Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| parasite control in transhumant situations. | transhumance is defined as 'seasonal moving of livestock to regions of different climate'. it is an integral part of livestock production in many parts of the world and takes several forms including moving of livestock from lowland to mountainous pastures or from dry to humid areas. the impact of transhumance on parasite populations of livestock and on parasite control is described, mainly using examples from europe. the epidemiology of trichostrongylidosis of cattle, mainly caused by ostertagia ... | 1994 | 7846845 |
| anthelmintic resistance. | anthelmintic resistance is widespread in nematode parasites of sheep, goats and horses. resistance is also developing in nematode parasites of cattle and has been detected in pig parasites. benzimidazole, levamisole/morantel and ivermectin resistances occur in nematodes of sheep and goats and closantel resistance has been found in haemonchus contortus. anthelmintic resistance is likely to develop wherever anthelmintics are frequently used and be detected if it is investigated. worm count or egg ... | 1994 | 7846855 |
| ingestion of host immunoglobulin by three non-blood-feeding nematode parasites of ruminants. | host immunoglobulin was detected in homogenates of adult worms or fourth stage larvae of haemonchus contortus, ostertagia ostertagi, o circumcincta and dictyocaulus viviparus, but not in preparasitic third stage larvae of h contortus. all the worms had been washed in detergent before being homogenised to remove any immunoglobulin adhering to the cuticle. this procedure, the concentrations of immunoglobulin detected and observations on sections of the worms stained with fluorescent anti-sheep imm ... | 1994 | 7871262 |
| cloning and characterization of ribosomal rna genes from three species of haemonchus (nematoda: trichostrongyloidea) and identification of pcr primers for rapid differentiation. | genomic dnas prepared from adult worms of haemonchus contortus, haemonchus placei, and haemonchus similis were used to clone and map complete ribosomal rna gene repeats from each species. the lengths of the repeating units were estimated at 7.2, 7.2, and 7.4 kb, respectively, with a second and distinct repeat 6.9 kb in length identified from h. contortus only. restriction enzyme recognition sites within all ribosomal rna genes were fully conserved except for the loss of a sali site within the la ... | 1994 | 8299758 |
| antibody-containing cells in the abomasal mucosa of sheep with genetic resistance to haemonchus contortus. | the frequency distribution of parasite-specific antibody-containing cells (acc) and total immunoglobulin-containing cells (icc) in the abomasal mucosa was examined in genetically resistant and random-bred sheep, following infection with haemonchus contortus, to determine whether the two genotypes differed in the development of a local immune response. immunofluorescence staining was used to detect acc and icc of iga, igg1, igg2 and igm classes. no acc were found in the abomasum of any of the she ... | 1994 | 8146452 |
| cloning and sequence analysis of the small subunit ribosomal rna gene from nematodirus battus. | the small subunit ribosomal rna gene (ssu rrna) from the nematode parasite, nematodirus battus, was cloned from amplified genomic dna using polymerase chain reaction primers complementary to the 5' and 3' ends of haemonchus contortus small subunit ribosomal dna (ssu rdna). the 1,758 base pair cloned fragment was sequenced in both directions using internally generated primers and aligned with those from the genus haemonchus. results indicated a 1.9% sequence difference between the genera with a 1 ... | 1994 | 8158485 |
| seasonal prevalence of gastrointestinal nematodes in communal land goats from the highveld of zimbabwe. | on six occasions during a 1 year period, goats run on communal pastures by small-scale farmers, were purchased, housed indoors for 3 weeks and autopsied for examination of their gastrointestinal nematode burden. all of the 32 goats examined were infected. the four dominant species, haemonchus contortus, trichostrongylus axei, trichostrongylus colubriformis and oesophagostomum columbianum, were present in 88-97% of the animals. three other nematodes, strongyloides papillosus, bunostomum spp. and ... | 1994 | 8171826 |
| development and recovery of haemonchus contortus first larval stages on experimental plots in mexico. | the objective of this study was to determine the influence of relative humidity, environmental temperature and precipitation on the development of haemonchus contortus from egg to infective larvae on experimental plots in a subtropical subhumid climate of mexico. the study was of 1 year duration, with the highest rates of recovery of first-stage (l1) and second-stage larvae (l2) obtained at the end of the rainy season, and of third-stage larvae (l3) in the post-rainy season during the autumn. th ... | 1994 | 8171829 |
| efficacy of moxidectin against gastrointestinal nematode infections in sheep. | the efficacy of moxidectin against gastrointestinal nematode infections was studied in 30 fleischschaf x rasa aragonesa male lambs aged 3 months at the beginning of the experiment. the lambs were distributed in three groups of 10 animals each and experimentally infected with a mixture of an equal number of infective (l3) larvae from each of the following species: haemonchus contortus (2000), ostertagia circumcincta (2000), trichostrongylus colubriformis (2000) and trichostrongylus vitrinus (2000 ... | 1994 | 8171833 |
