Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| 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 |
| 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 |
| immunization against ovine haemonchosis with three low molecular weight somatic antigens of adult haemonchus contortus. | individual bands (15) from electroblotted soluble extracts of adult haemonchus contortus were excised and three peptides of molecular weight ca. 56 (f4), 39 (f8) and 18.5 kda (f14) used to vaccinate 4-4.5-months-old lambs against the nematode. immunizing doses from each peptide were administered in 1 ml freund complete adjuvant (first 50 microg injection) and 1 ml freund incomplete adjuvant (second and third 50 microg injections) to six lambs. two weeks after last immunization, animals were chal ... | 2003 | 12675897 |
| 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 |
| 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 |
| 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 |
| immune rejection of trichostrongylus colubriformis in sheep; a possible role for intestinal mucus antibody against an l3-specific surface antigen. | sheep that have been immunized by multiple truncated infections with the parasitic nematode trichostrongylus colubriformis contain anti-larval activity in their intestinal mucus and high-speed mucus supernatants. this activity induces t. colubriformis l3 to clump in vitro and causes a significant reduction in larval establishment in naive sheep after infusion of larvae and mucus into the intestinal lumen via a duodenal cannula. in this report, we provide evidence that one factor contributing to ... | 2003 | 12753437 |
| 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 |
| 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 |
| distribution of glutamate-gated chloride channel subunits in the parasitic nematode haemonchus contortus. | glutamate-gated chloride channels (glucl) are related to gamma-aminobutyric acid-a (gaba(a)) receptors and are the target sites for the avermectin/milbemycin (a/m) anthelmintics, drugs that cause paralysis of the somatic and pharyngeal muscles in nematodes. we have previously identified four glucl subunits, hcgluclalpha, hcgluclbeta, hcgluclalpha3a, and hcgluclalpha3b from the sheep parasite haemonchus contortus. we raised specific antisera against all of these subunits and used them in immunofl ... | 2003 | 12794744 |
| 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 |
| characterization of a novel g-protein coupled receptor from the parasitic nematode h. contortus with high affinity for serotonin. | the neurotransmitter serotonin (5ht) has been shown to modulate mobility, feeding, egg-laying, and defecation behaviors in the saprophytic nematode caenorhabditis elegans. although the effects of serotonin on these behaviors in parasitic nematodes is under study, little is known about the diversity, ontogeny, signaling, and pharmacology of serotonin receptors in these organisms. in an effort to increase our understanding of this system, we cloned and characterized a novel cdna (5ht1hc) from the ... | 2003 | 12807445 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| progress and new technologies for developing vaccines against gastrointestinal nematode parasites of sheep. | despite the identification of highly effective native antigens for vaccination against haemonchus contortus, particularly 'hidden' antigens derived from the intestine of adult worms, to date similar efficacy has not been shown with recombinant antigens. in addition, progress towards identification of protective antigens from other sheep gastrointestinal (gi) nematode species is limited. coupled with this is an incomplete understanding of the mechanism of natural immunity to gi nematodes, making ... | 2003 | 12969446 |
| inhibition of populations of haemonchus contortus in sheep fed on white clover (trifolium repens) high in lotaustralin. | 1953 | 13036873 | |
| phenothiazine-salt mixture for control of haemonchus contortus in range sheep. | 1953 | 13069374 | |
| control of pasture-acquired infections of nematodirus spathiger and haemonchus contortus in lambs with phenothiazine-salt mixture. | 1954 | 13207580 | |
| cytological polymorphism in the nematode haemonchus contortus (rudolphi 1803) cobb 1898. | 1954 | 13213990 | |
| the effect of roughage on the number of eggs of haemonchus contortus per gram of feces from experimentally infected calves. | 1955 | 13263249 | |
