RÉSUMÉ
Duddingtonia flagrans is a nematode trapping fungus used for the control of gastrointestinal nematodes in livestock. The quantity of chlamydospores of D. flagrans required for the reduction of third-stage larvae (L3) of sheep gastrointestinal nematodes (GIN) is largely unknown, and a matter of discussion. The aim of this experiment was to determine in vitro the nematophagous activity of four different concentrations of D. flagrans (1000, 3000, 6250, or 11000 chlamydospores/ml) in the presence of varying numbers of GIN third-stage larvae (L3) (500, 1000, 1500). Additionally, the study sought to evaluate the efficacy of this fungus on Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis and Chabertia ovina. The results showed that as fungal concentrations increased, so did the larval reduction of third-stage infective larvae in each test. L3s number was not a determining factor in the efficacy against GIN. The comparison between various concentrations of chlamydospores revealed significant differences, particularly between 1000 and 11000 chlamydospores (P≤0.05). Regarding the larval reduction of the GIN species considered, D. flagrans demonstrated the same effectiveness across all species tested. The results of the current study confirm the efficacy and underscore the importance of D. flagrans as an alternative for controlling of GIN.
Sujet(s)
Ascomycota , Nematoda , Nématodoses , Maladies des ovins , Animaux , Ovis , Projets pilotes , Maladies des ovins/parasitologie , Maladies des ovins/prévention et contrôle , Nématodoses/médecine vétérinaire , Nématodoses/parasitologie , Nématodoses/prévention et contrôle , Ascomycota/physiologie , Larve , Lutte biologique contre les nuisibles/méthodes , Duddingtonia/physiologieRÉSUMÉ
This review outlines the current state of anthelmintic resistance (AHR) of gastrointestinal nematodes (GINs) among cattle in Argentina and Brazil, emphasizing the economic repercussions, animal health and welfare. The analysis explores factors associated with AHR and proposes a potential solution: the use of drug combinations. Both countries are grappling with a severe AHR scenario in cattle, having progressed through incipient, established, and advanced phases, leading to extreme cases of animal mortality due to ineffective control strategies. Genera such as Cooperia and Haemonchus have the highest reports of resistance, with Oesophagostomum radiatum also posing significant problems. While oral benzimidazoles and levamisole remain effective in most herds, moxidectin is entering an advanced resistance phase, and avermectins are increasingly deemed ineffective. The review explores the impact ofclimate, mixed grazing, animal movement and other husbandry practices, and the relationship between ectoparasite control and the emergence of resistant helminths. Notably, the discussion includes the strategic use of drug combinations as a valuable approach to address resistant GINs control in livestock, highlighting its significant potential to mitigate the challenges posed by AHR in the cattle industry of these countries.
Sujet(s)
Anthelminthiques , Maladies des bovins , Résistance aux substances , Nematoda , Nématodoses , Animaux , Bovins/parasitologie , Brésil , Argentine , Maladies des bovins/traitement médicamenteux , Maladies des bovins/parasitologie , Nématodoses/médecine vétérinaire , Nématodoses/traitement médicamenteux , Nématodoses/parasitologie , Anthelminthiques/usage thérapeutique , Nematoda/effets des médicaments et des substances chimiquesRÉSUMÉ
Exsheathment is crucial in the transition from free-living to parasitic phase for most strongyle nematode species. A greater understanding of this process could help in developing new parasitic control methods. This study aimed to identify commonalities in response to exsheathment triggers (heat acclimation, CO2 and pH) in a wide range of species (Haemonchus contortus, Trichostrongylus spp., Cooperia spp., Oesophagostomum spp., Chabertia ovina, and members of the subfamily Ostertagiinae) from sheep, cattle and farmed deer. The initial expectation of similarity in pH requirements amongst species residing within the same organ was not supported, with unexpected pH preferences for exsheathment of Trichostrongylus axei, Trichostrongylus vitrinus, Trichostrongylus colubriformis and Cooperia oncophora. We also found differences between species in their response to temperature acclimation, with higher exsheathment in response to heat shock observed for H. contortus, Ostertagia ostertagi, T. axei, T. vitrinus and Oesophagostomum sikae. Furthermore, some species showed poor exsheathment under all experimental conditions, such as Cooperia curticei and the large intestinal nematodes C. ovina and Oesophagostomum venulosum. Interestingly, there were some significant differences in response depending on the host from which the parasites were derived. The host species significantly impacted on the exsheathment response for H. contortus, Teladorsagia circumcincta, T. vitrinus and T. colubriformis. Overall, the data showed variability between nematode species in their response to these in vitro exsheathment triggers, highlighting the complexity of finding a common set of conditions for all species in order to develop a control method based on triggering the exsheathment process prematurely.
