Phytochemical analysis and anthelmintic activity of Combretum mucronatum leaf extract against infective larvae of soil-transmitted helminths including ruminant gastrointestinal nematodes.

BACKGROUND: Soil-transmitted helminths (STH) infect more than a quarter of the world's human population. In the absence of vaccines for most animal and human gastrointestinal nematodes (GIN), treatment of infections primarily relies on anthelmintic drugs, while resistance is a growing threat. Therefore, there is a need to find alternatives to current anthelmintic drugs, especially those with novel modes of action. The present work aimed to study the composition and anthelmintic activity of Combretum mucronatum leaf extract (CMLE) by phytochemical analysis and larval migration inhibition assays, respectively. METHODS: Combretum mucronatum leaves were defatted with petroleum ether and the residue was extracted by ethanol/water (1/1) followed by freeze-drying. The proanthocyanidins and flavonoids were characterized by thin layer chromatography (TLC) and ultra-high performance liquid chromatography (UPLC). To evaluate the inhibitory activity of this extract, larval migration assays with STH and GIN were performed. For this purpose, infective larvae of the helminths were, if necessary, exsheathed (Ancylostoma caninum, GIN) and incubated with different concentrations of CMLE. RESULTS: CMLE was found to be rich in flavonoids and proanthocyanidins; catechin and epicatechin were therefore quantified for standardization of the extract. Data indicate that CMLE had a significant effect on larval migration. The effect was dose-dependent and higher concentrations (1000 µg/mL) exerted significantly higher larvicidal effect (P < 0.001) compared with the negative control (1% dimethyl sulfoxide, DMSO) and lower concentrations (≤ 100 µg/ml). Infective larvae of Ascaris suum [half-maximal inhibitory concentration (IC50) = 5.5 µg/mL], Trichuris suis (IC50 = 7.4 µg/mL), and A. caninum (IC50 = 18.9 µg/mL) were more sensitive to CMLE than that of Toxocara canis (IC50 = 310.0 µg/mL), while infective larvae of Toxocara cati were largely unaffected (IC50 > 1000 µg/mL). Likewise, CMLE was active against most infective larvae of soil-transmitted ruminant GIN, except for Cooperia punctata. Trichostrongylus colubriformis was most sensitive to CMLE (IC50 = 2.1 µg/mL) followed by Cooperia oncophora (IC50 = 27.6 µg/mL), Ostertagia ostertagi (IC50 = 48.5 µg/mL), Trichostrongylus axei (IC50 = 54.7 µg/mL), Haemonchus contortus (IC50 = 145.6 µg/mL), and Cooperia curticei (IC50 = 156.6 µg/mL). CONCLUSIONS: These results indicate that CMLE exhibits promising anthelmintic properties against infective larvae of a large variety of soil-transmitted nematodes.

A molecular assessment of Ostertagia leptospicularis and Spiculopteragia asymmetrica among wild fallow deer in Northern Ireland and implications for false detection of livestock-associated species.

BACKGROUND: Wild deer populations utilizing livestock grazing areas risk cross-species transmission of gastrointestinal nematode parasites (GINs), including GINs with anthelmintic resistance (AR) traits. Wild deer have been shown to carry problematic GIN species such as Haemonchus contortus and Trichostrongylus species in the UK, but the presence of livestock GINs in Northern Ireland deer populations is unknown. Also, is it not known whether AR traits exist among GINs of deer such as Ostertagia leptospicularis and Spiculopteragia asymmetrica in pastureland where anthelmintics are heavily used. METHODS: Adult-stage GIN samples were retrieved from Northern Irish wild fallow deer abomasa. Individual specimens were subject to a species-specific PCR analysis for common sheep and cattle GIN species with ITS-2 sequence analysis to validate species identities. In addition, the beta-tubulin gene was subject to sequencing to identify benzimidazole (BZ) resistance markers. RESULTS: ITS-2 sequencing revealed O. leptospicularis and S. asymmetrica, but species-specific PCR yielded false-positive hits for H. contortus, Teladorsagia circimcincta, Trichostrongylus axei, T. colubriformis, T. vitrinus and Ostertagia ostertagi. For beta-tubulin, O. leptospicularis and S. asymmetrica yielded species-specific sequences at the E198 codon, but no resistance markers were identified in either species at positions 167, 198 or 200 of the coding region. DISCUSSION: From this report, no GIN species of significance in livestock were identified among Northern Ireland fallow deer. However, false-positive PCR hits for sheep and cattle-associated GINs is concerning as the presence of deer species in livestock areas could impact both deer and livestock diagnostics and lead to overestimation of both GIN burden in deer and the role as of deer as drivers of these pathogens. ITS-2 sequences from both O. leptospicularis and S. asymmetrica show minor sequence variations to geographically distinct isolates. AR has been noted among GINs of deer but molecular analyses are lacking for GINs of wildlife. In producing the first beta-tubulin sequences for both O. leptospicularis and S. asymmetrica, we report no BZ resistance in this cohort. CONCLUSIONS: This work contributes to genetic resources for wildlife species and considers the implications of such species when performing livestock GIN diagnostics.

