Rumen Fluke Research Articles

A Study into the Identity, Patterns of Infection and Potential Pathological Effects of Rumen Fluke and the Frequency of Co-Infections with Liver Fluke in Cattle and Sheep

Rumen fluke (RF) are trematode parasites that have increased in prevalence within European ruminant livestock since the 1990s. Morbidity and mortality can result from the development of juvenile flukes in the duodenum, however, evidence for significant impacts of adult fluke in the rumen of the final host is equivocal. The presence of rumen fluke in Scotland had not previously been quantified, so the purpose of this study was to use historical coprological data collected between 2008 and 2018 at the School of Veterinary Medicine in Glasgow to evaluate the frequency of rumen fluke infection and to compare this with the presence of liver fluke. This analysis showed evidence of adult rumen fluke in 6.6% of samples submitted, with a substantial and significant increase in positive diagnoses from 2016, following which positive rumen fluke diagnoses equaled or slightly outnumbered those of liver fluke. A prospective post-mortem examination study was also carried out to determine the presence of rumen and liver fluke in cattle and sheep, to quantify adult rumen fluke burdens and to assess any pathological changes in the reticulorumen and proximal duodenum associated with infection. The presence of rumen fluke in post-mortem cases was 26.9% (n = 18/67), the majority (66.7%, n = 12/18) with burdens of less than 100 adult rumen flukes. There was no significant difference in mean ruminal papillar density and length in animals with and without adult rumen fluke and no significant gross pathology was observed in the rumen or reticulum. Examination of animals with adult rumen fluke provided no evidence of any consistent associations with acute or chronic inflammatory changes in the duodenum. All rumen fluke collected at necropsy were identified by PCR and sequencing as Calicophoron daubneyi.

Calicophoron daubneyi (Dinnik, 1962) (Digenea) in beef and dairy cattle in the Czech Republic: prevalence and drug efficacy.

A total of 1,724 beef and 2,941 dairy cattle older than one year from 66 beef and 67 dairy farms in the Czech Republic were examined for the presence of rumen and liver fluke eggs in 2019-2022. Out of 227 positive animals, all were positive for paramphistome and five for fasciolid eggs. Molecular analysis of the ITS2 rDNA revealed the presence of Calicophoron daubneyi (Dinnik, 1962) and Fasciola hepatica Linnaeus, 1758. Faecal egg count (FEC) showed low infection intensity (12 EPG) in animals infected with F. hepatica and high variability in C. daubneyi infections (2-589 EPG). Efficacy of oxyclozanide, albendazole, ivermectin, and closantel against C. daubneyi infection was evaluated at eight beef cattle herds. Faecal samples were collected from all positive animals at 0 and 21days post-treatment. Based on FEC, albendazole, ivermectin and closantel reduced the number of C. daubneyi eggs shed by 0-9.9%, with no effect on the number of infected animals. The use of oxyclozanide on two beef farms showed 100% efficacy against C. daubneyi and F. hepatica. Follow-up examination 5-6 months after drug application showed reinfection of most animals with C. daubneyi, but the FEC was significantly lower. The finding of four dairy cows infected with C. daubneyi housed in a stable without pasture suggests the possibility of the infection being introduced through roughage.

A survey of sheep and/or cattle farmers in the UK shows confusion over the diagnosis and control of rumen fluke and liver fluke

Calicophoron daubneyi (rumen fluke) is an emerging parasitic infection of livestock across Europe. Despite increasing in prevalence, little is known about the level of awareness of rumen fluke or current control practices used by UK farmers. Fasciola hepatica (liver fluke) is a common parasitic infection of cattle and sheep in the UK. Co-infections with these parasites can present in sheep and cattle, but the only drug with reported efficacy against rumen fluke is oxyclozanide. Between December 2019 and March 2020, 451 sheep and/or cattle farmers completed an online questionnaire, capturing their awareness and current means of control for liver fluke and rumen fluke. Most respondents (70%) were aware of rumen fluke, with 14% recording its presence on their farms and 18% having previously treated for rumen fluke. Almost all respondents (99%) were aware of liver fluke and higher numbers of respondents reported its presence on farm (67%) with 88% having previously treated for liver fluke. Respondents who were aware of rumen fluke said they were concerned about the parasite (81%), although rumen fluke was less of a concern than liver fluke (p < 0.05). Of respondents who reported rumen fluke presence on their farm, 42% cited incorrect diagnostic methods, including those traditionally used to detect liver fluke. Respondents were more likely to treat annually for liver fluke, as opposed to rumen fluke (p < 0.05). The most frequently used drug for the treatment of liver fluke infection was triclabendazole (53% sheep treatments, 34% cattle treatments) and only a minority of farmers treated with a product effective against rumen fluke (oxyclozanide; 42% cattle treatments, 35% sheep treatments). A small proportion of farmers stated that they used a non-flukicide drug to treat sheep for liver fluke infection (1.6% sheep treatments). These results demonstrate a broad awareness of liver and rumen fluke in sheep and cattle, but reveal confusion amongst farmers about their diagnosis and treatment, highlighting the need to provide best practice advice to the livestock industry for the control of both parasites.