Sujet(s)
Cervidae , Nématodoses , Maladies des ovins , Animaux , Cervidae/parasitologie , Bovins , Ovis/parasitologie , Maladies des ovins/parasitologie , Nématodoses/parasitologie , Nématodoses/médecine vétérinaire , Concentration en ions d'hydrogène , Nematoda/physiologie , Nematoda/classification , Maladies des bovins/parasitologie , Dioxyde de carbone , Parasitoses intestinales/médecine vétérinaire , Parasitoses intestinales/parasitologie , Température élevéeRÉSUMÉ
Cuniculus paca, commonly known as the paca, is a rodent of the Cuniculidae family that is widely distributed throughout the Americas, including all Brazilian territories, and is abundant in the Amazon region. It is one of the most hunted species and faces significant predation in the extreme western Amazon region of Brazil because it constitutes a staple in the diet of local communities, for subsistence and commercial purposes. Understanding the helminthic fauna of these animals is of paramount importance, given that some nematodes have zoonotic potential and may pose risks to consumer health. This study aimed to contribute to the records of the nemtodes of this highly consumed species in the Amazon region, highlighting the occurrence of gastrointestinal parasites in free-living pacas intended for human subsistence consumption. The study was conducted in the Paranã da Floresta community, located in the municipality of Guajará, Amazonas from 2022 to 2023. The community members hunted this rodent for consumption and voluntarily provided the viscera for analysis. Nematodes were extracted from each organ. The organs were opened, and the contents were processed using a sieve (0.15 mm) and subsequently evaluated separately. In total, 10,157 nematodes were found in the 14 pacas. Based on morphological analyses, the nematodes were identified as Heligmostrongylus sedecimradiatus (n = 10,068), Trichuris sp. (n = 85), and Physaloptera sp. (n = 4). This study provides insights into the nematodes diversity of free-living pacas in the extreme Western Amazon region, emphasizing the importance of sanitary surveillance and public awareness of the risks associated with bushmeat consumption.
Sujet(s)
Nematoda , Nématodoses , Animaux , Brésil/épidémiologie , Nematoda/isolement et purification , Nematoda/classification , Nématodoses/médecine vétérinaire , Nématodoses/parasitologie , Nématodoses/épidémiologie , Cuniculidae/parasitologie , Mâle , Femelle , Maladies des rongeurs/parasitologie , Maladies des rongeurs/épidémiologie , HumainsRÉSUMÉ
The general aim of this study is to analyse the risk factors for gastrointestinal parasitosis in small ruminants in order to contribute to the emergence of targeted treatment methods, at herd and agro-climatic zone levels, for the integrated and sustainable management of parasitic diseases in Sahelian livestock systems. The methodology was based on a questionnaire survey conducted in 37 villages and coprological analysis using the McMaster method on faecal samples from 968 small ruminants, including 555 goats and 413 sheep. Multiple logistic regression was used to highlight the risk factors associated with each type of parasitosis encountered. The results showed that the most widespread farming system remained 100% traditional, with feeding based essentially on natural grazing. Coprological results showed the prevalence of nematodosis (70.2%), Cestodosis (4.1%) and Coccidiosis (79.9%), with an average prevalence of coinfection of 56.9%. These parasite loads were significantly higher during the rainy season and in the more arid northern Sahelian zone, with a marked reduction at the end of the season. Average parasitic egg excretions were 1089 EPG of nematodes and 6864 EPG of coccidia. Parasite loads were higher in the wetter southern strip and varied significantly by breed. Of the five breeds of small ruminants studied, the ara-ara sheep had the highest parasitic loads and prevalences for nematodosis (78.6%), coccidiosis (89,3%) and coinfection (70.9%), appears to be the most susceptible to parasitosis. As for risk factors for severe parasite pressure, animals at the end of the rainy season, older animals and those with poor body condition were at risk of nematodiasis or coinfection. On the other hand, animals at the beginning of the rainy season, farms located in less arid southern Sahelian zones and male subjects were the groups at significant risk of coccidiosis. In these extensive Sahelian farming conditions, the control of these parasitoses by selective treatment of animals could be developed, targeting in particular the risk groups highlighted in this study.
Sujet(s)
Maladies des chèvres , Capra , Maladies des ovins , Animaux , Facteurs de risque , Prévalence , Maladies des ovins/épidémiologie , Maladies des ovins/parasitologie , Ovis , Maladies des chèvres/parasitologie , Maladies des chèvres/épidémiologie , Capra/parasitologie , Mâle , Femelle , Niger/épidémiologie , Fèces/parasitologie , Coccidiose/médecine vétérinaire , Coccidiose/épidémiologie , Coccidiose/parasitologie , Saisons , Parasitoses intestinales/médecine vétérinaire , Parasitoses intestinales/épidémiologie , Parasitoses intestinales/parasitologie , Élevage/méthodes , Maladies gastro-intestinales/médecine vétérinaire , Maladies gastro-intestinales/parasitologie , Maladies gastro-intestinales/épidémiologie , Enquêtes et questionnaires , Nématodoses/médecine vétérinaire , Nématodoses/épidémiologie , Nématodoses/parasitologie , Numération des oeufs de parasites/médecine vétérinaireRÉSUMÉ
The objective of this study was to identify genomic regions and genes associated with resistance to gastrointestinal nematodes in Australian Merino sheep in Uruguay, using the single-step GWAS methodology (ssGWAS), which is based on genomic estimated breeding values (GEBVs) obtained from a combination of pedigree, genomic, and phenotypic data. This methodology converts GEBVs into SNP effects. The analysis included 26,638 animals with fecal egg count (FEC) records obtained in two independent parasitic cycles (FEC1 and FEC2) and 1700 50K SNP genotypes. The comparison of genomic regions was based on genetic variances (gVar(%)) explained by non-overlapping regions of 20 SNPs. For FEC1 and FEC2, 18 and 22 genomic windows exceeded the significance threshold (gVar(%) ≥ 0.22%), respectively. The genomic regions with strong associations with FEC1 were located on chromosomes OAR 2, 6, 11, 21, and 25, and for FEC2 on OAR 5, 6, and 11. The proportion of genetic variance attributed to the top windows was 0.83% and 1.9% for FEC1 and FEC2, respectively. The 33 candidate genes shared between the two traits were subjected to enrichment analysis, revealing a marked enrichment in biological processes related to immune system functions. These results contribute to the understanding of the genetics underlying gastrointestinal parasite resistance and its implications for other productive and welfare traits in animal breeding programs.
