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effects of host demography, season and rainfall on the prevalence and parasitic load of gastrointestinal parasites of free-living elephants (loxodonta africana) of the chad basin national park, nigeria.the effects of host demography, rainfall and season on the prevalence and parasitic load of gastrointestinal parasites of african elephants (loxodonta africana) of the chad basin national park were determined for the first time. out of the 274 elephants examined, 36.86% were infected. of the 178 males examined, 35.96% harboured strongyloides, coccidia and strongyles with worm burdens of 75.6 +/- 0.3, 125.2 +/- 1.4 and 420.2 +/- 0.1, respectively. among the males, the larvae of strongyloides papi ...201324506015
molecular basis for benzimidazole resistance from a novel β-tubulin binding site model.benzimidazole-2-carbamate derivatives (bzcs) are the most commonly used antiparasitic drugs for the treatment of protozoan and helminthic infections. bzcs inhibit the microtubule polymerization mechanism through binding selectively to the β-tubulin subunit in which mutations have been identified that lead to drug resistance. currently, the lack of crystallographic structures of β-tubulin in parasites has limited the study of the binding site and the analysis of the resistance to bzcs. recently, ...201323995453
novel expression of haemonchus contortus vaccine candidate aminopeptidase h11 using the free-living nematode caenorhabditis elegans.with the problem of parasitic nematode drug resistance increasing, vaccine development offers an alternative sustainable control approach. for some parasitic nematodes, native extracts enriched for specific proteins are highly protective. however, recombinant forms of these proteins have failed to replicate this protection. this is thought to be due to differences in glycosylation and/or conformation between native and recombinant proteins. we have exploited the free-living nematode caenorhabdit ...201324289031
the effect of different adjuvants on immune parameters and protection following vaccination of sheep with a larval-specific antigen of the gastrointestinal nematode, haemonchus contortus.it has recently been recognised that vaccine adjuvants play a critical role in directing the nature of a vaccine induced effector response. in the present study, several adjuvants were evaluated for their ability to protect sheep after field vaccination with the larval-specific haemonchus contortus antigen, hcsl3. using a suboptimal antigen dose, aluminium adjuvant was shown to reduce the cumulative faecal egg counts (cfec) and worm burden by 23% and 25% respectively, in agreement with a previou ...201324205209
multiple anthelmintic resistance of haemonchus contortus, including a case of moxidectin resistance, in a dutch sheep flock. 201324197434
[spatio-temporal pattern of larvae and eggs of gastrointestinal nematodes in cattle pastures in veracruz, mexico].the spatial and temporal distribution of gastrointestinal nematodes of cattle has been little studied in mexico. previous studies have described periods of higher larval presence, vertical and horizontal migration in grasslands, and the frequency of adult nematodes; as well as the effect of pasture trichomes on the migration and survival of haemonchus larvae. the aim of this study was to determine the time-space layout and spread of gastrointestinal nematode larvae on pasture, and to estimate th ...201324432531
seasonal prevalence of gastrointestinal helminths in sheep and goats of middle agro-climatic zone of jammu province.a total of 1920 faecal samples of sheep (960) and goats (960) of stationary flocks of the middle agro-climatic zone of jammu province were examined, out of which 67.24 % animals were positive for helminthic infections. the different nematodes observed were strongyles (50.1 %), trichurids (12.1 %) and strongyloides spp. (4.2 %). trematode ova recorded were of amphistomes (8.3 %), fasciola spp. (8.2 %) and dicrocoelium spp. (5.4 %). no significant difference was observed between the infection leve ...201324431535
genetic variability within and among haemonchus contortus isolates from goats and sheep in china.haemonchus contortus (order strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. knowledge of genetic variation within and among h. contortus populations can provide a foundation for understanding transmission patterns, the spread of drug resistance alleles and might assist in the control of haemonchosis.201324499637
the in vitro assay profile of macrocyclic lactone resistance in three species of sheep trichostrongyloids.anthelmintic resistance has emerged as an important problem in animal industries. understanding resistance mechanisms, especially against macrocyclic lactones (mls), is the first step in developing better diagnostic tools. effects of several mls including ivermectins and milbemycins were tested using two well established in vitro assays: the larval development assay (lda) and the larval migration inhibition assay (lmia). these were performed on free-living stages of susceptible and ml-resistant ...201324533300