Effect of rumen fluke on feed digestibility and methane emissions in sheep.

Thirty-six ewes aged 18months were assigned to one of three groups (n = 12) on the basis of faecal egg count (FEC) for rumen fluke; C: control (FEC = 0-5 epg), T: affected (FEC ≥ 6 epg) and treated, NT: affected (FEC ≥ 6 epg) and not treated. T ewes were treated with oxyclozanide 14days prior to the trial commencing. Ewes were fed grass silage ad libitum. Digestibility crates and respiration chambers were used to measure feed digestibility and methane production. Dry matter intake (DMI), feed digestibility and CH4/DMI did not differ (P > 0.05) between treatments. However, CH4/live weight (LW) was significantly greater (P < 0.001) for NT ewes, while that of C and T ewes were similar. This study indicates that a high rumen fluke burden can increase methane emissions but only when expressed on a body weight basis (per kg LW). As the link between rumen fluke infection and methane production has not previously been investigated within the literature, these findings demonstrate the need for further research to better understand these relationships.

The effect of naturally acquired rumen fluke infection on animal health and production in dairy and beef cattle in the UK.

The incidence of paramphistomosis, caused by the rumen fluke, Calicophoron daubneyi, has greatly increased within Europe in the last 15–20 years. However, the production impacts of this disease are poorly understood. This study firstly aimed to investigate the prevalence of rumen fluke in England and Northern Ireland (NI) by conducting an abattoir survey of dairy and beef cattle which also allowed the impact of rumen fluke on carcass weight, conformation and fat classification to be assessed. Secondly, an experiment aimed to assess the impact of C. daubneyi infection on diarrhea score, production loss and welfare in dairy heifers, while also evaluating the impacts of treating infected heifers with oxyclozanide. Rumen fluke prevalence was greater in NI than in England, with 53.8% (95% CI 51.9 - 55.9%) of the NI cattle carcases sampled being infected compared to 16.3% (95% CI 15.8 - 16.8%) and 17.9% (95% CI 17.4 - 18.4%) detected at the two abattoirs in England. However, there was no significant difference (P > 0.05) in the cold carcass weight between infected and non-infected cattle. Similarly, carcass conformation and fat classification were unaffected (P > 0.05) by the presence of rumen fluke. In the second experiment, daily live weight gain (DLWG), diarrhea score and welfare score were also unaffected (P > 0.05) by rumen fluke infection and by oxyclozanide treatment against rumen fluke. The farms in this experiment were managed to a high standard and animals had no intercurrent disease. Therefore, these findings suggest that on well–managed farms, production losses (growth rates) should not be compromised as a result of sub-clinical rumen fluke infection.

Morphological and molecular characterization of Calicophoron raja (Näsmark, 1937) collected from wild Bovidae in South Africa

Paramphistomes, commonly known as rumen flukes, are digenean parasites that infect ruminants. Accurate morphological identification of paramphistome species is challenging and often neglected. For instance, it requires sagittal midline sections of adult flukes, which are difficult to prepare. Therefore, the majority of the genetic information on paramphistomes found in the International Nucleotide Sequence Database is not supported by morphological descriptions, and the DNA barcodes of paramphistome species remain unreliable. In the present study, both morphological and molecular characterizations were simultaneously performed to ensure the reliability of the DNA information for the paramphistome species Calichophoron raja (Näsmark, 1937). The morphological characteristics of the sagittal and horizontal sections of adult flukes from a black wildebeest (Connochaetes gnou) and a waterbuck (Kobus ellipsiprymnus) in South Africa were identical to those previously described for Ca. raja. Additionally, this study represents a new host record of the species from Co. gnou. All sequences of the internal transcribed spacer 2 region of ribosomal DNA were 100% identical among the 18 flukes analyzed in the present study. A single nucleotide mutation was observed between Ca. raja in this study and Ca. raja detected in domestic ruminants in Kenya.

