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in vitro activities of acetonic extracts from leaves of three forage legumes (calliandra calotyrsus, gliricidia sepium and leucaena diversifolia) on haemonchus contortus.to assess ovicidal activity of three acetonic extracts from the leaves of three forage legume, calliandra calotyrsus (c. calotyrsus), gliricidia sepium (g. sepium) and leucaena diversifolia (l. diversifolia) in vitro on haemonchus contortus (h. contortus).201121771435
enzymes of the ornithine-glutamate-proline pathway in the sheep abomasal nematode parasites haemonchus contortus and teladorsagia circumcincta.a fully functional ornithine-glutamate-proline pathway was detected in l3 and adult haemonchus contortus and teladorsagia circumcincta, making the parasites capable of interconversion of these amino acids. ornithine aminotransferase (oat) (e.c. 2.6.1.13) was a reversible pyridoxal-5-phosphate (plp)-dependent enzyme with an optimum ph 8.5. hydroxylamine completely inhibited oat activity in both parasites. for all five enzymes, substrate affinity was similar for each species and life cycle stage, ...201121781965
glutamate-gated chloride channels of haemonchus contortus restore drug sensitivity to ivermectin resistant caenorhabditis elegans.anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. an important nematode infecting sheep and goats is haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. it is extremely polymorphic and to date it has proved impossible to relate any se ...201121818319
dose-dependent systemic exposure of albendazole metabolites in lambs.alvarez, l., su+írez, g., ceballos, l., moreno, l., lanusse, c. dose-dependent systemic exposure of albendazole metabolites in lambs. j. vet. pharmacol. therap. doi: 10.1111/j.1365-2885.2011.01326.x. the gastrointestinal absorption of most drugs follows a first-order kinetics, whereby a constant fraction of the total drug is absorbed in each equal time interval. although this related absorption principle is applicable to the most of the therapeutically used drugs, it remains unclear for poorly w ...201121819410
anthelmintic activity of cymbopogon martinii, cymbopogon schoenanthus and mentha piperita essential oils evaluated in four different in vitro tests.anthelmintic resistance is a worldwide concern in small ruminant industry and new plant-derived compounds are being studied for their potential use against gastrointestinal nematodes. mentha piperita, cymbopogon martinii and cymbopogon schoenanthus essential oils were evaluated against developmental stages of trichostrongylids from sheep naturally infected (95% haemonchus contortus and 5% trichostrogylus spp.) through the egg hatch assay (eha), larval development assay (lda), larval feeding inhi ...201121820807
no loss of production due to larval challenge in sheep given continuous anthelmintic treatment via a controlled release capsule.this study aimed to quantify production loss due to larval challenge in sheep administered a controlled release albendazole capsule (crc) and thus determine the suitability of crc treated sheep as a proxy for worm-free sheep in grazing experiments. the experiment used an incomplete 2+ù3 latin square design with 81 merino wethers. sheep were either infected (inf) with mixed oral infection of albendazole-susceptible haemonchus contortus, trichostrongylus colubriformis, and teladorsagia circumcinct ...201121824729
comparison of molecular and mcmaster microscopy techniques to confirm the presence of naturally acquired strongylid nematode infections in sheep.patent strongylid nematode infections were identified using mcmaster worm egg counts (wec) and pcr assays (its-2 nuclear ribosomal dna) to screen genomic dna extracted directly from lamb faecal samples. lambs from four different farms in southern western australia were sampled rectally on two separate occasions, with mcmaster wecs and pcrs conducted on a total of 858 samples. negative controls (n=96) (wec<50eggs per gram [epg]) and positive controls (n=96) (faecal samples spiked with a 100++l su ...201121827796
small ruminant resistance against gastrointestinal nematodes: a case of haemonchus contortus.gastrointestinal nematode (gin) infections are a common constraint to small ruminant industry throughout the world, and among those, haemonchosis has its own significance. control of gin primarily relies on the use of anthelmintics, but this approach has become less reliable due to the development of resistance in gins against commonly used anthelmintics and an increased consumer demand for environmentally friendly animal products. these issues have stimulated investigations to find alternative ...201121842390
Ups and downs of RNA interference in parasitic nematodes.RNA interference (RNAi) is widely used in Caenorhabiditis elegans to identify essential gene function. In parasitic nematodes RNAi has been reported to result in transcript knockdown of some target genes, but not others, thus limiting its use as a potential functional genomics tool. We recently extended work in Haemonchus contortus to examine why only some genes seem to be susceptible to RNAi and to test RNAi effects in vivo. Here we review our findings, which suggest that site of gene expressio ...201121854774
annotation of two large contiguous regions from the haemonchus contortus genome using rna-seq and comparative analysis with caenorhabditis elegans.the genomes of numerous parasitic nematodes are currently being sequenced, but their complexity and size, together with high levels of intra-specific sequence variation and a lack of reference genomes, makes their assembly and annotation a challenging task. haemonchus contortus is an economically significant parasite of livestock that is widely used for basic research as well as for vaccine development and drug discovery. it is one of many medically and economically important parasites within th ...201121858033
Molecular and biochemical characterisation of a Teladorsagia circumcincta glutamate dehydrogenase.A full length cDNA encoding glutamate dehydrogenase was cloned from Teladorsagia circumcincta (TcGDH). The TcGDH cDNA (1614 bp) encoded a 538 amino acid protein. The predicted amino acid sequence showed 96% and 93% similarity with Haemonchus contortus and Caenorhabditis elegans GDH, respectively. A soluble N-terminal 6xHis-tagged GDH protein was expressed in the recombinant Escherichia coli strain BL21 (DE3) pGroESL, purified and characterised. The recombinant TcGDH had similar kinetic propertie ...201121864529
the anthelmintic effect of plant extracts on haemonchus contortus and strongyloides venezuelensis.the indiscriminate use of anthelmintics has resulted in the establishment of parasite resistance. thus, this study aimed to evaluate the in vitro antiparasitic effect of plant extracts on haemonchus contortus in sheep and the in vivo effect on strongyloides venezuelensis in rattus norvegicus. the plant extracts from piper tuberculatum, lippia sidoides, mentha piperita, hura crepitans and carapa guianensis, produced at different research institutions, were chemically analyzed and evaluated throug ...201221872995
characteristics of dnase activities in excretory/secretory products of infective larvae of haemonchus contortus.while multiple dnase activities occur in the excretory/secretory products (esps) of the adult haemonchus contortus, the dnase activities in esps of the infective larvae (l3) have not been studied. thus, the dnase activities in esps of h. contortus l3 were investigated and compared to those of adults for developmental stage-specific analysis. the dnase activities had relative molecular masses (mrs) of 34 and 36 kda upon zymographic analysis at ph 5.0 and 7.0 when the larvae were incubated for ove ...201121875446