| ivermectin binding sites in sensitive and resistant haemonchus contortus. | membranes from both ivermectin-sensitive and -resistant haemonchus contortus l3 larvae were examined for the presence of high affinity [3h]ivermectin binding sites. both tissue preparations displayed high affinity drug binding sites (kd = 0.13 nm). receptor density (bmax = 0.4 pmol/mg) was the same in both the sensitive and resistant nematodes suggesting that target site modification was not involved in the development of drug resistance in this particular strain of h. contortus. the h. contortu ... | 1994 | 8195956 |
| effect of subclinical eimeria species infections in tropical goats subsequently challenged with caprine haemonchus contortus. | fourteen goat kids of the local indigenous breed naturally infected with eimeria species were divided into two equal groups. the first group was superinfected with 500,000 eimeria species oocysts and the second group was treated with amprolium. sixty days later both groups were infected with 5000 third-stage caprine haemonchus contortus larvae. the goats experimentally superinfected with eimeria shed more h contortus eggs and gained weight more slowly. | 1994 | 8197681 |
| haemonchus contortus: the role of two beta-tubulin gene subfamilies in the resistance to benzimidazole anthelmintics. | the role of beta-tubulin genes in benzimidazole (bz) resistance was investigated using one susceptible (s) and two resistant (rt and rc) strains of haemonchus contortus. the rt strain was isolated from the field on the basis of thiabendazole resistance. the rc strain was derived from the s strain by treatment with cambendazole. cdnas, derived from the s strain, encoding two isoforms of beta-tubulin (beta 12-16 and beta 8-9), alpha-tubulin and phosphofructokinase (pfk) were used as probes for sou ... | 1994 | 7910461 |
| benzimidazole resistance in haemonchus contortus is correlated with a conserved mutation at amino acid 200 in beta-tubulin isotype 1. | 1994 | 7911975 | |
| species identification of trichostrongyle nematodes by pcr-linked rflp. | restriction fragment length polymorphisms (rflp) of the second internal transcribed spacer (its-2) of ribosomal dna were examined for 6 species of ruminant nematodes; trichostrongylus colubriformis, t. axei, t. vitrinus, haemonchus contortus, teladorsagia circumcincta and cooperia oncophora. the its-2 of each species was amplified by pcr and restricted with the endonucleases drai, hinfi, rsai and vspi. using this approach, the 6 species could be distinguished. no intraspecific variation in rflp' ... | 1994 | 7913087 |
| cell-mediated immunity in merino lambs with genetic resistance to haemonchus contortus. | lymphocyte proliferation and skin hypersensitivity responses to parasite antigens were measured as indicators of cell-mediated immunity in genetically resistant and random-bred lambs following infection with haemonchus contortus. responses of pbmc to the mitogens pha, pwm and lps were also assessed to determine if infection was associated with suppression of general immune function. all lambs demonstrated significant antigen-specific lymphocyte proliferation prior to experimental infection. the ... | 1994 | 7928079 |
| purification and characterization of surface-associated proteins from adult haemonchus contortus. | extrinsic radioiodination experiments have shown that male and female adults of haemonchus contortus (bpl strain) express a stage-specific set of surface-associated proteins with apparent molecular mass values of 30, 58, 81, and 143 kda. a quantitatively different pattern of iodinated surface proteins is expressed by adults of the ppr strain of h. contortus, whereas the pattern of iodinated proteins expressed by haemonchus similis is qualitatively distinct (38, 68, and 121 kda). the 58-, 81-, an ... | 1994 | 7931909 |
| theoretical perspectives on anthelmintic drug discovery: interplay of transport kinetics, physicochemical properties, and in vitro activity of anthelmintic drugs. | this multidisciplinary study demonstrates the utility of the biophysical model approach to assess biological activity of anthelmintics in light of drug-delivery principles. the relationships between drug absorption and efficacy for a set of structurally disparate anthelmintics were determined in cultures of haemonchus contortus, a nematode that parasitizes the ruminant gastrointestinal tract. uptake, parameterized by the permeability coefficient, pe, was shown to occur by absorption across the c ... | 1994 | 7965664 |
| a middle-repetitive dna sequence element in the sheep parasitic nematode, trichostrongylus colubriformis. | a novel repetitive dna sequence in the sheep parasitic nematode trichostrongylus colubriformis was cloned and sequenced. a 1.1 kb repetitive sequence (tc15) which hybridized with dna from t. colubriformis but not with dna from two other parasitic nematodes, haemonchus contortus and ostertagia circumcincta, or sheep was further characterized. southern blot analysis showed that the repeat hybridized to a range of fragments in restriction digested t. colubriformis dna and existed in multiple copy n ... | 1994 | 7970890 |
| serum antibody responses of texel sheep experimentally infected with haemonchus contortus. | the primary and secondary serum antibody responses of texel sheep to infective larvae (l3) and adult worms of haemonchus contortus were studied. ten-month-old sheep were infected with 20,000 h contortus l3, treated with ivermectin seven weeks later and, after four weeks, reinfected with 10,000 l3 once a week for six weeks. faecal egg counts were significantly lower during the secondary infection than during the primary infection, but both infections induced antibody responses, as demonstrated by ... | 1994 | 7973095 |
| comparative efficacy of moxidectin and mebendazole against gastrointestinal nematodes in experimentally infected lambs. | a controlled trial was conducted to determine the anthelmintic efficacies of moxidectin and mebendazole. the compounds were administered orally at doses of 0.2 mg/kg bodyweight and 15.0 mg/kg bodyweight, respectively, to lambs infected experimentally with large numbers of gastrointestinal nematode larvae including a benzimidazole-resistant strain of haemonchus contortus. moxidectin was 100 per cent effective against adult h contortus, ostertagia species, trichostrongylus colubriformis, cooperia ... | 1994 | 7975106 |
