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cross-infection between tropical goats and heifers with haemonchus contortus.developing effective biological control without the systematic use of anthelmintics is necessary to reduce the impact of gastrointestinal nematodes on small ruminants. therefore, grazing management systems that use different host species to dilute nematodes in pasture appear to be promising for worm control. a trial was carried out to investigate the specificity of haemonchus contortus for goats and cattle and to evaluate cross-infection between ruminant species. the effect of an experimental in ...201121924553
evaluation of cymbopogon schoenanthus essential oil in lambs experimentally infected with haemonchus contortus.hematophagous gastrointestinal parasites cause significant economic losses in small ruminant grazing systems. the growing reports of multi-drug resistant parasites call for intensive research on alternative treatments for anthelmintics to help small ruminants cope with these parasites. two-month-old lambs with mean body weight (bw) of 22.5kg were experimentally infected with a multidrug-resistant haemonchus contortus strain. infected animals were dosed orally with cymbopogon schoenanthus essenti ...201122206645
Differential immune response between fundic and pyloric abomasal regions upon experimental ovine infection with Haemonchus contortus.The effect of experimental haemonchosis on the number of tissue eosinophils, plasma cells and lymphocyte subpopulations was evaluated in the fundic abomasal region, the pyloric abomasal region and the abomasal lymph node of Blackbelly lambs, which are resistant to infection, and Columbia lambs, which are susceptible to infection. An increase in the number of tissue eosinophils and CD4+ and WC1(+)?d T-cells was observed in the pyloric abomasal region of Blackbelly lambs and correlated with lower ...201122153120
is the establishment rate and fecundity of haemonchus contortus related to body or abomasal measurements in sheep?the relationship among parasitological parameters, abomasal size and body size measurements was investigated in lambs following an experimental infection with haemonchus contortus. in total, 100 lambs from five different genotypes (german merino (gm), texel × gm, suffolk × gm, german blackhead mutton × gm and ile de france × gm) were experimentally infected with 5000 infective third stage larvae of h. contortus at the time of weaning at 12 weeks of age. four and six weeks after infection, indivi ...201122440180
in vitro anthelmintic effect of anogeissus leiocarpus (dc.) guill. & perr. leaf extracts and fractions on developmental stages of haemonchus contortus.the anthelmintic effect of acetone leaf extract and fractions of anogeissus leiocarpus was investigated to determine the relative efficacy of the components as anthelmintic against haemonchus contortus (rudolphi). the fractions were obtained by solvent-solvent group separation of the leaf extract. the fractions were evaluated for ovicidal and larvicidal activity by egg hatch inhibition assay and larval development viability assay. best-fit lc(50) values for egg hatch test were 0.360, 0.316, 0.09 ...201122238493
the distribution of snp marker effects for faecal worm egg count in sheep, and the feasibility of using these markers to predict genetic merit for resistance to worm infections.summarygenetic resistance to gastrointestinal worms is a complex trait of great importance in both livestock and humans. in order to gain insights into the genetic architecture of this trait, a mixed breed population of sheep was artificially infected with trichostrongylus colubriformis (n=3326) and then haemonchus contortus (n=2669) to measure faecal worm egg count (wec). the population was genotyped with the illumina ovinesnp50 beadchip and 48 640 single nucleotide polymorphism (snp) markers p ...201124725775
the influence of water on the migration of infective trichostrongyloid larvae onto grass.detailed knowledge of the effects of water on the migration of infective larvae of economically important trichostrongyloid species is urgently needed to feed into prediction models of future epidemiology. the influence of water on the migration of the parasitic nematodes nematodirus battus, haemonchus contortus and teladorsagia circumcincta from sheep dung onto grass was examined in a series of laboratory experiments. turf plots were seeded with larvae, which were recovered from grass clippings ...201124650934
the astacin metalloprotease moulting enzyme nas-36 is required for normal cuticle ecdysis in free-living and parasitic nematodes.nematodes represent one of the most abundant and species-rich groups of animals on the planet, with parasitic species causing chronic, debilitating infections in both livestock and humans worldwide. the prevalence and success of the nematodes is a direct consequence of the exceptionally protective properties of their cuticle. the synthesis of this cuticle is a complex multi-step process, which is repeated 4 times from hatchling to adult and has been investigated in detail in the free-living nema ...201120800010
validation of the famacha© eye colour chart using sensitivity/specificity analysis on two south african sheep farms.a validation study of the famacha(©) system for clinical evaluation of anaemia due to haemonchus contortus was conducted on two commercial sheep farms in the summer rainfall region of south africa. in this region, the haemonchus season lasts from october to april. on farm 1 the system was tested over a period of five successive years in consecutive sets of young stud merino replacement rams and ewes examined at intervals of 3-5 weeks over each haemonchus season, under routine farming conditions. ...201119775816