tactical treatment with copper oxide wire particles and symptomatic levamisole treatment using the famacha(©) system in indigenous goats in south africa.haemonchosis is considered to be the most economically important gastrointestinal disease of small ruminants in the tropics and subtropics. however, chemical anthelmintics, which were the mainstay of control, have been compromised by a high prevalence of resistance worldwide. copper oxide wire particles (cowp) have been shown to have anthelmintic effects, but few studies have examined their use under field conditions. the use of cowp was therefore evaluated as a tactical anthelmintic treatment i ...201121880430
impacts of naturally acquired protozoa and strongylid nematode infections on growth and faecal attributes in lambs.on two separate sampling occasions, faecal samples were collected from lambs (2-5 months of age) grazing pasture on two separate sheep farms in southern western australia. live weight, body condition score (bcs), faecal consistency score (fcs) and faecal dry matter percentage (dm%) were measured. faecal samples were screened by pcr for cryptosporidium (18s rrna, actin and 60kda glycoprotein [gp60] loci), giardia duodenalis (glutamate dehydrogenase [gdh] and β-giardin) and patent strongylid nemat ...201121889852
anthelmintic activity of jatropha curcas l. seeds on haemonchus contortus.the aim of this study was to evaluate the anthelmintic activity of hexane (he), ethyl acetate (ea) and ethanol (ee) extracts obtained from the seeds of jatropha curcas using the egg hatch inhibition assay (eha) and the artificial larval exsheathment inhibition assay (leia). for the egg hatch assay, he, ea and ee were used in concentrations of 3.12, 6.25, 12.5, 25 and 50 mg ml(-1), accompanied by a negative control (5% tween 80) and a positive control (0.025 g ml(-1) thiabendazole). in leia, the ...201121890274
thermodynamic evaluation of ligand binding in the plant-like phosphoethanolamine methyltransferases of the parasitic nematode haemonchus contortus.nematodes are a major cause of disease and the discovery of new pathways not found in hosts is critical for development of therapeutic targets. previous studies suggest that caenorhabditis elegans synthesizes phosphocholine via two s-adenosylmethionine (adomet)-dependent phosphoethanolamine methyltransferases (pmt). here we examine two pmt from the parasitic nematode haemonchus contortus. sequence analysis suggests that hcpmt1 contains a methyltransferase domain in the n-terminal half of the pro ...201121914812
cross-infection between tropical goats and heifers with haemonchus contortus.developing effective biological control without the systematic use of anthelmintics is necessary to reduce the impact of gastrointestinal nematodes on small ruminants. therefore, grazing management systems that use different host species to dilute nematodes in pasture appear to be promising for worm control. a trial was carried out to investigate the specificity of haemonchus contortus for goats and cattle and to evaluate cross-infection between ruminant species. the effect of an experimental in ...201121924553
role of host and environment in mediating reduced gastrointestinal nematode infections in sheep due to intensive rotational grazing.we have previously reported marked reductions in faecal worm egg counts (wecs) and drenching frequency in sheep on an intensive rotational grazing system (irg) in a cool temperate environment with summer-dominant rainfall. these experiments were designed to determine the role of the host and environmental factors in mediating this. the role of host factors was investigated by administering a fixed larval challenge in each of the 4 seasons of the year to groups of 20 young sheep on three differen ...201121924833
Candidate anthelmintic resistance-associated gene expression and sequence polymorphisms in a triple-resistant field isolate of Haemonchus contortus.An isolate of Haemonchus contortus, UGA/2004, highly resistant to benzimidazoles, levamisole, and ivermectin was isolated from sheep at the University of Georgia, and passaged through experimentally infected goats. We measured the expression of twenty-nine mRNAs encoding drug targets and P-glycoproteins (P-gps), comparing the results to a fully susceptible laboratory passaged isolate. Expression levels of some nicotinic acetylcholine receptor mRNAs were markedly different in UGA/2004. Levels of ...201121945142
evaluation of eucalyptus citriodora essential oil on goat gastrointestinal nematodes.phytotherapy may be an alternative strategy for controlling gastrointestinal parasites. this study evaluated the anthelmintic efficacy of eucalyptus citriodora essential oil (eceo). the in vitro effects of eceo were determined through testing the inhibition of egg hatching and larval development of haemonchus contortus. eceo was subjected to acute toxicity testing on mice, orally and intraperitoneally. the in vivo effects of eceo were determined by the fecal egg count reduction test (fecrt) in g ...201121961753
pyrosequencing analysis of the beta-tubulin gene in spanish teladorsagia circumcincta field isolates.benzimidazole (bz) resistance in gastrointestinal nematodes has been associated with single nucleotide polymorphisms (snps) at codons 200, 167 and 198 in the beta-tubulin isotype 1 gene and, recently, these snps have also been found in macrocyclic lactone (ml) resistant strains of haemonchus contortus. on this basis, we have studied the same putative snps in spanish teladorsagia circumcincta field isolates by pyrosequencing. single l3 (infective 3rd stage larvae) from five sheep flocks were test ...201121962969
Doramectin resistance in Haemonchus contortus on an alpaca farm in Belgium.Parasitism by gastrointestinal nematodes is a health concern in New World Camelids (NWC) worldwide, and anthelmintic treatment is often needed for parasite control. Although anthelmintic resistance has been reported in ruminants worldwide, data in NWC are only scarce. In the present study, a case of suspected doramectin resistance in alpacas was examined. A field efficacy study was conducted for the evaluation of two different dosages of doramectin using a faecal egg count reduction test. A grou ...201122035850
dynamics of the free-living stages of sheep intestinal parasites on pasture in the north island of new zealand. 1. patterns of seasonal development.to describe the seasonal pattern of development of third-stage infective larvae (l3) from eggs of teladorsagia (=ostertagia) circumcincta, trichostrongylus colubriformis and haemonchus contortus on pasture in the north island of new zealand.201122040332
dynamics of the free-living stages of sheep intestinal parasites on pasture in the north island of new zealand. 2. weather variables associated with development.to identify weather variables associated with the development of eggs of teladorsagia (=ostertagia) circumcincta, trichostrongylus colubriformis and haemonchus contortus to third-stage infective larvae (l3) under a range of climatic conditions on pasture in the north island of new zealand.201122040333
Pharmacological characterization of the Haemonchus contortus GABA-gated chloride channel, Hco-UNC-49: Modulation by macrocyclic lactone anthelmintics and a receptor for piperazine.Invertebrate ligand-gated chloride channels are well recognized as important targets for several insecticides and anthlemintics. Hco-UNC-49 is a GABA-gated chloride channel from the parasitic nematode Haemonchus contortus and is an orthologue to the neuromuscular receptor (Cel-UNC-49) from the free-living nematode Caenorhabditis elegans. While the receptors from the two nematodes are similar in sequence, they exhibit different sensitivities to GABA which may reflect differences in in vivo functi ...201122075040