| farm history and breeding management influences on the intensity and specific diversity of nematode infection of dairy goats. | sixteen dairy-goat farms were investigated in the centre-west of france for nematode infection. the intensity of infection was assessed by means of faecal egg counts and nematode counts at necropsy for digestive-tract nematodes and faecal larval counts for muellerius capillaris. the specific diversity and prevalence were estimated by worm counts of 28 necropsied culled goats. the history and breeding management were recorded by means of a questionnaire. specific diversity was estimated on two cu ... | 1994 | 7975117 |
| control of haemonchosis in malaysian goats with closantel. | the therapeutic and prophylactic effects of closantel on natural infections with haemonchus contortus were studied in goats in peninsular malaysia. closantel was highly effective against h. contortus, either at a subcutaneous (s.c.) injection of 5.0 mg kg-1 body weight (100%), or in an oral drench mixture with mebendazole at a dose of 10.0 mg kg-1 (99.2%), as indicated by faecal egg counts. h. contortus larvae were absent from faecal cultures for 5, 6 and 7 weeks following treatment with s.c. in ... | 1994 | 7975118 |
| cross antigenicity among ovine trichostrongyloidea. preliminary report. | a preliminary trial on the extent of cross-antigenicity among the sheep strongylids haemonchus contortus, trichostrongylus colubriformis, teladorsagia circumcincta and nematodirus battus in 2.5- to 4-month-old lambs has been carried out using elisa and western blotting (wb). cross antigenicity was tested using soluble extracts from adult and third stage larvae (l3) of h. contortus as antigenic source probed with sera from lambs with monospecific heterologous infections. there was cross-antigenic ... | 1994 | 7975119 |
| the heritability and specificity of responsiveness to infection with haemonchus contortus in sheep. | high responder (hr) and low responder (lr) lines of sheep of the hungarian merino breed were selected by using faecal egg counts (epg) as parameter of responsiveness after double artificial haemonchus contortus test infections. a total of 81 lambs born to assortative matings of hr rams with hr ewes and lr rams with lr ewes, as well as 28 control lambs from unselected parent sheep, were studied to estimate the heritability of responsiveness. a relatively high level of heritability (h2 = 0.49 +/- ... | 1994 | 7982749 |
| genetic variability of the beta-tubulin genes in benzimidazole-susceptible and -resistant strains of haemonchus contortus. | benzimidazole anthelmintics are the most common chemotherapeutic agents used to remove intestinal helminths from farm animals. the development of drug resistance within helminth populations is wide-spread and can render these drugs essentially useless. the mechanism of benzimidazole resistance appears to be common to many species ranging from fungi to nematodes and involves alterations in the genes encoding beta-tubulin. during the selection process resulting in resistance, there must be quantit ... | 1994 | 8001777 |
| characterization of a tandemly repetitive dna sequence from haemonchus contortus. | genomic dna from the sheep parasitic nematode haemonchus contortus was shotgun cloned in the plasmid vector puc18. recombinants which gave the strongest hybridization signals to 32p-radiolabelled genomic dna were selected as representatives of the repetitive component of the parasite dna. one repetitive sequence which hybridized only with dna from h. contortus and not with dna from two other sheep nematodes (trichostrongylus colubriformis and ostertagia circumcincta) was further characterized by ... | 1994 | 8021102 |
| anthelmintic resistance in australian sheep nematode populations. | the resistance status of gastro-intestinal nematodes to anthelmintics was evaluated on 881 sheep farms throughout australia during 1991-92. resistance was shown to be widespread. overall, 85% of farms had sheep infected with nematodes resistant to benzimidazole, 65% to levamisole and 34% to combination (benzimidazole+levamisole) products. resistance to ivermectin was not detected. on only 9% of farms did all anthelmintic groups reduce egg counts by greater than or equal to 95%. the culture of fa ... | 1994 | 8048907 |
| the effects of anthelmintics on ovine larval nematode parasite migration in vitro. | the anthelmintics ivermectin, levamisole, morantel tartrate and thiabendazole all inhibited, in vitro, the motility of third stage larvae (l3) of trichostrongylus colubriformis. the bioassay, based on the inhibition of l3 migration from agar gels, yielded sigmoid dose-response curves for ivermectin, levamisole and morantel tartrate, but not thiabendazole. the concentration of levamisole giving 50% inhibition of migration (ec50) was determined for cooperia curticei, haemonchus contortus, nematodi ... | 1994 | 8070948 |
| protection studies with integral membrane fractions of haemonchus contortus. | techniques for targetting glycoproteins integral to the luminal membrane of the intestinal cells of haemonchus contortus were used to isolate fractions of whole parasites with protective antigen potential. sheep immunization trials with various candidate fractions revealed one which selectively bound to lectins with specificity for n-acetylgalactosamine and which reduced mean challenge worm burdens by up to 72% and mean faecal egg counts by up to 93%. the luminal surface of the intestines of the ... | 1994 | 8072767 |