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.

First insight into strongylid nematode diversity and anthelmintic treatment effectiveness in beef cattle in the Czech Republic explored by HTS metagenomics.

Parasitic diseases and mitigation of their effects play an important role in the health management of grazing livestock worldwide, with gastrointestinal strongylid nematodes being of prominent importance. These helminths typically occur in complex communities, often composed of species from numerous strongylid genera. Detecting the full diversity of strongylid species in non-invasively collected faecal samples is nearly impossible using conventional methods. In contrast, high-throughput amplicon sequencing (HTS) can effectively identify co-occurring species. During the four-year project, we collected and analysed faecal samples from beef cattle on >120 farms throughout the Czech Republic. Strongylids were the predominant nematodes, detected in 56% of the samples, but at a low level of infection. The apparent limitations in identifying strongylid taxa prompted this pilot study on a representative group of samples testing positive for strongylids using ITS-2 metabarcoding. The most widespread genera parasitizing Czech cattle were Ostertagia (O. ostertagi) and Oesophagostomum spp., followed by Trichostrongylus and Cooperia, while Bunostomum, Nematodirus and Chabertia were present only in a minority. As comparative material, 21 samples of cattle from the Danube Delta in Romania were used, which, in contrast, were dominated by Haemonchus placei. Finally, the effect of ivermectin treatment was tested at two Czech farms. After treatment with the anthelmintic, there was a shift in the strongylid communities, with a dominance of Cooperia and Ostertagia.

In Vitro anthelmintic efficacy of medicinal plant essential oils against Marshallagia marshalli: Evidence on oxidative/nitrosative stress biomarkers, DNA damage, and egg hatchability.

One of the major public health problems is drug resistance in parasitic diseases. It is therefore important to find new active ingredients to combat parasites. Herbal products such as essential oils (EOs) may show promise in treating infections caused by gastrointestinal nematodes (GINs). This study investigated the in vitro anthelmintic activity of the EOs of Lavandula angustifolia and Quercus infectoria against Marshallagia marshalli. The in vitro study was based on an egg hatch test (EHT), adult and larval motility inhibition tests, DNA damage, and several biomarkers of oxidative/nitrosative stress, including superoxide dismutase [SOD], catalase [CAT], and glutathione peroxidase [GSH -Px], protein carbonylation [PCO], malondialdehyde [MDA], total antioxidant status [TAS], and nitric oxide levels [NO]. Different concentrations of Lavandula angustifolia and Quercus infectoria EOs (1, 5, 10, 25 and 50 mg/ml) were used to determine the anthelmintic effect on three stages of the life cycle of M. marshalli, i.e. eggs, larvae and adult parasites, for 24 hr. The results showed that EOs of L. angustifolia and Q. infectoria play an important role as anthelmintics. These essential oils significantly reduced the egg hatching and motility of larval and adult worms. This anthelmintic effect is dependent on concentration and time. Furthermore, the EOs of L. angustifolia and Q. infectoria caused oxidative/nitrosative stress (reduced SOD, GSH-Px and CAT and increased MDA, PCO and NO) and DNA damage, thereby providing significant antihelminthic effects. Based on the results, it seems that the EOs extracted from L. angustifolia and Q. infectoria may be effective in the control and treatment of M. marshalli infections. Further research is needed to investigate their potential for in vivo use in the treatment of parasitic infections.

