Exploiting parallels between livestock and wildlife: Predicting the impact of climate change on gastrointestinal nematodes in ruminants

Multi-scale habitat modeling framework for predicting the potential distribution of sheep gastrointestinal nematodes across Iran's three distinct climatic zones: a MaxEnt machine-learning algorithm

Ecological niche models (ENMs) serve as valuable tools in assessing the potential species distribution, identifying crucial habitat components for species associations, and facilitating conservation efforts. The current study aimed to investigate the gastrointestinal nematodes (GINs) infection in sheep, predict and analyze their ecological niches and ranges, and identify the key bioclimatic variables influencing their distribution across three distinct climatic regions in Iran. In a cross-sectional study, a total of 2140 fecal samples were collected from semi-arid (n = 800), arid (n = 500), and humid-subtropical (n = 840) climates in East Azerbaijan, Kerman, and Guilan provinces, respectively. The flotation method was employed to assess stool samples, whereby the fecal egg count (the number of parasite eggs per gram [EPG]) was ascertained for each individual specimen. Employing a presence-only approach, the multi-scale maximum entropy (MaxEnt) method was used to model GINs' habitat suitability using 93 selected points/locations. The findings revealed that Guilan (34.2%) and East Azerbaijan (19.62%) exhibited the utmost proportion of Strongyle-type eggs. East Azerbaijan province also displayed the highest proportion of Marshallagia and Nematodirus, respectively (approximately 40% and 27%), followed by Guilan and Kerman provinces, while Kerman province had the highest proportion of Trichuris (approximately 15%). Ecological niche modeling revealed that the precipitation of the driest quarter (Bio17) exerted the most significant influence on Marshallagia, Nematodirus, Trichuris, and ُSُُُtrongyle-type eggs' presence in East Azerbaijan and Kerman provinces. For Guilan province, the most influential factor defining habitat suitability for Strongyle-type eggs, Marshallagia, and Nematodirus was increasing slope. Additionally, the distribution of Trichuris was most affected by the variable Bio2 in Guilan province. The study highlights the response of GINs to climate drivers in highly suitable regions, providing insights into ecologically favorable areas for GINs. In conclusion, this study provides a better understanding of GINs and the environmental factors influencing their transmission dynamics.

An improved model for the population dynamics of cattle gastrointestinal nematodes on pasture: parameterisation and field validation for Ostertagia ostertagi and Cooperia oncophora in northern temperate zones

Gastrointestinal nematodes (GIN) are amongst the most important pathogens of grazing ruminants worldwide, resulting in negative impacts on cattle health and production. The dynamics of infection are driven in large part by the influence of climate and weather on free-living stages on pasture, and computer models have been developed to predict infective larval abundance and guide management strategies. Significant uncertainties around key model parameters limits effective application of these models to GIN in cattle, however, and these parameters are difficult to estimate in natural populations of mixed GIN species. In this paper, recent advances in molecular biology, specifically ITS-2 rDNA 'nemabiome' metabarcoding, are synthesised with a modern population dynamic model, GLOWORM-FL, to overcome this limitation. Experiments under controlled conditions were used to estimate rainfall constraints on migration of infective L3 larvae out of faeces, and their survival in faeces and soil across a temperature gradient, with nemabiome metabarcoding data permitting species-specific estimates for Ostertagia ostertagi and Cooperia oncophora in mixed natural populations. Results showed that L3 of both species survived well in faeces and soil between 0 and 30 °C, and required at least 5 mm of rainfall daily to migrate out of faeces, with the proportion migrating increasing with the amount of rainfall. These estimates were applied within the model using weather and grazing data and use to predict patterns of larval availability on pasture on three commercial beef farms in western Canada. The model performed well overall in predicting the observed seasonal patterns but some discrepancies were evident which should guide further iterative improvements in model development and field methods. The model was also applied to illustrate its use in exploring differences in predicted seasonal transmission patterns in different regions. Such predictive modelling can help inform evidence-based parasite control strategies which are increasingly needed due climate change and drug resistance. The work presented here also illustrates the added value of combining molecular biology and population dynamics to advance predictive understanding of parasite infections.