safety and efficacy against fourth-stage gastrointestinal nematode larvae, of monepantel in 6-week old lambs.a controlled, blinded study was undertaken in 6-week old, pre-weaned lambs to demonstrate the safety and efficacy against fourth-stage gastrointestinal nematode larvae, of monepantel administered per os at 2.5mg/kg body weight. worm burdens of 10 monepantel-treated lambs were compared to those from 10 untreated control lambs. geometric mean derived efficacies of 100, 100, 96.4 and 99.9% were demonstrated against haemonchus contortus, teladorsagia spp., cooperia curticei and trichostrongylus colu ...201122075043
Parasitism by Oestrus ovis: Influence of sheep breed and nematode infections.Previous studies showed that Santa Ines (SI) hair sheep were more resistant to gastrointestinal nematode infections (GIN) than Ile de France (IF) sheep. The present experiment aimed to evaluate if that reported resistance difference against GIN also occurred against Oestrus ovis infestation and also to evaluate the influence of O. ovis infestation on the gastrointestinal nematodes (GIN) infections. SI (n=12) and IF (n=12) young male lambs were weaned at 2 months of age and moved to a paddock (0. ...201122105081
in vitro screening of plant lectins and tropical plant extracts for anthelmintic properties.lectins are plant secondary metabolites (psm) found in many forages and which may confer anthelmintic properties to gastrointestinal parasites through disrupting the development of parasitic larvae throughout its life cycle. in experiment 1, the ability of the plant lectins jacalin (jac), concanavalin a (con a), phytohemagglutinin e2l2 (pha-e2l2), phytohemagglutinin l4 (pha-l4), phytohemagglutinin e3l (pha-e3l), kidney bean albumin (kba), robinia pseudoacacia agglutinin (rpa), maackia amurensis ...201122130336
Differential immune response between fundic and pyloric abomasal regions upon experimental ovine infection with Haemonchus contortus.The effect of experimental haemonchosis on the number of tissue eosinophils, plasma cells and lymphocyte subpopulations was evaluated in the fundic abomasal region, the pyloric abomasal region and the abomasal lymph node of Blackbelly lambs, which are resistant to infection, and Columbia lambs, which are susceptible to infection. An increase in the number of tissue eosinophils and CD4+ and WC1(+)?d T-cells was observed in the pyloric abomasal region of Blackbelly lambs and correlated with lower ...201122153120
Preserving new anthelmintics: A simple method for estimating faecal egg count reduction test (FECRT) confidence limits when efficacy and/or nematode aggregation is high.As it has been 30 years since a new anthelmintic class was released, it is appropriate to review management practices aimed at slowing the development of anthelmintic resistance to all drug classes. Recommendations to delay anthelmintic resistance, provide refugia and the use of a simulation model were reviewed to find optimum treatment strategies that maintain nematode control. Simulated Australian conditions indicated that a common successful low-risk treatment program was a rapid rotation bet ...201122154971
nucleotide allosteric regulation of the glutamate dehydrogenases of teladorsagia circumcincta and haemonchus contortus.the expression of glutamate dehydrogenase (gdh; ec 1.4.1.3) in l3 of the nematode haemonchus contortus was confirmed by detecting gdh mrna, contrary to earlier reports. the enzyme was active in both l3 and adult h. contortus homogenates either with nad(+)/h or nadp(+)/h as co-factor. although it was a dual co-factor gdh, activity was greater with nad(+)/h than with nadp(+)/h. the rate of the aminating reaction (glutamate formation) was approximately three times higher than for the deaminating re ...201122155552
why is it important to correctly identify haemonchus species?parasitic gastroenteritis caused by haemonchus spp. is a major cause of economic losses in the livestock industry because it impairs weight gain and increases mortality in cattle and small ruminants, especially in tropical and subtropical areas. the proper identification of the various species, as well as knowledge regarding the epidemiology of parasitic gastroenteritis, is essential for the establishment of sustainable strategies of parasite control. this review focuses on the use of easily app ...201122166378
efficacy of monepantel and anthelmintic combinations against multiple-resistant haemonchus contortus in sheep, including characterisation of the nematode isolate.three experiments defined the resistance profile of a population of haemonchus contortus, which was shown to express multiple resistances to the benzimidazole, levamisole, macrocyclic lactone and salicylanilide anthelmintic classes when given as a registered combination. study 1 was a faecal egg count reduction (fecr) test and the efficacies for the anthelmintics were monepantel, 100%; abamectin+levamisole+oxfendazole, 40.0%; and abamectin+levamisole+oxfendazole+naphthalophos, 100%. no larvae we ...201122169404
experiences with integrated concepts for the control of haemonchus contortus in sheep and goats in the united states.the generally warm, moist environmental conditions in the southern united states (u.s.) are ideal for survival and growth of the egg and larval stages of haemonchus contortus and other gastrointestinal nematodes (gin) of sheep and goats. consequently, infection with gin is the greatest threat to economic small ruminant production in this region. with anthelmintic resistance now reaching epidemic proportions in small ruminants in the u.s., non-chemical control alternatives are critically needed. ...201122178411
Purification, molecular characterization and gene expression analysis of an aspartic protease (Sc-ASP113) from the nematode Steinernema carpocapsae during the parasitic stage.Steinernema carpocapsae is an insect parasitic nematode associated with the bacterium Xenorhabdus nematophila. During invasion, this nematode is able to express many proteases, including aspartic proteases. Genes encoding these aspartic proteases have been identified in the EST, and aspartic protease has been found in excretory-secretory products. The total protease was shown to digest blood hemoglobin in a zymogram gel. When the protein was partially purified by pepstatin affinity chromatograph ...201122178695
genetic analysis of the potential role of iga and ige responses against haemonchus contortus in parasite resistance of creole goats.small ruminants are affected by gastrointestinal nematode (gin) infection. a promising alternative strategy for control of gin infection is to increase the level of resistance in the population by taking advantage of the host's immune response. immunoglobulin a (iga) and e (ige) are known to be involved in immune response to gin. the aim of this study was thus to investigate genetic parameters of iga and ige responses against haemonchus contortus in creole kids naturally challenged at pasture an ...201122188980
relationship between increased albendazole systemic exposure and changes in single nucleotide polymorphisms on the β-tubulin isotype 1 encoding gene in haemonchus contortus.resistance to benzimidazole anthelmintics in the nematode haemonchus contortus has been correlated with single nucleotide polymorphisms (snps) on the β-tubulin isotype 1 gene. three mutations can be used as markers for the detection of resistance, namely snps at position 200 and 167 (both ttc to tac) or at position 198 (gaa to gca). harbouring a resistance genotype at any one of these codons can lead to a resistant phenotype. our objective in this study was to analyse the frequencies of the thre ...201122192770
