Search

Various studies have shown that the transmission and passage of alien and native pathogens play a critical role in the establishment process of an invasive species and its further spread. Egyptian geese (Alopochen aegyptiaca) are neozotic birds on various continents. They live not only in the countryside near fresh water bodies but also in urban habitats in Central Europe with close contact to humans and their pets. Although their rapid distribution in Europe is widely debated, scientific studies on the anthropozoonotic risks of the population and studies on the present endoparasites in Egyptian geese are rare worldwide. In the present study, 114 shot Egyptian geese and 148 non-invasively collected faecal samples of wild Egyptian geese from 11 different Federal States in Germany were examined. A total of 13 metazoan endoparasite species in 12 different genera were identified. The main endoparasites found were Hystrichis tricolor, Polymorphus minutus, and, in lesser abundance, Cloacotaenia sp. and Echinuria uncinata. Adult stages of Echinostoma revolutum, an anthropozoonotic heteroxenic trematode, were found in 7.9% of the animals examined postmortem. This species was additionally identified by molecular analysis. Although Egyptian geese live in communities with native waterfowl, it appears that they have a lower parasitic load in general. The acquisition of generalistic parasites in an alien species and the associated increased risk of infection for native species is known as "spill-back" and raises the question of impacts on native waterfowl. Differences between animals from rural populations and urban populations were observed. The present study represents the first large-scale survey on gastrointestinal parasites of free-ranging Egyptian geese. [ABSTRACT FROM AUTHOR]

Various studies have shown that the transmission and passage of alien and native pathogens play a critical role in the establishment process of an invasive species and its further spread. Egyptian geese (Alopochen aegyptiaca) are neozotic birds on various continents. They live not only in the countryside near fresh water bodies but also in urban habitats in Central Europe with close contact to humans and their pets. Although their rapid distribution in Europe is widely debated, scientific studies on the anthropozoonotic risks of the population and studies on the present endoparasites in Egyptian geese are rare worldwide. In the present study, 114 shot Egyptian geese and 148 non-invasively collected faecal samples of wild Egyptian geese from 11 different Federal States in Germany were examined. A total of 13 metazoan endoparasite species in 12 different genera were identified. The main endoparasites found were Hystrichis tricolor, Polymorphus minutus, and, in lesser abundance, Cloacotaenia sp. and Echinuria uncinata. Adult stages of Echinostoma revolutum, an anthropozoonotic heteroxenic trematode, were found in 7.9% of the animals examined postmortem. This species was additionally identified by molecular analysis. Although Egyptian geese live in communities with native waterfowl, it appears that they have a lower parasitic load in general. The acquisition of generalistic parasites in an alien species and the associated increased risk of infection for native species is known as “spill-back” and raises the question of impacts on native waterfowl. Differences between animals from rural populations and urban populations were observed. The present study represents the first large-scale survey on gastrointestinal parasites of free-ranging Egyptian geese.

The mallard Anas platyrhynchos is the most abundant water bird species in Austria, but there is no record of its helminth community. Therefore, this work aimed to close that gap by recording and analysing the parasite community of a large number of birds from Austria for the first time. A total of 60 specimens shot by hunters in autumn were examined for intestinal parasites. The following taxa were recovered (prevalence given in parentheses): Cestoda: Diorchis sp. (31.7%) and Fimbriarioides intermedia (1.7%); Acanthocephala: Filicollis anatis (5%), Polymorphus minutus (30%) and one cystacanth unidentified (1.7%); Trematoda: Apatemon gracilis (3.3%), Echinostoma grandis (6.7%), Echinostoma revolutum (6.7%) and Notocotylus attenuatus (23.3%); Nematoda: Porrocaecum crassum (1.7%) and one not identified (1.7%). The frequency distribution of parasites showed a typical pattern in which 39 birds (65%) were either not parasitized or were harbouring up to five worms, whereas more intense infestations occurred in a lesser number of hosts. Compared to other studies from central and eastern Europe, an extremely depauperate helminth community, particularly of the cestodes and nematodes, was found. Polymorphus minutus was observed as having highly variable morphology and, therefore, molecular genetic characterization by DNA barcoding was carried out. Species identification was confirmed by comparing data with the reference cytochrome c oxidase subunit 1 gene sequence from P. minutus available in GenBank. [ABSTRACT FROM AUTHOR]