A tale of two nematodes: Climate mediates mustelid infection by nematodes across the geographical range

Parasites have the potential to negatively affect host populations, if infection intensity is high. For parasites in which part of life cycle takes place outside the host, host infection intensity is likely affected by climate condition. Therefore, the parasite's impact on the host populations could be related to climatic conditions and may be altered with climate change. The aim of our study was to analyse the prevalence and infection intensity of two nematodes (Aonchotheca putorii and Molineus patens) from the Northern Hemisphere in relation to variations in climatic conditions. We reviewed 54 published studies on the occurrence of these two nematode species in 7 mustelid hosts. For A. putorii, infection parameters were higher when the stomach was included in the analyses compared to M. patens. The seasonality of precipitation influenced the prevalence the most, and the mean temperature of the warmest quarter had the strongest influence on infection intensity. The predicted prevalence of M. patens increased with increasing seasonal variation in precipitation, while the prevalence of A. putorii decreased. The predicted infection intensity of M. patens decreased with increasing precipitation seasonality, whereas the intensity of A. putorii infection did not change much. A. putorii infection intensity significantly decreased with increasing mean temperature of the warmest quarter, while the infection intensity of M. patens was not significantly related to this variable. Prevalence and infection intensity varied over the geographic range for both parasites, broadly with higher levels in northern latitudes for A. putorii and in southern latitudes for M. patens. Our study highlights the differences between these two nematode species and shows that the severity of host infection by these parasites is complex and mediated by climatic conditions. The results suggest that current climate change may potentially modify susceptibility and exposure to parasitic infections in mustelids.

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Analyses of the infection intensity of two nematodes on seven mustelid species on a large geographical scale.

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Climate modulates the infection parameters of the studied nematodes.

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Climatic conditions have contrasting effects on the two nematode species.

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The different effect of climate on parasite infection intensity is related to differences in their life cycles.

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Climate change may modify parasite infections and parasite impacts on wild carnivores.

A Review of the Impact of Climate Change on the Epidemiology of Gastrointestinal Nematode Infections in Small Ruminants and Wildlife in Tropical Conditions

Climate change is causing detrimental changes in living organisms, including pathogens. This review aimed to determine how climate change has impacted livestock system management, and consequently, what factors influenced the gastrointestinal nematodes epidemiology in small ruminants under tropical conditions. The latter is orientated to find out the possible solutions responding to climate change adverse effects. Climate factors that affect the patterns of transmission of gastrointestinal parasites of domesticated ruminants are reviewed. Climate change has modified the behavior of several animal species, including parasites. For this reason, new control methods are required for controlling parasitic infections in livestock animals. After a pertinent literature analysis, conclusions and perspectives of control are given.

Predicting Parasite Dynamics in Mixed-Use Trans-Himalayan Pastures to Underpin Management of Cross-Transmission Between Livestock and Bharal

The complexities of multi-use landscapes require sophisticated approaches to addressing disease transmission risks. We explored gastro-intestinal nematode (GINs) infections in the North India Trans-Himalayas through a socio-ecological lens, integrating parasite transmission modelling with field surveys and local knowledge, and evaluated the likely effectiveness of potential interventions. Bharal (blue sheep; Pseudois nayaur), a native wild herbivore, and livestock share pasture year-round and livestock commonly show signs of GINs infection. While both wild and domestic ungulates had GINs infections, egg counts indicated significantly higher parasite burdens in bharal than livestock. However, due to higher livestock densities, they contributed more to the total count of eggs and infective larvae on pasture. Herders also reported health issues in their sheep and goats consistent with parasite infections. Model simulations suggested that pasture infectivity in this system is governed by historical pasture use and gradually accumulated larval development during the summer, with no distinct short-term flashpoints for transmission. The most effective intervention was consequently predicted to be early-season parasite suppression in livestock using temperature in spring as a cue. A 1-month pause in egg output from livestock could lead to a reduction in total annual availability of infective larvae on pasture of 76%, potentially benefitting the health of both livestock and bharal. Modelling suggested that climate change over the past 33 years has led to no overall change in GINs transmission potential, but an increase in the relative influence of temperature over precipitation in driving pasture infectivity. Our study provides a transferable multi-pronged approach to investigating disease transmission, in order to support herders' livelihoods and conserve wild ungulates.