Use of a mixed sericea lespedeza and grass pasture system for control of gastrointestinal nematodes in lambs and kids.Because of a high prevalence of anthelmintic resistance and consumer demand for chemical free meat products, management tools to minimize the need for deworming are needed. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) in a mixed grass or a pure forage system for control of gastrointestinal nematodes (GIN); in other words pasture systems included grass, grass plus SL, or SL alone (Experiments 2 and 3). Selective use of copper oxide wire particles (COWP) based o ...201122192772
evaluation of cymbopogon schoenanthus essential oil in lambs experimentally infected with haemonchus contortus.hematophagous gastrointestinal parasites cause significant economic losses in small ruminant grazing systems. the growing reports of multi-drug resistant parasites call for intensive research on alternative treatments for anthelmintics to help small ruminants cope with these parasites. two-month-old lambs with mean body weight (bw) of 22.5kg were experimentally infected with a multidrug-resistant haemonchus contortus strain. infected animals were dosed orally with cymbopogon schoenanthus essenti ...201122206645
responses of the humid zone ecotype of the nigerian west african dwarf sheep to mixed infections with haemonchus contortus and trichostrongylus colubriformis.the responses of the nigerian west african dwarf sheep to experimental infections with two of its most important gastrointestinal (gi) nematodes, namely, haemonchus contortus and trichostrongylus colubriformis were studied by means of two measures of parasitological response, namely, faecal egg count (fec) and worm burden (wb), and three measures of host pathology, namely, packed cell volume (pcv), body weight (bwt) and body condition score (bcs). following exposure to weekly escalating infectio ...201222215194
diversity in parasitic nematode genomes: the micrornas of brugia pahangi and haemonchus contortus are largely novel.micrornas (mirnas) play key roles in regulating post-transcriptional gene expression and are essential for development in the free-living nematode caenorhabditis elegans and in higher organisms. whether micrornas are involved in regulating developmental programs of parasitic nematodes is currently unknown. here we describe the the mirna repertoire of two important parasitic nematodes as an essential first step in addressing this question.201222216965
mitochondrial fumarate reductase as a target of chemotherapy: from parasites to cancer cells.recent research on respiratory chain of the parasitic helminth, ascaris suum has shown that the mitochondrial nadh-fumarate reductase system (fumarate respiration), which is composed of complex i (nadh-rhodoquinone reductase), rhodoquinone and complex ii (rhodoquinol-fumarate reductase) plays an important role in the anaerobic energy metabolism of adult parasites inhabiting hosts. the enzymes in these parasite-specific pathways are potential target for chemotherapy. we isolated a novel compound, ...201122226661
in vitro anthelmintic effect of anogeissus leiocarpus (dc.) guill. & perr. leaf extracts and fractions on developmental stages of haemonchus contortus.the anthelmintic effect of acetone leaf extract and fractions of anogeissus leiocarpus was investigated to determine the relative efficacy of the components as anthelmintic against haemonchus contortus (rudolphi). the fractions were obtained by solvent-solvent group separation of the leaf extract. the fractions were evaluated for ovicidal and larvicidal activity by egg hatch inhibition assay and larval development viability assay. best-fit lc(50) values for egg hatch test were 0.360, 0.316, 0.09 ...201122238493
anthelmintic efficacy of five tropical native australian plants against haemonchus contortus and trichostrongylus colubriformis in experimentally infected goats (capra hircus).the study of the anthelmintic properties of plants rich in plant secondary metabolites can provide ecologically sound methods for the treatment of parasites on grazing animals. the purpose of the present study was to evaluate the anthelmintic effect of five tropical native australian plant species rich in plant secondary metabolites on adult haemonchus contortus and trichostrongylus colubriformis in experimentally infected goats. thirty young, nematode-free goats were infected with 2500 h. conto ...201222265804
towards finding effective indicators (diarrhoea and anaemia scores and weight gains) for the implementation of targeted selective treatment against the gastro-intestinal nematodes in lambs in a steppic environment.the effective application of targeted selective treatment (tst) against gastro-intestinal nematodes depends on the accurate identification of those animals in need of anthelmintic treatment. finding cost and labour effective measures to identify such animals is paramount. this study tested the efficacy of three indicators on lambs in a farm in eastern algeria: anaemia score (famacha(©)), diarrhoea score (disco) and weight gain. these were contrasted against traditional parasitological infection ...201222270033
genetic and environmental influences on faecal nematode egg counts of jamunapari goats in india.the present study was carried out from 1999 to 2003 to determine the genetic and environmental influences of faecal egg count (fec), an indicator of host resistance, in adult jamunapari goats with naturally acquired gastrointestinal nematode parasite infections (predominantly haemonchus contortus). fec data on 670 records of jamunapari goats descended from 54 bucks and 208 does were used in this study. analyses were carried out by restricted maximum likelihood estimation, fitting an animal model ...201222278635
molecular identification of naturally acquired strongylid infections in lambs--an investigation into how lamb age influences diagnostic sensitivity.faecal samples (n=1155) were collected from n=111 (farm a) and n=124 (farm b) 2-6 week old female lambs on two farms in southern western australia across five sampling occasions (spanning 8 months). genomic dna was extracted directly from faecal samples and screened by pcr for its-2 nuclear ribosomal dna to detect patent strongylid infections, specifically teladorsagia circumcincta, trichostrongylus spp., haemonchus contortus, oesophagostomum spp. and chabertia ovina. the minimum amount of extra ...201222284303
proteomic analysis of the abomasal mucosal response following infection by the nematode, haemonchus contortus, in genetically resistant and susceptible sheep.sheep have a variable ability to resist gastrointestinal nematode infection, but the key factors mediating this response are poorly defined. here we report the first large-scale application of quantitative proteomic technologies to define proteins that are differentially abundant between sheep selectively bred to have an enhanced (resistant) or reduced (susceptible) ability to eliminate nematodes. samples were collected from the abomasal mucosa three days after experimental challenge with the ne ...201222285630
the anthelmintic effect of aqueous methanol extract of combretum molle (r. br. x. g. don) (combretaceae) in lambs experimentally infected with haemonchus contortus.the aqueous methanol extract from the stem-bark of combretum molle was evaluated for anthelmintic activity in lambs infected with haemonchus contortus using faecal egg count (fec) reduction assay. the extract showed a dose-dependent reduction in fec in infected animals. at doses of 500, 1000 and 2000 mg kg(-1), the extract caused fec reduction of 63%, 69.25% and 96.23%, respectively. similarly, the standard anthelmintic (albendazole) at a dose of 200 mg kg(-1) produced fec reduction of 99.24%. f ...201222293150