acetylcholine receptor subunit and p-glycoprotein transcription patterns in levamisole-susceptible and -resistant haemonchus contortus.the mechanism of resistance to the anthelmintic levamisole in parasitic nematodes is poorly understood, although there is some evidence implicating changes in expression of nicotinic acetylcholine receptor (nachr) subunit genes. hence, in order to define levamisole resistance mechanisms in some australian field-derived isolates of haemonchus contortus we examined gene expression patterns and snps in nachr subunit genes, as well as expression levels for p-glycoprotein (p-gp) and receptor ancillar ...201324533293
comparative tissue pharmacokinetics and efficacy of moxidectin, abamectin and ivermectin in lambs infected with resistant nematodes: impact of drug treatments on parasite p-glycoprotein expression.the high level of resistance to the macrocyclic lactones has encouraged the search for strategies to optimize their potential as antiparasitic agents. there is a need for pharmaco-parasitological studies addressing the kinetic-dynamic differences between various macrocyclic lactones under standardized in vivo conditions. the current work evaluated the relationship among systemic drug exposure, target tissue availabilities and the pattern of drug accumulation within resistant haemonchus contortus ...201324533290
influence of dietary supplementation of condensed tannins through leaf meal mixture on intake, nutrient utilization and performance of haemonchus contortus infected sheep.the study assessed the effect of dietary supplementation of leaf meal mixture (lmm) containing condensed tannins (ct) on feed intake, nutrient utilization and performance of sheep infected with haemonchus contortus. eighteen adult sheep of similar age and body weight (25.03±1.52) were included in this study and out of these, 12 sheep were infected with single dose of infective third stage larvae of h. contortus at 2,000 larvae per sheep. the experimental sheep were allocated in three different g ...201325049728
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
the metabolic fate of ivermectin in host (ovis aries) and parasite (haemonchus contortus).ivermectin (ive), one of the most important anthelmintics, is often used in the treatment of haemonchosis in ruminants. the objective of our work was (1) to find and identify phase i and ii metabolites of ive formed by the barber's pole worm (haemonchus contortus), and (2) to compare ive metabolites in helminths with ive biotransformation in sheep (ovis aries) as host species. ultrahigh-performance liquid chromatography/tandem mass spectrometry (uhplc/ms/ms) was used for this purpose. during in ...201323089373
effects of single or trickle haemonchus contortus experimental infection on digestibility and host responses of naïve creole kids reared indoor.the objective of this study was to compare the effects of the type of haemonchus contortus experimental infection (trickle infection, ti versus single infection, si) on feed intake, nutrients digestibility, parasitological and haematological measures, and plasma leptin in creole kids. the animals were infected over 2 periods (challenge 1 and challenge 2) of 6 weeks each, corresponding respectively to the primary and the secondary infection. periods prior infection (1 week each) were considered a ...201323069494
in vitro influence of temperature on the biological control activity of the fungus duddingtonia flagrans against haemonchus contortus in sheep.recently, research for alternative methods to combat gastrointestinal parasites has increased, and the biological control activity of the fungus duddingtonia flagrans stands out. in this study, the possible influence of temperature on the nematophagous activity of d. flagrans, after gastrointestinal passage, against haemonchus contortus in sheep was analysed. four female sheep, between 2 and 3 years of age and weighing between 40 and 50 kg, were used. two sheep were parasitised with h. contortus ...201323052786
quantitative trait loci for resistance to haemonchus contortus artificial challenge in red maasai and dorper sheep of east africa.a genome-wide scan was performed to detect quantitative trait loci (qtl) for resistance to the gastrointestinal nematode haemonchus contortus in a double backcross population of red maasai and dorper sheep. the mapping population comprised six sire families, with 1026 lambs in total. the lambs were artificially challenged with h. contortus at about 6.5 months of age, and nine phenotypes were measured: fecal egg count, packed cell volume decline, two weight traits and five worm traits. a subset o ...201323051556
effect of supplemental sericea lespedeza leaf meal pellets on gastrointestinal nematode infection in grazing goats.feeding sun-dried sericea lespedeza [sl; lespedeza cuneata (dum-cours.) g. don.] reduces gastrointestinal nematode (gin) infection in goats fed in confinement, but effects of this forage when fed as a supplement to goats on pasture are unclear. a study was completed in which supplemental feeds (75 and 95% sl leaf meal pellets and a commercial pellet, all fed at 0.91 kg/head/day) were offered to thirty growing male spanish goats (9 months old, 20.6 ± 2.8 kg, 10/treatment) grazing perennial warm-s ...201322985929
sensitivity of two in vitro assays for evaluating plant activity against the infective stage of haemonchus contortus strains.the sensitivity of larval paralysis assay (lpa) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide-formazan (mtt-formazan) assay was compared to evaluate the anthelmintic activity of plant extracts. in this study, the methanolic extract of azadirachta indica (neem) was evaluated for its activity against the infective-stage larvae (l(3)) of susceptible and resistant haemonchus contortus strains using the two aforementioned assays. in both in vitro assays, the same serial concentrat ...201322961237