development of graphidium strigosum (nematoda, haemonchidae) in its natural host, the rabbit (oryctolagus cuniculus) and comparison with several haemonchidae parasites of ruminants.the morphogenesis (studied for the first time) and the chronology of the life cycle of graphidium strigosum (dujardin, 1845) were studied in detail in its natural host, oryctolagus cuniculus. naive rabbits were each infected per os with g. strigosum infective larvae (l3). animals were euthanized each day for the first 10 days after infection (dai), then every 2 days from 12 to 40 dai. the free living period lasted 5-8 days at 24°c. by 1 dai, all the larvae were exsheathed in the stomach. the thi ...201121210152
the unique resistance and resilience of the nigerian west african dwarf goat to gastrointestinal nematode infections.west african dwarf (wad) goats serve an important role in the rural village economy of west africa, especially among small-holder livestock owners. they have been shown to be trypanotolerant and to resist infections with haemonchus contortus more effectively than any other known breed of goat.201121291550
evaluation and application of a molecular method to assess the composition of strongylid nematode populations in sheep with naturally acquired infections.we evaluated the performance of a pcr method for the diagnosis of naturally acquired strongylid nematode infections in sheep (n = 470; in a temperate climatic zone of south-eastern australia), using a panel of 100 'negative control' samples from sheep known not to harbour parasitic helminths. we compared the diagnostic sensitivity (98%) and specificity (100%) of this assay against a conventional faecal flotation method and also established a system to rank the contribution of particular strongyl ...201121256979
atypical (rio) protein kinases from haemonchus contortus--promise as new targets for nematocidal drugs.almost nothing is known about atypical kinases in multicellular organisms, including parasites. supported by information and data available for the free-living nematode, caenorhabditis elegans, and other eukaryotes, the present article describes three rio kinase genes, riok-1, riok-2 and riok-3, from haemonchus contortus, one of the most important parasitic nematodes of small ruminants. analyses of these genes and their products predict that they each play critical roles in the developmental pat ...201121262337
fecundity in adult haemonchus contortus parasites is correlated with abomasal tissue eosinophils and ?d t cells in resistant canaria hair breed sheep.canaria hair breed (chb) sheep are more resistant than canaria sheep (cs) to experimental haemonchus contortus infection. protective responses appear effective against the adult stage of the parasite, not as commonly reported in other breeds against the larval stages. in this study we have quantified several abomasal immune cells and correlated these with parasitological variables for each breed. a significant negative correlation between cd4+ t cell numbers and worm burden or length at 28 dpi w ...201121277683
the kinetic properties of the glutamate dehydrogenase of teladorsagia circumcincta and their significance for the lifestyle of the parasite.like other nematodes, both l(3) and adult teladosagia circumcincta secrete or excrete nh(3)/nh(4)(+), but the reactions involved in the production are unclear. glutamate dehydrogenase is a significant source nh(3)/nh(4)(+) in some species, but previous reports indicate that the enzyme is absent from l(3)haemonchus contortus. we show that glutamate dehydrogenase was active in both l(3) and adult t. circumcincta. the apparent k(m)s of the l(3) enzyme differed from those of the adult enzyme, the mo ...201121296180
voluntary feed intake and diet selection of merino sheep divergently selected for genetic difference in resistance to haemonchus contortus.this research was designed to determine if divergent selection for resistance to haemonchus contortus had produced correlated changes in voluntary feed intake and diet selection. voluntary feed intake, diet selection and production were determined in 54 merino weaner rams from the csiro haemonchus selection flock, increased resistance to haemonchus (irh), decreased resistance to haemonchus (drh) and random bred control (c) selection lines. weaner rams were fed ad libitum either a high (9.2 mj me ...201121330058
vaccination of goats with dna vaccines encoding h11 and il-2 induces partial protection against haemonchus contortus infection.dna vaccines expressing haemonchus contortus h11 antigen with or without interleukin (il)-2 were tested for protection against h. contortus infection in goats. sixteen goats (8-10months of age) were allocated into four trial groups. on days 0 and 14, group 1 was immunised with a dna vaccine expressing h11 and il-2 and group 2 was immunised with a dna vaccine expressing h11 only. group 3 was an unvaccinated positive control group challenged with h. contortus third stage larvae (l3). group 4 was a ...201121330170
a comparison of two integrated approaches of controlling nematode parasites in small ruminants.control of gastrointestinal nematodes (gin) in small ruminants in regions of the world where anthelmintic resistance is prevalent must rely on more than just chemical deworming strategies. the objective of this experiment was to compare two integrated treatment protocols for control of gin (primarily haemonchus contortus in this region) using anthelmintics, copper oxide wire particles (cowp) and famacha(©), compared to traditional anthelmintic use only. three separate trials were conducted on ma ...201121333450