Echinostome metacercariae were investigated in freshwater snails from 26 districts in 7 provinces of upper northern Thailand. The species identification was carried out based on the morphologies of the metacercariae and adult flukes harvested from experimental hamsters, and on nucleotide sequences of internal transcribed spacer 2 (ITS2) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) genes. Twenty-four out of 26 districts were found to be infected with echinostome metacercariae in freshwater snails with the prevalence of 40.4%. The metacercariae were found in all 6 species of snails, including Filopaludina martensi martensi (21.9%), Filopaludina doliaris (50.8%), F. sumatrensis polygramma (61.3%), Bithynia siamensis siamensis (14.5%), Bithynia pulchella (38.0%), and Anenthome helena (4.9%). The echinostome metacercariae found in these snails were identified as Echinostoma revolutum (37-collar-spined) and Echinostoma macrorchis (45-collar-spined) morphologically and molecularly. The 2-week-old adult flukes of E. revolutum revealed unique features of the cirrus sac extending to middle of the ventral sucker and smooth testes. E. macrorchis adults revealed the cirrus sac close to the right lateral margin of the ventral sucker and 2 large and elliptical testes with slight indentations and pointed posterior end of the posterior testis. The ITS2 and nad1 sequences confirmed the species identification of E. revolutum, and the sequences of E. macrorchis have been deposited for the first time in Gen- Bank. The presence of the life cycle of E. macrorchis is a new record in Thailand and the snail F. doliaris as their second intermediate host seems to be new among the literature. [ABSTRACT FROM AUTHOR]

Echinostoma flukes armed with 37 collar spines on their head collar are called as 37-collar-spined Echinostoma spp. (group) or 'Echinostoma revolutum group'. At least 56 nominal species have been described in this group. However, many of them were morphologically close to and difficult to distinguish from the other, thus synonymized with the others. However, some of the synonymies were disagreed by other researchers, and taxonomic debates have been continued. Fortunately, recent development of molecular techniques, in particular, sequencing of the mitochondrial (nad1 and cox1) and nuclear genes (ITS region; ITS1-5.8S-ITS2), has enabled us to obtain highly useful data on phylogenetic relationships of these 37-collar-spined Echinostoma spp. Thus, 16 different species are currently acknowledged to be valid worldwide, which include E. revolutum, E. bolschewense, E. caproni, E. cinetorchis, E. deserticum, E. lindoense, E. luisreyi, E. mekongi, E. miyagawai, E. nasincovae, E. novaezealandense, E. paraensei, E. paraulum, E. robustum, E. trivolvis, and Echinostoma sp. IG of Georgieva et al., 2013. The validity of the other 10 species is retained until further evaluation, including molecular analyses; E. acuticauda, E. barbosai, E. chloephagae, E. echinatum, E. jurini, E. nudicaudatum, E. parvocirrus, E. pinnicaudatum, E. ralli, and E. rodriguesi. In this review, the history of discovery and taxonomic debates on these 26 valid or validity-retained species are briefly reviewed. [ABSTRACT FROM AUTHOR]

Echinostoma revolutum is a zoonotic food-borne intestinal trematode that can cause intestinal bleeding, enteritis, and diarrhea in human and birds. To identify a suspected E. revolutum trematode from a red-crowned crane (Grus japonensis) and to reveal the genetic characteristics of its mitochondrial (mt) genome, the internal transcribed spacer (ITS) and complete mt genome sequence of this trematode were amplified. The results identified the trematode as E. revolutum. Its entire mt genome sequence was 15,714 bp in length, including 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and one non-coding region (NCR), with 61.73% A+T base content and a significant AT preference. The length of the 22 tRNA genes ranged from 59 bp to 70 bp, and their secondary structure showed the typical cloverleaf and D-loop structure. The length of the large subunit of rRNA (rrnL) and the small subunit of rRNA (rrnS) gene was 1,011 bp and 742 bp, respectively. Phylogenetic trees showed that E. revolutum and E. miyagawai clustered together, belonging to Echinostomatidae with Hypoderaeum conoideum. This study may enrich the mitochondrial gene database of Echinostoma trematodes and provide valuable data for studying the molecular identification and phylogeny of some digenean trematodes. [ABSTRACT FROM AUTHOR]