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
bioactivity studies on musa seminifera lour.musa seminifera lour is a tree-like perennial herb that has been used in folk medicine in bangladesh to heal a number of ailments.201324124283
anthelmintic activity of securidaca longepedunculata (family: polygalaceae) root extract in mice, in vitro and in vivo.to elucidate the pharmacological bases of oral administration of securidaca longepedunculata (s. longepedunculata) root extract as an anthelmintic in folkloric medicine.201324083577
attenuation effect of uv on haemonchus contortus larvae in experimentally infected goats.haemonchus contortus causes severe economic losses in small ruminants, so this study was conducted to study the uv effect on h. contortus larvae and its protective effect.201325516737
research offers hope of new treatments for barber pole worm. 201324038274
evolution of structure and mechanistic divergence in di-domain methyltransferases from nematode phosphocholine biosynthesis.the phosphobase methylation pathway is the major route for supplying phosphocholine to phospholipid biosynthesis in plants, nematodes, and plasmodium. in this pathway, phosphoethanolamine n-methyltransferase (pmt) catalyzes the sequential methylation of phosphoethanolamine to phosphocholine. in the pmt, one domain (mt1) catalyzes methylation of phosphoethanolamine to phosphomonomethylethanolamine and a second domain (mt2) completes the synthesis of phosphocholine. the x-ray crystal structures of ...201324012478
haemonchus contortus as a paradigm and model to study anthelmintic drug resistance.anthelmintic resistance is a major problem for the control livestock parasites and a potential threat to the sustainability of community-wide treatment programmes being used to control human parasites in the developing world. anthelmintic resistance is essentially a complex quantitative trait in which multiple mutations contribute to the resistance phenotype in an additive manner. consequently, a combination of forward genetic and genomic approaches are needed to identify the causal mutations an ...201323998513
detection of ivermectin resistance by a larval development test--back to the past or a step forward?the aim of this study was to evaluate the potential of the larval development test for the detection of ivermectin (ivm) resistance in haemonchus contortus of sheep. single infections with 5000 third-stage larvae of five resistant and two susceptible isolates of h. contortus were given to sheep. fecal samples were collected four times during patency, and the micro-agar version of the larval development test (maldt) was performed. three macrocyclic lactone drugs (ivm, eprinomectin and ivm aglycon ...201323993637
assessment of benzimidazole resistance in haemonchus contortus in sheep flocks in ontario, canada: comparison of detection methods for drug resistance.in 2011, a field study was conducted to assess drug resistance of gastro-intestinal nematodes in sheep flocks in ontario, canada. benzimidazole resistance in haemonchus contortus was assessed by genetic analysis of eggs; measurement of resistant allele percentages at codons 167, 198 and 200 in the β-tubulin gene was determined on pools of h. contortus eggs using pyrosequencing. susceptibility to benzimidazoles in gastro-intestinal nematodes was also determined using a faecal egg count reduction ...201323993632
the genome and developmental transcriptome of the strongylid nematode haemonchus contortus.the barber's pole worm, haemonchus contortus, is one of the most economically important parasites of small ruminants worldwide. although this parasite can be controlled using anthelmintic drugs, resistance against most drugs in common use has become a widespread problem. we provide a draft of the genome and the transcriptomes of all key developmental stages of h. contortus to support biological and biotechnological research areas of this and related parasites.201323985341
the genome and transcriptome of haemonchus contortus, a key model parasite for drug and vaccine discovery.the small ruminant parasite haemonchus contortus is the most widely used parasitic nematode in drug discovery, vaccine development and anthelmintic resistance research. its remarkable propensity to develop resistance threatens the viability of the sheep industry in many regions of the world and provides a cautionary example of the effect of mass drug administration to control parasitic nematodes. its phylogenetic position makes it particularly well placed for comparison with the free-living nema ...201323985316
efficacy of ivermectin versus dual infections of haemonchus contortus and heligmosomoides polygyrus in the mouse.this report describes a novel assay for the detection of gastrointestinal anthelmintics using mice infected with haemonchus contortus and adapted to the 1 animal/test group protocol. mice infected with both h. contortus and heligmosomoides polygyrus were fed ivermectin-medicated diets for 6 days. a dietary level of 0.09375 ppm was 98.1% effective against the 0- to 6-day-old abomasal stomach worm of sheep, whereas a level of 0.75 ppm reduced the 3- to 9-day-old h. polygyrus worm burden by 94.0%. ...201323145469
