Parasites Of Livestock Research Articles

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.

Sheep nemabiome diversity and its response to anthelmintic treatment in Swedish sheep herds

BackgroundA novel way to study the species composition and diversity of nematode parasites in livestock is to perform deep sequencing on composite samples containing a mixture of different species. Herein we describe for the first time the nematode community structures (nemabiomes) inhabiting Swedish sheep and how these are/were affected by host age and recent anthelmintic treatments.MethodsA total of 158 fecal samples were collected (n = 35 in 2007 and n = 123 in 2013–2016) and cultured from groups of sheep on 61 commercial farms in the south-central part of the country where most animals are grazed. Among the samples, 2 × 44 (56%) were paired collections from the same groups pre- and post-treatment with anthelmintics such as macrocyclic lactones, benzimidazoles or levamisole. Samples were analyzed for their nemabiome using the PacBio platform followed by bioinformatic sequence analysis with SCATA. Species richness and diversity were calculated and analyzed in R.ResultsNematode ITS2 sequences were found in all larval culture samples except two, even though the fecal egg counts were below the McMaster threshold in 20 samples. Sequencing yielded, on average, 1008 sequences per sample. In total, 16 operational taxonomical units (OTU), all with ≥ 98 % identity to sequences in the NCBI database, were recognized. The OTUs found represented nematode species of which ten are commonly associated with sheep. Multiple species were identified in all pre-anthelmintic treatment larval culture samples. No effects on nematode diversity were found in relation to host age. On the other hand, recent anthelmintic treatment lowered species richness, especially after use of ivermectin and albendazole. Interestingly, despite zero egg counts after use of levamisole, these samples still contained nematode DNA and especially H. contortus.ConclusionsOur findings provide evidence that nemabiome analysis combined with diversity index analysis provides an objective methodology in the study of the efficacy of anthelmintic treatment as both high and low abundant species were detected.Graphical

Supplemented nutrition decreases helminth burden and increases drug efficacy in a natural host–helminth system

Gastrointestinal (GI) helminths are common parasites of humans, wildlife, and livestock, causing chronic infections. In humans and wildlife, poor nutrition or limited resources can compromise an individual's immune response, predisposing them to higher helminth burdens. This relationship has been tested in laboratory models by investigating infection outcomes following reductions of specific nutrients. However, much less is known about how diet supplementation can impact susceptibility to infection, acquisition of immunity, and drug efficacy in natural host–helminth systems. We experimentally supplemented the diet of wood mice (Apodemus sylvaticus) with high-quality nutrition and measured resistance to the common GI nematode Heligmosomoides polygyrus. To test whether diet can enhance immunity to reinfection, we also administered anthelmintic treatment in both natural and captive populations. Supplemented wood mice were more resistant to H. polygyrus infection, cleared worms more efficiently after treatment, avoided a post-treatment infection rebound, produced stronger general and parasite-specific antibody responses, and maintained better body condition. In addition, when applied in conjunction with anthelmintic treatment, supplemented nutrition significantly reduced H. polygyrus transmission potential. These results show the rapid and extensive benefits of a well-balanced diet and have important implications for both disease control and wildlife health under changing environmental conditions.

A Retrospective Survey of Gastrointestinal Parasites in Livestock of Hilly Areas in Mymensingh

A Retrospective Survey of Gastrointestinal Parasites in Livestock of Hilly Areas in Mymensingh

Wild deer in the United Kingdom are a potential reservoir for the livestock parasite Babesia divergens

Redwater fever is an economically important disease of cattle in the United Kingdom caused by the protozoan parasite Babesia divergens. Control efforts are dependent on accurate local historic knowledge of disease occurrence, together with an accurate appreciation of current underlying risk factors. Importantly, the involvement of red deer in the transmission of this pathogen in the UK remains unclear. We employed a polymerase chain reaction approach combined with DNA sequencing to investigate Babesia infections in livestock and red deer at a UK farm with a history of tick-borne disease. This revealed several B. divergens-infected cattle that were not displaying overt clinical signs. Additionally, 11% of red deer on the farmland and surrounding areas were infected with this parasite. We also found that 16% of the red deer were infected with Babesia odocoilei, the first time this parasite has been detected in the UK. The finding of B. divergens in the red deer population updates our knowledge of epidemiology in the UK and has implications for the effective control of redwater fever.

