A loop-mediated isothermal amplification (LAMP) assay to identify isotype 1 β-tubulin locus SNPs in synthetic double-stranded Haemonchus contortus DNA

Development of sustainable gastrointestinal nematode (GIN) control strategies depends on the ability to identify the frequencies of drug-susceptible and resistant genotypes in GIN populations arising from management practices undertaken on individual farms. Resistance to BZ drugs in GINs has been shown to be conferred by the presence of defined SNPs in the isotype 1 β-tubulin locus. Loop-mediated isothermal amplification (LAMP) assays are amenable to use on a range of DNA templates and are potentially adaptable to use in practical, cost-effective, pen-side diagnostic platforms that are needed to detect anthelmintic resistance in the field. In this study, we designed primers and examined LAMP assays to detect each of the three major isotype 1 β-tubulin SNPs conferring genetic susceptibility to BZ drugs. We used artificial pools of synthetic DNA, containing different proportions of susceptible and resistant SNPs to determine reproducibility of the assays. We demonstrated the detection of each of the isotype 1 β-tubulin SNPs conferring susceptibility to BZ drugs using the optimal LAMP assay. Isotype 1 β-tubulin SNP typing was effective in detecting BZ susceptibility, but the accuracy was reduced in samples with less than 60 % susceptible DNA. Our results show the potential for LAMP SNP typing to detect genetic susceptibility or resistance to anthelmintic drugs in livestock GINs, and some of the limitations in our approach that will need to be overcome in order to evaluate this assay using field samples. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12639-021-01414-w

Strategies to Optimize the Efficacy of Anthelmintic Drugs in Ruminants

Anthelmintic resistance in human and animal pathogenic helminths has been spreading in prevalence and severity. Multidrug resistance is a widespread problem in livestock animals. The use of available pharmacology-based information is critical to the design of successful future approaches for parasite control. Relevant scientific work supporting the main strategies to optimize anthelmintic therapy in ruminants under the current drug-resistance scenario is described here. We emphasize the need for further integrated pharmaco-parasitological knowledge to extend the lifespan of both traditional and novel anthelmintic compounds, and to progress in the identification of complementary/alternative measures of parasite control in livestock animals.Fil: Lanusse, Carlos Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Cantón, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Virkel, Guillermo Leon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Alvarez, Luis Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Costa Junior, Livio. Universidade Federal Do Maranhao; BrasilFil: Lifschitz, Adrian Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentin

Nemabiome metabarcoding shows a high prevalence of Haemonchus contortus and predominance of Camelostrongylus mentulatus in alpaca herds in the northern UK

Gastrointestinal nematodes (GINs) are a common threat faced by pastoral livestock. Since their major introduction to the UK in the early 1990s, South American camelids have been co-grazed with sheep, horses, and other livestock, allowing exposure to a range of GIN species. However, there have been no molecular-based studies to investigate the GIN populations present in these camelids. In the current study, we sampled nine alpaca herds from northern England and southern Scotland and used high-throughput metabarcoded sequencing to describe their GIN species composition. A total of 71 amplicon sequence variants (ASVs) were identified representing eight known GIN species. Haemonchus contortus was the most prevalent species found in almost all herds in significant proportions. The identification of H. contortus in other livestock species is unusual in the northern UK, implying that alpacas may be suitable hosts and potential reservoirs for infection in other hosts. In addition, the camelid-adapted GIN species Camelostrongylus mentulatus was identified predominantly in herds with higher faecal egg counts. These findings highlight the value of applying advanced molecular methods, such as nemabiome metabarcoding to describe the dynamics of gastrointestinal nematode infections in novel situations. The results provide a strong base for further studies involving co-grazing animals to confirm the potential role of alpacas in transmitting GIN species between hosts

Association of synthetic anthelmintics and natural monoterpenes against Haemonchus contortus