A curated multivariate approach to study efficacy and optimisation of a prototype vaccine against teladorsagiasis in sheep.

This work discusses and demonstrates the novel use of multivariate analysis and data dimensionality reduction techniques to handle the variety and complexity of data generated in efficacy trials for the development of a prototype vaccine to protect sheep against the Teladorsagia circumcincta nematode. A curated collection of data dimension reduction and visualisation techniques, in conjunction with sensible statistical modelling and testing which explicitly model key features of the data, offers a synthetic view of the relationships between the multiple biological parameters measured. New biological insight is gained into the patterns and associations involving antigen-specific antibody levels, antibody avidity and parasitological parameters of efficacy that is not achievable by standard statistical practice in the field. This approach can therefore be used to guide vaccine refinement and simplification through identifying the most immunologically relevant antigens, and it can be analogously implemented for similar studies in other areas. To facilitate this, the associated data and computer codes written for the R open system for statistical computing are made freely available.

Simultaneous resistance to multiple anthelmintic classes in nematode parasites of cattle in New Zealand.

Resistance to the benzimidazole and macrocyclic lactone anthelmintics is widespread in Cooperia spp. on cattle farms in New Zealand. Since this was first documented in 2006 little has changed in cattle farming systems except for the widespread use of levamisole to control Cooperia spp. in young cattle (i.e., parasite control has maintained an almost total reliance on use of anthelmintics). Here we report the emergence of simultaneous resistance to the benzimidazole, macrocyclic lactone and levamisole anthelmintics in Cooperia spp. and in Ostertagia spp. Anthelmintic efficacy against nematode parasites of cattle was investigated on four commercial farms following reports of poor animal growth rates and welfare, and positive faecal egg counts, despite routine treatment with combination anthelmintics, which included levamisole. Faecal egg count reduction tests involved 15 animals per treatment group, individual egg counts (paired samples) conducted pre- and post-treatment, with eggs counted to ≤ 15 eggs per g faeces and larval cultures for morphological identification. Actives tested varied between farms but always included levamisole alone and several combination products containing levamisole. Of the 20 tests conducted (i.e., 5 products on each of 4 farms) only 3 exceeded 90% efficacy against Cooperia spp. even though 8 of the products tested were combinations containing levamisole and at least one other broad-spectrum anthelmintic. Levamisole used alone achieved efficacies between 44% and 71% against Cooperia spp. across the four trials. The only product to exceed 95% efficacy against Cooperia spp. was a combination of monepantel + abamectin which was 100% effective against all parasites. Resistance to oxfendazole in Ostertagia spp. was indicated on 3 farms, while on one farm efficacy of all the tested products was ≤75% against this parasite. All the farms involved in this study were farming intensive cattle operations with an almost total reliance on anthelmintics to control parasitism. The results clearly demonstrate the emergence of simultaneous resistance to oxfendazole, levamisole and the macrocyclic lactone anthelmintics. Despite years of advice and recommendations to change farming practices away from intensive monocultures, many farmers have continued with the practice, and some are now faced with the very real possibility of being unable to control cattle parasites on their farms.

Oswaldocruzia franciscoensis n. sp. (Nematoda: Molineidae) in Leptodactylus macrosternum Miranda-Ribeiro, 1926 (Anura: Leptodactylidae) from Caatinga morphoclimatic domain, Brazil: morphological and molecular characterisation.

A new species of Oswaldocruzia Travassos, 1917 (Nematoda, Molineidae), parasite of Leptodactylus macrosternum Miranda-Ribeiro, 1926 (Anura: Leptodactylidae), from Caatinga morphoclimatic domain, Brazil, is described based on morphological and molecular data. Oswaldocruzia franciscoensis n. sp. is characterised by an anterior extremity with a cephalic vesicle divided into two portions, a body covered by cuticular longitudinal ridges, and cervical alae. Males of the new species have caudal bursa of type I with a 2-1-2 pattern, spicules divided into a shoe, bifurcated fork, and blade with two unequal branches, in which the longer branch bifurcates at its distal portion end and the smaller branch with three distal processes, each with distal bifurcations. Females have didelphic and amphidelphic uteri, an ovijector divided into vestibule, anterior and posterior sphincters, and anterior and posterior infundibula. The new species differs from its Neotropical congeners that have caudal bursa of type I, based on the presence of cervical alae and by having a spicular blade distally divided into two unequal branches, with the longer branch bifurcating at its distal portion and smaller branch with three distal processes, each distally bifurcated. The partial 18S rDNA sequence generated for Oswaldocruzia franciscoensis n. sp. is the first of a representative belonging to this genus in the Neotropical region.