Abstract Precise discrimination of Echinostoma species within the ' revolutum ' group is quite difficult because of their morphological similarities. The objective of this study was to precisely characterize the echinostomes of ducks from Bangladesh based on both morphological and molecular characteristics. Two Echinostoma species were identified: E. revolutum and E. robustum. In the phylogenetic trees (ITS2 and nad1), E. revolutum and E. robustum belonged to their respective Eurasian clade, which is distinct from the American clade. These results suggest that both species have two distinct and geographically separated lineages, Eurasian and American. Our molecular and morphological data combined with previously published data supports the synonymy of E. robustum , E. miyagawai , and E. friedi previously based on either molecular or morphological evidence. This study thus improves our understanding of species diversity of the ' revolutum ' group, particularly in Asia. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The specific primer of E. revolutum was developed based on 18 s ribosomal DNA. • Discriminated the larval stage of E. revolutum from other Echinostome species. • Comparison of classical and molecular biology method for parasite identification. • Epidemiological situation of E. revolutum in Lopburi province, Thailand. Abstract Echinostomiasis caused by the Echinostoma group, in particular E. revolutum are a significant problem for both humans and other animals. This group has a large number of morphological similarities that are difficult and time-consuming to identify. The present study aimed to develop high-performance tools for the detection of the prevalence of E. revolutum and to reveal the prevalence of E. revolutum infections in intermediate snail hosts in Lopburi province, Thailand. The snail specimens were collected by stratified sampling method and examined to collect trematodes in the larval stage. The specific primer was manually designed and based on 18 s rDNA and verified the specificity and sensitivity for use as an identification tool to compare with classical method, constructed by epidemic mapping. The overall prevalence value of E. revolutum was found to be 16.26%. Tha Luang district had the highest prevalence (70.14%), followed by Chai Badan, Phatthana Nikhom, Tha Wung, Ban Mi, Khok Samrong, Nong Muang and Sa Bot at 42%, 25.14%, 2.52%, 1.73%, 2%, 1.33% and 0.40%, respectively. With regard to the specific primer, it can amplify both cercarial and metacercarial DNA (90 pg/μl.) and discriminated E. revolutum from its hosts, other trematodes and other echinostome larvae with no cross-reactions. Therefore, the developed specific primer can be used as a species-specific identification tool with a high degree of sensitivity and specificity. Consequently, this data is important for monitoring the outbreak of E. revolutum. It can be applied for initiating surveillance programs of snail-borne diseases in both medical and veterinary studies. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos de Ciências Veterinárias e Zoologia da Unipar is the property of Associacao Paranaense de Ensino e Cultura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Host-parasite interactions are often influenced by environmental factors through multiple mechanisms. For example, changes in host food resources may affect multiple host traits (e.g., body size, behavior, immunocompetence), which may increase or decrease infection levels and the impact of parasites on host fitness. We often lack an understanding of which traits are most important for parasite transmission and fitness effects, posing challenges to predicting consequences of changing environmental conditions (e.g., eutrophication). Here, I examined the effects of food resources and host traits experimentally in a larval frog ( Rana clamitans Latreille, 1801)-trematode parasite ( Echinostoma revolutum Looss, 1899) system. I hypothesized that higher food resources reduce parasite infection and parasite effects on host growth and survival, due to increased host investment in parasite defenses, which I tested in a laboratory experiment. Contrary to my hypothesis, the results indicated that increased food levels enhanced infection in hosts, while the effect of parasites on survival did not depend on host food resources. A potential explanation for the positive effect of food level on infection was size-dependent infection rates (i.e., higher food levels increased infection through increased host growth), which is supported by a positive relationship between host body size and infection. These findings emphasize the complex relationship between host food resources and parasitism and the importance of environmental context and host traits (i.e., body size) in mediating interactions with parasites. The results also have relevance for conservation in light of rising anthropogenic impacts on aquatic systems and recent amphibian declines. [ABSTRACT FROM AUTHOR]

Copyright of Avian Diseases is the property of American Association of Avian Pathologists, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To determine the prevalence of helminthic infections in Pursat Province, Cambodia, we tested fecal specimens from 471 children, 10–14 years of age, in June 2007. The prevalence of infection with echinostome flukes ranged from 7.5% to 22.4% in 4 schools surveyed. Adult worms were identified as Echinostoma revolutum.