Characterizing parasitic nematode faunas in faeces and soil using DNA metabarcoding

Background

Gastrointestinal parasitic nematodes can impact fecundity, development, behaviour, and survival in wild vertebrate populations. Conventional monitoring of gastrointestinal parasitic nematodes in wild populations involves morphological identification of eggs, larvae, and adults from faeces or intestinal samples. Adult worms are typically required for species-level identification, meaning intestinal material from dead animals is needed to characterize the nematode community with high taxonomic resolution. DNA metabarcoding of environmental samples is increasingly used for time- and cost-effective, high-throughput biodiversity monitoring of small-bodied organisms, including parasite communities. Here, we evaluate the potential of DNA metabarcoding of faeces and soil samples for non-invasive monitoring of gastrointestinal parasitic nematode communities in a wild ruminant population.

Methods

Faeces and intestines were collected from a population of wild reindeer, and soil was collected both from areas showing signs of animal congregation, as well as areas with no signs of animal activity. Gastrointestinal parasitic nematode faunas were characterized using traditional morphological methods that involve flotation and sedimentation steps to concentrate nematode biomass, as well as using DNA metabarcoding. DNA metabarcoding was conducted on bulk samples, in addition to samples having undergone sedimentation and flotation treatments.

Results

DNA metabarcoding and morphological approaches were largely congruent, recovering similar nematode faunas from all samples. However, metabarcoding provided higher-resolution taxonomic data than morphological identification in both faeces and soil samples. Although concentration of nematode biomass by sedimentation or flotation prior to DNA metabarcoding reduced non-target amplification and increased the diversity of sequence variants recovered from each sample, the pretreatments did not improve species detection rates in soil and faeces samples.

Conclusions

DNA metabarcoding of bulk faeces samples is a non-invasive, time- and cost-effective method for assessing parasitic nematode populations that provides data with comparable taxonomic resolution to morphological methods that depend on parasitological investigations of dead animals. The successful detection of parasitic gastrointestinal nematodes from soils demonstrates the utility of this approach for mapping distribution and occurrences of the free-living stages of gastrointestinal parasitic nematodes.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04935-8.

A desired gains approach for the prediction of genetic gain in resistance to gastrointestinal nematodes in a multi-trait breeding objective in Uruguayan Merino sheep

Gastrointestinal nematodes (GIN) constitute a problem in many sheep production systems, including those in Uruguay, causing reduced productivity and increased expenses. The main strategy to control GIN has consisted of the use of anthelmintics. However, GINs have developed resistance to anthelmintics, reducing their effectiveness. Genetic resistance to GINs has been found in flocks of different breeds. To date, there have been no reports about GINs breaking down genetic resistance in sheep. Heritability estimates of resistance to GIN within breeds are generally moderate, so that achieving genetic gain within a flock is possible. In this study, we predicted genetic gain in worm egg count (WEC), an indirect (and generally preferred) criterion of resistance to GIN, following different strategies. A multi-trait breeding objective including wool and meat traits was assumed and genetic gain over 10 years of selection in a Merino flock was estimated. We used a desired gains approach, examining situations in which the economic contribution of genetic gain in resistance to GIN in percentage terms was 0, 25, 50, 75 or 100. Except when the level of infestation with GIN was low, a considerable amount of emphasis had to be placed on selection for low WEC in order to reach the threshold below which the administration of anthelmintics is not required. High emphasis on reducing WEC lead to a reduction in genetic gain in wool and meat traits, or to their deterioration in the extreme case of 100 per cent emphasis on WEC. Given this finding, coupled with the difficulties encountered in accurately recording and selecting for WEC, we concluded that in addition to embarking upon a programme of within flock selection, sheep breeders interested in improving genetic resistance to GIN should also consider using breeding stock identified as superior for both resistance and production traits in across flock genetic evaluations.