effect of simulated rainfall timing on faecal moisture and development of haemonchus contortus and trichostrongylus colubriformis eggs to infective larvae.three climate-controlled chamber experiments were conducted to determine the effect of 32 mm simulated rainfall applied prior to (days -4 to -1) or after (days 0-7) faecal deposition and as a single (32 mm) or split (2 × 16 mm) application on faecal moisture (fm) and development of h. contortus and t. colubriformis to third stage infective larvae (l3). the timing of simulated rainfall regulated extra-pellet l3 recovery for h. contortus (p<0.05) but not t. colubriformis. recovery of l3 was highes ...201323142178
anthelmintic efficacy of an oral formulation of aurixazol against gastrointestinal nematodes of naturally and experimentally infected sheep.as a result of the need to develop new active principles for the control of endoparasites in ruminants, the present in vivo study evaluated a formulation containing 24% aurixazol (48 mg/kg), a parasiticide molecule based on disophenolate of levamisole. two experiments were conducted: one evaluating the anthelmintic efficacy of 24% aurixazol (48 mg/kg) against gastrointestinal nematodes in naturally infected sheep, compared to an association of ivermectin (0.2mg/kg)+albendazole (5.0mg/kg)+levamis ...201324138723
detection of benzimidazole resistance in gastrointestinal nematodes of sheep and goats of sub-himalyan region of northern india using different tests.the present investigation was planned with the objective of studying the status of benzimidazole (bz) resistance in gastrointestinal nematodes (gin) of sheep and goats of different agro-climatic zones of sub-himalyan region of northern india using in vivo faecal egg count reduction test (fecrt) and in vitro tests namely egg hatch assay (eha) and larval development assay (lda). out of fourteen flocks, fecrt detected resistance in eight flocks (two sheep flocks and six goat flocks) with fecr% rang ...201324126090
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
acr-23 encodes a monepantel-sensitive channel in caenorhabditis elegans.monepantel is a member of the recently identified class of anthelmintics known as the amino-acetonitrile derivatives (aads). monepantel controls all major gastro-intestinal nematodes in sheep including those that are resistant to the classical anthelmintics. previous studies have shown that the caenorhabditis elegans acr-23 and the haemonchus contortus hco-mptl-1 genes may be prominent targets of monepantel. with this discovery it became possible to investigate the mode of action of monepantel i ...201323950710
effect of experimental infection with haemonchus contortus on parasitological and local cellular responses in resistant and susceptible young creole goats.this study was carried out to evaluate the relationships of cellular changes in the abomasal mucosa and parasitological parameters, by comparing resistant and susceptible young creole goats (kids) after experimental infection with haemonchus contortus. the kids were infected over 2 periods (challenges 1 and 2) of 7 and 6 weeks, respectively. fecal egg count (fec), blood eosinophilia, packed cell volume (pcv), and body weight were weekly monitored. at the end of both challenges a subgroup of kids ...201323936855
discovery of anthelmintic drug targets and drugs using chokepoints in nematode metabolic pathways.parasitic roundworm infections plague more than 2 billion people (1/3 of humanity) and cause drastic losses in crops and livestock. new anthelmintic drugs are urgently needed as new drug resistance and environmental concerns arise. a "chokepoint reaction" is defined as a reaction that either consumes a unique substrate or produces a unique product. a chokepoint analysis provides a systematic method of identifying novel potential drug targets. chokepoint enzymes were identified in the genomes of ...201323935495
e-ada activity in erythrocytes of lambs experimentally infected with haemonchus contortus and its possible functional correlations with anemia.the aim of this study was to evaluate the ecto-adenosine deaminase (e-ada) activity in erythrocytes of lambs experimentally infected with haemonchus contortus, correlating it with the degrees of anemia of the experimental animals. a total of 14 healthy lambs, with negative fecal exam for parasites, were to carry out the present study. they were divided into two groups, composed by seven animals: group a represented the healthy animals (uninfected), while in group b the animals were infected with ...201323928180
the effect of purified condensed tannins of forage plants from botswana on the free-living stages of gastrointestinal nematode parasites of livestock.the effect of condensed tannins (ct) extracted from forage plants from botswana on the free-living stages of a number of species of gastrointestinal nematode parasites derived from infected sheep were investigated using in vitro assays. fresh samples of five different plants (viscum rotundifolium, viscum verrucosum, tapinanthus oleifolius, grewia flava and ipomoea sinensis) were collected over two summers (february 2009 and 2010). fractionation of each crude extract on a sephadex lh-20 column yi ...201323927915