Tolerance of liver fluke infection varies between breeds and producers in beef cattle

Liver flukes (Fasciola spp.) are important helminth parasites of livestock globally and cause substantial reductions in health and productivity of beef cattle. Attempts to control fluke have been thwarted by the difficulty of vaccine design, the evolution of flukicide resistance and the need to control the intermediate snail host. Mechanisms to reduce the impact of parasites on animal performance have typically focused on promoting host resistance – defined as the ability of the host to kill and remove the parasite from its system – and such strategies include improving protein nutrition or selective breeding for resistance. Organisms, however, have another broad mechanism for mitigating the impact of parasites: they can show tolerance, defined as the ability to maintain health or performance under increasing parasite burden. Tolerance has been studied in the plant literature for over a century, but there are very few empirical studies of parasite tolerance in livestock. In this study, we used data collected from >90 000 beef cattle to estimate the impact of the severity of liver fluke infection on performance and variation in tolerance of fluke. Severity of liver fluke infection was estimated using liver “fibrosis score” on a scale of 0–3 and performance estimated as (1) age at slaughter and (2) daily dead weight gain. Animals with higher fibrosis scores were slaughtered around 2 weeks later than animals with no fluke and gained around 10 g less weight per day. There was also considerable variation in these effects of fibrosis score, such that animals from different producers and breeds varied in their tolerance of fluke infection. While breeds did not vary in the association between fibrosis and age at slaughter, there was considerable variation among producers: high fibrosis score delayed slaughter by up to 50 days in some producers, but not at all in others. Meanwhile, there was support for variation in the slope of daily dead weight gain on fibrosis score among both breeds and producers, with some unaffected by high fluke scores and some breeds and producers experiencing a 20 g/day lower weight gain under high fluke scores. Our results point to the potential for both environmental and genetic variation in tolerance of liver fluke in cattle, paving the way for quantitative genetic and nutritional research into the feasibility of promoting tolerance as a disease mitigation strategy.

EPIGENETIC IN LIVESTOCK ANIMALS: A NEW PERSPECTIVE FOR HOST-PARASITE RELATIONSHIP AND A POSSIBLE TOOL FOR A SUSTAINABLE PARASITE CONTROL

EPIGENETIC IN LIVESTOCK ANIMALS: A NEW PERSPECTIVE FOR HOST-PARASITE RELATIONSHIP AND A POSSIBLE TOOL FOR A SUSTAINABLE PARASITE CONTROL

PLANT EXTRACTS USED FOR THE CONTROL OF ENDO AND ECTOPARASITES OF LIVESTOCK: A REVIEW OF THE LAST 13 YEARS OF SCIENCE

A variety of endo and ectoparasites can affect livestock, causing poor animal performance and low welfare conditions. Haemonchus contortus (Trichostrongyloidae), Rhipicephalus microplus (Ixodidae), Cochliomyia sp. and Lucilia sp. (Calliphoridae) are some of the most important parasites to livestock in Brazil and in many other tropical and subtropical countries, where farmers need to be vigilant. Although a constant parasite control uses large-spectrum anthelmintics or synthetic insecticides, giving a timely potent reduction of the infections, they also represent a threat to the lifespan of these compounds due to drug-selected parasites. Thus, the development of plant-based therapies is a solid alternative for standard, agroecological, and holistic farming systems, as well as it is an important ally to combat drug resistant parasite populations. In this article, we discussed the scientific literature on plant extracts, notably hydroalcoholic extract or essential oils, used for the control of the above livestock parasites published in the last 13 years. Our objective was to pinpoint the most important issues for this promising area of research, exploring the potential and the challenges that are facing us by examining more than 150 in vitro and in vivo studies. Almost all the authors reported positive data from plants or isolates, the most important challenges that were faced during our search were the lack of a proper experimental study design, and the deficiency in the characterization of the plants used. It is our opinion that plant-based products may be a solid choice for parasite control in livestock animals achieving high welfare standards and mitigate farming input (i.e. use of chemicals and their waste into the environment).

Tick Fauna and Associated Rickettsia, Theileria, and Babesia spp. in Domestic Animals in Sudan (North Kordofan and Kassala States).