| the effect of diet on the length of third stage larvae produced by adult haemonchus contortus harbored by lambs. | 1955 | 13264029 | |
| effects of trace minerals, dicalcium phosphate, phenothiazine, and combinations of these on the resistance of lambs to haemonchus contortus and other nematodes. | 1956 | 13302648 | |
| strain variation in the response of sheep nematodes to the action of phenothiazine. ii. studies on pure infections of haemonchus contortus. | 1957 | 13424923 | |
| physiological and nutritional changes in lambs infected with the nematodes, haemonchus contortus, trichostrongylus colubriformis and menatodirus spathiger. | 1957 | 13424925 | |
| in vitro cultivation of the histotrophic stages of haemonchus contortus and ostertagia spp. | 1959 | 13622748 | |
| antigenic stimulus of exsheathing fluid in self-cure of sheep infested with haemonchus contortus. | 1959 | 13632796 | |
| studies on parasitic worms of sheep in scotland. i. embryonic and larval development of haemonchus contortus at constant conditions. | 1959 | 13657514 | |
| a note on exsheathing mechanisms of third-stage larvae of haemonchus contortus. | 1959 | 13663576 | |
| electrophoretic patterns of the serum proteins of sheep infected with haemonchus contortus. | 1959 | 13666879 | |
| the nature and prospects for gut membrane proteins as vaccine candidates for haemonchus contortus and other ruminant trichostrongyloids. | substantial progress has been made in the last decade in identifying several antigens from haemonchus contortus which, in their native form, stimulate useful levels of protective immunity (70-95% reductions in faecal egg output) in the ovine host. much work has focussed on proteins/protein complexes expressed on the surface of the worm gut which are exposed to the blood meal, and, hence, antibody ingested with it. the antigens generally, but not in all cases, show protease activity and antibody ... | 2003 | 13678629 |
| the avermectin receptors of haemonchus contortus and caenorhabditis elegans. | most of the recent evidence suggests that the avermectin/milbemycin family of anthelmintics act via specific interactions with glutamate-gated chloride channels. these channels are encoded by a small family of genes in nematodes, though the composition of the gene family and the function of the individual members of the family may vary between species. we review our current knowledge concerning the properties of the glutamate-gated chloride channels from caenorhabditis elegans and the related pa ... | 2003 | 13678634 |
| cyclooctadepsipeptides--an anthelmintically active class of compounds exhibiting a novel mode of action. | there are three major classes of anthelmintics for veterinary use: the benzimidazoles/prebenzimidazoles, the tetrahydropyrimidines/imidazothiazoles, and the macrocyclic lactones. in nematodes, there are five targets for the existing anthelmintics: the nicotinergic acetylcholine receptor which is the target of tetrahydropyrimidines/imidazothiazoles and indirectly that of the acetylcholineesterase inhibitors; the gaba receptor which is the target of piperazine, the glutamate-gated chloride channel ... | 2003 | 13678839 |
| p-glycoprotein in helminths: function and perspectives for anthelmintic treatment and reversal of resistance. | infestation with parasitic helminths is a common problem in human populations of third world countries and is ubiquitous in livestock and other domestic animals. the cell-membrane efflux pump, p-glycoprotein (pgp), appears to contribute to anthelmintic resistance. pgp have been identified from both phyla of parasitic helminths, platyhelmintha and nematoda, and alterations in expression levels and allele frequencies of pgp in anthelmintic-resistant populations have been observed in nematodes. loc ... | 2003 | 13678840 |
| studies on immunity to haemonchus contortus infection--double vaccination of sheep with irradiated larvae. | 1961 | 13789595 | |
| subspeciation in haemonchus contortus (rudolphi, 1803) nemata, trichostrongyloidea. | 1960 | 13814170 | |
| the exsheathing stimulus for infective larvae of haemonchus contortus. | 1960 | 13837100 | |
| development of haemonchus contortus in weaned and unweaned lambs. | 1959 | 13837608 | |
| measurements of blood loss caused by haemonchus contortus infection in sheep. | 1962 | 13879671 | |
| effects on the stomach worm, haemonchus contortus, of feeding lambs natural versus semipurified diets. | 1963 | 13996983 | |
