Publications

reduced efficacy of ivermectin, abamectin and moxidectin against field isolates of haemonchus contortus.	to investigate the reduced efficacy of ivermectin, abamectin and moxidectin against two field isolates of haemonchus contortus. these isolates were identified on separate properties in the new england region of new south wales.	2001	11837906
high-affinity ivermectin binding to recombinant subunits of the haemonchus contortus glutamate-gated chloride channel.	glutamate-gated chloride channels (glucls) are targets for the avermectin anthelmintics. a family of five glucl subunit genes encoding seven subunits has been identified in caenorhabditis elegans. we have previously shown that two orthologous genes in the parasite, haemonchus contortus, encode three glucl subunits (hcgluclbeta, hcgbr-2a and hcgbr-2b) with high amino-acid identity (>80%) to their c. elegans counterparts. we amplified and cloned a further subunit cdna, hcgluclalpha, from h. contor ...	2001	11378196
studies on the immunoglobulin e responses to teladorsagia circumcincta in sheep: purification of a major high molecular weight allergen.	studies on the immunoglobulin (ig)e immune responses to the gastric nematode, teladorsagia circumcincta, have demonstrated a major high molecular weight allergen (hmwtc). cross reactive allergens of similar mw were demonstrated for trichostrongylus colubriformis and cooperia curticei, but not for haemonchus contortus. purification of hmwtc was achieved by gel-filtration chromatography, and nonreducing sds-page and western blot analysis revealed two closely associated bands with a molecular weigh ...	2001	11309133
synthesis and anthelmintic activity of thioamide analogues of cyclic octadepsipeptides such as pf1022a.	the tetra- and mono-thionated cyclic octadepsipeptides represent novel cyclic octadepsipeptide derivatives with broad-spectrum activity against parasitic nematodes in mice and sheep. some of these show better activity than the potent natural anthelmintic cyclic octadepsipeptide pf1022a against hymenolepis nana, heterakis spumosa and trichinella spiralis larvae in mice. in particular, they show improved efficacy against haemonchus contortus and trichostrongylus colubriformis in sheep compared wit ...	2001	11721515
the dynamics, prevalence and impact of nematode infections in organically raised sheep in sweden.	a three-year survey (1997-99) was carried out on organically reared sheep flocks throughout sweden. the aim was to determine the prevalence and intensity of nematode infections and to establish relationships between sheep management practices and parasite infections. faecal samples from ewes and lambs were collected from 152 organic flocks around lambing-time and during the grazing-period for analysis. results were compared with the different management practices that farmers use to prevent para ...	2001	11887398
a multiplex pcr assay for differentiating economically important gastrointestinal nematodes of cattle.	a multiplex polymerase chain reaction (pcr) test was developed for identifying gastrointestinal (gi) nematodes that commonly infect cattle. this assay was developed using adult-derived genomic dna and shown capable of discriminating parasite eggs from the feces of experimentally-infected animals at both the species and genus levels. sequence data from internal (its) and external (ets) transcribed spacers of the ribosomal dna (rdna) repeats as well as the 3'-end of the small subunit rdna and 5'-e ...	2001	11390072
cloning and structural analysis of partial acetylcholine receptor subunit genes from the parasitic nematode teladorsagia circumcincta.	nematode nicotinic acetylcholine receptors (nachrs) are the sites of action for the anthelmintic drug levamisole. recent findings indicate that the molecular mechanism of levamisole resistance may involve changes in the number and/or functions of target nachrs. accordingly, we have used an rt-pcr approach to isolate and characterise partial cdna clones (tca-1 and tca-2) encoding putative nachr subunits from the economically important trichostrongyloid, teladorsagia circumcincta. the predicted tc ...	2001	11390086
comparison of ivermectin, doramectin, selamectin, and eleven intermediates in a nematode larval development assay.	chemical substitutions at pharmacologically relevant sites such as c-5, c-13, c-22,23, and c-25 were examined in ivermectin, doramectin, selamectin, and a series of 11 other intermediates using a larval development assay with haemonchus contortus. a range of activities spanning 5 orders of magnitude were manifest with small changes in the substituents to the 14 avermectins. within this compound series, there was no major potency advantage or disadvantage to a disaccharide over a monosaccharide s ...	2001	11426737
assessment of genetic variability of resistance to gastrointestinal nematode parasites in creole goats in the humid tropics.	goat production is widespread in the tropics. goats are very susceptible to gastrointestinal nematode infection, but there is less evidence of their genetic resistance. genetic resistance of creole goats to gastrointestinal nematodes has been studied at guadeloupe in the french west indies since 1995. the objective of this research was to investigate genetic variation for resistance to gastrointestinal nematode infection, in order to introduce this trait into breeding schemes. genetic variabilit ...	2001	11465357
direct anthelmintic effects of condensed tannins towards different gastrointestinal nematodes of sheep: in vitro and in vivo studies.	in vitro and in vivo studies were conducted to determine possible direct anthelmintic effects of condensed tannins towards different ovine gastrointestinal nematodes. a larval development/viability assay was used to investigate the effect of a condensed tannin extract (quebracho) towards larvae of haemonchus contortus, teladorsagia circumcincta and trichostrongylus vitrinus. the development to infective larvae and their viability was assessed in all three species and ld 50 values were calculated ...	2001	11502368
analysis of developmentally regulated genes of the parasite haemonchus contortus.	differential regulation of gene expression in the development of haemonchus contortus was analysed using rna arbitrarily-primed pcr. a study of third-stage larval and adult h. contortus revealed large differences between the two stages; 32 and 30% unique third-stage larval and adult rna arbitrarily-primed pcr products, respectively. this finding is consistent with a high degree of differential gene expression between these developmental stages. a number of adult products were sequenced, revealin ...	2001	11513893
parasite vaccines--a reality?	over the last decade, the anti-parasitics market has been the fastest growing sector of the overall $18 billion animal health market. while drugs for the treatment of parasites of livestock still dominate this sector and will continue to be developed or re-formulated, because of consumer demands for chemical-free food and of concerns regarding the environment and animal welfare there is a growing interest in the development of safe and effective vaccines. there is also a call for vaccines in the ...	2001	11516584
haemonchus contortus utilises catalase in defence against exogenous hydrogen peroxide in vitro.	the toxicity of activated oxygen species towards adult haemonchus contortus nematodes was examined in in vitro assays using ingestion of [3h]inulin to assess nematode viability. both glucose/glucose oxidase (generation of hydrogen peroxide) and xanthine/xanthine oxidase (generation of superoxide anion) systems showed concentration-dependent toxicity to the nematodes. both adult and larval haemonchus contortus enzyme preparations showed significant catalase activities. adult nematodes exposed to ...	2001	11730782