Sujet(s)
Polymorphisme de nucléotide simple , Maladies des ovins , Animaux , Ovis/parasitologie , Ovis/génétique , Maladies des ovins/génétique , Maladies des ovins/parasitologie , Résistance à la maladie/génétique , Étude d'association pangénomique , Nématodoses/génétique , Nématodoses/médecine vétérinaire , Nématodoses/parasitologie , Australie , Numération des oeufs de parasites/médecine vétérinaire , Parasitoses intestinales/génétique , Parasitoses intestinales/médecine vétérinaire , Parasitoses intestinales/parasitologieRÉSUMÉ
Parasites negatively affect the fitness of ungulate hosts directly, and in wild ungulates, these effects may be synzootic with other stressors, such as limited nutritional resources. In the Arctic, muskoxen (Ovibos moschatus) occur in a highly seasonal environment and must rely on finite energetic resources for survival and productivity. We investigated the costs of gastrointestinal nematodes on the body condition and reproductive status of 141 muskoxen, on Banks Island, Canada, when the population was at a peak in numbers and density. Using a Partial Least Squares Path Modelling approach, we found that high adult nematode abundance was associated with lower body condition, and high parasite abundance was associated with female reproduction including the indirect effect through on body condition (n = 87). These findings suggest that individuals prioritize energetic reserves for reproduction over parasite defence. In fall 2003, a severe icing event that restricted access to forage was associated with high overwinter mortality of muskoxen and a population crash. Through direct and indirect costs of parasite infection on body condition and reproduction, the high abundance of parasites may have contributed to the effects of this extreme weather event. Understanding the mechanisms in which parasites impact fitness can help explain the ecological drivers of ungulate populations and predict the interactions between the environment and populations.
Sujet(s)
Ruminants , Animaux , Régions arctiques , Ruminants/parasitologie , Femelle , Interactions hôte-parasite , Reproduction , Dynamique des populations , Saisons , Nematoda/physiologie , Nematoda/pathogénicité , Mâle , Canada , Nématodoses/médecine vétérinaire , Nématodoses/parasitologieRÉSUMÉ
BACKGROUND: Human parasitic infections caused by Adenophorean nematodes encompass a range of diseases, including dioctophymiasis, trichuriasis, capillariasis, trichinellosis, and myositis. These infection can result in adverse impacts on human health and cause societal and economic concerns in tropical and subtropical regions. METHODS: This review conducted searches in PubMed, Embase and Google Scholar for relevant studies that published in established databases up to April 26, 2024. Studies that focused on the common morphology, life cycle, disease distribution, clinical manifestations, and prevention and control strategies for Adenophorean parasitic diseases in humans were included. RESULTS: Adenophorean nematodes exhibit shared morphological characteristics with a four-layered cuticle; uninucleate epidermal cells; pseudocoelom with six or more coelomocytes; generally three caudal glands; five esophageal glands; two testes in males with median-ventral supplementary glands in a single row; tail in males rarely possessing caudal alae; amphids always postlabial; presence of cephalic sensory organs; absence of phasmids; and a secretory-excretory system consisting of a single ventral gland cell, usually with a non-cuticularized terminal duct. Humans play two important roles in the life cycle of the nematode class, Adenophorea: 1) as a definitive host infected by ingesting undercooked paratenic hosts, embryonated eggs, infective larvae in fish tissue and meat contaminated with encysted or non-encysted larvae, and 2) as an accidental host infected by ingesting parasitic eggs in undercooked meat. Many organs are targeted by the Adenophorean nematode in humans such as the intestines, lungs, liver, kidneys, lymphatic circulation and blood vessels, resulting in gastrointestinal problems, excessive immunological responses, cell disruption, and even death. Most of these infections have significant incidence rates in the developing countries of Africa, Asia and Latin America; however, some parasitic diseases have restricted dissemination in outbreaks. To prevent these diseases, interventions together with education, sanitation, hygiene and animal control measures have been introduced in order to reduce and control parasite populations. CONCLUSIONS: The common morphology, life cycle, global epidemiology and pathology of human Adenophorean nematode-borne parasitic diseases were highlighted, as well as their prevention and control. The findings of this review will contribute to improvement of monitoring and predicting human-parasitic infections, understanding the relationship between animals, humans and parasites, and preventing and controlling parasitic diseases.
Sujet(s)
Santé mondiale , Animaux , Humains , Étapes du cycle de vie , Nematoda/physiologie , Nématodoses/épidémiologie , Nématodoses/prévention et contrôle , Nématodoses/parasitologieRÉSUMÉ
The economic impact of gastrointestinal (GI) nematode infections on livestock production is well documented worldwide. Increasing evidence supports the hypothesis that parasite colonization induces significant changes in the GI tract environment and, therefore, in the landscape where the microbiota and parasites occur. Understanding the interactions between bacterial and parasite populations in the digestive tract of livestock may be useful to design parasite control strategies based on microbiota modification. The aims of this work were to investigate the impact of the oxytetracycline-mediated manipulation of the gut microbial community on the composition of GI nematode populations in naturally infected sheep and to explore changes in the GI microbial communities after nematode population treatment with the anthelmintic compound monepantel. Extensive manipulation of the GI microbiota with a therapeutic dose of the long-acting oxytetracycline formulation did not induce significant changes in the GI nematode burden. The gut microbiota of treated animals returned to control levels 17 days after treatment, suggesting strong resilience of the sheep microbial community to antibiotic-mediated microbiota perturbation. A significant decrease of the bacterial Mycoplasmataceae family (Log2FC = -4, Padj = 0.001) and a marked increase of the Methanobacteriaceae family (Log2FC = 2.9, Padj = 0.018) were observed in the abomasum of sheep receiving the monepantel treatment. While a comprehensive evaluation of the interactions among GI mycoplasma, methanobacteria and nematode populations deserves further assessment, the bacteria-nematode population interactions should be included in future control programs in livestock production. Understanding how bacteria and parasites may influence each other in the GI tract environment may substantially contribute to the knowledge of the role of microbiota composition in nematode parasite establishment and the role of the parasites in the microbiota composition.