The resistance of Haemonchus contortus to synthetic anthelmintics is an increasing concern and different strategies are being evaluated. The present trial studied the in vitro effect of the association of synthetic compound and natural monoterpene on eggs and larvae of H. contortus. The monoterpenes carvacrol, thymol, r-carvone, s-carvone, citral and p-cymene, and the synthetic antihelmintic ivermectin, and albendazole were used. Egg Hatch Test (EHT) and Larval Migration Inhibition Test (LMIT) were performed. The lowest efficient concentration of monoterpenes in EHT (≤ 11% of efficacy) and LMIT (≤ 18% of efficacy) was used in association with different concentration of synthetic compound. The IC50 and Synergism Rate (SR) were calculated. The highest efficiency of monoterpenes in EHT was obtained with r-carvone (IC50 = 0.25 mg/mL) and s-carvone (IC50 = 0.79 mg/mL) and in the LMIT with r-carvone (IC50 = 0.60 mg/mL). The best association was observed in the EHT with albendazol (thymol SR: 2.9 and r-carvone SR: 1.6) and ivermectin (citral SR: 1.9 and carvacrol SR:1.7). No synergistic effect was obtaining using the LMIT. The combination of synthetic compound and natural monoterpenes could be positive to gastrointestinal nematodes control: However this strategy should be carefully analysed due to the possibility of antagonic effects among the different compounds.Fil: Costa Junior, Livio. Universidade Federal do Maranhao; BrasilFil: Silva, Carolina R.. Universidade Federal do Maranhao; BrasilFil: Macedo, Sara R. D.. Universidade Federal do Maranhao; BrasilFil: Campos, Nagilla R. C. L.. Universidade Federal do Maranhao; BrasilFil: Lifschitz, Adrian Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina26th Conference World Association for the Advancement of Veterinary ParasitologyKuala LumpurMalasiaWorld Association for the Advancement of Veterinary Parasitolog

Plant-derived compounds as a tool for the control of gastrointestinal nematodes: Modulation of abamectin pharmacological action by carvone

The combination of synthetic anthelmintics and bioactive phytochemicals may be a pharmacological tool for improving nematode control in livestock. Carvone (R-CNE) has shown in vitro activity against gastrointestinal nematodes; however, the anthelmintic effect of bioactive phytochemicals either alone or combined with synthetic drugs has been little explored in vivo. Here, the pharmacological interaction of abamectin (ABM) and R-CNE was assessed in vitro and in vivo. The efficacy of this combination was evaluated in lambs naturally infected with resistant gastrointestinal nematodes. Additionally, the ligand and molecular docking of both molecules to P-glycoprotein (P-gp) was studied in silico. The presence of R-CNE produced a significant (p 90%. In vitro/in vivo pharmacoparasitological studies are relevant for the knowledge of the interactions and the efficacy of bioactive natural products combined with synthetic anthelmintics. While ADMET (absorption, distribution, metabolism, excretion, and toxicity) predictions and the molecular docking study showed a good interaction between ABM and P-gp, R-CNE does not appear to modulate this efflux protein. Therefore, the pharmacokinetic–pharmacodynamic effect of R-CNE on ABM should be attributed to its effect on membrane permeability. The development of pharmacology-based information is critical for the design of successful strategies for the parasite control.Fil: Miró, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Luque, Sonia Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Cardozo, Patricia Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Balcarce; ArgentinaFil: Lloberas, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Balcarce; ArgentinaFil: Sousa, Dauana Mesquita. Universidade Federal Do Maranhao; BrasilFil: Soares, A.M.S.. Universidade Federal Do Maranhao; BrasilFil: Costa Junior, Livio Martins. Universidade Federal Do Maranhao; BrasilFil: Virkel, Guillermo Leon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Lifschitz, Adrian Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentin

ATIVIDADE IN VITRO DE Carapa guianensis Aublet, Copaifera officinalis Jacquin Linnaeus e Psidium guajava Linnaeus SOBRE Haemonchus contortus

Avaliou-se a atividade anti-helmíntica in vitro do óleo fixo da semente de Carapa guianensis (andiroba) e Copaifera officinalis (copaíba) e do óleo essencial de Psidium guajava (goiaba), sobre ovos e larvas de H. contortus de caprinos. Foram utilizados testes in vitro do óleo das três plantas, avaliando-se a inibição da eclodibilidade dos ovos e do desembainhamento larvar. O óleo de C. guianensis foi o que apresentou melhor resultado, com maior média de inibição de eclodibilidade larvar (54,60%) obtida na maior concentração (20 mg mL-1), que inclusive diferiu das demais concentrações (p0,05). Nesta concentração, os óleos da C. officinalis e da P. guajava apresentaram um percentual de apenas 6,69 e 10,33% dos ovos. Para a C. guianensis, a CE50 encontrada foi de 17,92 (16,92 - 18,93) mg mL-1. Na segunda avaliação, alíquotas de larvas de terceiro estágio foram incubadas com o óleo e solução de hipoclorito em placas estéreis, observando-se os índices de desembainhamento em intervalos de 20 minutos, finalizando com 60 minutos. Durante as quatro observações (0, 20, 40 e 60 minutos) os percentuais de larvas de H. contortus sem bainhas encontrados nas placas tratadas com os óleos, independente da concentração, não diferiram daqueles percentuais nos respectivos grupos controles.