cathepsin b-like cysteine proteases and caenorhabditis elegans homologues dominate gene products expressed in adult haemonchus contortus intestine.	proteins expressed by nematode intestinal cells are potential targets for parasite control by immune or chemical based strategies. to expand our knowledge on nematode intestinal proteins, expressed sequence tags were generated for 131 cdna clones from the intestine of adult female haemonchus contortus. an estimated 55 distinct protein genes or gene families were identified. predicted proteins represented diverse functions. several predicted polypeptides were related to h. contortus proteins impl ...	2001	11522349
vaccination against gastrointestinal nematode parasites of ruminants using gut-expressed antigens.	to date, proteins isolated from the surface of the gut of gastrointestinal nematodes, particularly haemonchus contortus, have generally proved to be useful protective antigens and several are being progressed towards recombinant protein-based vaccines. this paper describes the properties of some of the most promising antigens and summarises their performance in laboratory and field based trials. the antigens described include contortin, h11, h-gal-gp, gpi and cysteine proteinases. in addition, t ...	2001	11522403
preliminary observations on the potential of gut membrane proteins of haemonchus contortus as candidate vaccine antigens in sheep on naturally infected pasture.	in a trial lasting 11 months in south africa, faecal egg counts and haematocrits of sheep vaccinated with gut membrane proteins of adult haemonchus contortus were compared with unvaccinated controls grazing pasture contaminated with the parasite. vaccination reduced egg output by >82% on average during one 4 month period of the trial and simultaneously significantly reduced the degree of anaemia and deaths due to haemonchosis. although vaccine immunity was not sufficiently long lasting to preven ...	2001	11423186
genetic variability following selection of haemonchus contortus with anthelmintics.	genetic diversity in nematodes leads to variation in response to anthelmintics. haemonchus contortus shows enormous genetic diversity, allowing anthelmintic resistance alleles to be rapidly selected. anthelmintic resistance is now a widespread problem, especially in h. contortus. here, i compare the genes involved in anthelmintic resistance in h. contortus with those that confer susceptibility or resistance on the free living nematode caenorhabditis elegans. i also discuss the latest knowledge o ...	2001	11530357
in vitro metabolism of moxidectin in haemonchus contortus adult stages.	we studied the implication of cytochrome p450 enzymes in the in vitro metabolism of moxidectin (mxd) in homogenates of haemonchus contortus adult stages (susceptible isolate, weybridge, uk). after homogenisation in a phosphate buffer, 2 ml of homogenates (equivalent to 1 g of nematodes) were incubated with 5 microg [14c] mxd at 37 degrees c for 24 h. mxd and its metabolites were separated by hplc with radiodetection on-line. only one metabolite was detected and its production was inhibited by ca ...	2001	11570553
isolation, characterisation and expression of mrnas encoding the ovine cc chemokines, monocyte chemoattractant protein (mcp)-1alpha and -2.	cc chemokines are important mediators of immune responses, orchestrating the differential recruitment of various leukocyte populations. despite the large number of known cc chemokines in other species, no cdna encoding ovine cc chemokines have been isolated. a homology cloning strategy was utilised to isolate the cdna of ovine cc chemokines. full-length monocyte chemoattractant protein (mcp)-1alpha and -2 cdna have been isolated. the predicted ovine mcp-1alpha amino acid sequence shares 87 and 7 ...	2001	11587731
pathological and immunohistochemical study of the abomasum and abomasal lymph nodes in goats experimentally infected with haemonchus contortus.	histopathological changes and the distributions of t and b lymphocytes and igg producing plasma cells were recorded in the abomasum and abomasal lymph nodes of goats 3, 7 and 21 weeks post-infection (wpi) after an experimental infection with h. contortus. the low rate of worm recovery by 3 wpi (5.6%) might have been due to larvae death as suggested by the presence of granulomas in the abomasal mucosa at 3 and 7 wpi, or simply due to a poor larval establishment. marked increase in the secretion o ...	2001	11592616
the contribution of molecular biology to the development of vaccines against nematode and trematode parasites of domestic ruminants.	rapid developments in molecular biology have had an enormous impact on the prospects for the development of vaccines to control the major nematode and trematode infestations of livestock. vaccine candidates are purified using conventional protein chemistry techniques but the limitations imposed by the scarcity of parasite material provide an insurmountable barrier for commercial vaccine production by this means. the ability to purify mrna from different parasite life-cycle stages and to prepare ...	2001	11707304
secreted metalloprotease gene family of microsporum canis.	keratinolytic proteases secreted by dermatophytes are likely to be virulence-related factors. microsporum canis, the main agent of dermatophytosis in dogs and cats, causes a zoonosis that is frequently reported. using aspergillus fumigatus metalloprotease genomic sequence (mep) as a probe, three genes (mep1, mep2, and mep3) were isolated from an m. canis genomic library. they presented a quite-high percentage of identity with both a. fumigatus mep and aspergillus oryzae neutral protease i genes. ...	2002	12228297
selection for resistance to macrocyclic lactones by haemonchus contortus in sheep.	an anthelmintic-sensitive haemonchus contortus strain was selected for moxidectin and ivermectin resistance concurrently for 22 generations. treatment with 0.002 mg moxidectin/kg bw or 0.02 mg ivermectin/kg bw produced >99% efficacy against the susceptible parent strain passaged for 22 generations without any anthelmintic exposure. however, to obtain similar efficacy the moxidectin-selected and the ivermectin-selected strains of h. contortus required 0.05 mg moxidectin/kg bw or 0.4 mg ivermectin ...	2002	11751006
response of corriedale and crioula lanada sheep to artificial primary infection with haemonchus contortus.	clinical, parasitological and biochemical parameters were evaluated in corriedale and crioula lanada sheep after a single experimental infection with haemonchus contortus. ten 4-month-old worm-free lambs, of each breed, were infected with 200 l3 h. contortus per kg live weight and four uninfected animals of each breed were used as controls. every week, the animals were weighed and blood and faecal samples were collected for measurement of packed cell volume (pcv), total serum protein (tsp) and a ...	2002	12241098
identification of immunodominant antigens of adult haemonchus contortus (nematoda: trichostrongylidae).		2002	12121049
anthelmintic activity of preparations derived from myrsine africana and rapanea melanophloeos against the nematode parasite, haemonchus contortus, of sheep.	myrsine africana l. and rapanea melanophloeos l. belong to the plant family myrsinaceae. various rural communities in kenya, such as smallholder farmers and pastoralists, use them to treat their livestock. the anthelmintic effects/activities of leaves and fruits of m. africana and fruits of r. melanophloeos were tested in sheep experimentally infected with the nematode parasite haemonchus contortus. male lambs were infected with 3000-5000 third stage larvae of h. contortus and treated 28 days af ...	2002	12007709