Ticks and tick-borne diseases (TBDs) have a major economic impact on animal production worldwide. In the present study, 2410 ticks were collected from January to August 2017 from livestock and other domestic animals in North Kordofan and Kassala, Sudan, for species identification and investigation of Rickettsia spp. and piroplasms, either individually or as pools containing up to 10 ticks by molecular methods. In total, 13 tick species were identified by morphology and 16S rDNA sequencing. The most frequent tick species were Hyalomma impeltatum (24.90%), Rhipicephalus evertsi evertsi (18.84%), Amblyomma lepidum (16.06%), and Rhipicephalus camicasi (12.49%). A pan-Rickettsia real-time PCR revealed an overall minimum infection rate (MIR) with Rickettsia spp. of 5.64% (136 positive tick pools/2410 total ticks). Rickettsia africae and Rickettsia aeschlimannii were the most frequently identified species by sequencing. Furthermore, the following highly pathogenic livestock parasites were detected: Theileria annulata, Theileria lestoquardi, Theileria equi, and Babesia caballi. The present study documented Rhipicephalus afranicus as well as Rickettsia conorii israelensis, Rickettsia massiliae, and Babesia pecorum for the first time in Sudan. These findings are significant for the animal production sector as well as in terms of One Health, as the detected Rickettsia spp. can cause serious illness in humans.

Differences in the antibody response to adult Fasciola hepatica excretory/secretory products in experimentally and naturally infected cattle and sheep

Fasciola hepatica (the liver fluke) is a common, global parasite of livestock. It can be highly pathogenic and has health and welfare implications for infected individuals. Typically, in ruminants, infections are sub-clinical, but if undiagnosed, they can lead to significant production losses. Accurate diagnosis is crucial to identify infection. Antibody detection ELISAs are commonly used to diagnose infection due to their high sensitivity and specificity and are typically based on native fluke excretory/secretory (ES) products or cathepsin L1 (CL1), the immunodominant antigen within ES products. These tests have been developed based on the antibody response of experimentally infected animals; however, this response has not been well characterised in naturally infected animals. We compared the antibody recognition of a recombinant CL1 (rCL1) antigen and native adult fluke ES products. Whilst samples from experimentally infected animals showed strong recognition of rCL1, serum antibodies from naturally infected animals did not. These results were confirmed by peptide array. Immunoblotting sera against ES products showed that experimentally infected animals had a strong, specific response to CL1/CL2 proteins whilst antibodies from naturally infected animals recognised multiple proteins and had a variable response to CL1/CL2. Mass spectrometry of proteins separated by 2D SDS PAGE, identified several antigens recognised by serum antibodies from a naturally infected cow, including cathepsins L1, L2 and L5, glutathione S-transferase and a dihydrolipoyl dehydrogenase. Overall, these results show that the antibody response in naturally infected animals to adult fluke ES products is qualitatively different to experimentally infected animals. This suggests that a diagnostic test based on CL1 alone may not be appropriate for diagnosis of natural F. hepatica infections in sheep and cattle.

Mosquito-borne parasites in the Great Plains: searching for vectors of nematodes and avian malaria parasites

Vector-borne diseases in the United States have recently increased as a result of the changing nature of vectors, hosts, reservoirs, parasite/pathogens, and the ecological and environmental conditions. While most focus has been on mosquito-borne pathogens affecting humans, little is known regarding parasites of companion animal, livestock and wildlife and their potential mosquito hosts in the United States. This study assessed the prevalence of mature infections of Dirofilaria immitis and avian malaria parasites (Haemosporida) within urban mosquito (Diptera, Culicidae) communities in Oklahoma. 2,620 pools consisting of 12,686 mosquitoes from 13 species collected over two summers were tested for the presence of filarioid and haemosporidian DNA. Dirofilaria immitis-infected mosquitoes were detected only in Aedes albopictus (MIR=0.18-0.22) and Culex pipiens complex (MIR=0.12) collected in cities in central and southern Oklahoma. Two other filarioid nematode species with 91-92% similarity with Onchocerca spp. and Mansonella spp. were also detected. Haemosporidian DNA was detected in 13 mosquito pools (0.9% of pools tested) from seven mosquito species out of 13 species tested. Plasmodium DNA in four species (Cx. coronator, Cx. pipiens complex, Cx. tarsalis, and Psorophora columbiae) had high homology with published sequences of avian Plasmodium species while DNA in four other species (Cx. nigripalpus, Ps. columbiae, Anopheles quadrimaculatus, and An. punctipennis) were closely related to Plasmodium species from deer. One pool of Cx. tarsalis was positive with a 100% sequence identity of Haemoproteus sacharovi. This study provides a baseline concerning the diversity of parasites in different mosquito species present in the southern Great Plains. These studies provide important information for understanding the factors of transmission involving the mosquito community, potential hosts, and different mosquito-borne parasites in this important region involved in livestock management and wildlife conservation.