The “37 collar-spined” or “ revolutum ” group of echinostomes is recognized as a species complex. The identification of members of this complex by morphological taxonomic characters is difficult and confusing, and hence, molecular analyses are a useful alternative method for molecular systematic studies. The current study examined the genetic diversity of those 37 collar-spined echinostomes which are recognized morphologically as Echinostoma revolutum in Thailand and Lao PDR using the cytochrome c oxidase subunit 1 (CO1) and the NADH dehydrogenase subunit 1 (ND1) sequences. On the basis of molecular investigations, at least two species of 37 collar-spined echinostomes exist in Southeast Asia, namely E. revolutum and Echinostoma miyagawai . The specimens examined in this study, coming from ducks in Thailand and Lao PDR, were compared to isolates from America, Europe and Australia for which DNA sequences are available in public databases. Haplotype analysis detected 6 and 26 haplotypes when comparing the CO1 sequences of E. revolutum and E. miyagawai , respectively, from different geographical isolates from Thailand and Lao PDR. The phylogenetic trees, ND1 haplotype network and genetic differentiation ( ɸ ST ) analyses showed that E. revolutum were genetically different on a continental scale, i.e. Eurasian and American lineages. [ABSTRACT FROM AUTHOR]

The aim of this work is to contribute to the knowledge of gastrointestinal parasites of the European starling Sturnus vulgaris, an invasive bird from Argentina. Seventy-six birds were collected during the spring of 2007 and were examined for helminths. Six parasite species were found: one trematoda of the Echinostoma revolutum 'group,' four nematodes ( Synhimantus nasuta, Microtetrameres sp., Pterothominx exilis, and Ornithocapillaria ovopunctata), and one acanthocephalan ( Plagiorhynchus cylindraceus). All species found have been recorded in Eurasia and/or North America previously, although present reports enlarge their geographical distribution. As expected in an invasive host, the parasite community shows much lower species richness ( n = 6) than those observed in their native area (79 and 35 in the Eurasia and North America, respectively). [ABSTRACT FROM AUTHOR]

Invasive species have the ability to rapidly and extensively alter native ecosystems, and there is accumulating evidence to suggest that the introduction of invasive hosts can have influences on parasite transmission in native communities. In 2002, the aquatic snail Bithynia tentaculata was discovered in the Upper Mississippi River (UMR) where it now co-occurs with several native snails and their parasites. The goal of this study was to determine the competencies of a native snail (Physa gyrina) and an invasive snail (B. tentaculata) after controlled exposure to a native parasite species (Echinostoma revolutum). Results of our laboratory experiment indicated no difference in either the prevalence or intensity of infection between native and invasive snails, which was unexpected given past work on B. tentaculata. In addition, infection had no discernible influence on host life-history traits such as growth and survival. Together, these results may have a number of consequences for hosts and parasites within the UMR region. First, the presence of an additional competent host in the snail assemblage may reduce infection risk for native snail species through parasite dilution. Second, the occurrence of a competent invasive host may increase the transmission of E. revolutum to native definitive host species such as waterfowl and mammals. Ultimately, a better understanding of how native parasites cycle through the UMR snail assemblage could allow us to better predict: 1) transmission/invasion outcomes in the UMR and 2) the potential alterations that may occur in ecosystems at high risk of B. tentaculata invasion. [ABSTRACT FROM AUTHOR]

Free-grazing ducks play a major role in the rural economy of Eastern Asia in the form of egg and meat production. In Thailand, the geographical location, tropical climate conditions and wetland areas of the country are suitable for their husbandry. These environmental factors also favor growth, multiplication, development, survival, and spread of duck parasites. In this study, a total of 90 free-grazing ducks from northern, central, and northeastern regions of Thailand were examined for intestinal helminth parasites, with special emphasis on zoonotic echinostomes. Of these, 51 (56.7%) were infected by one or more species of zoonotic echinostomes, Echinostoma revolutum, Echinoparyphium recurvatum, and Hypoderaeum conoideum. Echinostomes found were identified using morphological criteria when possible. ITS2 sequences were used to identify juvenile and incomplete worms. The prevalence of infection was relatively high in each region, namely, north, central, and northeast region was 63.2%, 54.5%, and 55.3%, respectively. The intensity of infection ranged up to 49 worms/infected duck. Free-grazing ducks clearly play an important role in the life cycle maintenance, spread, and transmission of these medically important echinostomes in Thailand. [ABSTRACT FROM AUTHOR]