| polio-encephalomalacia associated with myocardial degeneration in a group of housed sheep experimentally infected with haemonchus contortus. | 1963 | 14003829 | |
| variation in counts of haemonchus contortus eggs in the faeces of housed sheep. | 1963 | 14014911 | |
| improved methods of obtaining clean larvae of haemonchus contortus. | 1963 | 14054390 | |
| cholinesterase activity in haemonchus contortus and its inhibition by organophosphorus anthelmintics. | 1963 | 14078913 | |
| relationship of different species of forage to the survival and infectivity of haemonchus contortus in lambs. | 1964 | 14125157 | |
| efficiency of phenothiazine of varying purity and particle size against a phenothiazine-resistant strain of haemonchus contortus. | 1964 | 14125915 | |
| differences in the susceptibility of two populations of haemonchus contortus to phenothiazine of varying purity and particle size. | 1964 | 14125916 | |
| some effects of temperature on the development and activity of haemonchus contortus larvae. | 1964 | 14140879 | |
| variance in the effectiveness of thiabendazole against haemonchus contortus in sheep. | 1964 | 14141529 | |
| relationship between environment and the development and migration of the free-living stages of haemonchus contortus. | 1964 | 14155355 | |
| effect of carbon dioxide on the development of third-stage larvae of haemonchus contortus in vitro. | 1964 | 14167812 | |
| abomasal bleeding caused by immature stages of haemonchus contortus in sheep showing 'age resistance'. | 1964 | 14198344 | |
| resistance to a challenge infection with haemonchus contortus conferred by previous experience of immature stages only. | 1964 | 14212103 | |
| worm populations in young sheep dosed daily with 10,000 larvae of haemonchus contortus. | 1964 | 14212104 | |
| the larvicidal effect of various chemical compounds and plant products on the free-living stages of haemonchus contortus rud. (nematoda). | 1964 | 14250811 | |
| effect of low-level 2- to 3-mu purified phenothiazine on immature worms of a phenothiazine-resistant isolate of haemonchus contortus, kentucky strain b. | 1964 | 14266898 | |
| effect of host diet on egg production of haemonchus contortus in lambs. | 1965 | 14266917 | |
| a study of the variables influencing artificial infections with haemonchus contortus. | 1965 | 14284446 | |
| ecology and biological plasticity of sheep nematodes. ii. genetic environmental plasticity in haemonchus contortus (rud. 1803). | 1965 | 14317484 | |
| low-level feeding of thiabendazole for control of haemonchus contortus. | 1965 | 14323372 | |
| some relationships between trichostrongylid infestation and cobalt status in lambs: haemonchus contortus infestation. | 1965 | 14329309 | |
| the effect of low level dosing with haloxon on sheep naturally infected with haemonchus contortus and trichostrongylus spp. | 1965 | 14344198 | |
| histotrophic (parasitic) stages of haemonchus contortus. | 1960 | 14446766 | |
| metalloendopeptidases from the intestinal brush border of haemonchus contortus as protective antigens for sheep. | substantial protection against the economically important nematode haemonchus contortus has been achieved by immunizing sheep with a glycoprotein fraction isolated from the intestinal membranes of this parasite. this fraction has been termed haemonchus galactose-containing glycoprotein complex (h-gal-gp) since it was originally isolated through its selective binding to lectins with a specificity for n-acetylgalactosamine. a major component of this highly protective antigen complex is a family of ... | 2003 | 14507329 |
| 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 |
| selection at a gamma-aminobutyric acid receptor gene in haemonchus contortus resistant to avermectins/milbemycins. | gamma-aminobutyric acid (gaba) type a receptors are inhibitory chloride channels in membranes of vertebrate and invertebrate neuromuscular cells. gating of the channels by gaba leads to an influx of chloride ions into, and hyperpolarisation of, the cell. gaba receptors are believed to form channels by the association of five protein molecules of varying subunit types, with the second transmembrane (m2) domain of each protein molecule forming a central pore through which chloride ions can pass. w ... | 2003 | 14511812 |
| 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 | |