genetic parameters for resistance to haemonchus contortus in merino sheep in south africa.	resistance to natural infections of haemonchus contortus (wireworm) was studied in merino sheep. from february 1995 to july 1996 data were collected from the otk merino stud on the farm wildebeesfontein near hendrina in mpumalanga province. from march 1998 to january 2000 another merino flock at irene in gauteng province was included in the study. in both cases, 50 randomly-chosen animals from each group of lambs weaned were sampled weekly for faecal egg count (fec) until a mean of 2500 eggs per ...	2002	12088074
estimating genetic differences in natural resistance in rhön and merinoland sheep following experimental haemonchus contortus infection.	genetic parameters of natural resistance were estimated in rhön and merinoland (german merino) sheep following experimental infection with haemonchus contortus. a total of 133 rhön and 244 merinoland lambs descending from 5 and 6 rams, respectively, were evaluated. each helminth-naive lamb was orally infected with 5000 infective third-stage larvae (l(3)) of the nematode h. contortus at 12 weeks of age. faecal egg counts (fec) and haematocrit values were measured in all lambs at 16 and 20 weeks o ...	2002	11992711
benzimidazole binding to haemonchus contortus tubulin: a question of structure.		2002	11998698
a glutamate-gated chloride channel subunit from haemonchus contortus: expression in a mammalian cell line, ligand binding, and modulation of anthelmintic binding by glutamate.	glutamate-gated chloride channels (glucls) are inhibitory ion channels that are sensitive to the antiparasitic drugs ivermectin (ivm) and moxidectin (mox). we have transiently transfected cos-7 cells with a subunit of a glucl (hcglucla) from the parasitic nematode haemonchus contortus. this subunit bound [3h]-ivm and [3h]-mox with k(d) values of 0.11+/-0.021 and 0.18+/-0.02nm, respectively. displacement analysis revealed that ivm and mox bind to the same site on hcglucla and that this site is li ...	2002	11931838
molecular cloning and characterization of ac-mep-1, a developmentally regulated gut luminal metalloendopeptidase from adult ancylostoma caninum hookworms.	a zinc metalloendopeptidase cdna (ac-mep-1) was cloned from ancylostoma caninum adult hookworms. ac-mep-1 is encoded by a 2.8 kb mrna with a predicted open reading frame (orf) of 870 amino acids (predicted pi=5.5, m.w.=98.7 kda) that contains four potential n-linked glycosylation sites and predicted zinc-binding domains (hexxh and enxadxgg). these domains represent signature sequences of the neutral endopeptidase 24.11 (neprilysin) family of enzymes. the orf corresponding to ac-mep-1 exhibited s ...	2002	11755191
helminth intensity and diversity in organic meat sheep farms in centre of france.	a helminthological study was undertaken at five sheep meat organic farms in the centre of france. the data obtained were compared with two extensive (contemporary of present study) or semi-intensive (literature data) conventional sheep meat farms. the nematode fauna of the region could be characterised by the presence of trichostrongylus axei alongside with the dominant species recorded in other areas (teladorsagia circumcincta and trichostrongylus colubriformis with few haemonchus contortus). t ...	2002	11879965
use of lectin binding characteristics to identify gastrointestinal parasite eggs in faeces.	identification of the presence and abundance of species is important when choosing therapies and control strategies for internal parasitism of livestock. here we examine lectin binding characteristics of eggs isolated from sheep faeces as a means for identifying the parasite genera contributing to infection. the intensity of lectin staining varied with incubation time, incubation volume, concentration of lectin and concentration of eggs. formalin fixed eggs had greater autofluorescence but exhib ...	2002	11934462
kinetics of antibody response by dot-elisa in rabbits immunized with adult haemonchus contortus antigen.	whole adult soluble extract of haemonchus contortus as an antigen along with freund's complete adjuvant, was used to immunize rabbits. antisera from immunized rabbits were collected at intervals of 30, 60, 90, 120, 150 and 180 days. for the detection and titration of anti-h. contortus antibodies in these sera, dot-elisa was developed. sera collected 30 days post-immunization exhibited a titre of 1:5,000 in all the rabbits except one, where a titre of 20,000 was recorded. later, all the rabbits a ...	2002	12514952
morbidity and mortality factors in key deer (odocoileus virginianus clavium).	the population health of endangered key deer (odocoileus virginianus clavium) was monitored from 10 february 1986 to 28 september 2000 by necropsy of animals that were killed by vehicles, euthanized because of terminal injuries or disease conditions, or found dead. the predominant mortality factor during the period was collision with motor vehicles; however, several infectious diseases were diagnosed, including infections with arcanobacterium pyogenes, haemonchus contortus, salmonella spp., and ...	2002	12528433
protection studies with recombinant excretory/secretory proteins of haemonchus contortus.	the efficacy of two recombinant proteins of haemonchus contortus was studied in both adult sheep and young lambs. these 15 and 24 kda excretory/secretory proteins were given combined, either supplemented or not with a glycan-rich insect cell extract. in 9-month-old sheep (trial 1), faecal egg output and worm burden were reduced by 49% and 55%, respectively, after vaccination with rec15/24, and by 46% and 65% after vaccination with rec15/24 and glycan extract. no reduction in egg output or number ...	2002	12010484
a cathepsin l protease essential for caenorhabditis elegans embryogenesis is functionally conserved in parasitic nematodes.	proteolytic enzymes are involved in processes important to development and survival of many organisms. parasite proteases are considered potential targets of parasite control yet, for most, their precise physiological functions are unknown. validation of potential targets requires analysis of function. we have recently identified a cathepsin l (cpl) cysteine protease, ce-cpl-1, which is essential for embryonic development of the free-living nematode caenorhabditis elegans. we now show that cpl g ...	2002	12076767
excretory/secretory products of haemonchus contortus inhibit aminopyrine accumulation by rabbit gastric glands in vitro.	abomasal parasites inhibit gastric acid secretion and reduce the number of acid secreting parietal cells either through physical contact with gastric tissue, the release of inhibitory excretory/secretory (es) products or by initiating the host inflammatory response. to examine the role of parasite es products, adult haemonchus contortus were incubated in a medium based on hank's balanced salt solution and three incubates were tested for the presence of inhibitors of acid secretion by dispersed r ...	2002	11812620
mechanisms of immunity to haemonchus contortus infection in sheep.	in two separate experiments, sheep were immunized by nine to 12 weekly immunizing infections with 4000 haemonchus contortus third stage larva (l3), drenched with anthelminthics and maintained free of h. contortus infection for a further 12 weeks. the anamnestic cellular immune responses in both the abomasal lymph node (aln) and mucosa of the immunized sheep were examined 3 and 5 days post challenge with 50 000 h. contortus l3. sheep in the two experiments clearly segregated out in two distinct g ...	2002	11856445