Diversity and burden of helminthiasis in wild ruminants in Iran

This paper aimed to investigate the diversity and burden of helminthiasis in Ovis orientalis (n = 26), Capra aegagrus (n = 29) and Gazella subgutturosa (n = 24) grazed in 37 National Parks in 9 provinces of Iran. The organs and body cavities infected by helminths included gastrointestinal tract, peritoneal cavity, heart, liver and lungs. The contents were extracted and washed under running water and intestinal and lung-isolated nematodes were cleared in lactophenol and subsequently fixed, and cestodes were stained with alum carmine and mounted en face in Berlese's fluid under slight pressure between a microscopic slide and cover slip. The helminth species identified in this study include: intestinal nematodes (Marshallagia marshalli, Teladorsagia circumcincta, Ostertagia ostertagi, Nematodirus oiratianus, Nematodirella longispiculata, Skrjabinema ovis, Trichuris ovis, Trichuris discolor, Parabronema skrjabini), lungworms (Protostrongylus rufescens, Cystocaulus ocreatus), adult cestodes (Moniezia expansa, Helicometra giardi, Avitellina centripunctata, Stilesia globipunctata) and metacestodes (Cysticercus spp., hydatid cyst, Cysticercus tenuicollis). The proportion of the different helminth species ranged from low to moderate (3.45-46.15%) and the intensity of helminth isolation from the different ruminants ranged between 2 and 20. All the taxa identified in our study have been reported in wild animal species around the world. The presence of Cysticercus spp. with cardiac involvement in G. subgutturosa and all helminths of C. aegagrus was reported for the first time in Iran. A significant reduction was observed in worm burden, compared with previous studies in Iran, indicating changes in wildlife host-parasite systems, which can be linked to many reasons including climate changes, public health policies (e.g., strategic anthelmintic use in domestic ruminants), anthropogenic factors and environmental changes (e.g., urbanization or agricultural expansion, physical barriers), as well as vegetation growth and host availability.

Parasite intensity drives fetal development and sex allocation in a wild ungulate

An understanding of the mechanisms influencing prenatal characteristics is fundamental to comprehend the role of ecological and evolutionary processes behind survival and reproductive success in animals. Although the negative influence of parasites on host fitness is undisputable, we know very little about how parasitic infection in reproductive females might influence prenatal factors such as fetal development and sex allocation. Using an archival collection of Dall’s sheep (Ovis dalli dalli), a capital breeder that depends on its body reserves to overcome the arctic winter, we investigated the direct and indirect impacts of the parasite community on fetal development and sex allocation. Using partial least squares modelling, we observed a negative effect of parasite community on fetal development, driven primarily by the nematode Marshallagia marshalli. Principal component analysis demonstrated that mothers with low parasite burden and in good body condition were more likely to have female versus male fetuses. This association was primarily driven by the indirect effect of M. marshalli on ewe body condition. Refining our knowledge of the direct and indirect impact that parasite communities can have on reproduction in mammals is critical for understanding the effects of infectious diseases on wildlife populations. This can be particularly relevant for species living in ecosystems sensitive to the effects of global climate change.

GLOWORM-PARA: a flexible framework to simulate the population dynamics of the parasitic phase of gastrointestinal nematodes infecting grazing livestock