Sujet(s)
Microbiome gastro-intestinal , Tube digestif , Nematoda , Nématodoses , Oxytétracycline , Maladies des ovins , Animaux , Ovis/parasitologie , Ovis/microbiologie , Microbiome gastro-intestinal/effets des médicaments et des substances chimiques , Maladies des ovins/parasitologie , Maladies des ovins/microbiologie , Maladies des ovins/traitement médicamenteux , Nématodoses/médecine vétérinaire , Nématodoses/traitement médicamenteux , Nématodoses/parasitologie , Nématodoses/microbiologie , Nematoda/microbiologie , Nematoda/effets des médicaments et des substances chimiques , Nematoda/physiologie , Oxytétracycline/pharmacologie , Tube digestif/microbiologie , Tube digestif/parasitologie , Amino-acétonitrile/analogues et dérivés , Amino-acétonitrile/pharmacologie , Bactéries/effets des médicaments et des substances chimiquesRÉSUMÉ
Infections with gastrointestinal nematodes (GINs) reduce the economic efficiency of sheep operations and compromise animal welfare. Understanding the host's response to GIN infection can help producers identify animals that are naturally resistant to infection. The objective of this study was to characterize the hepatic transcriptome of sheep that had been naturally exposed to GIN parasites. The hepatic transcriptome was studied using RNA-Sequencing technology in animals characterized as high (n = 5) or medium (n = 6) based on their innate immune acute-phase (AP) response phenotype compared with uninfected controls (n = 4), and with biased antibody-mediated (AbMR, n = 5) or cell-mediated (CMR, n = 5) adaptive immune responsiveness compared to uninfected controls (n = 3). Following the assessment of sheep selected for innate responses, 0, 136, and 167 genes were differentially expressed (DE) between high- and medium-responding animals, high-responding and uninfected control animals, and medium-responding and uninfected control animals, respectively (false discovery rate (FDR) < 0.05, and fold change |FC| > 2). When adaptive immune responses were assessed, 0, 53, and 57 genes were DE between antibody- and cell-biased animals, antibody-biased and uninfected control animals, and cell-biased and uninfected control animals, respectively (FDR < 0.05, |FC| > 2). Functional analyses identified enriched gene ontology (GO) terms and metabolic pathways related to the innate immune response and energy metabolism. Six functional candidate genes were identified for further functional and validation studies to better understand the underlying biological mechanisms of host responses to GINs. These, in turn, can potentially help improve decision making and management practices to increase the overall host immune response to GIN infection.
Sujet(s)
Immunité innée , Foie , Nématodoses , Maladies des ovins , Transcriptome , Animaux , Ovis/parasitologie , Foie/parasitologie , Foie/métabolisme , Foie/immunologie , Nématodoses/médecine vétérinaire , Nématodoses/génétique , Nématodoses/immunologie , Nématodoses/parasitologie , Maladies des ovins/parasitologie , Maladies des ovins/génétique , Maladies des ovins/immunologie , Immunité innée/génétique , Nematoda/pathogénicité , Immunité acquise/génétique , Maladies gastro-intestinales/génétique , Maladies gastro-intestinales/parasitologie , Maladies gastro-intestinales/immunologie , Maladies gastro-intestinales/médecine vétérinaireRÉSUMÉ
In Sudan, resistance to benzimidazoles has been reported recently in cattle and goats from South Darfur. Herein, ivermectin efficacy against gastrointestinal nematodes (GINs) was evaluated in sheep and goats in three study areas in South Darfur. The faecal egg count reduction test (FECRT) was used to evaluate the efficacy of ivermectin in sheep and goats naturally infected with GINs in the region of Bulbul (goats: n = 106), Kass (goats: n = 40) and Nyala (Domaia (sheep: n = 47, goats: n = 77) and the University farm (goats: n = 52)), using different treatment plans, and the efficacy was evaluated 12 days after treatment. Ivermectin efficacy was also evaluated in goats experimentally infected using local Haemonchus contortus isolates from Kass and Nyala. Nematodes surviving ivermectin treatment in goats in Bulbul and Nyala were harvested and larvae used to infect worm-free male sheep (n = 6, ≤6 months old). Infected sheep were dosed subcutaneously with ivermectin every eight days with increasing doses from 0.2 mg/kg to 1.6 mg/kg bodyweight (bw). Reduced ivermectin efficacy was identified in sheep and goats in the four study locations. Using a paired statistic, the efficacy of a therapeutic dose in sheep was 75.6% (90% upper credible limit (UCrL): 77.5%), while twice the recommended dose led to a reduction of 92.6% (90% UCrL: 93.3%). In goats, the FECRs of a therapeutic dose were 72.9-95.3% (90% UCrL range: 73.6-95.7%) in Bulbul, Nyala Domaia, Nyala University farm and Kass. Twice the dose recommended for goats in Bulbul revealed a 90% UCrL of 87.6%. All post-treatment faecal cultures contained only Haemonchus spp. larvae. The experimental infection trials in sheep and goats supported our findings from field trials and calculated upper 90% CrL of below 98.9%. For the first time highly ivermectin resistant H. contortus populations have been identified in sheep and goats in Sudan, and resistance was experimentally confirmed.