Ancient diversity in host-parasite interaction genes in a model parasitic nematode.

Host-parasite interactions exert strong selection pressures on the genomes of both host and parasite. These interactions can lead to negative frequency-dependent selection, a form of balancing selection that is hypothesised to explain the high levels of polymorphism seen in many host immune and parasite antigen loci. Here, we sequence the genomes of several individuals of Heligmosomoides bakeri, a model parasite of house mice, and Heligmosomoides polygyrus, a closely related parasite of wood mice. Although H. bakeri is commonly referred to as H. polygyrus in the literature, their genomes show levels of divergence that are consistent with at least a million years of independent evolution. The genomes of both species contain hyper-divergent haplotypes that are enriched for proteins that interact with the host immune response. Many of these haplotypes originated prior to the divergence between H. bakeri and H. polygyrus, suggesting that they have been maintained by long-term balancing selection. Together, our results suggest that the selection pressures exerted by the host immune response have played a key role in shaping patterns of genetic diversity in the genomes of parasitic nematodes.

A fecal egg count reduction test in grazing beef steers using topical pioneer and generic eprinomectin and fenbendazole oral suspension.

Many generic anthelmintics are commercially available; however, little information exists regarding product effectiveness compared to pioneer brands. The objective of this study was to compare the effectiveness of a generic eprinomectin to the pioneer eprinomectin, as well as to fenbendazole and fenbendazole in combination with the pioneer eprinomectin in grazing beef steers via a fecal egg count reduction test. Forty naturally infected steers were allocated into five treatment groups based on ranked fecal egg counts: 1. pioneer eprinomectin (Eprinex®, topical), 2. generic eprinomectin (Eprizero®, topical), 3. fenbendazole (Safeguard® 0.5% oral suspension), 4. combination of pioneer eprinomectin topical and fenbendazole oral suspension, 5. negative control. Fecal samples were collected on days -14, 0, 14, and 29. Data were analyzed using the MIXED procedure of SAS 9.4. Neither the pioneer nor the generic eprinomectin groups reached a 90% fecal egg count reduction (FECR) throughout the study with reductions of 50% and 11% for pioneer eprinomectin and 79% and - 5% for generic eprinomectin at days 14 and 29 post-treatment, respectively. Both the fenbendazole and combination groups showed 98% and 99% FECR, respectively, at 14 days post-treatment; these reductions dropped slightly at day 29 post-treatment to 94% and 89%, respectively. Primarily Cooperia punctata, Cooperia oncophora and Ostertagia ostertagi larvae were recovered from the coprocultures across all treatment groups. Interestingly, the proportions of C. punctata and C. oncophora essentially demonstrated a post-treatment reversal in the both the fenbendazole and combination treatment groups when comparing days 0 and 29, demonstrating prepatency period differences or a fenbendazole treatment effect.

A review of the nematode assemblage of the Australian bandicoot, Isoodon macrourus (Peramelidae), from material held in the South Australian Museum with the description of Sprattellus cassonei n. sp. (Mackerrastrongylidae).

A total of 235 vials of nematodes held in the Australian Helminthological Collection of the South Australian Museum from 125 individuals of Isoodon macrourus were examined. The nematode assemblage of I. macrourus, comprising 12 families, including 16 genera and 23 identified species, was compared with the sympatric bandicoot species Perameles nasuta, 20 identified species (Sorensen's index of similarity 0.56) and P. pallescens, 12 identified species (Sorensen's index 0.51). Sprattellus cassonei n. sp. is distinguished from its congeners by having a synlophe with 7-8 ridges with the anterior ventral ridges interrupted, the morphology of the dorsal ray and the branching of the spicule tips. A single male specimen identified as Linstowinema sp. 1. is characterised by seven circles of body hooks, the oesophagus terminating at the level of the seventh circle and robust scale-like spines on the posterior ventral body. A complete description of the species will require additional material, including females. Difficulties in identifying individuals of the genus Mackerrastrongylus to species level are discussed. Overall similarities in the nematode assemblages of the three bandicoot hosts are likely due to shared relationships and similar behaviours.