the effect of pasture species on parasitism and performance of lambs grazing one of three grass-white clover pasture swards.	lamb parasitism and performance were compared on three pasture treatments: browntop/white clover, yorkshire fog/white clover, and ryegrass/white clover swards maintained at a sward height of 5cm in each of two years by using continuous variable stocking management. in year 1, lamb performance (both suppressively drenched (sd) and trigger drenched (td)) was similar on ryegrass and browntop swards but was poorer (p<0.05) on yorkshire fog swards. in year 2, lamb performance (both sd and td) was mar ...	2002	11983305
response to carbon dioxide by the infective larvae of three species of parasitic nematodes.	the response of infective third-stage larvae (l3) of three species of parasitic nematodes, ancylostoma caninum, strongyloides stercoralis, and haemonchus contortus to carbon dioxide (co(2)) at physiological concentrations was investigated. l3 of the skin-penetrating species, a. caninum and s. stercoralis, were stimulated by co(2) at the concentration found in human breath (3.3-4%); these larvae responded by crawling actively, but not directionally. crawling was not stimulated by breath passed th ...	2002	11880227
characterization and purification of cytosolic and membrane-bound protease(s) in adults of haemonchus contortus.	the activity of protease(s) was observed separately in cytosolic and membrane-bound protease(s) from male and female hae monchus contortus (nematoda: trichostrongylidae). different fractions showed optimum protease activity at 37 degrees c, ph 8.5 and 8.0 mg casein concentration. the female fractions had a particularly high activity of protease(s) in comparison with the male fractions, especially of membrane-bound enzymes in the anterior half. inhibition, activation studies revealed the presence ...	2002	12002422
hcstk, a caenorhabditis elegans par-1 homologue from the parasitic nematode, haemonchus contortus.	a putative serine/threonine protein kinase (hcstk) from the parasitic nematode haemonchus contortus was characterised at the mrna and amino acid levels. hcstk displays a high level of identity (85-93% in the catalytic domain) with proteins of the par-1/mark serine/threonine protein kinase (stk) subfamily, which represent signal transduction molecules involved in establishing and maintaining polarity in proliferating and differentiating cells. the transcript of hcstk is expressed in different dev ...	2002	12062493
diversity of benzimidazole-resistance alleles in populations of small ruminant parasites.	the resistance of gastro-intestinal nematodes of small ruminants (sheep and goat) to benzimidazole anthelmintic drugs seems to be linked primarily to a single mutation in the isotype 1 beta-tubulin gene. this study was carried out to investigate the origin and diversity of benzimidazole-resistance alleles in trichostrongylid nematodes. we sequenced a 550 bp fragment of the isotype 1 beta-tubulin gene from several benzimidazole-resistant teladorsagia circumcincta populations isolated from dairy g ...	2002	12062563
benefit of the control of gastrointestinal nematode infection in goats in the dry zone of sri lanka.	the benefit of gastrointestinal nematode control in cross-bred goats in the dry area of sri lanka was studied throughout 1 year by comparing the performances of three groups: group 1 animals (n = 11) were left untreated against gastrointestinal nematodes; group 2 animals (n = 11) were given monthly anthelmintic treatment. doramectin, at the dose rate of 300 microg/kg bodyweight during the entire study period; group 3 animals (n = 11) were also given monthly doramectin treatment at the dose rate ...	2002	12019940
synthesis of anthelmintically active n-methylated amidoxime analogues of the cyclic octadepsipeptide pf1022a.	the n-methylated amidoxime analogues of the cyclic octadepsipeptide pf1022a represent novel derivatives with activity against trichinella spiralis owen and nippostrongylus brasiliensis lane in vitro and against parasitic nematodes in mice and sheep. some of them show better activity against hymenolepis nana siebold, heterakis spumosa schneider and heligmosomoides polygyrus dujardin in mice than the natural product pf1022a. in particular an improved efficacy against haemonchus contortus rudolphi ...	2002	12476993
the parasitic hematophagous worm haemonchus contortus inhibits human platelet aggregation and adhesion: partial purification of a platelet inhibitor.	blood sucking parasites elaborate mechanisms to counteract the hemostatic system of their victim. haemonchus contortus worms use several mechanisms directed against the normal platelet hemostatic function. platelet adhesion onto collagen and fibrinogen, and the ristocetin-mediated interaction of von willebrand factor with glycoprotein (gp) ib were inhibited by the protein extract of adult worms. also platelet aggregation induced by collagen, thrombin, adp, ristocetin or a23187 was inhibited. alt ...	2002	12038795
high affinity as a disease determinant factor in anti-gm(1) antibodies: comparative characterization of experimentally induced vs. disease-associated antibodies.	elevated titers of serum anti-gm(1) antibodies of igg isotype are found frequently in patients with guillain-barré syndrome. much evidence indicates that these autoantibodies are involved in disease progression, but their exact function and the mechanism of their appearance are still unclear. in an attempt to reproduce "ganglioside syndrome", the experimental model of neuropathy developed by nagai et al. (neurosci. lett. 2 (1976) 107), rabbits were intensively immunized with gm(1) in complete fr ...	2002	12098512
localization of p-glycoprotein mrna in the tissues of haemonchus contortus adult worms and its relative abundance in drug-selected and susceptible strains.	membrane transporter p-glycoproteins (pgps) are present in a number of nematode species, including haemonchus contortus. allelic variation in some pgp genes has been found to be associated with resistance to the anthelmintic ivermectin (ivm), although functional verification of a role for pgps in ivm resistance has yet to be demonstrated. by in situ hybridization, the distribution of pgp mrna was visualized in transverse cryosections of adult h. contortus, using a digoxigenin-labeled cdna probe ...	2002	12099436
analysis and partial reversal of multidrug resistance to anthelmintics due to p-glycoprotein in haemonchus contortus eggs using lens culinaris lectin.	our previous work has shown that drug efflux pumps close to mdr1 p-glycoprotein (pgp) can regulate anthelmintic efflux in nematodes in a way similar to that of the mutidrug resistance system (mdr) in vertebrate cancer cells. in the present study, the role of the glycosylation of pgp was studied using a lectin specific for the alpha-mannosyl residues ( lens culinaris agglutinin, lca). highly significant reversion (up to 50%) in the resistance to thiabendazole of eggs pre-treated with the lectin w ...	2002	12172813
kinetics of exsheathment of infective ovine and bovine strongylid larvae in vivo and in vitro.	the aim of the study was to investigate the longitudinal changes of exsheathment of ovine and bovine 3rd-stage strongylid larvae in an artificial rumen (rusitec) and to compare the results with in vivo data obtained from rumen-fistulated sheep. infective larvae were incubated in nylon mesh bags in the sheep rumen or the rusitec apparatus for periods of 1, 6 and 12 h, respectively. the 12 h exsheathment rates in the rumen and the rusitec apparatus (in parentheses) were as follows: haemonchus cont ...	2002	12166522