serine protease inhibitors of parasitic helminths.serine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. a number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. this review describes the serpins and smapins (small seri ...201222310379
evaluation of benzimidazole resistance in haemonchus contortus using comparative pcr-rflp methods.in order to deworm the ruminants especially of sheep in iran, consumption of benzimidazoles has more than 2 decades history and today farmers are using imidazothiazoles, macrocyclic lactones and mostly benzimidazole compounds (bzs) to treat infected farm animals. it has been demonstrated that the most common molecular mechanism leading to bzsresistance in haemonchus contortus is a single mutation at amino acid 200 (phenylalanine to tyrosine) of the isotype 1 of beta tubulin gene. according to th ...201122347287
silencing of essential genes by rna interference in haemonchus contortus.in this study we assessed three technologies for silencing gene expression by rna interference (rnai) in the sheep parasitic nematode haemonchus contortus. we chose as targets five genes that are essential in caenorhabditis elegans (mitr-1, pat-12, vha-19, glf-1 and noah-1), orthologues of which are present and expressed in h. contortus, plus four genes previously tested by rnai in h. contortus (ubiquitin, tubulin, paramyosin, tropomyosin). to introduce double-stranded rna (dsrna) into the nemat ...201222348596
introgression of ivermectin resistance genes into a susceptible haemonchus contortus strain by multiple backcrossing.anthelmintic drug resistance in livestock parasites is already widespread and in recent years there has been an increasing level of anthelmintic drug selection pressure applied to parasitic nematode populations in humans leading to concerns regarding the emergence of resistance. however, most parasitic nematodes, particularly those of humans, are difficult experimental subjects making mechanistic studies of drug resistance extremely difficult. the small ruminant parasitic nematode haemonchus con ...201222359506
amino acid residues of both the extracellular and transmembrane domains influence binding of the antiparasitic agent milbemycin to haemonchus contortus avr-14b glutamate-gated chloride channels.glutamate-gated chloride (glucl) channels are pentameric receptors for the inhibitory neurotransmitter glutamate in invertebrates and are a major target for macrolide anthelmintics. three amino acids in glucl channels are reported to render macrolide resistance in nematodes and insects. to examine whether these three amino acids are involved in binding of the antiparasitic agent milbemycin (mlm) to the glucl channels of the nematode parasite haemonchus contortus, the equivalent amino acids (l256 ...201222369940
susceptibility assay of haemonchus contortus to commonly used anthelmintics in jimma, southwest ethiopia.an experimental study to investigate the susceptibility pattern of haemonchus contortus to commonly used anthelmintics (albendazole, tetramisole, ivermectin, and triclobendazole) was conducted between june and september 2009. adult h. contortus parasites were collected from a total of 30 sheep slaughtered at jimma municipal abattoir. the anthelmintics were assessed for egg hatch inhibition ability against h. contortus eggs. the eggs (500 eggs/ml) were incubated with different concentrations (0.2 ...201222402797
import and efflux of flubendazole in haemonchus contortus strains susceptible and resistant to anthelmintics.drug entry into the body of a helminth is a key factor in the efficacy of anthelmintics. the present project was designed to study the ex vivo uptake and efflux of the benzimidazole anthelmintic flubendazole (flu) in four strains of h. contortus: the ise strain (fully susceptible to anthelmintics), the ise-s strain (resistant to ivermectin), the br strain (resistant to benzimidazoles) and the wr strain (multi-resistant). the transport of flu between dead and living nematodes was also compared as ...201222417686
influence of pluronic 85 and ketoconazole on disposition and efficacy of ivermectin in sheep infected with a multiple resistant haemonchus contortus isolate.non-specific mechanisms involving atp-binding cassette drug efflux transporters may play an important role in xenobiotic clearance in ovine gastro-intestinal nematodes. by using transporter inhibitors, the aim of this trial was to assess the possibility of increasing drug bioavailability in the host in an attempt to improve treatment efficacy. thirty-six lambs were infected with 5000 multiple-drug resistant haemonchus contortus third stage larvae and separated into six groups (n=6): ivermectin a ...201222429700
changes in the body condition scores of nigerian west african dwarf sheep experimentally infected with mixed infections of haemonchus contortus and trichostrongylus colubriformis.weekly changes in body condition scores and body weights were determined in west african dwarf sheep following trickle exposure to weekly escalating mixed infections with haemonchus contortus and trichostrongylus colubriformis starting with single doses of 500 infective larvae (l(3)) at wk1, 1000 l(3) at wk2, 2000 l(3) at wk3 and 4000 l(3) at wk4. thirty-three animals were randomly assigned to two groups namely, group 1 (n=27) and group 2 (n=6). group 1 animals were used for experimental infecti ...201222436424
cloning and characterization of a selenium-independent glutathione peroxidase (hc29) from adult haemonchus contortus.the complete coding sequence of haemonchus (h.) contortus hc29 cdna was generated by rapid amplification of cdna ends in combination with pcr using primers targeting the 5'- and 3'-ends of the partial mrna sequence. the cloned hc29 cdna was shown to be 1,113 bp in size with an open reading frame of 507 bp, encoding a protein of 168 amino acid with a calculated molecular mass of 18.9 kda. amino acid sequence analysis revealed that the cloned hc29 cdna contained the conserved catalytic triad and d ...201222437536
is the establishment rate and fecundity of haemonchus contortus related to body or abomasal measurements in sheep?the relationship among parasitological parameters, abomasal size and body size measurements was investigated in lambs following an experimental infection with haemonchus contortus. in total, 100 lambs from five different genotypes (german merino (gm), texel × gm, suffolk × gm, german blackhead mutton × gm and ile de france × gm) were experimentally infected with 5000 infective third stage larvae of h. contortus at the time of weaning at 12 weeks of age. four and six weeks after infection, indivi ...201122440180
in vitro anthelmintic activity of crude extracts of selected medicinal plants against haemonchus contortus from sheep.ethanol extracts of 25 plant species were screened for anthelmintic effects against haemonchus contortus. ethanol extracts of each plant were used at various concentrations (10, 20 and 30%) to treat 10-day faecal cultures, incubated at 27°c with control cultures which were treated with ethanol for 48 h. five plants with high efficacies (ananas comosus, aloe ferox, allium sativum, lespedeza cuneata and warburgia salutaris) were selected from the first screening for further investigation using eth ...201322449714