oral dosing with papaya latex is an effective anthelmintic treatment for sheep infected with haemonchus contortus.the cysteine proteinases in papaya latex have been shown to have potent anthelmintic properties in monogastric hosts such as rodents, pigs and humans, but this has not been demonstrated in ruminants.201121406090
anthelmintic screening of fractions of elephantorrhiza elephantina root extract against haemonchus contortus.in the previous work conducted, it was found that the root extract of elephantorrhiza elephantina (bruch.) skeels. exhibited good anthelmintic efficacy against eggs and larvae of haemonchus contortus. this study was therefore undertaken to screen fractions of the extracts of e. elephantina for their anthelmintic activity against adult h. contortus using a bioactivity-guided assay. the adult worm bioassay was conducted using aqueous, hexane and ethyl acetate fractions of the plant extracts at con ...201121643660
proteases in blood-feeding nematodes and their potential as vaccine candidates.parasitic nematodes express and secrete a variety of proteases which they use for many purposes including the penetration of host tissues, digestion of host protein for nutrients, evasion of host immune responses and for internal processes such as tissue catabolism and apoptosis. for these broad reasons they have been examined as possible parasite control targets. blood-feeding nematodes such as the barber-pole worm haemonchus contortus that infect sheep and goats and the hookworms, ancylostoma ...201121660664
neutrophil and eosinophil chemotactic factors in the excretory/secretory products of sheep abomasal nematode parasites : ncf and ecf in abomasal nematodes.both eosinophil chemotactic factor (ecf) and neutrophil chemotactic factor (ncf) activities were demonstrated in excretory/secretory (es) products and homogenates of haemonchus contortus and teladorsagia circumcincta larvae and adult worms in a modified checkerboard assay using a micro-chemotaxis chamber. neutrophil chemotaxis was seen in 28 of 35 experiments and eosinophil chemotaxis in 20 of 38 experiments. chemokinetic activity for neutrophils and eosinophils (accounting for 40-50% of total c ...201121424403
a stochastic model accommodating the famacha© system for estimating worm burdens and associated risk factors in sheep naturally infected with haemonchus contortus.a previously developed multiple regression algorithm was used as the basis of a stochastic model to simulate worm burdens in sheep naturally infected with haemonchus contortus over five consecutive haemonchus seasons (november to january/february) on a farm in the summer rainfall region in south africa, although only one season is discussed. the algorithm associates haemoglobin levels with worm counts in individual animals. variables were represented by distributions based on famacha(©) scores a ...201121334812
functional reconstitution of haemonchus contortus acetylcholine receptors in xenopus oocytes provides mechanistic insights into levamisole resistance.background and purpose the cholinergic agonist levamisole is widely used to treat parasitic nematode infestations. this anthelmintic drug paralyses worms by activating a class of levamisole-sensitive acetylcholine receptors (l-achrs) expressed in nematode muscle cells. however, levamisole efficacy has been compromised by the emergence of drug resistant parasites, especially in gastrointestinal nematodes such as haemonchus contortus. we report here the first functional reconstitution and pharmaco ...201121486278
ovicidal and larvicidal activity of the crude extracts from phytolacca icosandra against haemonchus contortus.the development of anthelmintic resistance has impacted on the success of conventional anthelmintics (ah) for the control of gastrointestinal nematodes in grazing/browsing sheep and goats. medicinal plants from the traditional herbolary in mexico may provide new candidates that can be explored as alternative sources of ahs for ruminants. this study evaluated the leaf extracts derived from phytolacca icosandra against infective l(3) larvae and eggs from haemonchus contortus collected from sheep. ...201121439732
anthelmintic activity of trianthema portulacastrum l. and musa paradisiaca l. against gastrointestinal nematodes of sheep.evaluation of anthelmintic effects of trianthema (t.) portulacastrum l. (aizoaceae) whole plant and musa (m.) paradisiaca l. (musaceae) leaves against prevalent gastrointestinal worms of sheep was done that may justify their traditional use in veterinary clinical medicine. in vitro anthelmintic activity of the crude aqueous methanolic extract (came) of both the plants was determined using mature female haemonchus (h.) contortus and their eggs in adult motility assay (ama) and egg hatch test (eht ...201121440370
molecular cloning, expression and characterization of enolase from adult haemonchus contortus.enolase represents a multifunctional protein involved in basic energy metabolism. in the present research, the enolase gene of haemonchus contortus (hceno) was cloned and characterized. specific primers for the rapid amplification of cdna ends (race) were designed based on the expression sequence tag (est, genbank accession no. bf422728) to amplify the 3'- and 5'-ends of hceno. the full length of cdna from this gene was obtained by overlapping the sequences of 3'- and 5'-extremities and amplific ...201121444098