freezing of sheep faeces invalidates haemonchus contortus faecal egg counts by the mcmaster technique.	faecal pellets from a sheep that was artificially infected with a monoculture of haemonchus contortus were collected over a 2-h period in the morning. in the laboratory the faeces were thoroughly mixed by hand and 48 by 1 g aliquots of the pellets were sealed in plastic bags, from which the air had gently been expressed. the faecal worm egg count of the sheep was about 14,000 g(-1). varying numbers of the bags were either processed for faecal worm egg counting (fec) by the mcmaster technique on ...	2002	12625382
susceptibility of trypanotolerant west african dwarf goats and f1 crosses with the susceptible sahelian breed to experimental trypanosoma congolense infection and interactions with helminth infections and different levels of diet.	forty pure west african dwarf (wad) goats and 35 of its f1 crosses with the sahelian breed were used in a multifactorial experimental design to evaluate the effects of an experimental trypanosoma congolense infection and interactions with natural helminth infections and different levels of diet on health and productivity of these two breeds. trypanosome infection caused a severe drop in packed cell volume (pcv), but this was not significantly affected by breed. neither deworming nor diet had any ...	2002	12208040
high-level ivermectin resistance in a field isolate of haemonchus contortus associated with a low level of resistance in the larval stage: implications for resistance detection.	the ivpro isolate of haemonchus contortus was isolated in 1999 after significant numbers of the parasite survived an ivermectin capsule treatment of grazing sheep acquiring a natural infection at prospect, nsw, australia. the isolate shows high-level resistance to ivermectin (faecal egg count is unaffected by ivermectin oral treatment at 0.2mg kg(-1)). the larval lc(50), as assessed by larval development assays (ldas), is only approximately two-fold higher than several susceptible isolates, maki ...	2002	12237144
effectiveness of copper oxide wire particles for haemonchus contortus control in sheep.	to assess the efficacy of copper oxide wire particles (cowp) for the control of h contortus infections in grazing sheep.	2002	12054286
the effects of ivermectin and moxidectin on egg viability and larval development of ivermectin-resistant haemonchus contortus.	the in vivo effects of ivermectin and moxidectin on egg viability and larval development of ivermectin-resistant haemonchus contortus were examined over time after anthelmintic treatment of sheep. twenty merino sheep, (12 months old) were allocated to five treatment groups and infected with ivermectin-resistant h. contortus. thirty one days later, the sheep were treated with intraruminal ivermectin capsules, oral ivermectin, oral moxidectin or injectable moxidectin at the manufacturer's recommen ...	2002	12072216
the effects of stage-specific selection on the development of benzimidazole resistance in haemonchus contortus in sheep.	resistance to the benzimidazole (bdz) class of anthelmintics in nematodes of sheep has become a common and global phenomenon. the rate at which the selection process and development of resistance occurs is influenced by a number of factors. of these, the effects of stage-specific exposures to anthelmintic were investigated with a bdz-resistant strain of haemonchus contortus (hcr) over five parasite generations. sheep were infected at each generation with the hcr strain and were treated with thia ...	2002	12383623
anthelmintic activity of essential oil of ocimum gratissimum linn. and eugenol against haemonchus contortus.	the ovicidal activity of the essential oil of ocimum gratissimum linn. (labideae) and its main component eugenol was evaluated against haemonchus contortus, gastrointestinal parasite of small ruminants. the oil and eugenol were diluted in tween 20 (0.5%) at five different concentrations. in the egg hatch test, h. contortus eggs were obtained from feces of goats experimentally infected. at 0.50% concentration, the essential oil and eugenol showed a maximum eclodibility inhibition. these results s ...	2002	12383625
resistance to therapeutic treatment with macrocyclic lactone anthelmintics in ostertagia circumcincta.	eighty-eight lambs were allocated to one of four groups which were then dosed with 10,000 infective-stage larvae (l3) of one of four populations of ostertagia circumcincta; the first (s) was an isolate known to be anthelmintic-susceptible; the second (or) was a multiple anthelmintic-resistant isolate which had been recovered from the field following therapeutic failure of both ivermectin and moxidectin and subsequently maintained in the laboratory without further anthelmintic selection. the thir ...	2002	12383628
expression of acquired immunity to a local isolate of haemonchus contortus by the nigerian west african dwarf goat.	the capacity of young nigerian west african dwarf (wad) goats to express good acquired immunity to their native geographic strain of haemonchus contortus and the correlates of this responsiveness were studied in a laboratory experiment involving forty 7-8 month old kids. a primary immunising infection with 2000 l3 (equivalent to 260-450 l3/kg body weight) with or without challenge on d42 with 2000 l3 resulted in a mild chronic infection with a pre-patent period of 18-20 days and little or no red ...	2002	11812621
evaluation of duddingtonia flagrans in reducing infective larvae of haemonchus contortus in feces of sheep.	consequences of nematode infections due to haemonchus contortus are a serious constraint for the sheep industry worldwide. development of anthelmintic resistance and increasing concern about the impact of anthelmintic use dictate the need of alternative control. such an alternative is using the nematode trapping fungus duddingtonia flagrans to reduce infective larvae levels on pasture. two trials were conducted to determine the effect of d. flagrans in reducing infective larvae (predominantly h. ...	2002	11750119
a novel cathepsin b active site motif is shared by helminth bloodfeeders.	this study compared specific protein sequence motifs present within cathepsin b-like cysteine proteases from a number of helminth parasites. we have focused our efforts on cathepsin b-like proteases of haemonchus contortus, caenorhabditis elegans, schistosoma mansoni, schistosoma japonicum, ostertagia ostertagi, and ancylostoma caninum. the goal of this work is to correlate specific features, or proposed roles, of the cathepsin b-like proteases with primary sequence motifs discovered within the ...	2002	12427461
distinct characteristics of two intestinal protein compartments discriminated by using fenbendazole and a benzimidazole resistant isolate of haemonchus contortus.	the intestine of haemonchus contortus is hypersensitive to the effects of the anthelmintic fenbendazole (fbz). the effects are postulated to stem from disruption of microtubules and interference with apical secretory vesicle transport, followed by release of digestive enzymes into the intestinal cell cytoplasm. here, fbz caused marker proteins for both apical (pepsinogen-like protease, pep-1) and basal (cystatin-like protein) protein compartments to became homogeneously distributed in the cytopl ...	2002	12594960