Rumen Fluke in Cattle and Buffaloes in Asia: A Review

Rumen fluke is a parasitosis that infects ruminant animals across a wide geographical range of countries. It is a severe infection in temperate and tropical climate regions of Asia, Australia, Africa, and Europe, which cause significant economic losses. In this review, the available information to date on rumen fluke species infecting cattle and buffaloes in Asian countries is evaluated. The citation search was performed through specific keywords, literature published from 1964 to 2021, retrieved from electronic databases: Scopus, Web of Science, Pub Med, Education Resources Information Center (ERIC), Science Direct, Elsevier, and Google Scholar. Twenty-six (26) rumen fluke species belonging to two families: Paramphistomidae 61.5% (16/26) and Gastrothylacidae 38.4% (10/26), were reported in cattle and buffaloes in fourteen Asian countries. Paramphistomum cervi and Cotylophoron cotylophorum are the most prevalent species with broader distribution in countries than the other genera. The coprological prevalence varies from 0.8% to 98.17% and 0.86% to 78.4% in cattle and buffaloes, respectively. The prevalence of rumen fluke by fluke counts method range between 6.45% to 90.6% and 4.29% to 75.07% in cattle and buffaloes, respectively. The sedimentation method and fluke count are reliable tests for detecting rumen fluke in live and slaughtered animals. In conclusion, the rumen fluke should be considered a critical production disease that affects cattle and buffaloes in Asia. Further studies are necessary to determine the rumen fluke-snail associations, develop diagnostic tests to detect prepatent infections in the definitive host, determine the economic importance of rumen fluke, and determine the efficacy of different anthelmintic in the treatment of patent infections in the definitive host.

Introduced European bison (Bison bonasus) in a confined forest district: A ten year parasitological survey.

In the year 2012 a total of seven individuals (one bull and six cows) of European bison (Bison bonasus) were introduced to a fenced 200 ha area in a forest district (Almindingen, Island Bornholm, Denmark) in the Baltic Sea. In 2017 the herd was supplemented by introduction of another bull. The animals all originated from a population in the Polish Bialowieza forest. Faecal samples were recovered with intervals and subjected to a copro-parasitological investigation (applying egg flotation, sedimentation and Baermann technique). In addition, parasites were sampled during necropsy of animals euthanized or found dead three years after introduction. The animals carried a range of parasite types including trematodes (liver fluke Fasciola and rumen fluke), cestodes (Moniezia), nematodes (Dictyocaulus viviparus, trichurids, and other gastrointestinal nematodes (GIN) including Trichostrongylus axei and Haemonchus contortus). Egg and larval morphology also suggested presence of GIN genera Nematodirus, Ostertagia and Cooperia. The trematodes did not establish a life cycle in the recipient area, as judged by examination of calves born in the new area, but the cestode and several nematode species occurred in these animals. Especially Dictyocaulus viviparus was successfully spread and occurred together with GIN at moderate to high infection intensities at most sampling points. The reproduction among bison in the herd was high during the first few years. The exact birth rate is unknown but up to 24 calves are believed to be born during the ten year study period. Mortality among adults and calves occurred and in early June 2022 the total number of live animals was 11 (seven males, three females, one calf). The possible impact of the parasite infections on the bison health and future wildlife infection status is discussed.

Results of Parasitological Monitoring of Beef Cattle Herds in the Czech Republic, With First Description of the Occurrence of Invasive Rumen Fluke Calicophoron daubneyi in Beef Herds

Dynamic changes in the farming practices, growing numbers of beef farmers and geographic distribution of beef cattle herds in the Czech Republic impact on helminth parasites of cattle and vice versa. We summarize in a brief form results of parasitological examination of samples collected by farmers from range of beef cattle farms across the whole Czech Republic in order to provide baseline data for parasite control and to report occurrence of an invasive rumen fluke Calicophoron daubneyi in the country.

