Explanatum explanatum (Creplin, 1847) Fukui, 1929, in buffaloes in the Ahwaz area, southwest Iran

Assessment of antioxidant enzymes during the development of the digenetic trematode parasite Gastrothylax crumenifer, infecting the rumen of Indian water buffalo, Bubalus bubalis

The presence of antioxidant enzymes in helminth parasites is well known. These enzymes help the parasites to survive in their hosts by detoxifying host-generated reactive oxygen species (ROS). The literature survey reveals that most of the studies related to antioxidant enzymes in helminth parasites are restricted to the adult stage while the larval stages are neglected. The present investigation is designed to evaluate the level of antioxidant enzymes in the adult and larval stages of rumen-infecting paramphistome parasites, Gastrothylax crumenifer. The larval stages include 0-day eggs, 4-day eggs, and eggs containing mature miracidia, cercariae, and metacercariae. Antioxidant enzyme assays were performed using standard assay protocols. Our findings revealed an increasing pattern in the level of Glutathione-S-Transferase (GST), Superoxide Dismutase (SOD), Glutathione Reductase (GR), and Glutathione Peroxidase (GPx) antioxidant enzymes during the development from 0-day eggs to the adult stage. Overall analysis shows that adult worms have higher antioxidant enzyme activity as compared to the larval stages, indicating that adult flukes are more adapted to oxidative stress. It can be concluded that the miracidia, cercarial, and metacercarial developmental stages of G. crumenifer possess a considerable level of antioxidant enzymes suitable to overcome the oxidative stress encountered during the development and help them in the completion of the life cycle and survival in the definitive host.

Checklist of digenean trematodes of Iran

Digeneans are an important class of trematodes which infect variety of animals ranging from vertebrates (mainly final hosts) to invertebrates (mainly as intermediate hosts). Additionally, some of these parasites are zoonotic and one health importance. Diversity of digeneans in Iran and reports of several zoonotic cases show the importance of these parasites in this country. This is the checklist of digenean parasites reported from Iran representing a total of 118 species, from 105 genera, 43 families, 21 subfamilies, and 3 orders that are reported from 139 species of different hosts including humans. Some of the most important final number of families, genera, and species reported in Iran fauna include: Fasciolidae, Genus: Fasciola, Fasciola gigantica, Fasciola hepatica, Family: Dicrocoeliidae, Genus: Dicrocoelium, Dicrocoelium dendriticum, Family: Diplostomidae, Genus: Diplostomum, Diplostomum spathaceum, Family: Heterophyidae, Genus: Haplorchis, Haplorchis taichui, Family: Notocotylidae, Genus: Notocotylu, Notocotylus aegyptiacus, Family: Bucephalidae, Genus: Rhipidocotyle, Rhipidocotyle illense.

Geographic origin of Explanatum explanatum (Creplin, 1847) Fukui, 1929 detected from domestic water buffaloes in Sri Lanka

The adult stage of Explanatum explanatum has economic importance in the production of ruminants, especially water buffaloes. This species has been widely reported in the Indian sub-continent. Recently, molecular analyses to reveal the dispersal route of this species were performed in Bangladesh, Nepal, and India. In the present study, we focused on E. explanatum distributed in Sri Lanka. A total of 52 flukes were collected from water buffaloes in Sri Lanka and identified as E. explanatum based on the internal transcribed spacer 2 (ITS2) region of nuclear ribosomal DNA. Analysis of the mitochondrial NADH dehydrogenase subunit 1 (nad1) gene from DNA samples detected 18 haplotypes, and five of them were identical to those from the Indian E. explanatum. The pairwise fixation index value indicated that the Sri Lankan population had a comparatively closer relationship with the Indian population than with the Bangladeshi or Nepalese populations. The Sri Lankan population showed significantly lower genetic variability than the Indian population, suggesting that the Indian population was the ancestor of the Sri Lankan population. The movement of host ruminants, including water buffaloes, was probably involved in the introduction of the fluke into Sri Lanka. The results of our study provide useful information for elucidating the geographic origin of E. explanatum distributed in the Indian subcontinent.

Prevalence and risk factors associated with amphistome parasites in cattle in Iran

Amphistomiasis, a neglected trematode infection of ruminants, has recently come up as an important reason for economic losses. The aim of this study was to determine the prevalence of bovine amphistomiasis and associated risk factors such as: age, gender, breed, season, water source, pastureland and grazing system. Between January 2016 and 2017, a total of 1,000 faecal samples and 1,000 rumens of cattle were collected from slaughterhouse of Zabol, Iran ante-mortem and post-mortem, respectively, and examined. The overall prevalence was 34.6% and 19.5% in terms of amphistome adults and eggs respectively. The identified amphistome species and their prevalence were Paramphistomumcervi (13.3%), Cotylophoroncotylophorum (19.5%), Gastrothylaxcrumenifer (5.9%) and Carmyeriusspatiosus (2.7%). The correlation between prevalence and season, age, breed, water source, pastureland and grazing system was significant (p < .0001). The presented information about the prevalence of amphistomes of cattle and individual and management risk factors can be used to design appropriate control measures.