preference for condensed tannins by sheep in response to challenge infection with haemonchus contortus.herbivores prefer feeds that supply required nutrients and avoid those with excess nutrients and plant secondary compounds (psc). nevertheless, psc such as condensed tannins can provide beneficial medicinal effects to herbivores as they act against infective diseases such as parasitism. the objectives of this study were to determine: (1) if parasitized lambs increased preference for a tannin-rich feed after they experienced the beneficial antiparasitic effects of condensed tannins relative to pa ...201222459112
lysine catabolism in haemonchus contortus and teladorsagia circumcincta.catabolism of lysine through the pipecolate, saccharopine and cadaverine pathways has been investigated in l3 and adult haemonchus contortus and teladorsagia circumcincta. both enzymes of the saccharopine pathway (lysine ketoglutarate reductase (lkr) and saccharopine dehydrogenase (sdh)) were active in l3 and adult worms of both species. all three enzymes which catabolise lysine to α-amino adipic semialdehyde via pipecolate (lysine oxidase (lo), δ(1)-piperideine-2-carboxylate reductase (pip2cr) ...201222459625
proteomic profiling and protein identification by maldi-tof mass spectrometry in unsequenced parasitic nematodes.lack of genomic sequence data and the relatively high cost of tandem mass spectrometry have hampered proteomic investigations into helminths, such as resolving the mechanism underpinning globally reported anthelmintic resistance. whilst detailed mechanisms of resistance remain unknown for the majority of drug-parasite interactions, gene mutations and changes in gene and protein expression are proposed key aspects of resistance. comparative proteomic analysis of drug-resistant and -susceptible ne ...201222479418
immunoprotective effect of cysteine proteinase fractions from two haemonchus contortus strains adapted to sheep and goats.a preliminary analysis of the significance of genetic diversity in cysteine proteinase genes has been performed simultaneously in sheep and goats, with regard to the immunological control using these enzymes against haemonchosis. for this purpose, we have studied the cross-immunoprotective effect of cysteine protease-enriched protein fractions (cpfs) in adult worms of two haemonchus contortus strains from north america and spain that are adapted to sheep and goats, respectively. previous genetic ...201222487211
detection of quantitative trait loci for resistance to gastrointestinal nematode infections in creole goats.this study aimed to identify regions of the genome affecting resistance to gastrointestinal nematodes in a creole goat population naturally exposed to a mixed nematode infection (haemonchus contortus, trichostrongylus colubriformis and oesophagostomum columbianum) by grazing on irrigated pasture. a genome-wide quantitative trait loci (qtl) scan was performed on 383 offspring from 12 half-sib families. a total of 101 microsatellite markers were genotyped. traits analysed were faecal egg count (fe ...201222502644
environmental factors influencing the transmission of haemonchus contortus.infection with the gastrointestinal nematode haemonchus contortus causes considerable losses in the sheep industry. in this study, we evaluated the effect that climate has on third-stage larvae (l3) of h. contortus in terms of their migration from sheep feces to brachiaria decumbens grass, as well as their distribution among the forage plants. fecal samples containing h. contortus l3 was deposited on the soil among the herbage at an initial height of 30 cm. sample collection began 24h after cont ...201222521972
the potential of elephantorrhiza elephantina as an anthelminthic in goats.elephantorrhiza elephantina bruch. skeels. is used by farmers in the eastern cape province to control helminths in goats. an in vitro study revealed efficacy of its fractions against adult haemonchus contortus. this study was conducted to validate efficacy of fractions in vivo, on gastrointestinal nematodes in naturally infected goats. a total of 36 goats (18 males and 18 females) between ages of 8 and 12 months were used; these were randomly assigned to six treatments (a-f). for treatments a an ...201222526291
selective effect of the anthelmintic bephenium on haemonchus contortus levamisole-sensitive acetylcholine receptors.acetylcholine receptors (achrs) are pentameric ligand-gated ion channels involved in the neurotransmission of both vertebrates and invertebrates. a number of anthelmintic compounds like levamisole and pyrantel target the achrs of nematodes producing spastic paralysis of the worms. the muscle achrs of nematode parasites fall into three pharmacological classes that are preferentially activated by the cholinergic agonists levamisole (l-type), nicotine (n-type) and bephenium (b-type), respectively. ...201222526556
gastrointestinal parasites of sheep, municipality of lajes, rio grande do norte, brazil.this study investigated the gastrointestinal parasitism by helminths and protozoa in sheep (ovis aries) santa inês breed, municipality of lajes, rio grande do norte. monthly, from april 2005 to august 2007, stool samples were collected from two tracer lambs in the first day of the experiment and performed a necropsy of these animals in 44th day. a total of 64 lambs were sampled, but only 62 lambs were slaughtered. the fecal samples were examined by sedimentation in water. the contents of the abo ...201222534950
genetic variation of haemonchus contortus (trichostrongylidae) in sheep and goats from malaysia and yemen.the large stomach worm, haemonchus contortus, commonly known as "the barber's pole worm", is a blood-sucking nematode found in the abomasa of sheep and goats. this work is the first documentation on the nd4 sequences of h. contortus from sheep and goats in malaysia and yemen and the results provide a preliminary insight on the genetic differences of h. contortus found in the two countries. in general, this study showed a high degree of diversity and low population structure of this species withi ...201222538095
condensed tannins from sesbania sesban and desmodium intortum as a means of haemonchus contortus control in goats.two experiments were conducted to determine whether the proanthocyanidin (condensed tannin)-containing forage legumes desmodium intortum cv greenleaf and sesbania sesban (accession 15019) could be integrated into a feeding management strategy as a means of haemonchus contortus control in goats. the anthelmintic effects of condensed tannin extracts from the two legumes on h. contortus l(3) larvae were studied in an in vitro larval migration inhibition system. the extracts inhibited larval migrati ...201222547111
possibilities to breed for resistance to nematode parasite infections in small ruminants in tropical production systems.gastrointestinal nematode parasitism is the most important disease affecting livestock production systems in developing countries, particularly small ruminant production systems. of particular importance are infections with the strongyle haemonchus contortus. integrated disease control strategies are required, including improved management, nutrition and wise use of anthelmintic chemicals. increasingly, selection of sheep or goats for improved nematode resistance is viewed as a valuable option t ...201222558922
a survey of the trichostrongylid nematode species present on uk sheep farms and associated anthelmintic control practices.a survey of sheep farms from across the uk was conducted to establish information on farming practices, the trichostrongylid nematode species present and anthelmintic usage. questionnaires and faecal samples were returned from 118 farms. first stage larvae (l(1)) were cultured from faecal samples and used for pcr analysis to determine the presence/absence of selected trichostrongylid species. teladorsagia circumcincta was the only species present on 100% of farms. haemonchus contortus was found ...201222560313