the use of redberry juniper (juniperus pinchotii) to reduce haemonchus contortus fecal egg counts and increase ivermectin efficacy.objectives of this study were to determine if a redberry juniper-based diet can reduce fecal egg counts (fec) and increase ivermectin (ivm) efficacy in ivm-resistant haemonchus contortus. predominant genera present were haemonchus (range 45-100%) and trichostrongylus (range 0-47%). the fec reduction for ivm in the ewe flock was 25% (95% confidence intervals 79% to -162%) and confirmed ivm resistance. after natural infection was established, barbados blackbelly and st. croix lambs (n=64, 6 months ...201323827040
translation of h. contortus and t. colubriformis from egg to establishment in grazing sheep is unaffected by rainfall timing, rainfall amount and herbage height under conditions of high soil moisture in the northern tablelands of nsw.a field experiment was conducted at armidale in the northern tablelands of nsw, australia to determine the effects of simulated rainfall amount (0, 12 and 24 mm), rainfall timing (days -1, 0 and 3 relative to plot contamination) and herbage height (4 and 12 cm), on translation of haemonchus contortus and trichostrongylus colubriformis from egg to established stages in grazing sheep under conditions of high soil moisture (22-23%). the experiment was conducted in summer when temperature was not an ...201323809211
efficiency of a genetic test to detect benzimidazole resistant haemonchus contortus nematodes in sheep farms in quebec, canada.haemonchus contortus is a hemophilic nematode which infects sheep and causes anemia and death to lambs. benzimidazole drugs are used to remove these parasites, but the phenomenon of resistance has arisen worldwide. a sensitive test to detect resistance before treatment would be a useful tool to enable farmers to anticipate the efficiency of the drug before drenching the flock. in this study, we compared a test for benzimidazole resistance based on detection of genetic markers in h. contortus bef ...201323773905
thymus capitatus from tunisian arid zone: chemical composition and in vitro anthelmintic effects on haemonchus contortus.the increasing prevalence of anthelmintic resistant strains of helminths, the drug residues in animal products and the high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintics. thymus capitatus (lamiales: lamiaceae) is used traditionally by people as spices and reported to possess some biological effects. the objective of this study is to evaluate the anthelmintic efficacy of t. capitatus in comparison to albendazole a ...201323768565
glycosyltransferases in chemo-enzymatic synthesis of oligosaccharides.many oligosaccharides are not commercially available, which limits studies focused on elucidation of glycan functions; therefore chemo-enzymatic methods to synthesize them can be very useful. here, we describe the procedure to synthesize the galα1-3galnacβ1-4glcnacβ-r (gal-ldn) moiety, containing the galα1-3galnac epitope found on the parasitic helminth haemonchus contortus. an acceptor substrate providing a terminal n-acetylglucosamine was prepared by coupling the fluorescent hydrophobic aglyco ...201323765675
in vitro effect of heather (ericaceae) extracts on different development stages of teladorsagia circumcincta and haemonchus contortus.the aim of the present study was to evaluate the in vitro effects of heather (ericaceae) phenolic extracts on the abomasal nematodes teladorsagia circumcincta and haemonchus contortus. extracts of three heather species (calluna vulgaris, erica cinerea, erica umbellata and a balanced mixture of all three) were tested in vitro on different development stages of t. circumcincta (eggs, infective larvae and adult worms) and h. contortus (eggs and infective larvae) using an egg hatching assay (eha), a ...201323764130
intranasal immunization of lambs with serine/threonine phosphatase 2a against gastrointestinal nematodes.seven 3-month-old, female, helminth-free lambs were immunized intranasally with three doses (1 mg total) of a recombinant part of the catalytic region of the serine/threonine phosphatase 2a (pp2ar) (group 1 [g1]). in addition, four lambs were used as an adjuvant control group (g2), four as unimmunized, infected controls (g3), and four as unimmunized, uninfected controls (g4). fifteen days after the last immunization, lambs from g1, g2, and g3 were challenged with 10,000 larval stage 3 (l3) organ ...201323761655
activity of chitosan-encapsulated eucalyptus staigeriana essential oil on haemonchus contortus.phytotherapy has been described as an alternative method for the control of gastrointestinal nematodes in small ruminants. goal of the encapsulation of essential oils in biopolymer matrices is to optimize the biological effects of these oils. the aim of the present study was to evaluate the in vitro and in vivo anthelmintic activity of encapsulated eucalyptus staigeriana essential oil (ences) on the eggs and larvae of haemonchus contortus. therefore, the egg hatching test (eht), larval developme ...201323748159
effect of using redberry juniper (juniperus pinchotii) to reduce haemonchus contortus in vitro motility and increase ivermectin efficacy.a modified larval migration inhibition assay was used to determine if redberry juniper (juniperus pinchotii sudw.) can reduce haemonchus contortus in vitro motility and increase ivermectin (ivm) efficacy. ruminal fluid was mixed with buffer solution and either no material (cntl) or tifton 85 bermudagrass hay (t85), dried juniper (dry), fresh juniper (fre), or distilled juniper terpenoid oil (oil) to make treatment solutions and anaerobically incubated for 16 h. for trial 1, larvae were incubated ...201323702157