Efficacy of a new fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) in Australian cattle against artificial infections of gastrointestinal nematodes.

We describe a new fixed-dose combination injectable (FDCI) formulated with doramectin and levamisole hydrochloride (HCl) to target broad and overlapping spectra of gastrointestinal nematodes (GINs) through two distinct modes of action. Here, we demonstrate the superior efficacy of the FDCI against mixed populations of cattle GINs in two dose confirmation studies conducted in Australia using artificially induced adult (Study 1) and immature (Study 2) GIN infections. Artificial infections consisted of Cooperia spp., Haemonchus placei, Ostertagia ostertagi, and Trichostrongylus axei. In both studies, cattle were inoculated with third-stage larvae and infections were confirmed by fecal egg count (FEC). Treatment groups in both studies were as follows: (1) negative control (saline, 0.9% sodium chloride), (2) positive control injectable endectocide (Study 1-0.2 mg/kg ivermectin; Study 2-0.2 mg/kg doramectin), (3) positive control injectable anthelmintic (7.5 mg/kg levamisole HCl), and (4) FDCI (0.2 mg/kg doramectin + 6.0 mg/kg levamisole HCl). Cattle were treated either 28 days (Study 1) or 6 days (Study 2) post-infection. On Days 14-16 (Study 1) or Days 20-21 (Study 2) post-treatment, cattle were euthanized and necropsied for the recovery, identification, and enumeration of worms. Treatment efficacy was calculated as reduction in worm burdens of treated cattle compared to saline-treated cattle, and treatments were considered effective if the geometric mean worm burden in the treatment group was reduced by ≥ 95% compared to the negative control group. In both studies, saline-treated cattle remained positive for GIN infections for the study duration. Ivermectin was less than 95% effective against Cooperia spp. (80.2%) and H. placei (24.8%) in Study 1, and levamisole HCl was less than 95% effective against Ostertagia spp. (47.1%) in Study 2. In contrast, the novel FDCI was 100% effective in treating adult and immature life stages of all cattle GINs included in the artificial infections, with no worms recovered at necropsy from doramectin + levamisole HCl-treated cattle. These data show a single administration of the FDCI provides broad-spectrum treatment of economically important cattle GINs.

Morphological and molecular description of Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) from the Manchurian wapiti Cervus elaphus xanthopygus.

Dictyocaulus xanthopygus sp. nov. (Nematoda: Trichostrongyloidea) was isolated from the lungs of the Manchurian wapiti in Primorsky kray, Russia. The newly described species exhibits morphological characteristics of Dictyocaulus but is distinct from congeneric species based on morphological (lengths of body and esophagus, distances from the anterior end to nerve ring and to excretory pore, the thickness of the buccal capsule, etc.) and molecular features. High levels of genetic divergence as well as Bayesian phylogenetic analyses based on 18S rRNA nuclear and cox1 mitochondrial genes supported the independence of Dictyocaulus xanthopygus sp. nov. Secondary structures of helix 39 of 18S rRNA were identical, while ES9 adjacent to the helix has a unique conformation for newly described worms. Energy-efficient conformational rearrangements of rRNA secondary structures can be applicable in studies on the pathogenesis, epidemiology, taxonomy and evolutionary biology of parasites. Additionally, bracketed dichotomous keys to six valid species of Dictyocaulus were prepared.

Transcriptional patterns of sexual dimorphism and in host developmental programs in the model parasitic nematode Heligmosomoides bakeri.