measurement of ivermectin concentrations in target worms and host gastrointestinal tissues: influence of the route of administration on the activity against resistant haemonchus contortus in lambs.the influence of the administration route on the relationship between efficacy and ivermectin concentration profiles achieved in the bloodstream, the gastrointestinal mucosal tissues/fluid contents and within a target abomasal parasite (haemonchus contortus) was evaluated in lambs. twenty-six (26) parasitized lambs were assigned into three experimental groups: untreated (control) and ivermectin treated by the subcutaneous and intraruminal route at 0.2mg/kg. blood samples were collected between 0 ...201222575734
efficacy of monepantel, derquantel and abamectin against adult stages of a multi-resistant haemonchus contortus isolate.drug resistance in gastrointestinal nematodes is a severe problem for sheep farmers. with the recent introduction of monepantel (zolvix®) and of derquantel plus abamectin (startect®) in new zealand, two new anthelmintic classes will be available to control gastrointestinal nematodes. while monepantel covers a broad spectrum of nematodes, the efficacy of derquantel is mid-spectrum and limited to a smaller number of species and stages. the combination of derquantel and abamectin allows to enlarge ...201222576857
in vivo anthelmintic activity of phytolacca icosandra against haemonchus contortus in goats.the in vivo anthelmintic (ah) activity of the ethanolic extract from leaves of phytolacca icosandra was evaluated in goats artificially infected with haemonchus contortus. parasite naïve goats were artificially infected with 3000 h. contortus infective larvae per animal. once the infection was patent (day 28 post-infection) all the animals were sampled to determine the faecal egg counts (fec) for five consecutive days. two groups of animals were formed balanced for their fec and body-weight (bw) ...201222579554
is the micro-agar larval development test reliable enough to detect ivermectin resistance?to aid the diagnosis of anthelmintic resistance, a range of in vivo and in vitro techniques have been developed. amongst in vitro techniques, the larval development test is the most widely employed. six lambs were infected with susceptible (three) and ivermectin-resistant (three) isolates of haemonchus contortus. the micro-agar larval development test (maldt) was able to easily distinguish between susceptible and resistant isolates. different proportions of resistant and susceptible eggs were su ...201222581298
in vitro and in vivo anthelmintic activity of euphorbia helioscopia l.the anthelmintic potentials of the aqueous and methanol extracts of euphorbia helioscopia were investigated. in folklore medicine, e. helioscopia (euphorbiaceae) is used in the treatment of various gastrointestinal ailments and diseases. a worm motility inhibition (wmi) assay and egg hatch assay (eha) were used for in vitro assessment, and a faecal egg count reduction (fecr) assay was used for an in vivo study. the in vitro study revealed anthelmintic effects of crude methanolic extracts of e. h ...201222633018
correlates of resistance to gastrointestinal nematode infection in nigerian west african dwarf sheep.to investigate correlates of resistance to gi nematode infection in nigerian west african dwarf (wad) sheep.201222647814
in vitro anthelmintic activity of five tropical legumes on the exsheathment and motility of haemonchus contortus infective larvae.this study investigated the in vitro anthelmintic (ah) activity of five tropical legume plants [arachis pintoi ciat 22160 (a.p. 22160), gliricidia sepium, cratylia argentea (c.a. yacapani), c. argentea ciat 22386 (c.a. 22386), c. argentea veranera (c.a. veranera)] against haemonchus contortus infective larvae and the role of tannins/polyphenolic compounds in the ah effect. lyophilized leaf extracts of each plant were evaluated using the larval exsheathment inhibition assay (leia) and the larval ...201222652531
cathepsin b-like and hemoglobin-type cysteine proteases: stage-specific gene expression in angiostrongy cantonensis.three cysteine protease genes, cathepsin b-like enzyme gene 1, 2 (ac-cathb-1, ac-cathb-2) and hemoglobin-type cysteine protease gene (ac-hem) were isolated and described from angiostrongylus cantonensis adult. the deduced amino acid sequence of ac-cathb-1 and ac-cathb-2 contain all of the conserved regions of cathepsin b. ac-cathb-2 is similar to a host intrusion-related cysteine protease b from parelaphostrongylus tenuis, and the ac-hem shares high similarity to legumain from haemonchus contort ...201222668746
the metabolism of flubendazole and the activities of selected biotransformation enzymes in haemonchus contortus strains susceptible and resistant to anthelmintics.haemonchus contortus is one of the most pathogenic parasites of small ruminants (e.g. sheep and goat). the treatment of haemonchosis is complicated because of recurrent resistance of h. contortus to common anthelmintics. the aim of this study was to compare the metabolism of the anthelmintic drug flubendazole (flu) and the activities of selected biotransformation enzymes towards model xenobiotics in 4 different strains of h. contortus: the ise strain (susceptible to common anthelmintics), ise-s ...201222717022
bacillus spp. toxicity against haemonchus contortus larvae in sheep fecal cultures.the gastrointestinal nematode haemonchus contortus is a major productivity constraint in sheep. in this study, the nematicidal effects of bacillus circulans, bacillus cereus, bacillus thuringiensis var. israelensis, bt. var. osvaldocruzi, bt. var. morrisoni, and bt. var. kurstaki were assessed in free-living larval stages of h. contortus. a spore-crystal suspension containing approximately 2×10(8)ufc/ml of each strain was added to sheep feces that were naturally infected with h. contortus eggs, ...201222728159
helminths of roe deer (capreolus capreolus) in the middle black sea region of turkey.fifteen roe deer were examined at necropsy from northern turkey in the period 2006-2010 for the helminth infections. totally 6470 helminth specimens were collected and identified by morphological criteria. twenty-five helminth species were identified (1 of the class trematoda, 1 of cestoda and 23 of nematoda). dicrocoelium dendriticum (prevalence 20%) was found in liver. cysticercus tenuicollis (6.6%) was found in mesentery. haemonchus contortus (53.3%), ostertagia leptospicularis (73.3%), o. le ...201222766455
a genome scan for qtl affecting resistance to haemonchus contortus in sheep.gastrointestinal nematodes are one of the main health issues in sheep breeding. to identify loci affecting the resistance to haemonchus contortus, a genome scan was carried out using 1,275 romane × martinik black belly backcross lambs. the entire population was challenged with haemonchus contortus in 2 consecutive experimental infections, and fecal egg counts (fec) and packed cell volumes were measured. a subgroup of 332 lambs with extreme fec was necropsied to determine the total worm burden, l ...201222767094
immune responses in sheep naturally infected with oestrus ovis (diptera: oestridae) and gastrointestinal nematodes.this study was carried out to evaluate the immune response in young ile de france (if) and santa ines (si) sheep naturally infected by oestrus ovis and gastrointestinal nematodes (gin). mast cells, eosinophils and globule leucocytes were enumerated in the upper respiratory tract (septum, middle meatus and ventral nasal conchae) and in the mucosa of abomasum and small intestine. immunoglobulin g (igg) levels in serum samples and immunoglobulin a (iga) levels in mucus from the nasal, abomasum and ...201222770703