dual oxidase 2 and glutathione peroxidase gene expression are elevated in hyperimmunized sheep challenged with haemonchus contortus.a sequential biopsy sampling method was used to investigate oxidant and antioxidant gene responses in resistant sheep challenged with haemonchus contortus larvae or a sham saline challenge. the expression of key sheep oxidant and antioxidant producing genes were measured in sequential samples removed from the abomasums at days 0, 1, 2, 3, 5, 7 and 28 post challenge. gene expression levels at each time point were compared to expression at day 0, and levels of the various genes were also correlate ...201121444154
effects of myracrodruon urundeuva extracts on egg hatching and larval exsheathment of haemonchus contortus.the anthelmintic resistance has limited the control of gastrointestinal nematodes of small ruminants and thus has awakened interest in the study of tanniferous plants as a source of anthelmintics. these experiments were carried out to evaluate the in vitro efficacy of myracrodruon urundeuva leaf extract (le) and stem extract (se) against haemonchus contortus. an inhibitor of tannins, polyvinyl polypyrrolidone (pvpp), was used to verify if these metabolites are involved in the anthelmintic activi ...201121465262
slo-1-channels of parasitic nematodes reconstitute locomotor behaviour and emodepside sensitivity in caenorhabditis elegans slo-1 loss of function mutants.the calcium-gated potassium channel slo-1 in caenorhabditis elegans was recently identified as key component for action of emodepside, a new anthelmintic drug with broad spectrum activity. in this study we identified orthologues of slo-1 in ancylostoma caninum, cooperia oncophora, and haemonchus contortus, all important parasitic nematodes in veterinary medicine. furthermore, functional analyses of these slo-1 orthologues were performed using heterologous expression in c. elegans. we expressed a ...201121490955
structural and functional characterisation of the ovine interferon gamma (ifng) gene: its role in nematode resistance in rasa aragonesa ewes.the ovine interferon gamma (ifng) gene was structurally and functionally characterised, and the association between its variants and the response to haemonchus contortus infection was examined in resistant and susceptible rasa aragonesa ewes in different physiological conditions. sequential faecal egg counts (fecs) were performed on a naturally infected flock of 400 rasa aragonesa ewes and two groups of ewes selected for high (n=38) or low (n=33) fec, which were subsequently challenged with h. c ...201121419496
minimising the development of anthelmintic resistance, and optimising the use of the novel anthelmintic monepantel, for the sustainable control of nematode parasites in australian sheep grazing systems.to compare the risk of different treatment scenarios on selecting for anthelmintic resistance on australian sheep farms.201121495986
involvement of tannins and flavonoids in the in vitro effects of newbouldia laevis and zanthoxylum zanthoxyloïdes extracts on the exsheathment of third-stage infective larvae of gastrointestinal nematodes.the present study aimed at examining the possible role of tannins and flavonoids on the in vitro anthelmintic properties of the extracts of two plants from the southern area of western africa, i.e. newbouldia laevis and zanthoxylum zanthoxyloïdes. extracts of the two plants were prepared by use of acetone/water (70/30) and their anthelmintic activity was measured by use of the larval exsheathment inhibition assay (leia) applied on the abomasal species, haemonchus contortus and the intestinal spe ...201121497021
in vitro analysis of the anthelmintic activity of forage chicory (cichorium intybus l.) sesquiterpene lactones against a predominantly haemonchus contortus egg population.the anthelmintic activity of chicory (cichorium intybus l.) herbage has been attributed to sesquiterpene lactones. chicory leaves contain significant amounts of lactucin (lac), 8-deoxylactucin (dol), and lactucopicrin (lpic), but the proportions of these three sesquiterpene lactones vary among forage chicory cultivars. to determine whether the individual compounds differ in anthelmintic activity, we prepared sesquiterpene lactone-enriched extracts from leaves of two forage chicory cultivars, 'gr ...201121477927
direct anthelmintic effects of cereus jamacaru (cactaceae) on trichostrongylid nematodes of sheep: in vivo studies.following claims of anthelmintic activity of cereus jamacaru dc (cactaceae) by a commercial farmer, in vivo studies were conducted to determine the possible direct anthelmintic effects of the plant on ovine gastrointestinal nematodes. eighteen sheep were infected with 4000 haemonchus contortus and 6000 trichostrongylus colubriformis larvae given in three divided doses over a period of three days. once the infections were patent, the sheep were allocated to three groups and were drenched once a w ...201121498000
ovicidal and larvicidal activity of cassia alata leaf acetone extract and fractions on haemonchus contortus: in vitro studies.the failure of modern anthelmintics to control nematode parasites of sheep and goats is a reality on many farms in the tropical/subtropical regions of the world. this necessitates chemotherapeutic control alternatives and plant secondary metabolite with activity is one of those potential solutions.201121501100
the haemonchus contortus unc-49b subunit possesses the residues required for gaba sensitivity in homomeric and heteromeric channels.hco-unc-49 is a gaba receptor from the parasitic nematode haemonchus contortus that has a relatively low overall sequence similarity to vertebrate gaba receptors but is very similar to the unc-49 receptor found in the free living nematode caenorhabditis elegans. while the nematode receptors do share >80% sequence similarity they exhibit different sensitivities to gaba. in addition, the unc-49c subunit appears to be a positive modulator of gaba sensitivity in the h. contortus heteromeric channel, ...201121524670