To determine geographical patterns of natural parasite infections among wild rodents, a total of 46 wild rodents from 3 different localities in northern Gangwon-do (Province), Korea were examined for intestinal parasite infections. Along with nematodes such as hookworms and Syphacia spp., Plagiorchis muris (2 specimens) (Trematoda) were collected from striped field mice, Apodemus agrarius. In a Korean wood mouse, Apodemus peninsulae, the overall nematode infections were similar to A. agrarius, but an adult worm of Echinostoma hortense (Trematoda) was collected. In addition, 2 species of cestodes, i.e., Hymenolepis nana and Hymenolepis diminuta, were collected from A. agrarius. Through this survey, A. agrarius and A. peninsule were confirmed as the natural definite hosts for zoonotic intestinal helminths, i.e., P. muris, E. hortense, H. nana, and H. diminuta, in northern Gangwon-do, Korea. Considering increased leisure activities around these areas, seasonal and further comprehensive surveys on wild rodents seem to be needed to prevent zoonotic parasite infections. [ABSTRACT FROM AUTHOR]

The article presents a study on echinostoma hortense infection with enteritis in a dog. It discusses the diagnosis of echinostoma hortense infection using upper gastrointestinal endoscopy, the symptoms experienced by the dog, results of the upper gastrointestinal endoscopy and treatment performed for parasites and enteritis.

A total of 124 specimens of the tufted duck, Aythya fuligula, and 63 greater scaup, A. marila, were examined for digenean parasites. Both duck species, which overwinter in a coastal lake connected with the southern Baltic (north-west Poland) were found to support Amblosoma exile, Cyathocotyle prussica,Paracoenogonimus ovatus, Australapatemon minor, Cotylurus cornutus, Echinoparyphium recurvatum, Echinostoma revolutum and Notocotylus attenuatus. In addition, the tufted duck hosted Hypoderaeum conoideum, Bilharziella polonica, Neoeucotyle zakharovi, Renicola mediovitellata, Psilochasmus oxyurus, Psilostomum brevicolle and Cryptocotyle concava; Echinostoma nordiana occurred in the greater scaup only. The two duck species differed significantly in the intensity and abundance of their digenean infection. Aythya marila harboured higher intensity levels and a wider assemblage of digeneans than A. fuligula, and this was likely to be due to differences in the pre-wintering exposure of the duck species to infective stages of these freshwater digeneans. Digenean communities in both duck species, strongly dominated by E. recurvatum, were relatively similar in their structure. No significant sex-dependent differences in digenean infections were revealed, except for the infection with N. attenuatus in A. fuligula. Similarly, there were no significant age-dependent differences (adult versus immature birds) in digenean infections, except for that with N. attenuatus in A. fuligula. The structural similarity between digenean communities in the two duck species is most likely an effect of overlapping diets based on freshwater molluscs, components of the digenean transmission pathway to definitive hosts. [ABSTRACT FROM AUTHOR]

Background: The digenean species of Echinostoma (Echinostomatidae) with 37 collar spines that comprise the socalled 'revolutum' species complex, qualify as cryptic due to the interspecific homogeneity of characters used to differentiate species. Only five species were considered valid in the most recent revision of the group but recent molecular studies have demonstrated a higher diversity within the group. In a study of the digeneans parasitising molluscs in central and northern Europe we found that Radix auricularia, R. peregra and Stagnicola palustris were infected with larval stages of two cryptic species of the 'revolutum' complex, one resembling E. revolutum and one undescribed species, Echinostoma sp. IG. This paper provides morphological and molecular evidence for their delimitation. Methods: Totals of 2,030 R. auricularia, 357 R. peregra and 577 S. palustris were collected in seven reservoirs of the River Ruhr catchment area in Germany and a total of 573 R. peregra was collected in five lakes in Iceland. Cercariae were examined and identified live and fixed in molecular grade ethanol for DNA isolation and in hot/cold 4% formaldehyde solution for obtaining measurements from fixed materials. Partial fragments of the mitochondrial gene nicotinamide adenine dinucleotide dehydrogenase subunit 1 (nad1) were amplified for 14 isolates. Results: Detailed examination of cercarial morphology allowed us to differentiate the cercariae of the two Echinostoma spp. of the 'revolutum' species complex. A total of 14 partial nad1 sequences was generated and aligned with selected published sequences for eight species of the 'revolutum' species complex. Both NJ and BI analyses resulted in consensus trees with similar topologies in which the isolates from Europe formed strongly supported reciprocally monophyletic lineages. The analyses also provided evidence that North American isolates identified as E. revolutum represent another cryptic species of the 'revolutum' species complex. Conclusion: Our findings highlight the need for further analyses of patterns of interspecific variation based on molecular and morphological evidence to enhance the re-evaluation of the species and advance our understanding of the relationships within the 'revolutum' group of Echinostoma. [ABSTRACT FROM AUTHOR]