| mortality of creole kids during infection with gastrointestinal strongyles: a survival analysis. | mortality due to strongyles infection in small ruminants is a critical component of flock productivity in a tropical climate. in goat production, few experiments have been conducted to estimate the variability of this trait. a survival analysis study was carried out in the creole experimental flock of inra-gardel (moule, guadeloupe) to identify management and genetic factors influencing mortality of kids reared at pasture and infected with gastrointestinal strongyles, predominantly haemonchus co ... | 2003 | 14552365 |
| haemonchus contortus: molecular characterisation of a small heat shock protein. | a cdna encoding a predicted small heat shock protein, hsp20, was isolated from the parasitic nematode haemonchus contortus. this cdna encoded a predicted protein of 156 amino acids, which had high sequence identity with other nematode small heat shock proteins. southern blot analysis of genomic dna suggested that in h. contortus hsp20 is encoded by a single copy gene. the hsp20 transcript and protein were expressed in the infective larvae (l3), early l4 and adult stages, but expression was not i ... | 2003 | 14552856 |
| non-classic characteristics define prominent dnase activities from the intestine and other tissues of haemonchus contortus. | the anthelmintic fenbendazole (fbz) induces nuclear dna fragmentation (df) in intestinal cells of haemonchus contortus. the dna fragments had 3'-oh, which suggests involvement of a neutral dnase. to identify candidate dnase(s) involved, dnase activity in h. contortus intestine and other worm fractions was characterized relative to classic dnases i (neutral) and ii (acidic). seven distinct dnase activities were identified and had mrs of 34, 36, 37 or 38.5 kda on zymographic analysis. the differen ... | 2003 | 14552860 |
| experimental infection of black belly and inra 401 straight and crossbred sheep with trichostrongyle nematode parasites. | compared to inra 401 lambs reared in france, black belly (bb) lambs reared in guadeloupe (f.w.i.) were highly resistant to both primary and secondary experimental infection with haemonchus contortus. to investigate this huge inter-breed difference, a nucleus flock of bb was constituted, and experiments were conducted to: (i) confirm this difference in lambs born in france, (ii) check whether it was similar for trichostrongylus colubriformis and teladorsagia circumcincta, and (iii) find out wheth ... | 2003 | 14559167 |
| 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 |
| the anthelmintic efficacy of five plant products against gastrointestinal trichostrongylids in artificially infected lambs. | forty-eight helminth-free lambs were divided into eight groups (a-h) of six animals. groups a-g were infected artificially with 10,000 third stage larvae of haemonchus contortus and 20,000 third stage larvae of trichostrongylus colubriformis, whereas group h remained uninfected. thirty days post-infection the lambs were treated orally with a single dosage of one of the following products: group a with 3 mg/kg body weight (bw) of an aqueous ethanol extract (70%, v/v) of the seeds of azadirachta i ... | 2003 | 14597279 |
| parasites of domestic and wild animals in south africa. xlii. helminths of sheep on four farms in the eastern cape province. | at monthly intervals for periods ranging from 9 to 25 consecutive months between three and four merino yearling-sheep and two merino lambs on three farms in eastern cape thornveld, and two dorper yearling-sheep on a farm in valley bushveld were slaughtered and examined for helminths. the merino sheep were infected with 15 nematode species, of which haemonchus contortus, nematodirus spathiger and trichostrongylus spp. were the most numerous, and with four cestode species. the dorper sheep were in ... | 2003 | 14621313 |
| the predatory capability of three nematophagous fungi in the control of haemonchus contortus infective larvae in ovine faeces. | the effect of oral administration of three different nematode-trapping fungi, in aqueous suspension containing either dactylaria sp. or arthrobotrys oligospora conidia or duddingtonia flagrans chlamydospores, on the number of haemonchus contortus infective larvae in sheep faeces, was evaluated. the three selected species of fungi produce three-dimensional adhesive nets in the presence of nematodes. sixteen creole sheep were divided into four groups of four animals each. groups 1 and 2 were orall ... | 2003 | 14627445 |