| rotational grazing for control of gastrointestinal nematodes of goats in a wet tropical environment. | a preliminary experiment involving contamination of pasture plots with eggs of haemonchus contortus, trichostronglyus colubriformis and oesophagostomum columbianum every month for a year established that in the tropical environment of the pacific island of tongatapu, hatching and development of all species was rapid and continuous, with a short survival on pasture (3-7 weeks) of the resulting infective larvae. these results indicated that a rotational grazing system consisting of ten paddocks gr ... | 1994 | 8091608 |
| anthelmintic resistance in haemonchus contortus from sheep in malaysia. | albendazole, oxfendazole, fenbendazole, levamisole, closantel, ivermectin and febantel were administered to sheep on four farms and their efficacy assessed by faecal egg count reduction test. high level of resistance of haemonchus contortus was found to benzimidazoles (albendazole, oxfendazole, fenbendazole) on all farms and to febantel on the one farm where it was tested. no resistance to closantel and levamisole was observed. resistance to ivermectin was absent on the three farms examined unde ... | 1994 | 8091619 |
| the residual anthelmintic efficacy of moxidectin against selected nematodes affecting sheep. | determination of the residual anthelmintic efficacy in sheep of an oral formulation of moxidectin at a dosage rate of 0.2 mg kg-1 was evaluated 27-29 (mean: 28) d after dosing and that of the injectable formulation of moxidectin at a dosage rate of 0.2 mg kg-1 at 27-29 (mean: 28) and 34-36 (mean: 35) d post-treatment. the injectable formulation was more than 80% effective in more than 80% of treated sheep against a third larval stage challenge of haemonchus contortus, teladorsagia (ostertagia) c ... | 1994 | 7602570 |
| anthelmintic resistance in goats in peninsular malaysia. | ninety-six randomly selected farms, located throughout peninsular malaysia, were surveyed for goat nematodes resistant to benzimidazoles (bz). on 33 farms bz resistance was demonstrated by means of an egg hatch assay. haemonchus contortus was found to be the main species involved in anthelmintic resistance. there was a positive association between the frequency of anthelmintic treatments on a farm and the presence of benzimidazole resistance. to assess the value of the egg hatch assay, faecal eg ... | 1994 | 7725626 |
| ivermectin resistant haemonchus contortus in louisiana lambs. | fifteen weaned crossbred (suffolk x louisiana native) lambs were treated with albendazole (10 mg kg-1) to remove existing nematode infections. they were inoculated with haemonchus contortus infective larvae from a residual population surviving treatment with the oral formulation of ivermectin (0.2 mg kg-1). one group of five lambs remained untreated, another group of five was treated with the injectable formulation of ivermectin (0.2 mg kg-1), and a third group of five was treated with the oral ... | 1994 | 7725627 |
| immune responses of texel sheep to excretory/secretory products of adult haemonchus contortus. | the excretory/secretory (e/s) products of adult haemonchus contortus comprise of at least 15 polypeptides with molecular weights ranging from 10 to > 100 kda. these e/s products induce an immune response in infected texel sheep, as demonstrated by specific igg1 levels and a significant lymphocyte proliferation index. moreover, immunoblotting analysis revealed that sera of primary h. contortus-infected sheep specifically recognize a 24 kda e/s product. in addition, sera of challenged sheep react ... | 1994 | 7517519 |
| cloning of a putative inhibitory amino acid receptor subunit from the parasitic nematode haemonchus contortus. | a cdna, hgl, encoding an inhibitory amino-acid receptor subunit has been cloned from a mixed egg population of the parasitic nematode haemonchus contortus. the predicted amino-acid sequence of the subunit shows 24% to 32% homology with other vertebrate and invertebrate gabaa and glycine receptor subunits and has all the expected motifs for a member of the ligand-gated ion channel superfamily. when expressed in xenopus oocytes hgl gives a small response to 1 mm glycine, but not to 1 mm gaba, glut ... | 1994 | 7525001 |
| t-cell receptor and immunoglobulin gene polymorphisms and resistance to haemonchus contortus in sheep. | summary: dna extracted from animals originating from three large half-sib sheep families derived from a single, highly resistant ram were probed with ovine t-cell receptor α and β chain and immunoglobulin lambda light chain variable and constant region cdna probes. when genomic dna was digested with taqi, 19 polymorphic bands were detected with the lambda light chain immunoglobulin variable region probe and 6,4 and 5 polymorphic bands were detected with the t-cell receptor α and β probes and the ... | 1994 | 21395753 |
| water, water compartments and water regulation in some nematodes parasitic in vertebrates. | while nematodes are sometimes regarded as osmoconformers, at least one species is capable of short-term osmoregulation over a wide range of osmotic environments, and the principal site of osmoregulation is the body wall. this general osmoregulation is important to the life of the nematode not only in confronting variations in the environment, but also in maintaining its hydrostatic skeleton. there is also evidence suggesting that compartments exist in some nematodes and that water exchange betwe ... | 1995 | 19277309 |
| the sensitization of mucosal mast cells during infections with trichostrongylus colubriformis or haemonchus contortus in sheep. | responses of isolated mucosal mast cells (mmc) during infections with either trichostrongylus colubriformis or haemonchus contortus were examined by measuring the release of sheep mast cell protease (smcp) in a degranulation assay. mmc from sheep immune to t. colubriformis released maximal amounts of smcp and histamine within 0.5h of incubation with larval antigen whereas maximum secretion of leukotrienes occurred 3h after addition of antigen. it was only after 8 weeks of a primary t. colubrifor ... | 1995 | 7544771 |