Sujet(s)
Résistance aux substances , Maladies des chèvres , Capra , Ivermectine , Nématodoses , Maladies des ovins , Animaux , Capra/parasitologie , Ivermectine/pharmacologie , Ivermectine/usage thérapeutique , Ovis/parasitologie , Maladies des ovins/traitement médicamenteux , Maladies des ovins/parasitologie , Maladies des chèvres/traitement médicamenteux , Maladies des chèvres/parasitologie , Soudan , Nématodoses/traitement médicamenteux , Nématodoses/médecine vétérinaire , Nématodoses/parasitologie , Fèces/parasitologie , Mâle , Numération des oeufs de parasites/médecine vétérinaire , Nematoda/effets des médicaments et des substances chimiques , Anthelminthiques/usage thérapeutique , Anthelminthiques/pharmacologie , Haemonchus/effets des médicaments et des substances chimiquesRÉSUMÉ
Anthelmintic resistance in sheep parasitic gastrointestinal nematodes is widespread and a severe health and economic issue but prevalence of resistance and involved parasite species are unknown in Germany. Here, the faecal egg count reduction test (FECRT) was performed on eight farms using fenbendazole, ivermectin and moxidectin and on four farms using only moxidectin. A questionnaire was used to obtain data on management practices to potentially identify risk factors for presence of resistance. All requirements of the recently revised WAAVP guideline for diagnosing anthelmintic resistance using the FECRT were applied. Nematode species composition in pre- and post-treatment samples was analysed with the nemabiome approach. Using the eggCounts statistic package, resistance against fenbendazole, ivermectin and moxidectin was found on 7/8, 8/8 and 8/12 farms, respectively. No formal risk factor analysis was conducted since resistance was present on most farms. Comparison with the bayescount R package results revealed substantial agreement between methods (Cohen's κ = 0.774). In contrast, interpretation of data comparing revised and original WAAVP guidelines resulted in moderate agreement (Cohen's κ = 0.444). The FECR for moxidectin was significantly higher than for ivermectin and fenbendazole. Nemabiome data identified 4 to 12 species in pre-treatment samples and treatments caused a small but significant decrease in species diversity (inverse Simpson index). Non-metric multidimensional scaling and k-means clustering were used to identify common patterns in pre- and post-treatment samples. However, post-treatment samples were scattered among the pre-treatment samples. Resistant parasite species differed between farms. In conclusion, the revised FECRT guideline allows robust detection of anthelmintic resistance. Resistance was widespread and involved multiple parasite species. Resistance against both drug classes on the same farm was common. Further studies including additional drugs (levamisole, monepantel, closantel) should combine sensitive FECRTs with nemabiome data to comprehensively characterise the anthelmintic susceptibility status of sheep nematodes in Germany.
Sujet(s)
Anthelminthiques , Fermes , Fèces , Macrolides , Numération des oeufs de parasites , Maladies des ovins , Animaux , Ovis , Allemagne/épidémiologie , Maladies des ovins/parasitologie , Maladies des ovins/épidémiologie , Numération des oeufs de parasites/méthodes , Numération des oeufs de parasites/médecine vétérinaire , Fèces/parasitologie , Anthelminthiques/pharmacologie , Macrolides/pharmacologie , Ivermectine/pharmacologie , Nématodoses/médecine vétérinaire , Nématodoses/parasitologie , Nématodoses/épidémiologie , Nématodoses/traitement médicamenteux , Fenbendazole/pharmacologie , Résistance aux substances , Nematoda/effets des médicaments et des substances chimiques , Nematoda/classification , Nematoda/isolement et purificationRÉSUMÉ
Complex cross-talk occurs between gastrointestinal nematodes and gut symbiotic microbiota, with consequences for animal metabolism. To investigate the connection between methane production and endoparasites, this study evaluated the effect of mixed infection with Haemonchus contortus and Trichostrongylus colubriformis on methanogenic and methanotrophic community in rumen microbiota of lambs using shotgun metagenomic and real-time quantitative PCR (qPCR). The rumen content was collected from six Santa Inês lambs, (7 months old) before and after 42 days infection by esophageal tube. The metagenomic analysis showed that the infection affected the microbial community structure leading to decreased abundance of methanotrophs bacteria, i.e. α-proteobacteria and ß-proteobacteria, anaerobic methanotrophic archaea (ANME), protozoa, sulfate-reducing bacteria, syntrophic bacteria with methanogens, geobacter, and genes related to pyruvate, fatty acid, nitrogen, and sulfur metabolisms, ribulose monophosphate cycle, and Entner-Doudoroff Pathway. Additionally, the abundance of methanogenic archaea and the mcrA gene did not change. The co-occurrence networks enabled us to identify the interactions between each taxon in microbial communities and to determine the reshaping of rumen microbiome associations by gastrointestinal nematode infection. Besides, the correlation between ANMEs was lower in the animal's postinfection. Our findings suggest that gastrointestinal parasites potentially lead to decreased methanotrophic metabolism-related microorganisms and genes.