| benzimidazole-resistant beta-tubulin alleles in a population of parasitic nematodes (cooperia oncophora) of cattle. | three anthelmintic classes with distinct mechanisms of action are commercially available. selection of nematode populations resistant to all these drugs has occurred, particularly in trichostrongyloid parasites of sheep. anthelmintic resistance in cattle parasites has only recently been recognized and appears to be less pronounced, even though very similar species infect both hosts. to understand the bases for differences in the rate of resistance development in sheep versus cattle parasites, it ... | 2003 | 14630425 |
| 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 |
| seasonal changes of gastrointestinal nematode burden in sheep under an intensive grazing system. | a study was conducted of the monthly fluctuations of worm burdens and arrested development of gastrointestinal (gi) nematodes in sheep from a commercial farm of the ebro valley (spain). twenty-four previously helminth-free female lambs (permanent lambs) grazed together with a flock of 500 resident ewes for 12 months following a three lambing/2-year reproductive management system. two helminth-free lambs (tracer lambs) were added to the flock each month and allowed to graze for 4 weeks. measureme ... | 2003 | 14651878 |
| 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 |
| ectopic expression of a haemonchus contortus gata transcription factor in caenorhabditis elegans reveals conserved function in spite of extensive sequence divergence. | comparative analysis between caenorhabditis elegans and other nematode species offers a powerful approach to study gene function. c. elegans also has great potential as a surrogate expression system to study the function of genes from parasitic nematode species where transgenic methodologies are unavailable. however there is little information on the extent to which the biology of c. elegans is conserved with other nematode species and very few parasitic nematode genes have yet been functionally ... | 2004 | 14698436 |
| cloning two full-length beta-tubulin isotype cdnas from cooperia oncophora, and screening for benzimidazole resistance-associated mutations in two isolates. | two full-length beta-tubulin cdnas, representing isotypes 1 and 2, were cloned from the cattle nematode cooperia oncophora. the predicted protein sequences span 448 amino acids, and show a high degree of identity to beta-tubulins from other nematodes. while c. oncophora isotype 1 sequence had the highest identity to haemonchus contortus isotype 1 and teladorsagia circumcincta sequences (95% identity), the c. oncophora isotype 2 sequence was most similar to h. contortus isotype 2 and trichostrong ... | 2003 | 14700194 |
| genetic analysis of inbreeding of two strains of the parasitic nematode haemonchus contortus. | haemonchus contortus is a sheep parasitic nematode that causes severe economic losses. previous studies have indicated a high degree of genetic heterogeneity, which is hardly affected by selection for drug resistance. as a tool for the analysis of the population dynamics of h. contortus and its response to drug resistance, we designed a strategy to study the inbreeding of a benzimidazole-sensitive and a benzimidazole-resistant strain. after 15 generations, a theoretical inbreeding coefficient of ... | 2004 | 14711596 |
| efficiency of feeding duddingtonia flagrans chlamydospores to grazing ewes on reducing availability of parasitic nematode larvae on pasture. | gastrointestinal nematodes are of concern in sheep production because of production and economic losses. control of these nematodes is primarily based on the use of anthelmintic treatment and pasture management. the almost exclusive use of anthelmintic treatment has resulted in development of anthelmintic resistance which has led to the need for other parasite control options to be explored. the blood sucking abomasal parasitic nematode haemonchus contortus causes severe losses in small ruminant ... | 2003 | 14729168 |