| genetic factors affecting antibody responses to four species of nematode parasite in romney ewe lambs. | serum levels of antibodies (ab) and immunoglobulin g1 (igg1) to the larval (l3) stage of the internal parasites cooperia curticei and trichostrongylus colubriformis and levels of ab to the l3 stages of haemonchus contortus and ostertagia circumcincta were determined in 1432 romney ewe lambs which were born on one farm in 1990 and 1991 and were the progeny of 63 rams. the objectives were to estimate heritabilities of, and genetic correlations among, the serum concentrations in newly weaned lambs ... | 1995 | 7558568 |
| vaccination of sheep against haemonchosis with h11, a gut membrane-derived protective antigen from the adult parasite: prevention of the periparturient rise and colostral transfer of protective immunity. | pregnant ewes were immunised with a fraction highly enriched in the membrane glycoprotein antigen h11, isolated from the intestinal brush border of adult haemonchus contortus. immunity induced by immunisation was able to abolish almost completely (98-99%) the worm egg output from pregnant ewes challenged with ca. 10,000 infective larvae of h. contortus during the last trimester. furthermore, lambs born and reared on vaccinated ewes had substantial antibody levels to h11 derived from maternal tra ... | 1995 | 7558570 |
| immune responses of sheep to microdissected parts of haemonchus contortus. | adult specimens of haemonchus contortus were microdissected into four body fragments: oesophagus, cuticle of oesophagus, gut and cuticle with adjacent muscle layer. the antigenicity of these different body fragments was analysed in comparison to total (whole) worm extracts with immunoblotting and elisa using sera of h. contortus-infected sheep. in particular, oesophagus-derived antigens appeared to be specifically recognized and may prove valuable in diagnostic assays. | 1995 | 7558573 |
| efficacy of pyrantel tartrate against experimental infections with haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis in goats. | the efficacy of pyrantel tartrate was evaluated in goats against induced infections with haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis. all the strains were of sheep origin and tested for susceptibility to pyrantel tartrate in sheep at the standard dose rate (20 mg kg-1) prior to the infection of goats. fifteen french alpine female goats were inoculated with the three nematode species. on day 25 post-infection, goats were randomized into an untreated control ... | 1995 | 7571339 |
| anthelmintic profile of the cyclodepsipeptide pf1022a in in vitro and in vivo models. | a novel cyclodepsipeptide of fungal origin, pf1022a, recently was reported to have anthelmintic activity. to supplement published reports and determine potential utility of pf1022a as a ruminant anthelmintic, the compound was examined in in vitro and in vivo models. assays used measured motility of haemonchus contortus (intrinsic drug potency), atp levels (parasite death), and activity against h. contortus, ostertagia ostertagi, and trichostrongylus colubriformis in the jird (spectrum, potency, ... | 1995 | 7592027 |
| levamisole resistance in haemonchus contortus selected at different stages of infection. | resistance to the anthelmintic levamisole is common amongst most genera of trichostrongylid nematodes of sheep, but is relatively rare in the species haemonchus contortus. the level of resistance in at least one strain of this species varies during the life cycle. investigation of this phenomenon, especially in parasitic stages of the parasite may reveal information on resistance mechanisms and factors affecting the selection of resistance. compared with adult worms of the same resistant strain, ... | 1995 | 7601592 |
| bafilolides, potent inhibitors of the motility and development of the free-living stages of parasitic nematodes. | three streptomyces isolates were identified as producing macrolide antibiotics of the bafilomycin or leucanicidin types during an evaluation of australian actinomyces for the production of inhibitors of larval development in the parasitic nematode, haemonchus contortus. bafilomycins a1, b1, c1, and d were obtained from culture a239 and the 2-o-methyl-l-rhamnosyl derivative of bafilomycin a1, leucanicidin, from cultures a223 and a240. all these 'bafilolides' gave similar patterns of inhibition ty ... | 1995 | 7601593 |
| effects of weaning, supplementation and gender on acquired immunity to haemonchus contortus in lambs. | this study was designed to investigate whether delaying the age of weaning, or feeding a protein-rich supplement alters the rate at which lambs develop immunity to haemonchus contortus and whether there is any interaction between nutrition, stress of weaning, and gender and the development of this immunity. ninety-six merino lambs were allocated to one of four treatment groups: supplemented-unweaned; supplemented-weaned; unsupplemented-unweaned; unsupplemented-weaned. there were approximately si ... | 1995 | 7601597 |
| characterization and localization of cathepsin b proteinases expressed by adult ancylostoma caninum hookworms. | the hookworm ancylostoma caninum induces human eosinophilic enteritis (ee), probably via allergic responses to its secretions. cysteine and metallo-proteinases may be the components of these secretions that elicit hypersensitivity reactions. in order to characterize genes encoding cysteine proteinases (cp) secreted by a. caninum, an adult hookworm cdna library was constructed and screened with a cloned fragment of a hookworm cp gene. this fragment was obtained using consensus oligonucleotide, cp ... | 1995 | 7477098 |