Sujet(s)
Microbiome gastro-intestinal , Méthane , Rumen , Maladies des ovins , Animaux , Rumen/microbiologie , Rumen/parasitologie , Ovis/microbiologie , Méthane/métabolisme , Maladies des ovins/microbiologie , Maladies des ovins/parasitologie , Bactéries/classification , Bactéries/génétique , Bactéries/isolement et purification , Archéobactéries/génétique , Archéobactéries/classification , Haemonchus/génétique , Trichostrongylus , Microbiote , Nématodoses/microbiologie , Nématodoses/médecine vétérinaireRÉSUMÉ
Sustainable parasite control practices are necessary to combat the negative effects of gastrointestinal nematodes on animal health and production while reducing the selection pressure for anthelmintic resistance. Parasite diagnostic tests can inform treatment decisions, the timing and effectiveness of treatment and enable livestock breeding programmes. In recent years new diagnostic methods have been developed, some incorporating machine learning (ML), to facilitate the detection and enumeration of parasite eggs. It is important to understand the technical characteristics and performance of such new methods compared to long standing and commonly utilised methods before they are widely implemented. The aim of the present study was to trial three new diagnostic tools relying on image analysis (FECPAKG2, Micron and OvaCyte) and to compare them to traditional manual devices (McMaster and Mini-FLOTAC). Faecal samples were obtained from 41 lambs naturally infected with gastrointestinal nematodes. Samples were mixed and separated into 2 aliquots for examination by each of the 5 methods: McMaster, Mini-FLOTAC, FECPAKG2, Micron and OvaCyte. The techniques were performed according to their respective standard protocols and results were collected by trained staff (McMaster and Mini-FLOTAC) or by the device (FECPAKG2, Micron and OvaCyte). Regarding strongyle worm egg count, McMaster values varied from 0 to 9,000 eggs per gram (EPG). When comparing replicate aliquots, both the Mini-FLOTAC and Micron methods displayed similar repeatability to McMaster. However, we found FECPAKG2 and OvaCyte significantly less precise than McMaster. When comparing parasite egg enumeration, significant positive linear correlations were established between McMaster and all other methods. No difference was observed in EPG between McMaster and Mini-FLOTAC or FECPAKG2; however, Micron and OvaCyte returned significantly higher and lower EPG, respectively, compared to McMaster. The number of eggs ascribed to other parasite species was not sufficient for performing a robust statistical comparison between all methods. However, it was noted that FECPAKG2 generally did not detect Strongyloides papillosus eggs, despite these being detected by other methods. In addition, Moniezia spp and Trichuris spp eggs were detected by OvaCyte and Mini-FLOTAC, respectively, but not by other methods. The observed variation between traditional and new methods for parasite diagnostics highlights the need for continued training and enhancing of ML models used and the importance of developing clear guidelines for validation of newly developed methods.
Sujet(s)
Fèces , Nématodoses , Maladies des ovins , Animaux , Ovis , Maladies des ovins/parasitologie , Maladies des ovins/diagnostic , Nématodoses/médecine vétérinaire , Nématodoses/diagnostic , Nématodoses/parasitologie , Fèces/parasitologie , Numération des oeufs de parasites/médecine vétérinaire , Numération des oeufs de parasites/méthodes , Numération des oeufs de parasites/instrumentation , Microscopie/médecine vétérinaire , Microscopie/méthodes , Maladies gastro-intestinales/médecine vétérinaire , Maladies gastro-intestinales/parasitologie , Maladies gastro-intestinales/diagnostic , Nematoda/isolement et purification , Traitement d'image par ordinateur , Parasitoses intestinales/médecine vétérinaire , Parasitoses intestinales/diagnostic , Parasitoses intestinales/parasitologie , Sensibilité et spécificitéRÉSUMÉ
Gastrointestinal nematodes (GINs) are a significant threat to the sustainability of global sheep production. Periparturient ewes play a key role in GIN epidemiology, with increased GIN faecal egg counts (FECs) in these ewes resulting in heavy pasture contamination that facilitates parasitic gastroenteritis in immunologically naïve lambs later during the grazing period. Traditionally, blanket anthelmintic treatment would suppress GIN egg outputs in these ewes and subsequent pasture contamination. However, farmers are now advised to implement targeted selective treatment (TST) to reduce anthelmintic use and subsequent anthelmintic resistance development, yet, there is currently limited evidence to determine optimal TST strategies in ewes. In this study, the characteristics of 226 ewes on seven Welsh farms were assessed postlambing to identify factors associated with their individual strongyle FECs using negative binomial mixed model analysis. Nemabiome analysis was conducted on 34 ewes across two study farms using the Oxford Nanopore MinIon platform with an aim of identifying factors associated with variations in ewe nemabiome composition within flocks. The best-fitted model of ewe FEC incorporated ewe body condition score, dag score, breed, and an interaction effect between ewe age and litter size as fixed factors. The addition of a mean FEC value for ewes of a specific litter size on each farm further improved model fit and reduced between-farm variance in the model. Nemabiome analysis revealed significant variation in within flock nemabiome diversity on individual farms, with significantly reduced nemabiome diversity recorded in ewes exhibiting dags and in twin-bearing ewes on respective farms, whilst T. circumcincta was present as a significantly higher proportion of the nemabiome in Suffolk ewes and twin bearing ewes (P < 0.05) in respective flocks. Our data demonstrate that commonly recorded ewe characteristics can be exploited to predict individual periparturient ewe FEC and subsequently may be used as a guide for TST strategies on sheep farms once specific TST thresholds are identified to deliver the optimal balance between minimal pasture contamination and maximal GIN refugia. This study is the first to utilise Oxford Nanopore MinIon sequencing to evaluate the nemabiome of sheep, and to molecularly assess the nemabiome of individual ruminants within a flock/herd, with results indicating that significant within flock variations in nemabiome composition which may have implications for TST and flock management strategies.