comparing the sensitivity of two in vitro assays to evaluate the anthelmintic activity of tropical tannin rich plant extracts against haemonchus contortus.the present trial aimed at comparing the sensitivity of two in vitro methods, i.e. the larval migration inhibition assay (lmia) and the larval exsheathment inhibition assay (leia), to evaluate the anthelmintic (ah) properties of tannin-rich plant extracts against haemonchus contortus infective larvae. the two assays were applied on the same batch of h. contortus infective larvae exposed to water/acetonic extracts obtained from four tropical plants with different tannin contents: acacia gaumeri, ...201121530082
protection of calves against haemonchus placei and haemonchus contortus after immunization with gut membrane proteins from h. contortus.a vaccine containing integral membrane glycoproteins from the intestine of haemonchus contortus was evaluated in 4 groups of 9 worm free calves challenged with either 8,000 h. contortus or haemonchus placei infective larvae. vaccinates received 50 μg of the antigen and 1mg quila adjuvant three times 21 days apart, while the controls got adjuvant alone. the calves were challenged 7 days after the last immunization and killed for worm counts 43 days later. immunization resulted in high titre antib ...201121535018
norcantharidin analogues with nematocidal activity in haemonchus contortus.with the major problems with resistance in parasitic nematodes of livestock to anthelmintic drugs, there is an urgent need to develop new nematocides. in the present study, we employed a targeted approach for the design of a series of norcantharidin analogues (n=54) for activity testing against the barber's pole worm (haemonchus contortus) of small ruminants in a larval development assay (lda) and also for toxicity testing on nine distinct human cell lines. although none of the 54 analogues synt ...201121536433
evaluation of immune response to artificial infections of haemonchus contortus in gulf coast native compared with suffolk lambs.the gulf coast native (native) breed of sheep among many others is identified as being relatively resistant to haemonchus contortus, an abomasal nematode parasite of small ruminants. understanding the mode of immune response that helps these breeds of sheep control infection could help design and implement appropriate control programs. in this experiment, the components of the immune response during the early infection period in resistant native lambs were evaluated and compared with susceptible ...201121570191
a multi-species model to assess the effect of refugia on worm control and anthelmintic resistance in sheep grazing systems.objective  develop a computer simulation model that uses daily meteorological data and farm management practices to predict populations of trichostrongylus colubriformis, haemonchus contortus and teladorsagia (ostertagia) circumcincta and the evolution of anthelmintic resistance within a sheep flock. use the model to explore if increased refugia, provided by leaving some adult sheep untreated, would delay development of anthelmintic resistance without compromising nematode control. procedures  c ...201121595639
in vitro anthelmintic activity of crude extracts of five medicinal plants against egg-hatching and larval development of haemonchus contortus.ethnopharmacological relevance: senna occidentalis, leonotis ocymifolia, leucas martinicensis, rumex abyssinicus, and albizia schimperiana are traditionally used for treatment of various ailments including helminth infection in ethiopia. materials and methods: in vitro egg hatch assay and larval development tests were conducted to determine the possible anthelmintic effects of crude aqueous and hydro-alcoholic extracts of the leaves of senna occidentalis, aerial parts of leonotis ocymifolia, leu ...201121605649
thermodynamic evaluation of ligand binding in the plant-like phosphoethanolamine methyltransferases of the parasitic nematode haemonchus contortus.nematodes are a major cause of disease and the discovery of new pathways not found in hosts is critical for development of therapeutic targets. previous studies suggest that caenorhabditis elegans synthesizes phosphocholine via two s-adenosylmethionine (adomet)-dependent phosphoethanolamine methyltransferases (pmt). here we examine two pmt from the parasitic nematode haemonchus contortus. sequence analysis suggests that hcpmt1 contains a methyltransferase domain in the n-terminal half of the pro ...201121914812
dose titration of sericea lespedeza leaf meal on haemonchus contortus infection in lambs and kids.the objective of three experiments was to determine the impact of supplementing sericea lespedeza (lespedeza cuneata; sl) in three concentrations in a loose or pelleted diet on gastrointestinal nematodes (gin) in small ruminants. experiments on lambs were conducted at the usda, agricultural research service in booneville, ar (exp. 1) and at louisiana state university in baton rouge, la (exp. 2); an experiment on goat kids occurred at university of maryland-eastern shore (exp. 3). exp. 1 used cro ...201121621921
using lectins to identify hidden antigens in fasciola hepatica.fasciola hepatica is the causative agent of fascioliasis, one of the most economically important helminth diseases of livestock worldwide. traditionally, fascioliasis has been controlled by the strategic use of fasciolicidal drugs, but the emergence of resistant parasites has spurred an interest in developing vaccines as an alternative means of control. most vaccine studies to date have evaluated conventional antigens, which are exposed to the host's immune system during the course of a natural ...201121208513