Rumen fluke infections (Paramphistomidae) in diarrhoeal cattle in western France and association with production parameters.

This study was conducted to assess the impact of rumen flukes (RFs) (Paramphistomatidae) on various production parameters of cattle in Normandy. Faecal and blood samples were taken between 1 January 2010 and 31 December 2019 as part of the routine diagnostic activity for diarrhoea in weaned cattle, including a quantitative parasitological analysis coupled with a search for Johne's disease (paratuberculosis). Information on slaughter and carcass weight, inter-farm movements and mortality was obtained from the French national registration database (BDNI). The study was conducted at two levels using adapted categorical RF variables: 1) at the cattle level (>12months), an estimation of presence of adult parasites using egg count in faecal samples (negative vs. positive) and 2) at the herd level, an estimation of 6-24months of the dairy heifers exposure to larval forms on the basis of the proportion of dairy cattle shedding eggs in the herd (three classes). At the cattle level, the outcome variables were carcass weight (model 1), case-control status for mortality within 30days of diagnosis (model 2) and case-control status for slaughter within 365days of diagnosis (model 3). At the herd level, the outcome variable was the mortality ratio for dairy heifers aged 6-24months (Model 4). Other important covariates were used to improve model fit. Multivariate analyses were performed using a linear mixed model (model 1), generalised estimating equations (GEE) (models 2 and 3) and a multinomial logistic model (model 4). Overall, 1291 out of 4315 cattle (29.9%) were found to excrete RF eggs and 19.6% of the positives had an excretion score of >200 eggs/g. The prevalence increased steadily with age class and was higher in beef cattle than dairy cattle (42.7% vs. 26.9%) in the years 2015-2019 compared to 2010-2014 (33.3% vs. 26.5%) and in November-February (33.2%) compared to March-June (28.9%) and July-October (27.3%). Rumen fluke variables were not found to be explanatory factors of outcome variables at both animal and herd levels. In contrast, significant negative associations were observed between outcome variables and other health covariates, such as Johne's disease, GI nematode, bovine viral diarrhoea and coccidia statuses. In conclusion, RFs are prevalent in cattle reared in Normandy but this does not result in significant production losses. Therefore, the value to farmers of oxyclozanide treatment at an effective dose for paramphistomosis after simple identification of RF eggs in the faeces seems limited.

Rumen and Liver Fluke Infections in Sheep and Goats in Northern and Southern Germany

Simple SummaryLittle is known about the distribution of rumen and liver flukes in sheep and goats in Germany or about the occurring rumen fluke species. These fluke infections can be detected by the parasite’s eggs in the host animal’s feces. Therefore, fecal samples from 223 sheep farms and 143 goat farms from northern and southern Germany were examined. The eggs of rumen flukes were detected on 2.2% of the samples, the eggs of common liver flukes on 2.7%, and the eggs of small liver flukes on 21.1% of the examined sheep farms. The rumen flukes were identified as the emerging species Calicophoron daubneyi. No rumen fluke eggs were detected on any of the goat farm samples, but common and small liver fluke eggs were detected in 5.6% and 7.0% of the goat herds, respectively. Differences in the geographical distribution of rumen and liver flukes between and within the two regions were identified. Rumen flukes were more frequently found in the north, while the two liver fluke species were more frequently found in the south of Germany. Sheep sharing the pasture with other ruminants were more likely to be infected with rumen flukes.Paramphistomidosis has recently been identified as an emerging parasitosis in Europe. This study estimated the prevalence of rumen flukes, Fasciola hepatica and Dicrocoelium dendriticum, in small ruminants in Germany and identified occurring rumen fluke species and potential predictors for fluke infections. Pooled fecal samples from 223 sheep farms and 143 goat farms in northern and southern Germany were examined by the sedimentation technique, and molecular species identification was performed on rumen-fluke-positive samples. In sheep, a flock prevalence of 2.2% was detected for rumen flukes. Calicophoron daubneyi was identified on four of five positive farms, while species identification failed in one flock. No rumen fluke eggs were detected in the examined goat herds. F. hepatica eggs were detected in 2.7% of the sheep flocks, while the herd prevalence was 5.6% in goats. Higher prevalence values of 21.1% (sheep) and 7.0% (goats) were observed for D. dendriticum. Mixed grazing with other ruminants and previously identified infections with rumen flukes and/or F. hepatica were identified as predictors for paramphistomidosis. The distribution of the three trematode species followed a geographical pattern associated with conditions favoring the relevant intermediate hosts. C. daubneyi is an established parasite in German sheep at a currently low prevalence.