Dung beetle species introductions: when an ecosystem service provider transforms into an invasive species.

Dung beetle introduction programmes were designed to accelerate exotic livestock dung degradation and to control dung breeding pestiferous flies and livestock parasites. The introduction programmes provided exotic dung beetle species with an opportunity to cross natural barriers and spread beyond their native range. There are no reports that explain what probable adaptation mechanisms enable particular dung beetle species to be the most successful invader. Here we identify the morphological, biological, physiological, ecological and behavioural attributes of the four most widespread and successful dung beetle species in introduced areas on a global scale in relation to the assumption that these species are different from other exotic and native dung beetles. We have recognised Digitonthophagus gazella (Fabricius), Onthophagus taurus (Schreber), Euoniticellus intermedius (Reiche) and Aphodius fimetarius (Linnaeus) as the most successful invaders based on their spread, predominance, distribution range and the reports of invasion. Each of these four species has different natural history traits that increase their fitness making them successful invaders. D. gazella has high fecundity and spreading ability, can instantly locate and colonise fresh and nutritious dung, and has a broad thermal window. O. taurus has morphological plasticity, high fecundity, high brood survival rate due to bi-parenting, and is adapted to extreme thermal and moisture conditions. E. intermedius has remnant-dung feeding abilities, a wide thermal window, functioning best at upper-temperature levels, and successful breeding and survival abilities at extremely low soil moisture conditions. A. fimetarius is small-sized, has high breeding and dispersal abilities, and is adapted to lower thermal and upper moisture extremes and variable soil conditions. Discussed here are perspectives on adaptive attributes of dung beetle species that are important to consider during their selection for redistributions. We have elaborated on the fitness and success characteristics of the four species individually. Further, we recommend a prior-introduction baseline monitoring of native dung beetle assemblages so as to evaluate the future impact of exotic dung beetle introductions on the recipient ecosystem.

The neuromuscular system of the sheep tapeworm Moniezia expansa.

Cestodes are common gastrointestinal parasites of humans and livestock. They attach to the host gut and, without a mouth or intestinal system, absorb nutrients through their epidermis. Here we show that despite this simplified anatomy and sessile lifestyle, they maintain a complex neuromuscular system. We used fluorescently labelled phalloidin as a specific probe for filamentous actin to define the overall organisation of several distinct muscle systems in the cyclophyllidean Moniezia expansa. Like all flatworms, the body wall musculature below the neodermis of this intestinal parasite of sheep is characterised by outer circular and inner longitudinal muscle fibres. Diagonal fibres, typically found in free-living and trematode platyhelminths, on the other hand, are notably absent. Prominent longitudinal sheaths dominate the parenchyma and provide retractor muscles to the four acetabula in the scolex; they attach at the bottom of each cup-shaped holdfast. Within sexually mature proglottids, circular fibres dominate the duct walls of the male and female reproductive systems. Nerve cells and fibres that express serotonin or neuropeptide F supply well-developed innervation to several of the described muscle systems: emanating from the central nervous system, fibres in the periphery develop pervasive nerve nets that anastomose within body wall musculature as well as the parenchymal longitudinal and oblique muscle fibres, and innervate the sexual organs and gonopore in mature proglottids. Using homology searches, we provide evidence for 20 neuropeptide precursors together with four prepropeptide processing enzymes as well as several 5-HT signalling components to be represented in the Moniezia transcriptome.

Climate change is likely to increase the development rate of anthelmintic resistance in equine cyathostomins in New Zealand

Climate change is likely to influence livestock production by increasing the prevalence of diseases, including parasites. The traditional practice of controlling nematodes in livestock by the application of anthelmintics is, however, increasingly compromised by the development of resistance to these drugs in parasite populations. This study used a previously developed simulation model of the entire equine cyathostomin lifecycle to investigate the effect a changing climate would have on the development of anthelmintic resistance. Climate data from six General Circulation Models based on four different Representative Concentration Pathways was available for three New Zealand locations. These projections were used to estimate the time resistance will take to develop in the middle (2040–49) and by the end (2090–99) of the century in relation to current (2006–15) conditions under two treatment scenarios of either two or six yearly whole-herd anthelmintic treatments. To facilitate comparison, a scenario without any treatments was included as a baseline. In addition, the size of the infective and parasitic stage nematode population during the third simulation year were estimated. The development of resistance varied between locations, time periods and anthelmintic treatment strategies. In general, the simulations indicated a more rapid development of resistance under future climates coinciding with an increase in the numbers of infective larvae on pasture and encysted parasitic stages. This was especially obvious when climate changes resulted in a longer period suitable for development of free-living parasite stages. A longer period suitable for larval development resulted in an increase in the average size of the parasite population with a larger contribution from eggs passed by resistant worms surviving the anthelmintic treatments. It is projected that climate change will decrease the ability to control livestock parasites by means of anthelmintic treatments and non-drug related strategies will become increasingly important for sustainable parasite control.