Gastrointestinal nematodes are a significant threat to the economic and environmental sustainability of keeping livestock, as adequate control becomes increasingly difficult due to the development of anthelmintic resistance in some systems and climate-driven changes to infection dynamics. To mitigate any negative impacts of climate on gastrointestinal nematode epidemiology and slow anthelmintic resistance development, there is a need to develop effective, targeted control strategies that minimise the unnecessary use of anthelmintic drugs and incorporate alternative strategies such as vaccination and evasive grazing. However, the impacts climate and gastrointestinal nematode epidemiology may have on the optimal control strategy are generally not considered, due to lack of available evidence to drive recommendations. Parasite transmission models can support control strategy evaluation to target field trials, thus reducing the resources and lead-time required to develop evidence-based control recommendations incorporating climate stochasticity. Gastrointestinal nematode population dynamics arising from natural infections have been difficult to replicate and model applications have often focussed on the free-living stages. A flexible framework is presented for the parasitic phase of gastrointestinal nematodes, GLOWORM-PARA, which complements an existing model of the free-living stages, GLOWORM-FL. Longitudinal parasitological data for two species that are of major economic importance in cattle, Ostertagia ostertagi and Cooperia oncophora, were obtained from seven cattle farms in Belgium for model validation. The framework replicated the observed seasonal dynamics of infection in cattle on these farms and overall, there was no evidence of systematic under- or over-prediction of faecal egg counts. However, the model under-predicted the faecal egg counts observed on one farm with very young calves, highlighting potential areas of uncertainty that may need further investigation if the model is to be applied to young livestock. The model could be used to drive further research into alternative parasite control strategies such as vaccine development and novel treatment approaches, and to understand gastrointestinal nematode epidemiology under changing climate and host management.

Local Ecological Knowledge on Climate Change and Ecosystem-Based Adaptation Strategies Promote Resilience in the Middle Zambezi Biosphere Reserve, Zimbabwe

Understanding local community perceptions on impacts, causes, and responses to climate change is vital for promotion of community resilience towards climate change. This study explored local ecological knowledge (LEK) held by local communities on climate change trends and impacts in the Middle Zambezi Biosphere Reserve (MZBR), Zimbabwe. The objectives of the study were to (i) investigate local community perceptions on trends and causes of climate change, (ii) identify biophysical impacts of climate change at the local level, and (iii) explore the ecosystem-based adaptation strategies towards climate change. The study used a mixed methods approach where a household questionnaire survey (n=320), key informant interviews (n=12), and focus group discussions (n=8) were used to collect data between April 2015 and October 2016. Results from the study show that local communities have observed decreasing rainfall and increasing temperatures as key indicators of climate change. Local communities observed water scarcity, changes in vegetation phenology, livestock and wildlife mortalities, and food shortages due to drought as the major impacts on their livelihoods. LEK can contribute to adaptive management strategies that enhance resilience of socioecological systems (SES) in the face of climate change by providing information on the status and use of biophysical components of the environment and by highlighting potential local adaptation strategies that can sustain key livelihood practices.

Pathomorphological changes in the large intestine of rabbits parasitised by Passalurus ambiguus (Nematoda, Oxyuridae)

Passaluriasis is a common infestation of lagomorphs, which clinically manifests in intense itching around the anus, various disorders of digestion and loss of weight. We performed a study of infested rabbits of the seryi veleten breed, which were kept in individual farms in Poltava Oblast (Ukraine). During the autopsy, in the cavity of the large intestine, there were found small, spindle-like helminths of white colour. Out of 10 rabbits, 846 nematodes were extracted (369 males and 477 females, identified as Passalurus ambiguus (Rudolphi, 1819) Dujardin, 1845. It was determined that the extensity of infestation in female rabbits reached 56.4%, male rabbits – 43.6%. The results of metric parameters of the nematodes are as follows: mean body length of males equaled 4.6 ± 0.4, females – 9.7 ± 1.21 mm, and maximum width – 257.4 ± 17.8 and 546.2 ± 37.1 µm respectively. A common feature of mature nematodes of this species is the presence of a rounded extension (bulbus) at the end of the esophagus. During chronic course of passaluriasis in rabbits, pathomorphological changes developed in the large intestine. The upper epithelium of the large intestine was damaged in some places, certain epithelian cells were found in the lumen of the intestine. The intestinal glands are widened, filled with slimy content of mostly dark blue-violet colour, especially in the upper sections of the glands. In the deep sections of the glands, slime was almost transparent. In deep sections of the glands the slime was almost transparent. In the epithelium cells of the glands, slimy granules were also of basophilic colour. The muscularis mucosae of the mucous membrane, especially between the intestinal glands was swollen, had practically no colour, the collagen fibers were stretched, thinned-out. Edemas were also recorded in the tela submucosa. In some preparations, the muscularis mucosae was notably infiltrated by lymphoid cells and histiocytes. On large extensions, we found some signs of hypersecretion of slime in goblet cells of the intestinal glands as accumulations of granules of slime in the cytoplasm, which had poorly developed colouration. On the side of the muscular and serous membranes, no pathological changes were found. The information presented here indicates the relevance of passaluriasis infestation as an etiological factor of occurrence of chronic catarrhal colitis with lymphohistiocytosis.