evolution of nematode community in grazing sheep selected for resistance and susceptibility to teladorsagia circumcincta and trichostrongylus colubriformis: a 4-year experiment.	field trials were undertaken to compare nematode population dynamics in two experimental flocks of rams selected for high and for low faecal egg counts (fecs) following two doses with 20000 infective larvae, 12000 teladorsagia circumcincta (tcirc) and 8000 trichostrongylus colubriformis (tcol) separated by a treatment. the selection was done by dosing 200 ram lambs (inra 401 breed) and fecs proceeded with egg identification on days 28 and 35 post-each-infection. the 30 lambs with the lowest fecs ...	2002	12423939
the famacha system for managing haemonchosis in sheep and goats by clinically identifying individual animals for treatment.	escalating anthelmintic resistance has made it essential to develop alternative ways of worm management for reducing selection for worm resistance, and one of the most promising approaches is to treat only those animals unable to cope with worm challenge, thus favouring unselected worms originating from untreated animals. only clinical evaluation of anaemia (famacha system) and the body condition score are regarded as being of practical value or having potential, respectively, for repeatedly exa ...	2002	12387487
study of the nematode putative gaba type-a receptor subunits: evidence for modulation by ivermectin.	two alleles of the hg1 gene, which encodes a putative gaba receptor alpha/gamma subunit, were isolated from haemonchus contortus. these two alleles were shown previously to be associated with ivermectin susceptibility (hg1a) and resistance (hg1e), respectively. sequence analysis indicates that they differ in four amino acids. to explore the functional properties of the two alleles, a full-length cdna encoding the beta subunit, a key functional component of the gaba receptor, was isolated from ca ...	2002	12421359
vertical migration by the infective larvae of three species of parasitic nematodes: is the behaviour really a response to gravity?	vertical migration by infective larvae (l3) of 3 species of nematodes was investigated. upright truncated agarose cones were used to test upward migration, and comparable truncated cone-shaped agarose hollows were used to test downward migration. flat agarose plates were control surfaces. when placed at the bases of upright cones, 74% of ancylostoma caninum l3 migrated up, whereas only 16.5% migrated down the indented cones; this latter value was not significantly different from larval migration ...	2002	12553574
nematophagous fungi as a biological control agent for nematode parasites of small ruminants in malaysia: a special emphasis on duddingtonia flagrans.	approximately 2,800 fresh dung samples from animals, mainly ruminant livestock, were screened for the presence of nematophagous fungi in malaysia. arthrobotrys spp. was noted on numerous occasions, but only one isolate of duddingtonia flagrans was made. for the purposes of producing sufficient quantities of this fungus for feeding trials in sheep, various, commonly available, cheap plant materials were tested as possible growth substrates. this showed that cereal grains (wheat, millet and rice) ...	2002	12498569
quantitative analysis of its2 sequences in trichostrongyle parasites.	real-time pcr assays were developed to identify and quantify common gastrointestinal nematodes of ruminants. the assays were based on genus-specific primer and probe combinations derived from the second internal transcribed spacer (its2) ribosomal dna transcription unit of haemonchus contortus, ostertagia leptospicularis, trichostrongylus colubriformis and cooperia curticei. the taqman probes for the first two species were labelled with 6-carboxyfluorescein and those for the latter two with vic ...	2002	12392918
sequence variation in the trichuris trichiura beta-tubulin locus: implications for the development of benzimidazole resistance.	benzimidazole resistance has evolved in a variety of organisms and typically results from mutations in the beta-tubulin locus at specific amino acid sites. despite widespread treatment of human intestinal nematodes with benzimidazole drugs, there have been no unambiguous reports of resistance. however, since beta-tubulin mutations conferring resistance are generally recessive, frequencies of resistance alleles less than 30% would be difficult to detect on the basis of drug treatment failures. he ...	2002	12392917
relative resistance of dorper crossbred ewes to gastrointestinal nematode infection compared with st. croix and katahdin ewes in the southeastern united states.	a study was conducted to evaluate relative resistance of dorper crossbred (do), katahdin (ka), st. croix (sc), and hampshire (ha) ewes to natural and experimental gastro-intestinal (gi) nematode infection over a 20-month period. the objective of experiment 1 was to evaluate breeds for resistance to infection acquired naturally from mixed grass pastures. in year 1 (may-december 2000) de-worming of ewes occurred during wet, hot conditions in july and during late pregnancy in december. in year 2 (j ...	2002	12423938
modulation of the multidrug resistance (mdr) system in the nematode haemonchus contortus by changing cholesterol content: effects on resistance to anthelmintics.	the efficiency of the anthelmintics used to treat small domestic ruminants infected with nematodes is compromised by the emergence of resistant parasites. both specific and non-specific mechanisms of resistance exist. the non-specific mechanisms involve multiple resistance phenomena and are dependent on the multidrug resistance (mdr) system, which is also responsible for the development of chemotherapy-resistant tumour cells. we showed previously that the system also exists in nematodes. membran ...	2003	12865394
synthesis and anthelmintic activity of cyclohexadepsipeptides with (s,s,s,r,s,r)-configuration.	the (s,s,s,r,s,r)-configurated cyclohexadepsipeptides (chdps) represent novel enniatin derivatives with strong in vivo activity against the parasitic nematode haemonchus contortus rudolphi in sheep. 2d nmr spectroscopic analysis revealed for the major conformation the asymmetric conformer, containing a cis-amide bond between c(alpha) protons of neighbouring 2-hydroxy-(s)-carboxylic acid and n-methyl-(s)-amino acid. the absolute configuration of the novel chdps was determined by x-ray crystallogr ...	2003	12951110
top dressing of feed with desiccated chlamydospores of duddingtonia flagrans for biological control of the pre-parasitic stages of ovine haemonchus contortus.	feeding trials were conducted with stall-fed sheep parasitized with haemonchus contortus. for 10 days they were offered 250 g of a concentrate feed that had been top-dressed with desiccated chlamydospores of duddingtonia flagrans at 1 x 10(5), 5 x 10(5), 1 x 10(6) or 2 x 10(6) chlamydospores/kg body weight. pooled faeces from each group on day 7 of spore feeding were spread on different pasture plots. on day 28 after the start of spore feeding, further pooled faeces from each group were spread o ...	2003	14509452
regulation of the resistance to nematode parasites of single- and twin-bearing merino ewes through nutrition and genetic selection.	periparturient merino ewes obtained from lines of sheep that had been selected either for increased resistance to haemonchus contortus (r) or at random (c) were supplemented, while grazing at pasture, with either nil or 250 g/day cottonseed meal (csm) for the 6 weeks prior to or the 6 weeks after the start of parturition. ewes from both supplement groups had lower (mean 66% reduction) faecal egg counts (fecs) during the postpartum period and this coincided with a period of maternal body weight l ...	2003	12732463