BACKGROUND: Heligmosomoides bakeri (often mistaken for Heligmosomoides polygyrus) is a promising model for parasitic nematodes with the key advantage of being amenable to study and manipulation within a controlled laboratory environment. While draft genome sequences are available for this worm, which allow for comparative genomic analyses between nematodes, there is a notable lack of information on its gene expression. METHODS: We generated biologically replicated RNA-seq datasets from samples taken throughout the parasitic life of H. bakeri. RNA from tissue-dwelling and lumen-dwelling worms, collected under a dissection microscope, was sequenced on an Illumina platform. RESULTS: We find extensive transcriptional sexual dimorphism throughout the fourth larval and adult stages of this parasite and identify alternative splicing, glycosylation, and ubiquitination as particularly important processes for establishing and/or maintaining sex-specific gene expression in this species. We find sex-linked differences in transcription related to aging and oxidative and osmotic stress responses. We observe a starvation-like signature among transcripts whose expression is consistently upregulated in males, which may reflect a higher energy expenditure by male worms. We detect evidence of increased importance for anaerobic respiration among the adult worms, which coincides with the parasite's migration into the physiologically hypoxic environment of the intestinal lumen. Furthermore, we hypothesize that oxygen concentration may be an important driver of the worms encysting in the intestinal mucosa as larvae, which not only fully exposes the worms to their host's immune system but also shapes many of the interactions between the host and parasite. We find stage- and sex-specific variation in the expression of immunomodulatory genes and in anthelmintic targets. CONCLUSIONS: We examine how different the male and female worms are at the molecular level and describe major developmental events that occur in the worm, which extend our understanding of the interactions between this parasite and its host. In addition to generating new hypotheses for follow-up experiments into the worm's behavior, physiology, and metabolism, our datasets enable future more in-depth comparisons between nematodes to better define the utility of H. bakeri as a model for parasitic nematodes in general.

Integration of ITS-2 rDNA nemabiome metabarcoding with Fecal Egg Count Reduction Testing (FECRT) reveals ivermectin resistance in multiple gastrointestinal nematode species, including hypobiotic Ostertagia ostertagi, in western Canadian beef cattle.

A large-scale Fecal Egg Count Reduction Test (FECRT) was integrated with ITS-2 rDNA nemabiome metabarcoding to investigate anthelmintic resistance in gastrointestinal nematode (GIN) parasites in western Canadian beef cattle. The study was designed to detect anthelmintic resistance with the low fecal egg counts that typically occur in cattle in northern temperate regions. Two hundred and thirty-four auction market-derived, fall-weaned steer calves coming off pasture were randomized into three groups in feedlot pens: an untreated control group, an injectable ivermectin treatment group, and an injectable ivermectin/oral fenbendazole combination treatment group. Each group was divided into six replicate pens with 13 calves per pen. Individual fecal samples were taken pre-treatment, day 14 post-treatment, and at monthly intervals for six months for strongyle egg counting and metabarcoding. Ivermectin treatment resulted in an 82.4% mean strongyle-type fecal egg count reduction (95% CI 67.8-90.4) at 14 days post-treatment, while the combination treatment was 100% effective, confirming the existence of ivermectin-resistant GIN. Nemabiome metabarcoding of third-stage larvae from coprocultures revealed an increase in the relative abundance of Cooperia oncophora, Cooperia punctata, and Haemonchus placei at 14 days post-ivermectin treatment indicating ivermectin resistance in adult worms. In contrast, Ostertagia ostertagi third-stage larvae were almost completely absent from day 14 coprocultures, indicating that adult worms of this species were not ivermectin resistant. However, there was a recrudescence of O. ostertagi third stage larvae in coprocultures at three to six months post-ivermectin treatment, which indicated ivermectin resistance in hypobiotic larvae. The calves were recruited from the auction market and, therefore, derived from multiple sources in western Canada, suggesting that ivermectin-resistant parasites, including hypobiotic O. ostertagi larvae, are likely widespread in western Canadian beef herds. This work demonstrates the value of integrating ITS-2 rDNA metabarcoding with the FECRT to enhance anthelmintic resistance detection and provide GIN species- and stage-specific information.

Multispecies helminth parasitism of grazing dairy cows in Germany and Austria, examined in the housing period.