GluClR-mediated inhibitory postsynaptic currents reveal targets for ivermectin and potential mechanisms of ivermectin resistance

Glutamate-gated chloride channel receptors (GluClRs) mediate inhibitory neurotransmission at invertebrate synapses and are primary targets of parasites that impact drastically on agriculture and human health. Ivermectin (IVM) is a broad-spectrum pesticide that binds and potentiates GluClR activity. Resistance to IVM is a major economic and health concern, but the molecular and synaptic mechanisms of resistance are ill-defined. Here we focus on GluClRs of the agricultural endoparasite, Haemonchus contortus. We demonstrate that IVM potentiates inhibitory input by inducing a tonic current that plateaus over 15 minutes and by enhancing post-synaptic current peak amplitude and decay times. We further demonstrate that IVM greatly enhances the active durations of single receptors. These effects are greatly attenuated when endogenous IVM-insensitive subunits are incorporated into GluClRs, suggesting a mechanism of IVM resistance that does not affect glutamate sensitivity. We discovered functional groups of IVM that contribute to tuning its potency at different isoforms and show that the dominant mode of access of IVM is via the cell membrane to the receptor.

Glutamate-gated chloride channel receptors (GluClRs) mediate chemoelectric inhibition in invertebrate animals and are targets for broad-spectrum pesticides such as ivermectin. However, resistance to ivermectin threatens the effective control of invertebrates that cause a range of agricultural and human diseases. This study investigates different isoforms of GluClR expressed by the major agricultural endoparasite, Haemonchus contortus, on a synaptic and single receptor level. We discovered that ivermectin enhances synaptic current amplitude and decay and lengthens single receptor activity. Furthermore, ivermectin is less efficacious at GluClRs that incorporate a naturally ivermectin-resistant subunit, suggesting a potential resistance mechanism. Finally, we identify two chemical interactions between the GluClR and ivermectin that determine its potency and show that ivermectin binds to GluClRs via cell membrane interactions.

Myracrodruon urundeuva seed exudates proteome and anthelmintic activity against Haemonchus contortus

Seed exudates are plant-derived natural bioactive compounds consisting of a complex mixture of organic and inorganic molecules. Plant seed exudates have been poorly studied against parasite nematodes. This study was undertaken to identify proteins in the Myracrodruon urundeuva seed exudates and to assess the anthelmintic activity against Haemonchus contortus, an important parasite of small ruminants. M. urundeuva seed exudates (SEX) was obtained after immersion of seeds in sodium acetate buffer. SEX was fractionated with ammonium sulfate at 0–90% concentration to generate the ressuspended pellet (SEXF1) and the supernatant (SEXF2). SEX, SEXF1, and SEXF2 were exhaustively dialyzed against distilled water (cut-off: 12 kDa) and the protein contents determined. Mass spectrometry analyses of SEX, SEXF1, and SEXF2 were done to identify proteins and secondary metabolites. The seed exudates contained protease, protease inhibitor, peptidase, chitinase, and lipases as well as the low molecular weight secondary compounds ellagic acid and quercetin rhamnoside. SEX inhibited H. contortus larval development (LDA) (IC₅₀ = 0.29 mg mL^-1), but did not affect larval exsheathment (LEIA). On the other hand, although SEXF1 and SEXF2 inhibited H. contortus LEIA (IC₅₀ = 1.04 and 0.93 mg mL^-1, respectively), they showed even greater inhibition efficiency of H. contortus larval development (IC₅₀ = 0.29 and 0.42 mg mL^-1, respectively). To the best of our knowledge, this study is the first to show the anthelmintic activity of plant exudates against a gastrointestinal nematode. Moreover, it suggests the potential of exuded proteins as candidates to negatively interfere with H. contortus life cycle.