Effect of arecoline, aqueous and methanolic areca nut extracts on rumen fluke

Paramphistomosis is a parasitic disease that causes a reduction of livestock production and economic losses worldwide. In order to avoid side effect and chemical residue from usage of chemical drugs, medicinal plant is an alternative drug for treatment. Areaca nut (Areaca catechu) which one of the domestic plants in Southeast Asia had antihelmintic activity. In this study, arecoline, aqueous and methanolic extracts of areca nut prepared in solutions were tested for antihelmintic activity against rumen flukes (Paramphistomum sp.). The parasites were incubated in a culture media (RPMI-1640, pH 8) at 39°C in a carbon dioxide-incubator containing 0.01, 0.1 and 1 mg/mL of the tested compounds for 15, 30 min, 1 h and 24 h. The results showed that the methanolic and aqueous crude extracts from seeds of Areaca catechu and arecoline HBr at concentration of 1 mg/mL solutions could destroy the tegument (surface membrane) of the flukes and killed them all at initial time. Thus, these areca nut extracts exhibited the potential alternative medicine with antihelmintic activity against rumen flukes.

Pasture rewetting in the context of nature conservation shows no long-term impact on endoparasite infections in sheep and cattle

BackgroundNature conservation with reduced drainage of pastures has been increasingly promoted in agriculture in recent years. However, moisture on pastures is a crucial factor for the development of free-living stages of many parasite species in ruminants. Hence, for the first time, we conducted a field study between 2015 and 2017 at the German North Sea coast to investigate the long-term effect of pasture rewetting (since 2004) on endoparasite infections in sheep and cattle.MethodsWe examined faecal samples of 474 sheep and 646 cattle from five farms in spring, summer and autumn each year for the presence of endoparasite infections. Animals were kept on conventionally drained, undrained and rewetted pastures. The association between pasture rewetting and endoparasite infection probability was analysed in generalized linear mixed models and including further potential confounders.ResultsInfection frequencies for gastrointestinal strongyles, Eimeria spp. and Strongyloides papillosus were significantly higher in sheep (62.9%, 31.7% and 16.7%) than in cattle (39.0%, 19.7% and 2.6%). Fasciola hepatica was detected with a frequency of 13.3% in sheep and 9.8% in cattle, while rumen fluke frequency was significantly higher in cattle (12.7%) than in sheep (3.8%). Nematodirus spp., lungworms (protostrongylids, Dictyocaulus viviparus), Moniezia spp., Trichuris spp. and Dicrocoelium dendriticum were identified in less than 7% of samples. Co-infection with more than three endoparasite taxa was present significantly more often in sheep than in cattle. We identified significant positive correlations above 0.2 for excretion intensities between S. papillosus with strongyles, Eimeria spp. and Nematodirus spp. in sheep and between strongyles and Nematodirus spp. in cattle. Pasture rewetting had no long-term effect on endoparasite infections, neither in sheep nor in cattle. Interestingly, F. hepatica infections decreased significantly in sheep and cattle from 2015 (10.9% and 13.9%) to 2017 (1.4% and 2.1%).ConclusionsPasture rewetting for nature conservation did not increase endoparasite infection probability in ruminants in the long term. This finding should be confirmed in ongoing studies aimed at further animal welfare parameters. The rapid decrease in F. hepatica infections over 3 years may suggest climatic impact or competition with rumen flukes in addition to potential anthelmintic treatment after feedback of the results to the farmers.Graphical

Exploration of factors associated with spatial-temporal veterinary surveillance diagnoses of rumen fluke (Calicophoron daubneyi) infections in ruminants using zero-inflated mixed modelling.