Characterisation of a Teladorsagia circumcincta glutathione transferase

A 615 bp full length cDNA encoding a Teladorsagia circumcincta glutathione transferase (TcGST) was cloned, expressed in Escherichia coli and the recombinant protein purified and its kinetic properties determined. The predicted protein consisted of 205 amino acids and was present as a single band of about 24 kDa on SDS-PAGE. Multiple alignments of the protein sequence of TcGST with homologues from other helminths showed that the highest identity of 53-68% with haem-binding nematode proteins designated as members of the nu class of GSTs. Substrate binding sites and conserved regions were identified and were generally conserved. The predicted 3-dimensional structures of TcGST and HcGST revealed highly open binding cavities typical of this class of GST, considered to allow greater accessibility to diverse ligands compared with other classes of GST. At 25 °C, the optimum pH for TcGST activity was pH 7, the Vmax was 1535 ± 33 nmoles.min-1. mg-1 protein and the apparent Km for the substrate 1-chloro-2,4-dinitrobenzene (CDNB) was 0.22 ± 0.01 mM (mean ± SD, n = 2). Antibodies in both serum and saliva from field-immune, but not nematode-naïve, sheep, recognised recombinant TcGST in enzyme-linked immunosorbent assays. The recognition of the recombinant protein by antibodies generated by exposure of sheep to the native enzyme indicates similar antigenicity of the two proteins. These findings could aid in the design of novel drugs and vaccine antigens for economically important parasites of livestock.

Alternative animal feeds from agroforestry plants

This special issue idea originated when a few researchers from around the world came together with the goal of compiling the most up-to-date information on the use of alternative animal feed resources derived from agroforestry plants, including woody perennials. It is a common animal feeding practice in many parts of the world, particularly in the tropics; however, no comprehensive source of this information exists as attempted in this special issue. In addition to exploring alternative resources such as foliage of woody plants and other plant products and by-products for animal feed, papers included in this issue also addressed their impacts on ruminant and non-ruminant performance, health and welfare, and ruminal fermentation metabolism and mitigation of methane emission. We received 78 manuscripts from more than 21 countries and 45 papers were accepted following appropriate peer reviews. Overall, alternative feed resources, including woody plant foliage, improved animal performance, particularly during dry season. Several bioactive compounds were identified in agroforestry plants and they had positive impacts as antimicrobials against some the pathogenic bacteria and for controlling gastrointestinal parasites in livestock, which improved the health, welfare and production. Most alternative feeds added at low proportions with regular feed improved digestibility and decreased methane production.

Preliminary evaluation of a novel, fully automated, Telenostic device for rapid field-diagnosis of cattle parasites.

New ideas for diagnostics in clinical parasitology are needed to overcome some of the difficulties experienced in the widespread adoption of detection methods for gastrointestinal parasites in livestock. Here we provide an initial evaluation of the performance of a newly developed automated device (Telenostic) to identify and quantify parasitic elements in fecal samples. This study compared the Telenostic device with the McMaster and Mini-FLOTAC for counting of strongyle eggs in a fecal sample. Three bovine fecal samples were examined, in triplicate, on each of the three fecal egg-counting devices. In addition, both manual (laboratory technician) and automated analysis (image analysis algorithm) were performed on the Telenostic device to calculate fecal egg counts (FEC). Overall, there were consistent egg counts reported across the three devices and calculation methods. The Telenostic device compared very favourably to the Mini-FLOTAC and McMaster. Only in sample C, a significant difference (P < 0.05) was observed between the egg counts obtained by Mini-FLOTAC and by the other methods. From this limited dataset it can be concluded that the Telenostic-automated test is comparable to currently used benchmark FEC methods, while improving the workflow, test turn-around time and not requiring trained laboratory personnel to operate or interpret the results.