In vitro anthelmintic effects of Spigelia anthelmia protein fractions against Haemonchus contortus

Gastrointestinal nematodes are a significant concern for animal health and well-being, and anthelmintic treatment is mainly performed through the use of chemical products. However, bioactive compounds produced by plants have shown promise for development as novel anthelmintics. The aim of this study is to assess the anthelmintic activity of protein fractions from Spigelia anthelmia on the gastrointestinal nematode Haemonchus contortus. Plant parts were separated into leaves, stems and roots, washed with distilled water, freeze-dried and ground into a fine powder. Protein extraction was performed with sodium phosphate buffer (75 mM, pH 7.0). The extract was fractionated using ammonium sulfate (0–90%) and extensively dialyzed. The resulting fractions were named LPF (leaf protein fraction), SPF (stem protein fraction) and RPF (root protein fraction), and the protein contents and activities of the fractions were analyzed. H. contortus egg hatching (EHA), larval exsheathment inhibition (LEIA) and larval migration inhibition (LMIA) assays were performed. Proteomic analysis was conducted, and high-performance liquid chromatography (HPLC) chromatographic profiles of the fractions were established to identify proteins and possible secondary metabolites. S. anthelmia fractions inhibited H. contortus egg hatching, with LPF having the most potent effects (EC₅₀ 0.17 mg mL^-1). During LEIA, SPF presented greater efficiency than the other fractions (EC₅₀ 0.25 mg mL^-1). According to LMIA, the fractions from roots, stems and leaves also reduced the number of larvae, with EC₅₀ values of 0.11, 0.14 and 0.21 mg mL^-1, respectively. Protein analysis indicated the presence of plant defense proteins in the S. anthelmia fractions, including protease, protease inhibitor, chitinase and others. Conversely, secondary metabolites were absent in the S. anthemia fractions. These results suggest that S. anthelmia proteins are promising for the control of the gastrointestinal nematode H. contortus.

Reliable molecular differentiation of Trichuris ovis and Trichuris discolor from sheep (Ovis orientalis aries) and roe deer (Capreolus capreolus) and morphological characterisation of their females: morphology does not work sufficiently

The main aim of the study was to evaluate associations between morphological variability of Trichuris females from sheep and roe deer and their rDNA polymorphism in whipworm populations from the Czech Republic. The results introduced the use of new molecular markers based on the internal transcribed spacer (ITS)1-5.8S RNA-ITS2 region polymorphisms, as useful tools for the unambiguous differentiation of congeners Trichuris ovis and Trichuris discolor. These markers revealed both parasites in roe deer and in sheep; however, T. ovis females predominated in sheep while T. discolor females occurred mostly in roe deer. Additional analysis of ITS1-5.8 rRNA-ITS2 discovered the genetic uniformity of the analysed T. discolor but high haplotype variation of T. ovis. Simultaneously, molecularly designated female individuals of both species were categorised into four morphotypes (MT) on the basis of morphology of genital pore area. MT1 and MT4 (vulvar opening on everted vaginal appendage/on visible cuticular bulge) occurred only in T. ovis, MT2 (uneverted vagina-vulvar opening without any elevation) was identified only in T. discolor and MT3 (transient type of vulvar opening on a small swelling) was observed in both species. Statistical analysis of biometric data confirmed that morphology of vulva is not a reliable marker for the species determination. On the basis of the ITS1-5.8S RNA-ITS2 region variability, we carried out a phylogenetic analysis (maximum likelihood method, Hasegawa-Kishino-Yano model) which showed that T. ovis haplotypes from the Czech Republic and Ireland and T. discolor haplotypes from the Czech Republic, Spain, Iran and Japan are sister OTUs.