Rumen fluke (Calicophoron daubneyi) has emerged as a prominent parasite of ruminants in Europe over the past decades. Epidemiological questions remain regarding this observed increase in prevalence as well as the prospect for future paramphistomosis risk. This study aimed to identify factors associated with the temporal−spatial prevalence of rumen fluke as measured by veterinary surveillance in a temperate region using zero-inflated negative binomial mixed modelling. Modelling revealed that summer rainfall, raindays and sunshine hours and mean winter temperature as significant positively associated climate variables for rumen fluke prevalence over space and time (P < 0.05). Rumen fluke prevalence was also higher in counties with higher cattle/sheep densities and was positively associated with rumen fluke case rates in the previous years (P < 0.05). Equivalent models for fasciolosis prevalence revealed no significant association with winter temperature and sunshine hours, (P > 0.05). These results confirm a strong association between rainfall and the prevalence of both fluke species in a temperate environment, likely due to the role of Galba truncatula as their intermediate snail host. It also highlights the potential added importance of winter temperature and sunshine hours in rumen fluke epidemiology when compared to liver fluke.

Rumen (Calicophoron/Paramphistomum spp.) and Liver Flukes (Fasciola hepatica) in Cattle—Prevalence, Distribution, and Impact of Management Factors in Germany

Simple SummaryParamphistomidosis is a parasitic disease of ruminants caused by so-called rumen flukes. To determine the current prevalence in German cattle, faecal samples from 614 herds were examined for parasite eggs. In addition, the occurring rumen fluke species were determined, resulting in Calicophoron daubneyi and Paramphistomum leydeni. In the course of the work, the occurrence of the common liver fluke, causing fasciolosis, was also documented. Rumen fluke eggs could be detected in 5.5% of German cattle farms, liver flukes in 9.5%. In 2.1% of the farms, both fluke types occurred. Regional differences between northern and southern Germany were detected. Cattle grazing and fed with fresh grass were more likely to be infected with rumen and liver flukes than cattle without such access. Cattle from organic farms were also more likely to have fluke infections than those from conventional farms, in suckler cows, however, this association only applied to rumen flukes.This study was carried out to determine the prevalence of rumen flukes on German cattle farms via the sedimentation technique, and to identify the rumen fluke species occurring in Germany. Additionally, the prevalence of patent Fasciola hepatica infections was determined. Furthermore, a short questionnaire was answered by the farmers. A prevalence of 5.5% and 9.5% was detected for rumen flukes and liver flukes, respectively. Coinfections occurred on 2.1% of farms. In northern Germany, the rumen fluke prevalence was higher than in southern Germany, while for liver fluke the distribution was reversed. Rumen flukes were mostly identified as Calicophoron daubneyi, but in four cases, sequencing revealed Paramphistomum leydeni for the first time in Germany. Grazing and feeding of fresh grass, as well as organic farming, were significantly associated with rumen and liver fluke occurrence. In contrast, suckler cow husbandry only had an influence on the occurrence of rumen flukes, but not liver flukes. Trematode eggs could be detected in both, farms with and without deworming. Since there were only a few studies about Paramphistomidosis in Germany, more attention should be paid to these parasitic diseases for animal welfare and animal health reasons.

Mapping the Spatial Distribution of the Rumen Fluke Calicophoron daubneyi in a Mediterranean Area.

Rumen flukes (Calicophoron daubneyi) represent a growing threat to the animal health, productivity and welfare of ruminants. The present study aimed to assess the spatial distribution of C. daubneyi infections in ruminants and to develop a predictive model of the environmental suitability for rumen flukes in a Mediterranean area. A cross-sectional coprological survey was conducted in 682 sheep, 73 goat and 307 cattle farms located in the Basilicata region (southern Italy). Faecal samples collected were analysed using the FLOTAC technique. Geographical Information Systems (GIS) and statistical models were developed to determine environmental risk factors and to delimitate the areas at highest risk of infections in small ruminants. The results showed 7.9% (95% CI 6.05–10.27) of sheep farms, 2.7% (95% CI 0.48–10.44) of goat farms and 55.0% (95% CI 49.62–60.99) of cattle farms were infected by C. daubneyi. The areas with high predicted risk were situated in the western part of the region. The soil texture, land use and the presence of streams and brooks were the variables statistically significant (p < 0.05) in explaining the C. daubneyi distribution in the study area. The study confirms the importance of geospatial technology in supporting parasite control strategies in livestock and demonstrates that a combined use of different geostatistical techniques can improve the prediction of the C. daubneyi infection risk in ruminants.

Morphology and Mitochondrial Genome of Fischoederius sp. 1 in Thailand.