| strongyle infections in sheep and goats under the traditional husbandry system in peninsular malaysia. | faecal egg counts were used to study patterns of trichostrongyle infections in sheep and goats according to season, age, pregnancy and lactation on traditional farms in west malaysia. haemonchus contortus and trichostrongylus spp. were the most important strongyles in sheep and in goats, h. contortus, trichostrongylus spp. and oesophagostomum spp. were most prevalent. the faecal egg counts of sheep and goats were apparently not influenced by the small seasonal climatic variations. strongyle infe ... | 1995 | 7732637 |
| dry areas: an example of seasonal evolution of helminth infection of sheep and goats in southern mauritania. | a total of 647 faecal egg counts and 53 necropsies were performed on sheep and goats originating from three sites of a sahelian region of mauritania (gorgol) over a period of 2 years (1990-1992). haemonchus contortus, oesophagostomum columbianum and stilesia globipunctata were the most prevalent species. the seasonal pattern was characterized by long survival of adults and high percentages of arrested fourth-stage larvae in the dry season, suggesting that two different strategies were used to su ... | 1995 | 7732638 |
| isotype-specific serum antibody responses of sheep to haemonchus contortus antigens. | in total, 19 8-month-old texel sheep were used to study the isotype-specific serum antibody responses against infective larvae and adult worms of haemonchus contortus. group group 1 sheep (n = 7) were infected with 20,000 l3 larvae (week 0), treated with ivermectin 6 weeks post-infection and subsequently challenged at week 10 of the experiment. this challenge consisted of a trickle infection of 10,000 l3 larvae per week for 5 weeks. group 2 sheep (n = 7) received a single infection at week 10 of ... | 1995 | 7732639 |
| [epidemiology of gastrointestinal helminthiasis in small ruminants in the tree-cropping pasture zone in senegal]. | an epidemiological survey on gastrointestinal helminthiasis in 51 sheep and 51 goats was held in the tree-cropping pasture region in senegal from october 1990 to september 1991. all the animals examined were infected with at least 1 helminth species. three trematodes (fasciola gigantica, schistosoma bovis, amphistomatids), 2 cestodes (moniezia expansa, cysticercus tenuicollis) and 9 nematodes were identified. the most important parasite in sheep was haemonchus contortus while trichostrongylus co ... | 1995 | 7735304 |
| high energy phosphate metabolites observed by nmr in infective larvae of haemonchus contortus. | phosphorus resonances consistent with phosphoarginine and atp were observed in the in vivo 31p-nuclear magnetic resonance (nmr) spectra of infective larvae of haemonchus contortus. the level of phosphoarginine quickly declined when nematode suspensions were purged with nitrogen and was restored upon return to aerobic conditions. saturation transfer nmr demonstrated forward and reverse exchange of phosphorus between phosphoarginine and atp. | 1995 | 7776130 |
| characterization of local antibody responses to the gastrointestinal parasite haemonchus contortus. | the ability to identify antigens associated with an infection has generally relied on the use of serum antibodies produced by infected or previously exposed individuals. a major drawback with the use of serum is that it does not necessarily reflect the local antibody response at mucosal tissue sites. this study describes an approach that allows the use of antibodies generated close to the infection site to detect the transient expression of stage-specific antigens during infection with the gastr ... | 1995 | 7790042 |
| the effect of reduced feed intake on the efficacy of oxfendazole against benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis in sheep. | within 12 h of reducing the daily intake of a 50:50 lucerne and wheaten hay ration from 800 to 400 g, there was an increase in digesta marker concentration indicating a reduction in the flow rate of digesta fluid and particulates through the abomasum of sheep. the efficacy of the recommended dose of oxfendazole (ofz) was then tested against benzimidazole resistant trichostrongylus colubriformis and haemonchus contortus in sheep whose feed intake was halved 36 h before and after drug treatment. i ... | 1995 | 7797375 |
| developmentally regulated secretion of cathepsin l-like cysteine proteases by haemonchus contortus. | cysteine protease activity was present in media collected after 24 hr in vitro culture of adult haemonchus contortus. the released cysteine protease hydrolyzed the fluorogenic 7-amino-4-trifluoromethyl coumarin (afc)-substituted synthetic peptides z-phe-arg-afc and z-ala-arg-arg-afc, but not z-arg-arg-afc or z-arg-afc, characterizing this activity as cathepsin l-like. within the parasite, cysteine protease activity was highest in extracts of intestinal tissue. secreted cysteine protease inhibite ... | 1995 | 7623189 |
| bilateral, perivulval cuticular pores in trichostrongylid nematodes. | a new hypodermal gland was discovered in female nematodes of the family trichostrongylidae. because the new structure appears to be associated with the vulva, it was named the perivulval pore. it is similar, based on light and scanning electron microscopy, to phasmids that are located laterally on the tails of nematodes of the class secernentea. like phasmids, perivulval pores are paired and bilateral, with cuticular ducts to the surface in the areas of the lateral chords. they are located sligh ... | 1995 | 7623208 |