vaccination of goats with glyceraldehyde-3-phosphate dehydrogenase dna vaccine induced partial protection against haemonchus contortus.owing to its critical functions in worm physiology, glyceraldehyde-3-phosphate dehydrogenase in haemonchus contortus (hcgapdh) is potential candidates for vaccine to control haemonchosis. in this study, dna vaccine expressing hcgapdh antigen was tested for protection against experimental h. contortus infections in goats. fifteen goats (9-10 months of age) were allocated into three trial groups. group 1 was vaccinated with hcgapdh dna vaccine twice on days 0 and 14, and then challenged with 5000 ...201222771197
the soluble proteome phenotypes of ivermectin resistant and ivermectin susceptible haemonchus contortus females compared.anthelmintics in the absence of vaccines have underpinned a parasite control strategy for over 50 years. however, the continued development of anthelmintic resistance (ar) threatens this control. measuring early ar is difficult as there many routes that resistance can arise from within multi-nematode populations operating complex metabolism capabilities coupled to different drug management pressures. there is an urgent need to identify and measure early resistance in the field situation. proteom ...201222785129
genetic diversity patterns of haemonchus placei and haemonchus contortus populations isolated from domestic ruminants in brazil.parasitic nematodes of the genus haemonchus infect a range of ruminant hosts and are of major veterinary and economic importance. in this study, the genetic variability of seven isolates of haemonchus placei and haemonchus contortus was evaluated using the mitochondrial gene cytochrome oxidase subunit i and the nuclear gene b-tubulin isotype 1. a total of 156 specimens were obtained from cattle, sheep, goat and buffalo herds raised on commercial properties from the southern and southeastern regi ...201222787588
persistence of the efficacy of copper oxide wire particles against haemonchus contortus in grazing south african goats.a study was conducted to examine the duration of anthelmintic effect of copper oxide wire particles (cowp) in grazing goats, as data for the persistence of efficacy of cowp in this host species is limited. forty-eight indigenous male goats were infected naturally by grazing them on haemonchus contortus-infected pasture. when the faecal egg count (fec) in the goats was 3179 ± 540 eggs per gram of faeces (mean ± standard error), half the animals were treated with 4 g cowp (day 0; mean live weight= ...201222789299
haemonchus contortus: a multiple-resistant brazilian isolate and the costs for its characterization and maintenance for research use.the aim of this work was to determine the resistance level of haemonchus contortus isolated from the santa inês flock of the embrapa (brazilian government's agricultural research company), southeast livestock unit (cppse), as well as to determine costs of characterizing and maintaining this isolate in host donors. forty-two male santa inês lambs were experimentally infected with 4000 h. contortus infective larvae of the field isolate of cppse, called embrapa2010, and divided into six treatment g ...201322809891
in vitro activity of lantana camara, alpinia zerumbet, mentha villosa and tagetes minuta decoctions on haemonchus contortus eggs and larvae.the resistance of gastrointestinal nematodes to anthelmintics has increased the need to evaluate natural products that can replace or assist current strategies to control gastrointestinal nematodes. the objective of this study was to evaluate the effect of decoctions of lantana camara (dlc), alpinia zerumbet (daz), mentha villosa (dmv) and tagetes minuta (dtm) on haemonchus contortus by two in vitro tests. the effects of increasing concentrations of lyophilized decoctions (0.31 to 10mg/ml) were ...201222835864
f200y polymorphism in the β-tubulin gene in field isolates of haemonchus contortus and risk factors of sheep flock management practices related to anthelmintic resistance.haemonchus contortus is the most prevalent and pathogenic nematode of sheep in tropical areas. the objectives of this study were to assess the frequency of the f200y polymorphism on the β-tubulin gene in third-stage larvae of h. contortus from 33 sheep flocks in são paulo state, brazil, and to associate this frequency to risk factors based on farm management practices. the resistance allele frequency varied from 9 to 74%, and the resistance genotype frequency varied from 0 to 66.7%. resistance g ...201222858226
development of a modified molecular diagnostic procedure for the identification and quantification of naturally occurring strongylid larvae on pastures.a molecular procedure was developed to detect and quantify larvae of different strongylid parasite species recovered from pasture samples. two lamb flocks (l and s) grazed separate paddocks with different natural larvae challenges (one low [paddock l] and one high [paddock s] challenge) on a commercial farm in western australia. pasture samples were collected and analysed for larvae on 9 separate occasions from each paddock. pregnant merino ewes were sampled on 3 separate occasions (2 pre-partum ...201222877827
the influence of temperature on the development and survival of the pre-infective free-living stages of nematode parasites of sheep.to develop a model for the development dynamics of the pre-infective stages of nematode parasites on pasture and to use it to investigate the importance of temperature fluctuations on the proportion of eggs developing to infective larvae.201322913582
benzimidazole resistance of sheep nematodes in norway confirmed through controlled efficacy test.resistance against benzimidazoles (bz) has recently been detected in norwegian sheep flocks through a large scale prevalence survey based on the faecal egg count reduction test (fecrt). the use of this test in combination with bulk larval culture only gives an indication of which gastrointestinal nematodes genera that are involved and these results have to be confirmed by a controlled efficacy test (cet) to get accurate information about resistant nematodes populations at species level. a cet wa ...201222932059
hco-lgc-38 is novel nematode cys-loop gaba receptor subunit.we have identified and characterized a novel cys-loop gaba receptor subunit (hco-lgc-38) from the parasitic nematode haemonchus contortus. this subunit is present in parasitic and free-living nematodes and shares similarity to both the unc-49 group of gaba receptor subunits from nematodes and the resistant to dieldrin (rdl) receptors of insects. expression of the hco-lgc-38 gene in xenopus oocytes and subsequent electrophysiological analysis has revealed that the gene encodes a homomeric channel ...201222940478
effects of co-grazing dairy heifers with goats on animal performance, dry matter yield, and pasture forage composition.mixed livestock grazing can offer an alternative management system for rearing dairy replacement heifers (bos taurus). a 2-yr study was conducted during 2009 (yr 1) and 2010 (yr 2) to determine the effects of co-grazing holstein heifers under rotational stocking with boer × kiko goats on animal performance, pasture dm yield, and botanical composition. each year, 24 heifers (134 ± 6 d of age and 147.4 ± 31.2 kg bw in yr 1; 166 ± 11 d of age and 168.0 ± 27.6 kg bw in yr 2) and 6 goats (2 yr old an ...201222952353
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