Helminth composition and burden data for dairy cows have not been reported for >40 years for Germany and even less information is available for Austria. In the context of two recent studies, helminth parasitism was studied in 32 cows (23 from six farms in Bavaria and Tyrol; 9 from one farm in Saxony) from pasture-based dairy farms necropsied during the housing period. Helminths were enumerated and identified based on morphological characters (all helminths but rumen flukes) or molecular techniques (rumen flukes). Thirteen species of gastrointestinal nematodes and two species each of liver flukes (Fasciola hepatica, Dicrocoelium dendriticum) and rumen flukes (Calicophoron daubneyi, Paramphistomum leydeni) were recorded; no lungworms were recovered from any cow. Early fourth-stage (inhibited) larval Ostertagia species nematodes (210 to 140,600) were recovered from all cows, 31 each had adult Ostertagia ostertagi/Ostertagia lyrata (40 to 2020) and Trichostrongylus axei (10 to 53,400), 23 Oesophagostomum radiatum (1 to 242) and 20 Cooperia punctata (10 to 3330). Other nematodes present in descending order of prevalence were: Cooperia oncophora/Cooperia surnabada, Ostertagia leptospicularis/Ostertagia kolchida, Oesophagostomum venulosum, Bunostomum phlebotomum, Chabertia ovina, Nematodirus helvetianus, Trichostrongylus longispicularis, Haemonchus contortus and Aonchotheca bilobata. The cows from Bavaria and Tyrol harbored more total gastrointestinal nematodes than that from Saxony (geometric mean adult plus inhibited larval nematodes, 6510 vs. 2051, respectively). However, in both cohorts of cows abomasal nematodes accounted for ∼97% of the total nematode burden with inhibited larval Ostertagia species nematodes contributing over 70% of the total gastrointestinal nematode burden and âˆ¼ 96% of the Ostertagia species burden. Approximately 44%, 37% and 19% of the cows harbored <5000, 5000 to 10,000 or > 10,000 total gastrointestinal nematodes, respectively. Fecal nematode egg and coproculture nematode larval counts significantly correlated with the cows' total adult nematode burden (rs = 0.354, p < 0.05, and rs = 0.608, p < 0.001, respectively). Although the magnitude of nematode burden to exert production effects on dairy cows is not well defined and may vary relative to several factors including nutritional supplementation, the level of mixed parasitism found in this investigation supports consideration of grazing dairy cows in helminth control measures, especially at the time of housing in autumn.

Molecular Characterization of Mitochondrial Cytochrome c oxidase subunit 1 (Cox1) gene from Trichostrongylus Species (Nematoda: Trichostrongylidae) in Northern Iran

Objective: The objective of the present study was to identify Trichostrongylus species by molecular analysis and also phylogenetic relationships of Trichostrongylus species by mitochondrial Cytochrome c oxidase subunit 1 (Cox1) gene in Guilan province, northern Iran. Methods: Abomasum and duodenum contents of 144 livestock were collected from sheep, goats, and cattle in Guilan province. Morphological survey was performed for initial screening. Total DNA was extracted, and the partial region of Cox1 gene was amplified and sequenced. Genetic diversity was calculated and phylogenetic analysis of the data on nucleotide sequence was conducted by MEGA7 software. Results: Three species of Trichostrongylus including T. colubriformis, T. vitrinus, and T. axei were identified by morphological characteristics. The genetic divergence within the species in the present study was observed for T. axei (0-2.5%), T. colubriformis (0.77%), and T. vitrinus (0%). The mean inter-species difference between the three species of Trichostrongylus obtained in this study was 14.4-15.4%. Conclusion: The Cox1 sequences of the members of Trichostrongylus spp. were highly variable and this could be used as a valuable measure to achieve a proper assessment on biodiversity. Sequence data generation from other species of Trichostrongylus will be needed to reconstruct the phylogenetic relationships of this genus of nematodes.

Life history matters: Differential effects of abomasal parasites on caribou fitness.

Parasites can impact wildlife populations through their effects on host fitness and survival. The life history strategies of a parasite species can dictate the mechanisms and timing through which it influences the host. However, unravelling this species-specific effect is difficult as parasites generally occur as part of a broader community of co-infecting parasites. Here, we use a unique study system to explore how life histories of different abomasal nematode species may influence host fitness. We examined abomasal nematodes in two adjacent, but isolated, West Greenland caribou (Rangifer tarandus groenlandicus) populations. One herd of caribou were naturally infected with Ostertagia gruehneri, a common and dominant summer nematode of Rangifer sspp., and the other with Marshallagia marshalli (abundant; winter) and Teladorsagia boreoarcticus (less abundant; summer), allowing us to determine if these nematode species have differing effects on host fitness. Using a Partial Least Squares Path Modelling approach, we found that in the caribou infected with O. gruehneri, higher infection intensity was associated with lower body condition, and that animals with lower body condition were less likely to be pregnant. In caribou infected with M. marshalli and T. boreoarcticus, we found that only M. marshalli infection intensity was negatively related to body condition and pregnancy, but that caribou with a calf at heel were more likely to have higher infection intensities of both nematode species. The differing effects of abomasal nematode species on caribou health outcomes in these herds may be due to parasite species-specific seasonal patterns which influence both transmission dynamics and when the parasites have the greatest impact on host condition. These results highlight the importance of considering parasite life history when testing associations between parasitic infection and host fitness.