Sujet(s)
Fèces , Nématodoses , Numération des oeufs de parasites , Maladies des ovins , Animaux , Ovis , Maladies des ovins/parasitologie , Maladies des ovins/prévention et contrôle , Femelle , Nématodoses/médecine vétérinaire , Fèces/parasitologie , Numération des oeufs de parasites/médecine vétérinaire , Anthelminthiques/usage thérapeutique , Nematoda/effets des médicaments et des substances chimiques , Période de péripartum , Élevage/méthodes , Grossesse , Pays de GallesRÉSUMÉ
BACKGROUND: Gastrointestinal nematodes (GINs) have a major impact on sheep production, health, and welfare worldwide. Norway is no exception, but there are only a few studies on the prevalence of GINs in Norwegian sheep. The aim of this study was to investigate the current occurrence of the most important nematodes in sheep flocks in Norway. Faecal samples were collected from flocks in 2021/2022, mainly from three geographical regions in Norway, i.e., northern, eastern, and western. In each of 134 flocks included, individual samples from 10 lambs (autumn) were pooled. Third stage larvae (L3) were cultivated and harvested (Baermann method) from the pooled samples. The DNA was then extracted and further analysed using droplet digital PCR (ddPCR). This enables assessment of the proportions of the three most important nematode species/genera, i.e., H. contortus, T. circumcincta, and Trichostrongylus. The fractional abundance/relative proportion of each species/genus was assessed by performing duplex assays with universal strongyle and species/genus-specific primers and probe sets. In addition, the occurrence of Nematodirus eggs was assessed by standard faecal egg counts (i.e., McMaster method). RESULTS: Of the 134 flocks sampled, 24 were from the northern region, 31 from eastern, and 71 from western Norway. In addition, some flocks from central (n = 7), and southern (n = 1) Norway were included. Among the sampled flocks, T. circumcincta occurred most commonly (94%), followed by H. contortus (60%) and Trichostrongylus (55%), and Nematodirus (51%). In general, mixed infections were observed, with 38% and 18% of flocks infected with three or all four genera, respectively. CONCLUSIONS: The results of this study indicate that GINs are widespread in Norway. Teladorsagia circumcincta seems to be present in most flocks based on this screening. Moreover, the results show that Nematodirus spp. infect lambs throughout the country, predominantly N. battus, and indicate that this nematode has become more abundant, which could lead to an increase in nematodirosis.
Sujet(s)
Fèces , Nématodoses , Réaction de polymérisation en chaîne , Maladies des ovins , Animaux , Norvège/épidémiologie , Ovis , Maladies des ovins/épidémiologie , Maladies des ovins/parasitologie , Réaction de polymérisation en chaîne/médecine vétérinaire , Fèces/parasitologie , Nématodoses/médecine vétérinaire , Nématodoses/épidémiologie , Nématodoses/parasitologie , Prévalence , Nematoda/isolement et purification , Microscopie/médecine vétérinaireRÉSUMÉ
Disease cross-transmission between wild and domestic ungulates can negatively impact livelihoods and wildlife conservation. In Pin valley, migratory sheep and goats share pastures seasonally with the resident Asiatic ibex (Capra sibirica), leading to potential disease cross-transmission. Focussing on gastro-intestinal nematodes (GINs) as determinants of health in ungulates, we hypothesized that infection on pastures would increase over summer from contamination by migrating livestock. Consequently, interventions in livestock that are well-timed should reduce infection pressure for ibex. Using a parasite life-cycle model, that predicts infective larval availability, we investigated GIN transmission dynamics and evaluated potential interventions. Migratory livestock were predicted to contribute most infective larvae onto shared pastures due to higher density and parasite levels, driving infections in both livestock and ibex. The model predicted a c.30-day antiparasitic intervention towards the end of the livestock's time in Pin would be most effective at reducing GINs in both hosts. Albeit with the caveats of not being able to provide evidence of interspecific parasite transmission due to the inability to identify parasite species, this case demonstrates the usefulness of our predictive model for investigating parasite transmission in landscapes where domestic and wild ungulates share pastures. Additionally, it suggests management options for further investigation.
Sujet(s)
Capra , Bétail , Animaux , Inde/épidémiologie , Capra/parasitologie , Bétail/parasitologie , Ovis/parasitologie , Migration animale , Maladies des chèvres/parasitologie , Maladies des chèvres/transmission , Animaux sauvages/parasitologie , Maladies des ovins/parasitologie , Maladies des ovins/transmission , Maladies des ovins/prévention et contrôle , Nématodoses/transmission , Nématodoses/médecine vétérinaire , Nématodoses/prévention et contrôle , Nématodoses/parasitologie , Nématodoses/épidémiologie , Saisons , Larve/parasitologie , Nematoda/pathogénicitéRÉSUMÉ
Biomarkers are specific molecular, histological, or physiological characteristics of normal or pathogenic biological processes and are promising in the diagnosis of gastrointestinal nematodes (GINs). Although some biomarkers have been validated for infection by Ostertagia sp. in cattle raised in temperate regions, there is a lack of information for tropical regions. The aim of this project was to assess potential biomarkers and validate the most promising. In the first study, 36 bovines (Nelore breed) naturally infected by GINs were distributed into two groups: infected (not treated with anthelmintic) and treated (treated with fenbendazole on days 0, 7, 14, 21, 28, 42, and 56). The variables of interest were live weight, fecal egg count, hemogram, serum biochemical markers, phosphorus, gastrin, and pepsinogen. In the second step, pepsinogen was assessed in cattle of the Nelore breed distributed among three groups: infected (not treated with anthelmintic), MOX (treated with moxidectin), and IVM + BZD (treated with ivermectin + albendazole). In the first study, no difference between groups was found for weight, albumin, hematocrit (corpuscular volume [CV]), erythrocytes, or hemoglobin. Negative correlations were found between pepsinogen and both CV and albumin, and albumin was negatively correlated with the percentage of Haemonchus sp. in the fecal culture. Among the biomarkers, only pepsinogen differentiated treated and infected (beginning with the 28th day of the study). In the second study, a reduction in pepsinogen was found after anthelmintic treatment. Therefore, pepsinogen is a promising biomarker of worms in cattle naturally infected by the genera Haemonchus and Cooperia in tropical areas.