glutamate synthase, but not gaba shunt enzymes, contributes to nitrogen metabolism of the sheep abomasal nematode parasites haemonchus contortus and teladorsagia circumcincta.glutamate synthase (e.c. 1.4.1.14) (gogat) activity was not detectable in l3 haemonchus contortus, but was present in l3 teladorsagia circumcincta and adult worms of both species. gogat activity was inhibited by 80% by azaserine. activity (nmol min(-1) mg(-1) protein) was 33-59 in adult h. contortus, 51-91 in adult t. circumcincta and 24-41 in l3 t. circumcincta, probably depending on exposure to ammonia, as incubation with 1mm nh(4)cl doubled gogat activity. the ph optimum was 7.5 in both speci ...201120576519
factors affecting susceptibility to rna interference in haemonchus contortus and in vivo silencing of an h11 aminopeptidase gene.gene silencing by rna interference (rnai) has been applied very successfully to caenorhabditis elegans to study gene function but has proven less effective in parasitic nematodes. in the sheep gastrointestinal nematode haemonchus contortus, previous studies demonstrated reproducible silencing of β-tubulin but not of other genes targeted. here we aimed to examine whether the level of target transcript or site of gene expression influence susceptibility to rnai by soaking. target genes represented ...201120699100
comparative analysis of destruction of the infective forms of trichuris trichiura and haemonchus contortus by nematophagous fungi pochonia chlamydosporia; duddingtonia flagrans and monacrosporium thaumasium by scanning electron microscopy.the present study aimed to demonstrate by scanning electron microscopy (sem) the in vitro predatory activity of nematophagous fungi pochonia chlamydosporia (vc1 and vc4 isolates) duddingtonia flagrans (ac001 isolate) and monacrosporium thaumasium (nf34a isolate) on eggs of trichuristrichiura and infective larvae (l3) of haemonchus contortus. the work was divided into two experimental tests (a and b). in tests a and b, the predatory activity of nematophagous fungi p. chlamydosporia, d. flagrans a ...201120638203
amino acid residues of both the extracellular and transmembrane domains influence binding of the antiparasitic agent milbemycin to haemonchus contortus avr-14b glutamate-gated chloride channels.glutamate-gated chloride (glucl) channels are pentameric receptors for the inhibitory neurotransmitter glutamate in invertebrates and are a major target for macrolide anthelmintics. three amino acids in glucl channels are reported to render macrolide resistance in nematodes and insects. to examine whether these three amino acids are involved in binding of the antiparasitic agent milbemycin (mlm) to the glucl channels of the nematode parasite haemonchus contortus, the equivalent amino acids (l256 ...201222369940
introgression of ivermectin resistance genes into a susceptible haemonchus contortus strain by multiple backcrossing.anthelmintic drug resistance in livestock parasites is already widespread and in recent years there has been an increasing level of anthelmintic drug selection pressure applied to parasitic nematode populations in humans leading to concerns regarding the emergence of resistance. however, most parasitic nematodes, particularly those of humans, are difficult experimental subjects making mechanistic studies of drug resistance extremely difficult. the small ruminant parasitic nematode haemonchus con ...201222359506
the anthelmintic effect of aqueous methanol extract of combretum molle (r. br. x. g. don) (combretaceae) in lambs experimentally infected with haemonchus contortus.the aqueous methanol extract from the stem-bark of combretum molle was evaluated for anthelmintic activity in lambs infected with haemonchus contortus using faecal egg count (fec) reduction assay. the extract showed a dose-dependent reduction in fec in infected animals. at doses of 500, 1000 and 2000 mg kg(-1), the extract caused fec reduction of 63%, 69.25% and 96.23%, respectively. similarly, the standard anthelmintic (albendazole) at a dose of 200 mg kg(-1) produced fec reduction of 99.24%. f ...201222293150
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
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
effects of co-grazing dairy heifers with goats on animal performance, dry matter yield, and pasture forage composition.mixed livestock grazing can offer an alternative management system for rearing dairy replacement heifers (bos taurus). a 2-yr study was conducted during 2009 (yr 1) and 2010 (yr 2) to determine the effects of co-grazing holstein heifers under rotational stocking with boer × kiko goats on animal performance, pasture dm yield, and botanical composition. each year, 24 heifers (134 ± 6 d of age and 147.4 ± 31.2 kg bw in yr 1; 166 ± 11 d of age and 168.0 ± 27.6 kg bw in yr 2) and 6 goats (2 yr old an ...201222952353
hco-lgc-38 is novel nematode cys-loop gaba receptor subunit.we have identified and characterized a novel cys-loop gaba receptor subunit (hco-lgc-38) from the parasitic nematode haemonchus contortus. this subunit is present in parasitic and free-living nematodes and shares similarity to both the unc-49 group of gaba receptor subunits from nematodes and the resistant to dieldrin (rdl) receptors of insects. expression of the hco-lgc-38 gene in xenopus oocytes and subsequent electrophysiological analysis has revealed that the gene encodes a homomeric channel ...201222940478
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