| avermectin inhibition of larval development in haemonchus contortus--effects of ivermectin resistance. | avermectin (avm) inhibition of the development of the free-living stages of haemonchus contortus has been quantified in an assay in which nematode eggs are placed on an agar matrix containing serial dilutions of a drug in the wells of a microtitre plate. development is allowed to proceed for 6 days by which time larvae in control wells (no drug) have reached the infective, third (l3) stage. at high concentrations (> 30 nm) ivermectin (ivm) paralyses l1 larvae soon after hatching, however, much l ... | 1995 | 7635622 |
| the epidemiology of helminth infections of growing sheep in argentina's western pampas. | seasonal population trends of helminth parasites of growing lambs were investigated over 4 years. successive worm-free lambs were grazed together with untreated lambs for 20-30 days and then slaughtered for helminth counts 2 weeks after their removal from pasture. likewise untreated lambs from the same flock were slaughtered from 2 to 15 months of age for worm counts in the same way as tracer lambs. the predominant parasites were haemonchus, nematodirus and trichostrongylus. haemonchus contortus ... | 1995 | 7635625 |
| interaction between ostertagia circumcincta and haemonchus contortus infection in young lambs. | twenty-one-week-old, worm-free, pen-reared lambs were infected with either 6000 o. circumcincta l3 per week, or 3000 h. contortus l3 per week, or both (9000 l3 per week). egg counts were monitored throughout the experiment, and worm burdens and larval establishment rates of both worm species were estimated after 4, 7, 10 and 13 weeks of infection. after 10-13 weeks of infection with h. contortus only, establishment of o. circumcincta was lower than in previously uninfected controls, demonstratin ... | 1995 | 7635626 |
| protection against multiply drug-resistant and geographically distant strains of haemonchus contortus by vaccination with h11, a gut membrane-derived protective antigen. | h11 is a "hidden antigen" derived from adult haemonchus contortus which is capable of conferring a high degree of protection against subsequent challenge. to be commercially useful, any vaccine based on this antigen must protect against field strains and drug-resistant worms. the results show that vaccination with h11 affords high levels of protection against the multiply drug-resistant (mdr) lawes strain of haemonchus contortus. moreover, there was no difference in protection whether the h11 wa ... | 1995 | 7635627 |
| analysis of proteins related to conditioning for arrested development and differentiation in haemonchus contortus by two-dimensional gel electrophoresis. | the abundance of the majority of proteins of infectious third-stage larvae (l3) of haemonchus contortus, conditioned for arrested development, remained unaltered. only seven proteins showed quantitative differences as observed by two-dimensional gel electrophoresis. these differences were also observed in a laboratory strain which has lost the ability for arrested development. the abundance of two of these proteins increased dramatically during conditioning of larvae for 5-10 weeks. this coincid ... | 1995 | 7635634 |
| variation in immune responsiveness of sheep to the antigens of intestinal nematodes and blowfly larvae. | the total and igg1 antibody responses to the intestinal nematode parasites haemonchus contortus and trichostrongylus colubriformis were measured in the serum of 160 lambs, 4 months of age. these antibodies had developed as the result of natural exposure to the parasites on pasture. three sires were examined and strong sire effects on half-sib progeny were found. plotting of elisa antibody results in two dimensions revealed clustering of responses within sire groups. bimodal antibody distribution ... | 1995 | 7635641 |
| isolation of a larval surface glycoprotein from haemonchus contortus and its possible role in evading host immunity. | 1995 | 7637698 | |
| characterisation of an avermectin resistant strain of australian haemonchus contortus. | a strain of haemonchus contortus (cavr) isolated in australia was found to be resistant to ivermectin (ivm) with 0.4 mg kg-1 of the anthelmintic failing to significantly reduce worm burdens. resistance to ivm was sex-influenced in the cavr strain with adult males showing a greater sensitivity to ivm. cross resistance to moxidectin was evident with approximately 15% of the population surviving a dose of 0.1 mg kg-1. the free-living stages of the cavr isolate had a reduced sensitivity to avermecti ... | 1995 | 7657454 |
| influence of supplementation with dietary soyabean meal on resistance to haemonchosis in hampshire down lambs. | the influence of dietary protein supplementation on resistance to haemonchosis was examined in hampshire down lambs fed either a basal diet or a diet supplemented with soyabean. at seven months of age the lambs were challenged with an initial loading dose of haemonchus contortus, followed by a trickle infection three times a week. blood and faecal samples were collected three times a week and bodyweights were recorded weekly. after 10 weeks the lambs were slaughtered and their worm burdens and c ... | 1995 | 7659847 |
| comparison of two enzyme immunoassays for the detection of haemonchus contortus infections in sheep. | two enzyme-linked immunosorbent assays (elisa) using either excretory/secretory (es) products or crude somatic antigens (csa) of adult haemonchus contortus were compared for their ability to detect antibodies against h. contortus in sheep. serum samples obtained from a group of 32 h. contortus mono-infected sheep were tested in the two elisas and the obtained data were compared with the results of the faecal examinations of these sheep. the first sheep became patent 3 weeks post infection (p.i.) ... | 1995 | 7660570 |