Sujet(s)
Marqueurs biologiques , Maladies des bovins , Fèces , Nématodoses , Climat tropical , Animaux , Bovins , Maladies des bovins/parasitologie , Maladies des bovins/traitement médicamenteux , Marqueurs biologiques/sang , Nématodoses/médecine vétérinaire , Nématodoses/parasitologie , Nématodoses/traitement médicamenteux , Fèces/parasitologie , Numération des oeufs de parasites , Anthelminthiques/usage thérapeutique , Nematoda/isolement et purification , Nematoda/classification , Nematoda/effets des médicaments et des substances chimiques , Maladies gastro-intestinales/parasitologie , Maladies gastro-intestinales/médecine vétérinaire , Parasitoses intestinales/médecine vétérinaire , Parasitoses intestinales/parasitologie , Fenbendazole/usage thérapeutiqueRÉSUMÉ
The developing brain is vulnerable to maternal bacterial and viral infections which induce strong inflammatory responses in the mother that are mimicked in the offspring brain, resulting in irreversible neurodevelopmental defects, and associated cognitive and behavioural impairments. In contrast, infection during pregnancy and lactation with the immunoregulatory murine intestinal nematode, Heligmosomoides bakeri, upregulates expression of genes associated with long-term potentiation (LTP) of synaptic networks in the brain of neonatal uninfected offspring, and enhances spatial memory in uninfected juvenile offspring. As the hippocampus is involved in spatial navigation and sensitive to immune events during development, here we assessed hippocampal gene expression, LTP, and neuroimmunity in 3-week-old uninfected offspring born to H. bakeri infected mothers. Further, as maternal immunity shapes the developing immune system, we assessed the impact of maternal H. bakeri infection on the ability of offspring to resist direct infection. In response to maternal infection, we found an enhanced propensity to induce LTP at Schaffer collateral synapses, consistent with RNA-seq data indicating accelerated development of glutamatergic synapses in uninfected offspring, relative to those from uninfected mothers. Hippocampal RNA-seq analysis of offspring of infected mothers revealed increased expression of genes associated with neurogenesis, gliogenesis, and myelination. Furthermore, maternal infection improved resistance to direct infection of H. bakeri in offspring, correlated with transfer of parasite-specific IgG1 to their serum. Hippocampal immunohistochemistry and gene expression suggest Th2/Treg biased neuroimmunity in offspring, recapitulating peripheral immunoregulation of H. bakeri infected mothers. These findings indicate maternal H. bakeri infection during pregnancy and lactation alters peripheral and neural immunity in uninfected offspring, in a manner that accelerates neural maturation to promote hippocampal LTP, and upregulates the expression of genes associated with neurogenesis, gliogenesis, and myelination.
Sujet(s)
Hippocampe , Plasticité neuronale , Animaux , Femelle , Hippocampe/métabolisme , Hippocampe/parasitologie , Grossesse , Souris , Nématodoses/immunologie , Nématodoses/parasitologie , Potentialisation à long terme , Effets différés de l'exposition prénatale à des facteurs de risque/immunologie , Infections à Strongylida/immunologie , Infections à Strongylida/parasitologie , Mâle , Neuro-immunomodulationRÉSUMÉ
BACKGROUND: The health and productivity of dairy goats continue to be impacted by gastrointestinal nematodes (GIN) and lungworms (LW). Eprinomectin (EPN) is frequently selected for treatment because it is generally effective and does not require a milk withdrawal period. However, some factors, such as lactation, can have an impact on EPN pharmacokinetics and potentially its efficacy. To evaluate whether this can alter the efficacy of Eprecis® 2%, an eprinomectin injectable solution, a study was performed in lactating goats using the dose currently registered in cattle, sheep and goats (0.2 mg/kg). METHODS: This study was a blinded, randomized, controlled trial performed according to the VICH guidelines. Eighteen (18) worm-free lactating goats were included and experimentally challenged on day 28 with a mixed culture of infective gastrointestinal and lung nematode larvae (Haemonchus contortus, Trichostrongylus colubriformis, Teladorsagia circumcincta, Dictyocaulus filaria). At D-1, fecal samples were collected to confirm patent infection in all animals. On D0, the goats were randomly allocated into two groups of nine goats; group 1 was treated with Eprecis® 2% at 0.2 mg/kg BW by subcutaneous injection, while group 2 remained untreated. Fecal samples for egg counts were collected from all animals on days 3, 5, 7, 9, 11 and 14. On D14, all goats were killed, and the abomasum, small intestine and lungs were removed, processed and subsampled to record the number and species of worms. RESULTS: The treatment was well tolerated. After treatment, the arithmetic mean FEC decreased in the treated group and remained < 5 EPG until the end of the study, while the arithmetic mean FEC in the control group remained > 849.0 EPG. At D14, goats in the treated group had very limited or zero total worm counts, whereas all animals from the control group had a high worm burden. The measured efficacy was 100.0% against H. contortus and T. colubriformis, 99.9% against T. circumcincta and 98.0% against D. filaria. CONCLUSIONS: Eprinomectin (Eprecis®, 20 mg/ml), administered at the label dose (0.2 mg/kg), is highly effective against gastrointestinal nematodes and lungworms in lactating goats.