The occurrence of 37-collar spined echinostome metacercariae in freshwater snails was investigated in 6 districts of Chiang Mai Province, Thailand, from October 2011 to April 2012. A total of 2,914 snails that belong to 12 species were examined, and 7 snail species (Clea helena, Eyriesia eyriesi, Bithynia funiculata, Bithynia siamensis siamensis, Filopaludina doliaris, Filopaludina sumatrensis polygramma, and Filopaludina martensi martens1) were found infected with echinostome metacercariae. The prevalence of metacercariae was the highest in Filopaludina spp. (38.5-58.7%) followed by B. funiculata (44.0%), E. eyriesi (12.5%), B. siamensis siamensis (8.2%), and C. helena (5.1%). Metacercariae were experimentally fed to hamsters and domestic chicks, and adult flukes were recovered from both hosts at days 15 and 20 post-infection. The adult flukes were identified based on morphological features, morphometrics, host-parasite relationships, and geographical distribution. They were compatible to Echinostoma revolutum or Echinostoma jurini, with only minor differences. As the adults were recovered from both hamsters and chicks, our specimens were more compatible to E. revolutum rather than E. jurini (reported only from mammals). This is the first report for metacercariae of E. revolutum in the snail host, C. helena, and also confirmed that Filopaludina spp., E. eryresi, and Bithynia spp. act as the second intermediate hosts of E. revolutum under natural conditions, which are indigenously distributed in Chiang Mai province. [ABSTRACT FROM AUTHOR]

The neuromuscular system in cercariae of Moliniella anceps, Echinostoma revolutum, Cathaemasia hians, Psilochasmus oxyurus, Sphaeridiotrema globulus, Paramphistomum cervi and Diplodiscus subclavatus was studied with immunocytochemical methods and confocal scanning laser microscopy. The patterns of F-actin in the musculature, 5-HT immunoreactive (IR), FMRFamide-IR neuronal elements and α-tubulin-IR sensory receptors were investigated. The general patterns of musculature, 5-HT- and FMRFamide-IR neuronal elements in the 12 species studied here and in paper I are similar to those observed in other cercariae and reflect the morphology of the groups. The musculature of the tail shows variations which are related to the different strategies of host finding. In the Echinostomatoidea and Paramphistomoidea, the striated musculature of the tail is well developed compared to that in the Xiphidiocercariae. Specialized muscle fibres were found in S. globulus, which are able to change the shape of the tail. Nine of the species studied have seven paired 5-HT-IR neurons in the body, and two species have eight. No correlation between the body size and the number of 5-HT-IR neurons was observed. However, the size of the neurons followed the body size. The number of 5-HT-IR neurons in the brain ganglia increased from the primitive to the advanced forms. The number of FMRFamide-IR transverse commissures in the body correlates with the size of the cercariae. Regardless of the differences in the second intermediate host, the distribution of α-tubulin-IR sensory receptors shows a high degree of conformity in all species except in P. cervi, which encysts on plants. [ABSTRACT FROM AUTHOR]

Echinostome eggs were detected in 22 (1.1 %) of 2,074 people residing in riparian villages along the Mekong River in Khammouane Province, Lao PDR. In order to recover the adult flukes, 9 persons were treated with praziquantel and purged with magnesium salts. A total of 55 echinostome specimens (4 species) were recovered from the 9 persons. Echinostoma revolutum (8 specimens) was recovered from 3 persons, Artyfechinostomum malayanum (8 specimens) was from 2 persons, Echinochasmusjaponicus (33 specimens) was from 7 persons, and Euparyphium sp. (6 specimens) was from 1 person. In Lao PDR, only human infections with E. japonicus were previously known. Therefore, the present study describes human infections with E. revolutum, A. malayanum, and Euparyphium sp. for the first time in Lao PDR. These results indicate that the surveyed villages of Khammouane Province, Lao PDR are low-grade endemic foci of echinostomiasis. [ABSTRACT FROM AUTHOR]