benzimidazole resistance of sheep nematodes in norway confirmed through controlled efficacy test.resistance against benzimidazoles (bz) has recently been detected in norwegian sheep flocks through a large scale prevalence survey based on the faecal egg count reduction test (fecrt). the use of this test in combination with bulk larval culture only gives an indication of which gastrointestinal nematodes genera that are involved and these results have to be confirmed by a controlled efficacy test (cet) to get accurate information about resistant nematodes populations at species level. a cet wa ...201222932059
efficacy of monepantel, derquantel and abamectin against adult stages of a multi-resistant haemonchus contortus isolate.drug resistance in gastrointestinal nematodes is a severe problem for sheep farmers. with the recent introduction of monepantel (zolvix®) and of derquantel plus abamectin (startect®) in new zealand, two new anthelmintic classes will be available to control gastrointestinal nematodes. while monepantel covers a broad spectrum of nematodes, the efficacy of derquantel is mid-spectrum and limited to a smaller number of species and stages. the combination of derquantel and abamectin allows to enlarge ...201222576857
in vivo anthelmintic activity of phytolacca icosandra against haemonchus contortus in goats.the in vivo anthelmintic (ah) activity of the ethanolic extract from leaves of phytolacca icosandra was evaluated in goats artificially infected with haemonchus contortus. parasite naïve goats were artificially infected with 3000 h. contortus infective larvae per animal. once the infection was patent (day 28 post-infection) all the animals were sampled to determine the faecal egg counts (fec) for five consecutive days. two groups of animals were formed balanced for their fec and body-weight (bw) ...201222579554
f200y polymorphism in the β-tubulin gene in field isolates of haemonchus contortus and risk factors of sheep flock management practices related to anthelmintic resistance.haemonchus contortus is the most prevalent and pathogenic nematode of sheep in tropical areas. the objectives of this study were to assess the frequency of the f200y polymorphism on the β-tubulin gene in third-stage larvae of h. contortus from 33 sheep flocks in são paulo state, brazil, and to associate this frequency to risk factors based on farm management practices. the resistance allele frequency varied from 9 to 74%, and the resistance genotype frequency varied from 0 to 66.7%. resistance g ...201222858226
in vitro activity of lantana camara, alpinia zerumbet, mentha villosa and tagetes minuta decoctions on haemonchus contortus eggs and larvae.the resistance of gastrointestinal nematodes to anthelmintics has increased the need to evaluate natural products that can replace or assist current strategies to control gastrointestinal nematodes. the objective of this study was to evaluate the effect of decoctions of lantana camara (dlc), alpinia zerumbet (daz), mentha villosa (dmv) and tagetes minuta (dtm) on haemonchus contortus by two in vitro tests. the effects of increasing concentrations of lyophilized decoctions (0.31 to 10mg/ml) were ...201222835864
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
immunoprotection in sheep against haemonchus contortus using its thiol-purified excretory/secretory proteins.excretory/secretory antigen was prepared by culturing live adult worms of haemonchus contortus in rpmi 1640 medium at a concentration of 50 worms per ml in a culture-flask at 37 ˚c for 24 hr and the culture supernatant was used as antigen. the e/s antigen was purified by thiol-sepharose affinity chromatography. on western blot analysis, it was demonstrated that thiol-purified antigen showed a single reactive band at 66 kda. in immunization trial, sheep were administered intramuscularly with 500 ...201225653765
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
towards finding effective indicators (diarrhoea and anaemia scores and weight gains) for the implementation of targeted selective treatment against the gastro-intestinal nematodes in lambs in a steppic environment.the effective application of targeted selective treatment (tst) against gastro-intestinal nematodes depends on the accurate identification of those animals in need of anthelmintic treatment. finding cost and labour effective measures to identify such animals is paramount. this study tested the efficacy of three indicators on lambs in a farm in eastern algeria: anaemia score (famacha(©)), diarrhoea score (disco) and weight gain. these were contrasted against traditional parasitological infection ...201222270033
responses of the humid zone ecotype of the nigerian west african dwarf sheep to mixed infections with haemonchus contortus and trichostrongylus colubriformis.the responses of the nigerian west african dwarf sheep to experimental infections with two of its most important gastrointestinal (gi) nematodes, namely, haemonchus contortus and trichostrongylus colubriformis were studied by means of two measures of parasitological response, namely, faecal egg count (fec) and worm burden (wb), and three measures of host pathology, namely, packed cell volume (pcv), body weight (bwt) and body condition score (bcs). following exposure to weekly escalating infectio ...201222215194
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
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
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
susceptibility assay of haemonchus contortus to commonly used anthelmintics in jimma, southwest ethiopia.an experimental study to investigate the susceptibility pattern of haemonchus contortus to commonly used anthelmintics (albendazole, tetramisole, ivermectin, and triclobendazole) was conducted between june and september 2009. adult h. contortus parasites were collected from a total of 30 sheep slaughtered at jimma municipal abattoir. the anthelmintics were assessed for egg hatch inhibition ability against h. contortus eggs. the eggs (500 eggs/ml) were incubated with different concentrations (0.2 ...201222402797