Trichostrongylosis: a zoonotic disease of small ruminants.

In the present world a significant threat to human health is posed by zoonotic diseases. Helminth parasites of ruminants are one of the most common zoonotic organisms on the planet. Among them, trichostrongylid nematodes of ruminants, found worldwide, parasitize humans in different parts of the world with varying rates of incidence, particularly among rural and tribal communities with poor hygiene, pastoral livelihood and poor access to health services. In the Trichostrongyloidea superfamily, Haemonchus contortus, Teladorsagia circumcincta, Marshallagia marshalli, Nematodirus abnormalis and Trichostrongylus spp. are zoonotic in nature. Species of the genus Trichostrongylus are the most prevalent gastrointestinal nematode parasites of ruminants that transmit to humans. This parasite is prevalent in pastoral communities around the world and causes gastrointestinal complications with hypereosinophilia which is typically treated with anthelmintic therapy. The scientific literature from 1938 to 2022 revealed the occasional incidence of trichostrongylosis throughout the world with abdominal complications and hypereosinophilia as the predominant manifestation in humans. The primary means of transmission of Trichostrongylus to humans was found to be close contact with small ruminants and food contaminated by their faeces. Studies revealed that conventional stool examination methods such as formalin-ethyl acetate concentration or Willi's technique combined with polymerase chain reaction-based approaches are important for the accurate diagnosis of human trichostrongylosis. This review further found that interleukin 33, immunoglobulin E, immunoglobulin G1, immunoglobulin G2, immunoglobulin M, histamine, leukotriene C4, 6-keto prostaglandin F1α, and thromboxane B2 are vital in the fight against Trichostrongylus infection with mast cells playing a key role. This review focuses on the prevalence, pathogenicity and immunological aspects of Trichostrongylus spp. in humans.

Description of Pudica wandiquei n. sp. (Heligmonellidae: Pudicinae), a nematode found infecting Proechimys simonsi (Rodentia: Echimyidae) in the Brazilian Amazon / Descrição de Pudica wandiquei n. sp. (Heligmonellidae: Pudicinae), nematódeo encontrado infectando Proechimys simonsi (Rodentia: Echimyidae) na Amazônia brasileira

Abstract A new species of nematode parasite of the subfamily Pudicinae (Heligmosomoidea: Heligmonellidae) is described from the small intestine of Proechimys simonsi (Rodentia: Echimyidae) from the locality of Nova Cintra in the municpality of Rodrigues Alves, Acre state, Brazil. The genus Pudica includes 15 species parasites of Neotropical rodents of the families Caviidae, Ctenomyidae, Dasyproctidae, Echimyidae, Erethizontidae, and Myocastoridae. Four species of this nematode were found parasitizing three different species rodents of the genus Proechimys in the Amazon biome. Pudica wandiquei n. sp. can be differentiated from all other Pudica species by the distance between the ends of rays 6 and 8 and the 1-3-1 pattern of the caudal bursa in both lobes.

Resumo Uma nova espécie de nematódeo da subfamília Pudicinae (Heligmosomoidea: Heligmonellidae) é descrito parasitando o intestino delgado de Proechimys simonsi (Rodentia: Echimyidae) em Nova Cintra, município de Rodrigues Alves, Estado do Acre, Brasil. O gênero Pudica inclui 15 espécies parasitas de roedores Neotropicais das famílias: Caviidae, Ctenomyidae, Dasyproctidae, Echimyidae, Erethizontidae e Myocastoridae. Destas, quatro espécies de nematódeos foram encontradas parasitando três diferentes espécies do roedor Proechimys no bioma Amazônia. Pudica wandiquei n. sp. é diferente das outras espécies de Pudica pela distância entre os raios 6 e 8 e pelo tipo da bolsa caudal, que é 1-3-1 em ambos os lados.