We detected metacercariae of Echinostoma revolutum in Filopaludina sp. snails purchased from a local market in Nam Dinh Province for the first time in Vietnam. Adult flukes were harvested from experimentally infected hamsters at days 14 and 17 post-infection. The metacercariae were round, 170-190 µm (n=15) in diameter, with a cyst wall thickness of about 12 µm. A total of 37 collar spines were arranged around the head collar, and large excretory granules were seen in 2 canals of the excretory bladder. The 14-day old adult flukes were elongated, ventrally curved, and 5.0-7.2 x 0.8-1.3 mm (n=20). The head collar had a total of 37 collar spines arranged in 2 alternating rows, including 5 corner spines on each side. The cirrus sac contained a saccular seminal vesicle, a prostatic gland, and an unarmed cirrus. Two tandem testes were smooth or slightly lobed. Eggs were ovoid to elliptical, 110-118 x 70-75 µm. These morphological characters were similar to those of E. revolutum and E. jurini. We tentatively identified it as E. revolutum because the validity of E. jurini remains to be elucidated. The taxonomic relationship of E. revolutum and E. jurini is discussed. [ABSTRACT FROM AUTHOR]

Abstract: A total of 314 individual Echinostoma revolutum were collected at different locations and times from domestic ducks from Khon Kaen Province, Thailand and Vientiane Province, the Lao People''s Democratic Republic (PDR). Genetic variation of these parasites was analyzed using multilocus enzyme electrophoresis at three polymorphic loci namely, glucose-6-phosphate dehydrogenase (G6pd), malic enzyme (Me) and peptidase valine-leucine (PepA). High levels of genetic variability were found within and between populations. Significant heterozygote deficiencies compared with the predictions under Hardy–Weinberg equilibrium were detected in populations from Thailand and the Lao PDR for all loci except G6pd-1. Significant genetic differentiation was observed between spatially separated populations from Thailand and the Lao PDR. This as also true for some samples collected at different times in Thailand. The variability found may be consistent with a Wahlund effect, genetic drift and/or other factors such as the population structure of snail hosts. Our data provide further insight into the process of genetic divergence within and among geographically and temporally isolated populations of E. revolutum, and potentially other medically important echinostomes in Southeast Asia. [Copyright &y& Elsevier]

The increasing threat of emerging infectious diseases in both wildlife and humans has spurred interest in the causes of disease emergence, including the role of anthropogenic change. A prior field study of infection patterns in amphibians suggests that echinostome infection may be an emerging disease of green frogs Rana clamitans living in urbanized environments. We examined the impact of echinostome infection on green frog tadpoles at a wide range of developmental stages (Gosner stage 25–39). Echinostome infection was associated with green frog mortality rates of up to 40% in an early developmental stage, and none in later developmental stages. Tadpoles exposed to higher echinostome doses exhibited higher edema rates, a potential sign of compromised renal function. Histopathological analysis further supported the hypothesis that echinostome-induced tadpole mortality resulted from compromised renal function. Given that the timing of highest cercarial shedding can coincide with the most vulnerable stages of green frog tadpole development, echinostomes could significantly impact green frog survival in nature. [ABSTRACT FROM AUTHOR]

Abstract: A field trial was carried out in West Java to investigate the potential for control of fasciolosis of antagonism between larvae of Fasciola gigantica and Echinostoma revolutum in Lymnaea rubiginosa. The trial was undertaken in 26 farmers’ irrigated rice fields, each chosen because it was adjacent to a cattle pen the effluent from which flowed into or was used as fertiliser in the rice field. Fourteen of the fields chosen at random were retained as controls and received no treatment while in 12, faeces from 5 to 15 ducks containing eggs of E. revolutum were introduced to the rice from a duck pen located over the effluent drain from the cattle pen before it emptied into the adjacent rice field, or at the site bovine faeces was added to the field as fertiliser. After harvest significantly fewer L. rubiginosa were found infected with F. gigantica in fields where duck and cattle dung entered the field together than in control fields, supporting a conclusion that this method of biological control would reduce the infectivity of rice fields fertilised with bovine dung (which are those with the highest potential for being a source of infection with F. gigantica). Positive features of using dung from ducks infected with E. revolutum to control F. gigantica are the minimum additional work and disruption to existing farming practices required to implement the scheme, the common natural infection with E. revolutum in village ducks, and effectiveness of dung from 5 to 15 ducks, a number commonly kept by farmers. [Copyright &y& Elsevier]