| efficacy of the nematode-trapping fungus duddingtonia flagrans against three species of gastro-intestinal nematodes in laboratory faecal cultures from sheep and goats. | the ability of the nematode-killing fungus duddingtonia flagrans to reduce number of infective larvae of three species of gastro-intestinal parasitic nematodes developing in dung was investigated in both goats and sheep. groups of lambs and kids (12-20 weeks old) were given mono-specific infections of haemonchus contortus, ostertagia (teladorsagia) circumcincta or trichostrongylus colubriformis. following patency of the infections (t1) faecal samples were collected for determination of faecal ne ... | 2003 | 14729170 |
| vaccination against the nematode haemonchus contortus with a thiol-binding fraction from the excretory/secretory products (es). | fractionated excretory/secretory products (es) of adult haemonchus contortus were evaluated as protective antigens. the proteins were successively eluted from a thiol sepharose column using 25 mm cysteine followed by 25 mm dl-dithiothreitol (dtt). sheep were vaccinated three times and challenged with 5000 third stage infective larvae (l3) of h. contortus. highest level of protection was found in sheep vaccinated with the dtt-eluted fraction in which egg output and worm burden were reduced by 52 ... | 2004 | 14741153 |
| effect of dexamethasone treatment on the immune response of gulf coast native lambs to haemonchus contortus infection. | neonatal and weaner gulf coast native (native) lambs were studied to determine whether an immunological basis underlies their natural resistance to haemonchus contortus infection. neonatal native lambs (n = 8) and weaner native lambs (n = 15) were randomly assigned to a treatment or a control group. lambs in the treatment group received dexamethasone by intramuscular injection three times a week for 10 weeks (neonatal) and 15 weeks (weaners). all lambs were monitored for fecal egg count (fec), b ... | 2004 | 14746981 |
| the differentiation of the eggs of haemonchus contortus and ostertagia species of the sheep and a note on the relative generic egg-laying rates. | 1950 | 14785967 | |
| performance of hair sheep composite breeds: resistance of lambs to haemonchus contortus. | this study was designed to evaluate breed differences in resistance to haemonchus contortus in lambs. a total of 181 ewe lambs representing crossbred dorsets (do) and dorpers (dp; out of 1/2-dorset, 1/4-rambouillet, 1/4-finnsheep ewes) and straight-bred katahdins (kt) were evaluated over 3 yr. an additional 144 do, dp, kt, and barbados blackbelly x st. croix (hh) wethers were evaluated over 2 yr. lambs were weaned at 60 to 90 d of age. after deworming at about 4 mo of age, ewe lambs received app ... | 2004 | 14974560 |
| genomic organization of an avermectin receptor subunit from haemonchus contortus and expression of its putative promoter region in caenorhabditis elegans. | avermectins and milbemycins are believed to exert their anthelmintic effects by binding to glutamate-gated chloride channels (glucls). two glucl subunits have been localized in the pharynx in caenorhabditis elegans, and the pharynx has been implicated as a major target for avermectins in c. elegans. however, in parasitic nematodes, the pharyngeal localization of the glucl subunits needs to be determined. the hcglucla gene encoding an alpha-type glucl subunit has been cloned from haemonchus conto ... | 2004 | 15003846 |
| agonist enhacement of macrocyclic lactone activity at a glutamate-gated chloride channel subunit from haemonchus contortus. | the mode of action of ivermectin (ivm) in nematodes appears to be the opening of inhibitory ion channels, including the glutamate-gated chloride channel (glucl). recently, it has been shown that ivm binds with high affinity to a haemonchus contortus glucl subunit (hcglucla) expressed in cos-7 cells, and this binding is potentiated in the presence of glutamate. to gain further insight into the potentiation of macrocyclic lactone anthlemintics we have screened various glutamatergic and nonglutamat ... | 2004 | 15006538 |
| resistance of santa ines, suffolk and ile de france sheep to naturally acquired gastrointestinal nematode infections. | a study was conducted to assess the breed resistance against nematode infections in santa ines, ile de france and suffolk male lambs over a 9-month period in são paulo state, brazil. lambs were born during the winter (year 2000) and were weaned at 2 months of age. the animals were then housed and treated with anthelmintics to eliminate natural infections by gastrointestinal nematodes. in late october 2000, lambs were placed in a paddock, where they stayed until august of the following year. feca ... | 2004 | 15019147 |