comparison of the resistance to sympatric and allopatric isolates of haemonchus contortus of black belly sheep in guadeloupe (fwi) and of inra 401 sheep in france.	the resistance of a tropical breed of sheep towards the nematode parasite haemonchus contortus (hc) was compared to that of a european breed after artificial infection with the parasite following a 2 x 2 x 2 experimental design: two isolates (hc gua from guadeloupe versus hc fra from france), two breeds each reared in their native habitats (black belly (bb) in guadeloupe, fwi, inra 401 reared in france), and two groups of lambs with differing infection status (one naive, i.e. infected for the fi ...	2003	14519318
host specificity of haemonchus spp. for domestic ruminants in the savanna in northern ivory coast.	three haemonchus species (haemonchus contortus, haemonchus placei and haemonchus similis) live in sympatry in the savanna of north côte d'ivoire. four domestic ruminant hosts (zebu-cattle, taurine-cattle, sheep and goats) share the same pastures throughout the year. our post-mortem data imply that a haemonchus spp. circulation exists among the different hosts species in the savanna of north côte d'ivoire. under field conditions, mixed congeneric infections were the rule except in sheep where mon ...	2003	14519319
the anthelmintic efficacy of the plant, albizia anthelmintica, against the nematode parasites haemonchus contortus of sheep and heligmosomoides polygyrus of mice.	albizia anthelmintica brong., belongs to the plant family mimosaceae. the plant is widely used in east africa by poor smallholder farmers and pastoralists to treat their livestock against internal parasites. the anthelmintic effects of water extracts from the bark of a. anthelmintica, obtained from three different geographic areas in kenya and using different methods of preparation, were tested at different doses in sheep and mice infected with the nematode parasites haemonchus contortus and hel ...	2003	14519324
haemonchus contortus unc-18 binds to caenorhabditis elegans neuronal syntaxin.		2003	14550897
comprehensive analysis of the secreted proteins of the parasite haemonchus contortus reveals extensive sequence variation and differential immune recognition.	haemonchus contortus is a nematode that infects small ruminants. it releases a variety of molecules, designated excretory/secretory products (esp), into the host. although the composition of esp is largely unknown, it is a source of potential vaccine components because esp are able to induce up to 90% protection in sheep. we used proteomic tools to analyze esp proteins and determined the recognition of these individual proteins by hyperimmune sera. following two-dimensional electrophoresis of es ...	2003	12576473
efficacy of eprinomectin pour-on against gastrointestinal nematode infections in sheep.	two field trials were conducted in two farms (farms a and b) in southern italy, to assess the efficacy of eprinomectin applied topically at the dose rate of 500 micro g/kg to sheep with naturally occurring infections of gastrointestinal nematodes (gin). the nematode population determined by necropsy consisted of teladorsagia circumcincta, haemonchus contortus, trichostrongylus vitrinus, t. capricola, nematodirus sp., and chabertia ovina in sheep from farm a, and of t. circumcincta, t. vitrinus, ...	2003	12591196
enhancing immunity to nematode parasites in single-bearing merino ewes through nutrition and genetic selection.	the effectiveness of protein supplementation and genetic selection to enhance the resistance of periparturient merino ewes to infection from gastrointestinal parasites was tested in a replicated grazing experiment. one hundred and twenty ewes from lines selected for increased resistance (r) to haemonchus contortus or at random (c) were subjected to one of the three supplement groups that provided 0 or 250 g per day cottonseed meal for 5 weeks prior to, or for 6 weeks after the start of lambing. ...	2003	12591197
evolution of high-level, multiple anthelmintic resistance on a sheep farm in malaysia.	anthelmintic resistance in nematode parasites of sheep and goats on a government farm in north malaysia was monitored over a 3-year period (1997-2000). the faecal egg count reduction test (fecrt) was conducted on young sheep at the beginning and end of this period. changes in management, designed to reduce the selection pressure for the development of anthelmintic resistance, were also implemented during this time. by far the most important parasite problem was haemonchus contortus. in 1997, thi ...	2003	12636358
ovicidal and larvicidal activity in vitro of spigelia anthelmia linn. extracts on haemonchus contortus.	the rapid development of anthelmintic resistance, associated with the high cost of the available anthelmintic drugs, had limited the success of gastrointestinal nematodiasis control in sheep and goats and thus awakened interest in the study of medicinal plants as alternative sources of anthelmintics. spigelia anthelmia extracts obtained with hexane, chloroform, ethyl acetate or methanol, were tested on haemonchus contortus eggs and larvae via egg hatch and larval development tests. the extracts ...	2003	14597278
in vitro screening of two nigerian medicinal plants (vernonia amygdalina and annona senegalensis) for anthelmintic activity.	vernonia amygdalina and annona senegalensis, two plants used by local/smallholder livestock farmers in nigeria as anthelmintic were screened for in vitro anthelmintic activity using haemonchus contortus eggs. the extract of v. amygdalina did not show any significant activity at concentrations up to 11.2mg/ml. the extract of a. senegalensis showed significant (p<0.001) reduction in egg hatch at a concentration of 7.1mg/ml. the in vitro fecal culture of eggs with a. senegalensis showed significant ...	2003	12651218
catalase induction protects haemonchus contortus against hydrogen peroxide in vitro.	the response of haemonchus contortus to oxidative stress in vitro was examined by measuring catalase activities in adult and l4 stage worms exposed to hydrogen peroxide generated by a glucose/glucose oxidase system. adult nematodes showed increases of up to 2.3-fold in catalase activity after 42 h exposure to the peroxide. l4 nematodes showed up to 4.6-fold induction. a two-stage dose-response was apparent, with catalase activities increasing as the peroxide levels increased, before a return to ...	2003	12705932
helminth vaccines: from mining genomic information for vaccine targets to systems used for protein expression.	the control of helminth diseases of people and livestock continues to rely on the widespread use of anti-helminthic drugs. however, concerns with the appearance of drug resistant parasites and the presence of pesticide residues in food and the environment, has given further incentive to the goal of discovering molecular vaccines against these pathogens. the exponential rate at which gene and protein sequence information is accruing for many helminth parasites requires new methods for the assimil ...	2003	12782060
haemonchus contortus: hcglucla expressed in xenopus oocytes forms a glutamate-gated ion channel that is activated by ibotenate and the antiparasitic drug ivermectin.	ion channels are targets for many drugs including insecticides and anthelminthic agents such as ivermectin (ivm) and moxidectin (mox). ivm has been shown to activate glutamate-gated chloride channels (glucls) from the free-living nematode, caenorhabditis elegans. haemonchus contortus is a parasitic nematode that is also extremely sensitive to ivm. the high sensitivity of h. contortus to ivm is probably the result of the fact that, like c. elegans, h. contortus also express glucls. to investigate ...	2003	12798512