in vitro and in vivo evaluation of the activity of pineapple (ananas comosus) on haemonchus contortus in santa inês sheep.the development of resistance to anthelmintics has prompted research into alternative methods of controlling intestinal nematodes in ruminants. this study aimed to assess the activity of ananas comosus on haemonchus contortus in santa inês sheep. the aqueous extract of pineapple skin (aeps), bromelain from pineapple stems (b4882) and residue from pineapple processing was evaluated in in vitro and in vivo tests. the enzymatic activity of substances was analyzed by the azocasein method. the egg ha ...201323688638
effects of mimosa tenuiflora on larval establishment of haemonchus contortus in sheep.anthelmintic resistance has limited the ability to control the gastrointestinal nematodes of small ruminants and has therefore awakened an interest in the study of tanniferous plants as a source of anthelmintics. this study was carried out to evaluate the effect of mimosa tenuiflora intake, a tanniferous plant that is fed to small ruminants in northeastern brazil, on the larval establishment of haemonchus contortus in sheep. in this experiment, 18 nematode-free sheep were divided into three grou ...201323643453
soil moisture modulates the effects of the timing and amount of rainfall on faecal moisture and development of haemonchus contortus and trichostrongylus colubriformis to infective third stage larvae.recent experiments on the effects of rainfall and/or soil moisture (sm) on development of sheep gastro-intestinal nematodes to infective l3 stage have used soil of relatively low moisture content in small experimental samples that dry out faster than field soil. to determine whether higher and more sustained sm content modulates the effects of rainfall amount and timing on faecal moisture (fm) and development of h. contortus and t. colubriformis to infective third stage larvae (l3), a climate-co ...201323632251
anthelmintic activity of arisaema franchetianum and arisaema lobatum essential oils against haemonchus contortus.arisaema franchetianum and arisaema lobatum are two perennial plants native to china. arisaema franchetianum is universally used to promote the subsidence of induration and swelling, quicken blood and relieve pains, and kill intestinal parasites in humans and animals. arisaema lobatum is used to treat malaria, intestinal parasites, and snake and insect bites in humans and animals. the aim of this study was to determine the composition of the essential oils from arisaema franchetianum and arisaem ...201323624115
biotransformation of albendazole and activities of selected detoxification enzymes in haemonchus contortus strains susceptible and resistant to anthelmintics.the increased activity of drug-metabolizing enzymes can protect helminths against the toxic effect of anthelmintics. the aim of this study was to compare the metabolism of the anthelmintic drug albendazole (abz) and the activities of selected biotransformation and antioxidant enzymes in three different strains of haemonchus contortus: the ise strain (susceptible to common anthelmintics), the br strain (resistant to benzimidazole anthelmintics) and the wr strain (multi-resistant). h. contortus ad ...201323587403
in vitro anthelmintic activity of aqueous leaf extract of annona muricata l. (annonaceae) against haemonchus contortus from sheep.despite the overall progress of sheep farming in brazil, infections with the gastrointestinal parasite haemonchus contortus represent one the most important problems in sheep production, aggravated by the increasing resistance of nematodes to traditional anthelmintic drugs caused by inadequate sheep flock management by breeders. ethnopharmacological data indicate annona muricata as a promising alternative for the control of gastrointestinal nematodes because of its general anthelmintic propertie ...201323583362
effects of parasitism on cellular immune response in sheep experimentally infected with haemonchus contortus.this work aimed to study the possible relationships among the magnitude of abomasal worm burden and the proliferation of globular leucocytes and mucosal mast cells in the abomasal mucosa, and the white blood cell count. eighteen suffolk × greyface lambs were infected with haemonchus contortus, and 12 were kept free of nematodes. blood samples were collected on days 0, 30, and 57 post-infection (p.i.) for leucogram determination. at day 62, all animals were euthanized to count the total number of ...201323522899
investigation of sainfoin (onobrychis viciifolia) cultivar differences on nitrogen balance and fecal egg count in artificially infected lambs.research in ruminant nutrition and helminth control with forages, which contain condensed tannins (ct), suggests that varying responses may depend not only on ct concentration but also on ct composition. an experiment was designed to test this by feeding 2 dried sainfoin cultivars (visnovsky and perly), which differed in ct properties, to lambs that were artificially infected with the abomasal blood-sucking nematode haemonchus contortus. twenty-four infected lambs received 1 of these 2 cultivars ...201323463570