Incidence and pathological study of Explanatum explanatum (Creplin, 1847) Fukui, 1929 in goats in Andhra Pradesh, India

Amphistomiasis, caused by species of Paramphistomatidae is an economically important disease in ruminants. Explanatum explanatum is a very common amphistome in bile ducts and gall bladder of cattle and buffaloes worldwide where as in goats, it is exclusively found in Asian countries. Screening of livers from 100 sheep and 154 goats during slaughter at local slaughter houses from October, 2014 to April, 2015 in Andhra Pradesh (India) revealed presence of amphistomes in main bile ducts and gall bladder in three goats (1.9%) and were not observed in livers of sheep. Grossly, the affected livers were congested and the bile ducts were firm, thickened and occluded with amphistomes along with light yellowish foul smelling fluid. There were no apparent changes in gall bladder. Amphistomes were identified as E. explanatum by the standard staining technique using borax caramine. Microscopically, sections of liver revealed areas of haemarrhage, necrosis and infiltration of mononuclear cells in the parenchyma and surrounding the bile ducts. The wall of bile ducts revealed connective tissue proliferation with a characteristic mucosal plug of bile duct drawn into the acetabulum. There was hyperplasia of bile duct epithelium along with marked proliferation of mucosal glands and mononuclear cell infiltration. This paper appears to be the first report of E. explanatum in goats from Andhra Pradesh, India.

Morphological and molecular identification of Explanatum explanatum in domestic water buffalo in Pakistan

More than 70 species of the family Paramphistomatidae, have been identified in ruminants in different parts of the world. Most are pathogenic, causing amphistomosis. Adult flukes of this Family have a predilection for the rumen, liver or bile duct of ruminants where they may cause damage to the epithelium. Identification of adult paramphistomes to the species level based on morphology alone requires specialized knowledge, whereas, molecular genetic marker analysis is more precise and transferable. In the present study, we performed both morphological and molecular characterization of fifteen adult flukes collected from the liver of domesticated buffalo in the Punjab province of Pakistan. The morphology of five of these flukes was examined in detail and on this basis these were identified as either Explanatum explanatum or Explanatum bathycotyle. PCR and sequencing of the ITS-2 rDNA region from these 5 flukes, plus 10 others, revealed a single haplotype in all cases. This differed by just a single nucleotide polymorphism from a previously described E. explanatum ITS-2 rDNA sequence. Phylogenetic comparison of these E. explanatum ITS2-rDNA sequences with those from other Paramphistomatidae, Fasciola and Dicrocoelium species was performed to assess within and between species variation and validate the use of ITS-2 rDNA as a robust species-specific marker for E. explanatum. This work provides a validated species-specific marker of E. explanatum and the first report of this parasite species from Pakistan.

Molecular characterization and phylogenetic analysis of Explanatum explanatum in India based on nucleotide sequences of ribosomal ITS2 and the mitochondrial gene nad1

The aim of this study was to analyze the phylogenetic relationship between Explanatum explanatum populations in India and other countries of the Indian subcontinent. Seventy liver amphistomes collected from four localities in India were identified as E. explanatum based on the nucleotide sequences of ribosomal ITS2. The flukes were then analyzed phylogenetically based on the nucleotide sequence of the mitochondrial gene nad1 in comparison with flukes from Bangladesh and Nepal. In the resulting phylogenetic tree, the nad1 haplotypes from India were divided into four clades, and the flukes showing the haplotypes of clades A and C were predominant in India. The haplotypes of the clades A and C have also been detected in Bangladesh and Nepal, and therefore, it seems they occur commonly throughout the Indian subcontinent. The results of AMOVA suggested that gene flow was likely to occur between E. explanatum populations in these countries. These countries are geographically close and have been historically and culturally connected to each other, and therefore, the movements of host ruminants among these countries might have been involved in the migration of the flukes and their gene flow.

Molecular and phylogenetic analyses of the liver amphistome Explanatum explanatum (Creplin, 1847) Fukui, 1929 in ruminants from Bangladesh and Nepal based on nuclear ribosomal ITS2 and mitochondrial nad1 sequences

Explanatum explanatum flukes, liver amphistomes of ruminants, cause significant economic loss in the livestock industry by inducing severe liver damage. A total of 66 flukes from 26 buffaloes and 7 cattle in four different geographic areas of Bangladesh and 20 flukes from 10 buffaloes in the Chitwan district of Nepal were subjected for analysis. The sequences (442 bp) of the second internal transcribed spacer (ITS2) of ribosomal DNA and the variable fragments (657 bp) of mitochondrial nicotinamide dehydrogenase subunit 1 (nad1) of E. explanatum flukes from Bangladesh and Nepal were analysed. The aim of this study was molecular characterization of the flukes and to elucidate their origin and biogeography. In the ITS2 region, two genotypes were detected among the flukes from Bangladesh, while flukes from Nepal were of only one genotype. Phylogenetic analyses inferred from the nad1 gene revealed that at least four divergent populations (groups I–IV) are distributed in Bangladesh, whereas two divergent populations were found to be distributed in Nepal. Fst values (pairwise fixation index) suggest that Bangladeshi and Nepalese populations of group I to IV are significantly different from each other; but within groups III and IV, the populations from Bangladesh and Nepal were genetically close. This divergence in the nad1 gene indicates that each lineage of E. explanatum from diverse geography was co-adapted during the multiple domestication events of ruminants. This study, for the first time, provides molecular characterization of E. explanatum in Bangladesh and Nepal, and may provide useful information for elucidating its origin and dispersal route in Asia.