A rumen fluke Fischoederius elongatus is assigned to the type species of genus Fischoederius, family Gastrothylacidae. However, the mitochondrial sequences recently published are thought to be of inconsistent species, suggesting that several morphologically similar but genetically distinct species might be classified as Fischoederius elongatus. Thus, mentions of F. elongatus from South, Southeast, and East Asia might unintentionally refer to different species. The present work describes morphology and a full mitochondrial genome sequence of one of these species. The fluke specimens were collected from 2 infected cattle in Thailand. An interesting finding was the presence of a second tRNA-Asp gene next to a partial ND1 gene. It is suggested that these duplicated sequences are the remnants of non-reciprocal recombination events caused by inverted repeats located between ND2 and ND1 mitochondrial genes.

Fischoederius elongatus (Poirier, 1883) Stiles & Goldberger, 1910, a cryptic species of pouched amphistome (Gastrothylacidae)?

Rumen flukes in the genus Fischoederius are neglected foodborne parasites of cattle in Asia. Fischoederius elongatus, first described in 1883 from a sample collected in Indonesia is the type-species of the genus and is found from South to East Asia. In this study Fischoederius spp were collected from cattle in Thailand. The flukes resembled F. elongatus and images of 48 specimens were taken and their DNA was isolated. The mtDNA sequence of the cytochrome c oxidase subunit I (COX1) gene was amplified by PCR and used for restriction analysis with MseI. Nine restriction patterns (A–I) were observed and the COX1 mtDNA sequence for each pattern was determined. Phylogenetic analysis clustered the nine COX1 sequences into five groups with 4.6–9.6 % sequence differences between the groups. This is beyond intragenic variation observed for the COX1 gene in other organisms and suggested that the analyzed specimens represented several species. A comparative transcriptome analysis of specimens with COX1 MseI patterns A, C, E supported this finding. The observed median base differences, both absolute and relative, in the protein coding sequences of 999 orthologs were similar to those between distinct fruit fly species. It is proposed that the genus Fischoederius contains undescribed species that follow the classic description of F. elongatus.

Analysis of internal transcribed spacer1 (ITS1) region of rDNA for genetic characterization of Paramphistomum sp.

Paramphistomosis is the most prevalent disease of domestic ruminants, causing heavy economic loss in many countries across the world. The morphological identification of these parasites is difficult, therefore molecular characterization is used to discriminate Paramphistomum species. The present study was conducted to identify Paramphistomum sp. at Mardan District, Khyber Pakhtunkhwa (KPK), Pakistan. All samples of these rumen flukes were collected from buffalo. The gDNA was isolated from the adult parasites and the ITS1 region was amplified for the sequence analysis. All flukes had 100% similarity and there was no intraspecific variation. The Blast results showed that all flukes were P. cervi as they form a single cluster with P. cervi reported from China. The results of the ITS1 sequences of the present study with reference sequencing from China showed eight specific SNPs. This was the first study in which P. cervi was genetically characterized through the ITS1 region of rDNA at District Mardan, Pakistan. It can also be used as a marker for the genetic identification of Paramphistomum species.

Modulation of Rumen Microbes Through Extracellular Vesicle Released by the Rumen Fluke Calicophoron daubneyi.

Parasite derived extracellular vesicles (EVs) have been proposed to play key roles in the establishment and maintenance of infection. Calicophoron daubneyi is a newly emerging parasite of livestock with many aspects of its underpinning biology yet to be resolved. This research is the first in-depth investigation of EVs released by adult C. daubneyi. EVs were successfully isolated using both differential centrifugation and size exclusion chromatography (SEC), and morphologically characterized though transmission electron microscopy (TEM). EV protein components were characterized using a GeLC approach allowing the elucidation of comprehensive proteomic profiles for both their soluble protein cargo and surface membrane bound proteins yielding a total of 378 soluble proteins identified. Notably, EVs contained Sigma-class GST and cathepsin L and B proteases, which have previously been described in immune modulation and successful establishment of parasitic flatworm infections. SEC purified C. daubneyi EVs were observed to modulate rumen bacterial populations by likely increasing microbial species diversity via antimicrobial activity. This data indicates EVs released from adult C. daubneyi have a role in establishment within the rumen through the regulation of microbial populations offering new routes to control rumen fluke infection and to develop molecular strategies to improve rumen efficiency.