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
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
proteomic analysis of the abomasal mucosal response following infection by the nematode, haemonchus contortus, in genetically resistant and susceptible sheep.sheep have a variable ability to resist gastrointestinal nematode infection, but the key factors mediating this response are poorly defined. here we report the first large-scale application of quantitative proteomic technologies to define proteins that are differentially abundant between sheep selectively bred to have an enhanced (resistant) or reduced (susceptible) ability to eliminate nematodes. samples were collected from the abomasal mucosa three days after experimental challenge with the ne ...201222285630
influence of pluronic 85 and ketoconazole on disposition and efficacy of ivermectin in sheep infected with a multiple resistant haemonchus contortus isolate.non-specific mechanisms involving atp-binding cassette drug efflux transporters may play an important role in xenobiotic clearance in ovine gastro-intestinal nematodes. by using transporter inhibitors, the aim of this trial was to assess the possibility of increasing drug bioavailability in the host in an attempt to improve treatment efficacy. thirty-six lambs were infected with 5000 multiple-drug resistant haemonchus contortus third stage larvae and separated into six groups (n=6): ivermectin a ...201222429700
import and efflux of flubendazole in haemonchus contortus strains susceptible and resistant to anthelmintics.drug entry into the body of a helminth is a key factor in the efficacy of anthelmintics. the present project was designed to study the ex vivo uptake and efflux of the benzimidazole anthelmintic flubendazole (flu) in four strains of h. contortus: the ise strain (fully susceptible to anthelmintics), the ise-s strain (resistant to ivermectin), the br strain (resistant to benzimidazoles) and the wr strain (multi-resistant). the transport of flu between dead and living nematodes was also compared as ...201222417686
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
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
changes in the body condition scores of nigerian west african dwarf sheep experimentally infected with mixed infections of haemonchus contortus and trichostrongylus colubriformis.weekly changes in body condition scores and body weights were determined in west african dwarf sheep following trickle exposure to weekly escalating mixed infections with haemonchus contortus and trichostrongylus colubriformis starting with single doses of 500 infective larvae (l(3)) at wk1, 1000 l(3) at wk2, 2000 l(3) at wk3 and 4000 l(3) at wk4. thirty-three animals were randomly assigned to two groups namely, group 1 (n=27) and group 2 (n=6). group 1 animals were used for experimental infecti ...201222436424
genetic and environmental influences on faecal nematode egg counts of jamunapari goats in india.the present study was carried out from 1999 to 2003 to determine the genetic and environmental influences of faecal egg count (fec), an indicator of host resistance, in adult jamunapari goats with naturally acquired gastrointestinal nematode parasite infections (predominantly haemonchus contortus). fec data on 670 records of jamunapari goats descended from 54 bucks and 208 does were used in this study. analyses were carried out by restricted maximum likelihood estimation, fitting an animal model ...201222278635
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
immune responses associated with resistance to haemonchosis in sheep.this paper examines the known immunological and genetic factors associated with sheep resistance to infection by haemonchus contortus. such resistance is an inheritable genetic trait (h(2), 0.22-0.63) associated with certain sheep breeds. resistant sheep do not completely reject the disease; they only harbor fewer parasites than susceptible sheep and therefore have a lower fecal egg count. protective immune response to haemonchosis is an expression of genetic resistance. genes associated with re ...201223509684
epidemiological study of sympatric haemonchus species and genetic characterization of haemonchus contortus in domestic ruminants in tunisia.parasitic gastroenteritis caused by haemonchus spp. is a major cause of economic losses in the livestock industry, especially in tropical and subtropical areas. the correct identification of various species, as well as knowledge regarding the epidemiology and genetic characterization of the principal circulating species, is essential for the establishment of sustainable control strategies. a study was carried out to determine the prevalence of haemonchus species in sheep, goats and cattle slaugh ...201223333137
bacillus spp. toxicity against haemonchus contortus larvae in sheep fecal cultures.the gastrointestinal nematode haemonchus contortus is a major productivity constraint in sheep. in this study, the nematicidal effects of bacillus circulans, bacillus cereus, bacillus thuringiensis var. israelensis, bt. var. osvaldocruzi, bt. var. morrisoni, and bt. var. kurstaki were assessed in free-living larval stages of h. contortus. a spore-crystal suspension containing approximately 2×10(8)ufc/ml of each strain was added to sheep feces that were naturally infected with h. contortus eggs, ...201222728159
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