efficacy and toxicity of thirteen plant leaf acetone extracts used in ethnoveterinary medicine in south africa on egg hatching and larval development of haemonchus contortus.helminthiasis is a major limitation to the livestock industry in africa. haemonchus contortus is the singular most important helminth responsible for major economic losses in small ruminants. the high cost of anthelmintics to small farmers, resistance to available anthelmintics and residue problems in meat and milk consumed by humans further complicates matters. the use of plants and plant extracts as a possible source of new anthelmintics has received more interest in the last decade. our aim w ...201323442744
overwintering strategies of a population of anthelmintic-resistant haemonchus contortus within a sheep flock from the united states northern great plains.haemonchus contortus infections have been increasingly reported in ungulates from cold climates even though past studies have shown that the free-living juveniles from this species survive poorly under freezing conditions. overwintering strategies of h. contortus have not been documented in the unites states northern great plains. a pcr survey identified h. contortus as vastly predominant trichostrongyle species present (in addition to occasional detections of teladorsagia sp.) in a closed farm ...201323433645
characterization and comparative analysis of the complete haemonchus contortus β-tubulin gene family and implications for benzimidazole resistance in strongylid nematodes.parasitic nematode β-tubulin genes are of particular interest because they are the targets of benzimidazole drugs. however, in spite of this, the full β-tubulin gene family has not been characterized for any parasitic nematode to date. haemonchus contortus is the parasite species for which we understand benzimidazole resistance the best and its close phylogenetic relationship with caenorhabditis elegans potentially allows inferences of gene function by comparative analysis. consequently, we have ...201323416426
hair-type sheep generate an accelerated and longer-lived humoral immune response to haemonchus contortus infection.antibody levels produced in response to gastro-intestinal nematode (gin) parasite infection are typically higher in gin-resistant breeds than susceptible breeds. consequently, gin-resistant ewes should generate greater parasite-specific antibody in colostrum and milk, potentially providing greater passive immunity to young lambs. to test this hypothesis, we monitored immunoglobulin levels in wool and hair-type sheep infected with haemonchus contortus for 35 days following the end of a 45-day aut ...201323414615
anthelmintic resistance in northern ireland (i): prevalence of resistance in ovine gastrointestinal nematodes, as determined through faecal egg count reduction testing.the prevalence of anthelmintic resistance in northern ireland sheep flocks was evaluated between july and october 2011. sampling kits were sent to 172 flock owners and returns were received from 91. within this survey population, 27 flock owners used benzimidazole products, 10 used levamisole products, 15 used avermectin products, 26 used milbemycin products and 4 flock owners used the amino acetonitrile derivative, monepantel. the remaining 9 flock owners used combination drenches (broad spectr ...201323398988
soil moisture influences the development of haemonchus contortus and trichostrongylus colubriformis to third stage larvae.two climate chamber experiments were conducted to determine the effect of varying initial soil moisture (0, 10 and 15%), simulated rainfall amount (0, 12 and 24 mm) and simulated rainfall timing (days -1, 0 and 3 relative to faecal deposition) on development (day 14) of haemonchus contortus and trichostrongylus colubriformis to the third stage larvae (l3) and faecal moisture (fm). increasing initial soil moisture content from 0 to 10 or 15% led to higher recovery of total l3 (p<0.001). total l3 ...201323398986
sarcosine metabolism in haemonchus contortus and teladorsagia circumcincta.sarcosine (n-methylglycine) is an intermediate in glycine degradation and can also be synthesised from glycine in mammals. sarcosine metabolism in haemonchus contortus and teladorsagia circumcincta differed from that of mammals in that creatinase activity was present and sarcosine was demethylated only by sarcosine oxidase (sox) and not by sarcosine dehydrogenase (sdh). the mean sox activity was 30 nmolmin(-1)mg(-1) protein in homogenates of l3 and adult worms of both parasites and the apparent ...201323376286
characterization of heat shock protein 70 gene from haemonchus contortus and its expression and promoter analysis in caenorhabditis elegans.haemonchus contortus infections in small ruminants are of major economic importance worldwide. heat shock proteins (hsps) are a family of molecular chaperones that play important roles in the process of invasion and survival of nematodes. although hsp70 has been identified in several parasitic nematodes, little is known of its distribution and function in haemonchus contortus. the aims of this study were to characterize hsp70 from haemonchus contortus (designed as hc-hsp70), express hc-hsp70 and ...201323360558
in vitro ovicidal and larvicidal activity of the essential oil of artemisia lancea against haemonchus contortus (strongylida).prolonged use of chemical anthelmintics has been found to result in anthelmintic resistance and environmental issues, thereby limiting the application of these drugs in domestic animals and prompting interest in the study of plant extracts as alternative sources thereof. the aim of this study was to evaluate the in vitro effect of the essential oil (eo) of artemisia lancea against the parasitic nematode haemonchus contortus using egg hatch assay, larval development assay, and larval migration in ...201323351974