A novel metabarcoded 18S ribosomal DNA sequencing tool for the detection of Plasmodium species in malaria positive patients

Various PCR based methods have been described for the diagnosis of malaria, but most depend on the use of Plasmodium species-specific probes and primers; hence only the tested species are identified and there is limited available data on the true circulating species diversity. Sensitive diagnostic tools and platforms for their use are needed to detect Plasmodium species in both clinical cases and asymptomatic infections that contribute to disease transmission. We have recently developed for the first time a novel high throughput ‘haemoprotobiome’ metabarcoded DNA sequencing method and applied it for the quantification of haemoprotozoan parasites (Theleria and Babesia) of livestock. Here, we describe a novel, high throughput method using an Illumina MiSeq platform to demonstrate the proportions of Plasmodium species in metabarcoded DNA samples derived from human malaria patients. Plasmodium falciparum and Plasmodium vivax positive control gDNA was used to prepare mock DNA pools of parasites to evaluate the detection threshold of the assay for each of the two species. The different mock pools demonstrate the accurate detection ability and to show the proportions of each of the species being present. We then applied the assay to malaria-positive human samples to show the species composition of Plasmodium communities in the Punjab province of Pakistan and in the Afghanistan-Pakistan tribal areas. The diagnostic performance of the deep amplicon sequencing method was compared to an immunochromatographic assay that is widely used in the region. The deep amplicon sequencing showed that P. vivax was present in 69.8%, P. falciparum in 29.5% and mixed infection in 0.7% patients examined. The immunochromatographic assay showed that P. vivax was present in 65.6%, P. falciparum in 27.4%, mixed infection 0.7% patients and 6.32% malaria-positive cases were negative in immunochromatographic assay, but positive in the deep amplicon sequencing. Overall, metabarcoded DNA sequencing demonstrates better diagnostic performance, greatly increasing the estimated prevalence of Plasmodium infection. The next-generation sequencing method using metabarcoded DNA has potential applications in the diagnosis, surveillance, treatment, and control of Plasmodium infections, as well as to study the parasite biology.

Horses are susceptible to natural, but resistant to experimental, infection with the liver fluke, Fasciola hepatica

Fasciola hepatica is a common parasite of livestock in Ireland, causing significant economic losses and affecting animal welfare. A previous abattoir study of 200 horses led to an estimated 9.5 % prevalence of infection in horses slaughtered in Ireland. However, the epidemiology and pathogenic significance of this infection in this species is not well-described.The objectives of this study were to determine the susceptibility of horses to oral challenge infection with F. hepatica metacercariae, and to document the course of the infection along with serological and biochemical response.We attempted an experimental infection of horses (n = 10; 9 geldings and 1 mare) with F. hepatica. Four were given 1000 metacercariae, four 500 metacercariae and two were sham-infected. Blood and faecal samples were taken at intervals up to 18 weeks post-infection (wpi). ELISA assays were used to assess sero-conversion in the experimental horses and also in a panel of sera from horses of known fluke status.No flukes were recovered from any of the livers, and neither were any lesions that could be attributed to F. hepatica infection observed. Coproantigen ELISA was negative throughout for all horses. Three antibody detection ELISAs, useful in diagnosing fasciolosis in other species, had limitations as diagnostic aids as determined using a panel of sera from horses of known F. hepatica infection status.This study is limited by the relatively small number of animals included, and the relatively short duration of the study period.Failure to establish infection after oral challenge raises fundamental questions on the pathophysiology and epidemiology of equine fasciolosis.

First record of the pest and parasitic intermediate host snail Cochlicella barbara (Linnaeus, 1758) in the south-eastern Anatolia

The objective of the present study is to inform the last distribution of the invasive and harmful species Cochlicella barbara (Linnaeus, 1758) in Turkey, as well as to draw attention to the possible danger of this distribution on regional vegetation, agriculture, and parasitism. C. barbara was found for the first time in south-eastern of Anatolia in April 2019 in the campus area of the Dicle University in Diyarbakır, Turkey. C. barbara is admitted as a harmful organism and classified as an agricultural pest in most of the countries. Species in this genus have been intercepted in postal packages, soil, and cargo as well as can be easily transported with plants, building materials, household goods, etc. Above all, it is an intermediate host of nematode and fluke parasites of livestock. Knowing the distribution of this species will not only contribute to the registration of a new species in the list of gastropods of the region but also facilitate the control of the species across Turkey.