little anthelmintic drenching required for lambs finished over winter and spring on annually re-established irrigated pasture on the highveld of gauteng province, south africa.	as part of a trial to test the profitability of finishing weaner lambs over winter and spring on the highveld of gauteng province, an investigation was carried out over 4 consecutive years as to whether or not worm control was necessary while the lambs were on irrigated, improved pastures. pastures that had not been grazed by sheep or other livestock for at least 5 years were planted to annual ryegrass (lolium multiflora) that was ploughed under and replanted annually. weaner lambs were randomly ...	2003	12836737
cholinesterase and phosphatase activities in adults and infective-stage larvae of levamisole-resistant and levamisole-susceptible isolates of haemonchus contortus.	cholinesterase (che) and acid phosphatase (ap) activities, but not alkaline phosphatase activities, were detected in cytosolic and membrane-bound fractions of adult and infective-stage larvae of levamisole-resistant and levamisole-susceptible haemonchus contortus. in contrast to other gastrointestinal nematodes, the che activity was higher in l3 than in adults and, in both cases, was mainly associated with membranes. che activity was inhibited by triton x-100 and was only detected in membrane-bo ...	2003	14672450
effects of condensed tannins on goats experimentally infected with haemonchus contortus.	although the use of tanniferous plants or condensed tannins as an alternative to anthelmintics to control gastrointestinal nematodes has been largely documented in sheep, studies remain scarce in goats. the objective of this study was therefore to assess the possible impact of condensed tannins in goats infected with adult haemonchus contortus. two groups of cull goats were experimentally infected with 10.000 l3 of h. contortus. after 4 weeks, quebracho extracts, representing 5% of the diet dm, ...	2003	12719140
detection of p-glycoprotein-mediated multidrug resistance against anthelmintics in haemonchus contortus using anti-human mdr1 monoclonal antibodies.	the "multidrug resistance" (mdr) system involves the action of transmembrane p-glycoproteins (pgp) which may be responsible for failure of chemotherapy in both invertebrates and vertebrates. we previously obtained partial reversion of anthelmintic resistance in nematodes subjected to both anthelmintics and inhibitors of this system. the results presented here are able to describe more accurately the presence of pgp in nematodes because of the use of c219 and uic2 monoclonal antibodies, which are ...	2003	12898231
vaccination-induced protection of lambs against the parasitic nematode haemonchus contortus correlates with high igg antibody responses to the ldnf glycan antigen.	lambs respond to vaccination against bacteria and viruses but have a poor immunological response to nematodes. here we report that they are protected against the parasitic nematode haemonchus contortus after vaccination with excretory/secretory (es) glycoproteins using alhydrogel as an adjuvant. lambs immunized with es in alhydrogel and challenged with 300 l3 larvae/kg body weight had a reduction in cumulative egg output of 89% and an increased percentage protection of 54% compared with the adju ...	2003	12907692
effects of acacia nilotica and acacia karoo diets on haemonchus contortus infection in goats.	this study was carried out to determine the effects of acacia karoo and acacia nilotica diets on haemonchus contortus infections in goats. twenty-four boer goats of mixed sex (live weight 17-22 kg) were randomly assigned to four treatment groups, namely: a. nilotica (an) group, a. karoo (ak) group, control infected with h. contortus (hc) group and the non-infected control (nhc) group. animals in the an, ak and hc groups were orally infected with a single dose of 3000 hc third stage larvae. the a ...	2003	12935742
digestive proteases of blood-feeding nematodes.	blood-feeding parasites employ a battery of proteolytic enzymes to digest the contents of their bloodmeal. host haemoglobin is a major substrate for these proteases and, therefore, a driving force in the evolution of parasite-derived proteolytic enzymes. this review will focus on the digestive proteases of the major blood-feeding nematodes - hookworms (ancylostoma spp. and necator americanus) and the ruminant parasite, haemonchus contortus - but also compares and contrasts these proteases with r ...	2003	12957519
abomasal lymph node responses to haemonchus contortus intestinal antigens established in kid goats by infection or immunization with intestinal antigens.	immune responses to haemonchus contortus intestinal antigens were evaluated using abomasal lymph node (aln) lymphocytes from kid goats protected against challenge infection by immunization with parasite intestinal antigen, and from kids that were challenged after immunization with ovalbumin. aln lymphocytes from the intestinal antigen-immunized group produced significantly higher antibody levels against intestinal antigens than the ovalbumin group, supporting the theory that immunization contrib ...	2003	12791101
the effect of duddingtonia flagrans on trichostrongyle infections of saanen goats on pasture.	four groups of nine saanen goat does with a naturally acquired mixed trichostrongylid infection were grazed on four paddocks. two groups received a daily dose of duddingtonia flagrans at the rate of 5 x 10(7) chlamydospores per animal per day for the 26-day grazing period. after a 19-day pasture resting period, 20 worm free 12-week-old tracer kids were introduced to the paddocks for 14 days prior to removal for worm burden analysis. four groups of five does and four kids were drenched then turne ...	2003	14651876
pyrosequencing analysis identifies discrete populations of haemonchus contortus from small ruminants.	the genus haemonchus consists of blood-sucking parasitic nematodes in the abomasum of ruminants. members of this genus are responsible for extensive production losses, particularly of small ruminants in the tropics but are also found in temperate regions. in this study, we examined the internal transcribed spacers-1 and -2 of rrna in haemonchus spp. the rrna region spanning the internal transcribed spacers-1, -2 and the 5.8s rrna gene was amplified by pcr from each of 10 worms from swedish sheep ...	2003	12814655
experimental haemonchosis in goats: effects of single and multiple infections in the host response.	histopathological changes and the distribution of t lymphocytes (cd3), b cells (cd79alpha) and igg secreting plasma cells were recorded in the abomasum and abomasal lymph nodes of goats during early and late post-infection stages with one to four doses of haemonchus contortus l3. the infiltration of eosinophils, mast cells, cd3(+) t lymphocytes, cd79alpha(+)b cells and igg(+) plasma cells in the abomasal mucosa increased dramatically from 10dpi onwards, whereas globule leukocytes were observed o ...	2003	12559712
amphidial structure of ivermectin-resistant and susceptible laboratory and field strains of haemonchus contortus.	the development of anthelmintic resistance by nematode parasites is a growing problem for veterinarians, pet owners, and producers. the intensive use of the macrocyclic lactones for the treatment of a variety of parasitic diseases has hastened the development of resistance to this family of parasiticides. as a result, resistance to ivermectin, moxidectin, nemadectin, and doramectin by haemonchus contortus has been documented throughout the world. sensory neurons located in the cephalic end of ne ...	2003	12482650