measurement of phenotypic resilience to gastro-intestinal nematodes in merino sheep and association with resistance and production variables.a cross-over experiment was conducted to compare six different phenotypic measures of resilience to gastro-intestinal nematodes (predominantly haemonchus contortus) in merino sheep and their association with resistance and production levels. on each of six farms, 120 ewes born in 2006 and 120 older mixed age ewes were selected at shearing in 2007. of these, 60 in each mob were serially treated with long-acting anthelmintics to suppress worm populations. the other 60 ewes were managed according t ...201323333138
scanning electron microscopy of haemonchus contortus exposed to tannin-rich plants under in vivo and in vitro conditions.the structural changes induced in adult haemonchus contortus after in vitro and in vivo contact with a tannin-rich (tr) plant, either tzalam (lysiloma latisiliquum) or sainfoin (onobrychis viciifolia), were assessed using scanning electron microscopy (sem). all the worms used in the study were adult females. the haemonchus adult worms were obtained from the abomasum of infected donor goats. adult h. contortus were kept in contact with the extracts of tr plants for 24h for the in vitro assays and ...201323246590
plant secondary compounds as complementary resources: are they always complementary?generalist herbivores typically grow better on mixed- than on single-component diets. this response has been attributed to food complementarities that either enhance the utilization of nutrients or dilute the negative impacts of plant secondary compounds (psc). for instance, when animals choose between foods that contain diverse psc, they eat more than animals offered a food that contains just one psc. in addition to their negative impacts on herbivore fitness, recent evidence suggests that at a ...201323223888
relative level of thiabendazole resistance associated with the e198a and f200y snps in larvae of a multi-drug resistant isolate of haemonchus contortus.while the f200y snp in the beta-tubulin gene is most commonly associated with benzimidazole resistance in trichostrongylid nematodes, other snps as well as drug efflux pathways have been implicated in the resistance. the relative contributions of all these mechanisms are not understood sufficiently to allow expected drug efficacy to be inferred from molecular data. as a component of developing better means to interpret molecular resistance tests, the present study utilised a drug resistant haemo ...201224533269
a reappraisal of the relative sensitivity of nematode pharyngeal and somatic musculature to macrocyclic lactone drugs.macrocyclic lactone (ml) drugs inhibit pharyngeal pumping, motility and egg laying in parasitic nematodes. previous work has indicated that in vitro effects on worm feeding occurred at lower ivermectin concentrations than effects on worm motility, suggesting that the pharynx musculature was a more important target site for the ml drugs than somatic musculature. we have reassessed this issue of relative sensitivity by examining the response of drug-susceptible and -resistant adult haemonchus cont ...201224533262
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
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
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
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
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
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
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
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
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 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
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 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
field vaccination of sheep with a larval-specific antigen of the gastrointestinal nematode, haemonchus contortus, confers significant protection against an experimental challenge infection.the availability of effective vaccines would add a valuable tool to the management of gastrointestinal nematode infections in livestock. while some experimental vaccines have shown protection in laboratory trials, few have been tested in the field. in the present study, eight month old sheep kept on pasture were treated with anthelmintic 8 weeks before vaccination with a larval surface antigen of the nematode parasite, haemonchus contortus, under a commercially acceptable protocol, i.e. 2 immuni ...201223107597
relevance of improved epidemiological knowledge to sustainable control of haemonchus contortus in nigeria.nigeria experiences losses in small ruminant production as a result of a high prevalence of infection with haemonchus contortus, but there have been very few investigative studies into the epidemiology of h. contortus in nigeria, particularly in the south and western parts of the country. for successful planning and execution of control of hemonchosis in nigeria, there is a need for insight into the epidemiology of free-living stages under the prevailing local conditions and models for climatic ...201223163980
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
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