequences of nuclear ribosomal DNA (rDNA) and mitochondrial (mt) DNA. Therefore, we determined the sequences of partial 18S, the complete internal transcribed spacer (ITS) rDNA and the complete mt genome of F. buski from China, compared the rDNA and mtDNA sequences with those of isolates from India and Vietnam, and assessed the phylogenetic relationships of this fluke and related fasciolid trematodes based on the mtDNA dataset.The complete mt genome sequence of F. buski from China is 14,833 bp, with 36 genes, including 12 protein-coding genes (PCGs), 22 tRNA genes, and two rRNA genes (rrnL and rrnS). The AT content of F. buski from China is 65.12%. The gene content and arrangement of the F. buski mt genome is similar to that of Fascioloides magna. Genetic distances between isolates of F. buski from China and India were high (28.2% in mtDNA, 13.2% in ITS-1 and 9.8% in ITS-2) and distinctly higher than the interspecific differences between Fasciola hepatica and Fasciola gigantica. The rDNA and mtDNA datasets for F. buski from China (isolate from pigs) and Vietnam (isolates from humans) were identical. The intergeneric differences in amino acid and nucleotide sequences among the genera Fasciolopsis, Fascioloides and Fasciola ranged between 24.64-25.56% and 26.35-28.46%, respectively.Our results indicate that F. buski from China and India may represent distinct taxa, while F. buski in Vietnam and China represent the same species. These findings might have implications for the implementation of appropriate control strategies in different regions. Further studies are needed to decode mtDNA and rDNA sequences of F. buski from various geographical isolates for the better understanding of the species complex of F. buski.
<h4>Background</h4>Fasciolopsis buski is a zoonotic intestinal fluke infecting humans and pigs, but it has been seriously neglected. It is yet to know whether there is any genetic diversity among F. buski from different geographical locations, particularly in sequences of nuclear ribosomal DNA (rDNA) and mitochondrial (mt) DNA. Therefore, we determined the sequences of partial 18S, the complete internal transcribed spacer (ITS) rDNA and the complete mt genome of F. buski from China, compared the ...[more]
Project description:Fasciolopsis buski is the largest fluke parasitizing the human small intestine. F. buski infections are not uncommon in Southeast Asia. The risk factors of F. buski infection mainly include eating of raw aquatic crops and infected snails. Most infections are asymptomatic. Heavy infection can be fatal as the flukes cause extensive intestinal inflammation, intestinal perforation, small bowel stricture, ulceration, hemorrhage, and abscess formation. Endoscopic diagnosis of this parasite has been described in a few case reports. Here, we describe and illustrate the endoscopic removal of F. buski from the stomach and duodenum.
Project description:A total of 134 Egyptian liver flukes were collected from different definitive hosts (cattle, sheep, and buffaloes) to identify them via the use of PCR-RFLP and sequence analysis of the first nuclear ribosomal internal transcribed spacer (ITS1). Specimens of F. hepatica from France, as well as F. gigantica from Cameroon were included in the study for comparison. PCR products of ITS1 were subjected for digestion by RsaI restriction enzyme and visualized on agarose gel. According to RFLP pattern, Egyptian flukes were allocated into two categories. The first was identical to that of French hepatica flukes to have a pattern of 360, 100, and 60 (bp) band size, whereas the second resembled to that of Cameroonian gigantica worms to have a profile of 360, 170, and 60 bp in size. Results of RFLP analysis were confirmed by sequence analysis of representative ITS1 amplicons. No hybrid forms were detected in the present study. Taken together, this study concluded that both species of Fasciola are present in Egypt, whereas the hybrid form may be not very common.
Project description:Fasciolid flukes are among the largest and best known digenetic trematodes and have considerable historical and veterinary significance. Fasciola hepatica is commonly implicated in causing disease in humans. The origins, patterns of diversification, and biogeography of fasciolids are all poorly known. We have undertaken a molecular phylogenetic study using 28S, internal transcribed spacer 1 and 2 (ITS-1 and ITS-2) of nuclear ribosomal DNA, and mitochondrial nicotinamide dehydrogenase subunit 1 (nad1) that included seven of the nine recognized species in the family. The fasciolids examined comprise a monophyletic group with the most basal species recovered from African elephants. We hypothesize fasciolids migrated from Africa to Eurasia, with secondary colonization of Africa. Fasciolids have been conservative in maintaining relatively large adult body size, but anatomical features of their digestive and reproductive systems are available. These flukes have been opportunistic, with respect to switching to new snail (planorbid to lymnaeid) and mammalian hosts and from intestinal to hepatic habitats within mammals.
Project description:Food-borne fluke infections/trematodiases are emerging as a major public health problem worldwide with over 40 million people affected and over 10% of world population at risk of infection. The major concentration of these infections is in Southeast Asian and Western Pacific Regions, where the epidemiological factors (including the prevalent socio-cultural food habits) are conducive for transmission of these infections. The preponderance of these infections is usually in food deficit poor communities that lack access to proper sanitary infrastructure. While targeting health for all, especially the poor rural tribal communities, it is imperative to take these infections into account. Bayesian analysis phylogeny of food-borne trematode parasites under study showed that they are closely related phylogenetic groups. To focus the control strategies at the target populations, the aim of the present study was to establish molecular methods for accurate discrimination between common food-borne trematodes parasites Paragonimus (lung fluke), Fasciolopsis (giant intestinal fluke) and Fasciola (liver fluke), the infections of which commonly prevail in NE India. In the first step, we amplified and sequenced the second internal transcribed spacer (ITS2) region of ribosomal DNA, utilizing nucleotide differences between the multiple sequence alignments of the parasites under study. Based upon the differences in nucleotide sequences of conserved regions, we designed species-specific primers that can unequivocally discriminate one species from another. ITS2 sequence motifs allowed an accurate in-silico distinction of the trematodes. The data indicate that ITS2 motifs (≤ 50 bp in size) can be considered promising tool for trematode species identification. Using molecular morphometrics that is based on ITS2 secondary structure homologies, phylogenetic relationships with various isolates of several trematode species have been discussed. The present results suggest that the ITS2 specific primers can be used for epidemiological investigations of the prevalence of trematodiasis.