| seasonal changes and inhibited development of the abomasal nematodes of sheep and goats in saudi arabia. | from august 1991 to july 1992, a total of 48 abomasa from sheep and 48 from goats were examined at the jeddah abattoir for the presence of adult and larval nematodes. twenty-three of the sheep (47.9%) and 21 of the goats (43.8%) were infected with nematodes, a total of eight species being found. haemonchus contortus and marshallagia marshalli appeared to be the most important parasites. other species were less prevalent: trichostrongylus axei, camelostrongylus mentulatus, parabronema skrjabini, ... | 1995 | 7676605 |
| beta-tubulin genes from the parasitic nematode haemonchus contortus modulate drug resistance in caenorhabditis elegans. | resistance to antimitotic chemotherapeutics in pathogenic nematodes, fungi and mammalian cells is closely associated with structural changes in cytoskeletal beta-tubulin. we investigated the possibility of using the well-characterised free-living nematode caenorhabditis elegans as a model for studying the mechanism of resistance against benzimidazole (bz) drugs in the parasitic nematode haemonchus contortus. functional analysis of a conserved beta-tubulin isotype (tub-1) mutation near gtp-bindin ... | 1995 | 7877171 |
| [anthelmintic resistance in sheep nematodes in the netherlands]. | the prevalence of anthelmintic resistant nematodes in sheep was investigated in 1994 with a faecal egg count reduction test (fecrt) and an egg hatch assay (eha) on 71 farms in the netherlands. a benzimidazole (oxfendazole) was tested on 70 farms, ivermectin on 51 farms, and levamisole on 35 farms. based on the fecrt benzimidazole resistance was present on 56 farms, 2 were suspected, on 9 no resistance was observed, while 3 farms could not be tested due to a too low egg output before treatment. n ... | 1995 | 7900149 |
| efficacy of oral moxidectin against benzimidazole-resistant isolates of gastrointestinal nematodes in sheep. | the efficacy of orally administered moxidectin was determined against four benzimidazole-resistant nematode isolates. at the start of the trial, 30 lambs were each infected experimentally with 20,000 third stage larvae (5000 haemonchus contortus, 7000 teladorsagia circumcincta, 3000 trichostrongylus colubriformis and 5000 cooperia curticei); 28 days later they were allocated randomly to three groups of 10: one untreated group, one group treated orally with fenbendazole (5 mg/kg bodyweight) and o ... | 1995 | 7900256 |
| use of random amplified polymorphic dna for identification of ruminant trichostrongylid nematodes. | the aim of this work was to evaluate random amplified polymorphic dna (rapd) as a source of markers for species identification and phylogenetic analysis of ruminant trichostrongylid nematodes. as these nematodes are often polymorphic, species identification may be difficult. we tested eight species and several of their morphs: haemonchus contortus (three vulvar morphotypes: flap, smooth, and knobbed), teladorsagia circumcincta, ashworthius gagarini, spiculopteragia boehmi, ostertagia leptospicul ... | 1995 | 7724508 |
| helminth parasites and hypobiosis of nematodes in n'dama cattle during the dry season in the gambia. | three series of necropsies of cattle were performed, corresponding to early dry season, approximately 1 month after the last rains (november, n = 6), mid dry season (february, n = 6) and end dry season (april, n = 3). eggs per gram of faeces (epg) were determined just before necropsy. three trematodes (fasciola gigantica, schistosoma spp. and paramphistomatids) and 11 nematodes were identified from cattle, with the prevalence rate varying from 6.7% to 100%. haemonchus contortus was the most abun ... | 1995 | 8644452 |
| a comparison of the responses to repeated experimental infections with haemonchus contortus among scottish blackface lambs. | twenty helminth-naive scottish blackface lambs were given three infections with 10,000 infective larvae of haemonchus contortus at 8 week intervals. an additional six lambs served as uninfected controls and eight lambs were infectivity controls. the lambs were 7 months old at the start of the infection. four of the 20 lambs developed severe haemonchosis and were put down during the experiment. the remaining 16 lambs plus uninfected controls were necropsied 8 weeks after the third infection. the ... | 1995 | 8644460 |
| cryopreservation of the first-stage larvae of trichostrongylid nematode parasites. | first stage (l1) larvae of haemonchus contortus, trichostrongylus colubriformis and ostertagia circumcincta can be cryopreserved in the presence of dmso using a two-step freezing protocol involving an initial period at -80 degrees c prior to transfer to liquid nitrogen. thawed l1 larvae continue development in vitro producing third stage (l3) larvae that are infective to sheep when dosed per os. establishment rates for l3 larvae grown from thawed l1 larvae were 40 and 80% for h. contortus and t. ... | 1995 | 8719953 |
| [epidemiology of gastrointestinal nematodes in small ruminants in the plateau areas in togo]. | post-mortem helminthological examinations were performed in togo on small ruminants of the djallonké breed (59 sheep, 60 goats), revealing the presence of eight gastrointestinal nematode species which were, in decreasing prevalence order, trichostrongylus sp. (t. axei and t. colubriformis) (99%), haemonchus contortus (82%), strongyloides papillosus (67%), cooperia curticei (43%), oesophagostomum columbianum (40%), gaigeria pachyscelis (36%) and trichuris ovis (4%). the average worm burden was 1, ... | 1995 | 8734228 |
| r4, a non-ltr retrotransposon specific to the large subunit rrna genes of nematodes. | a 4.7 kb sequence-specific insertion in the 26s ribosomal rna gene of ascaris lumbricoides, named r4, is shown to be a non-long terminal repeat (non-ltr) retrotransposable element. the r4 element inserts at a site in the large subunit rrna gene which is midway between two other sequence-specific non-ltr retrotransposable elements, r1 and r2, found in most insect species. based on the structure of its open reading frame and the sequence of its reverse transcriptase domain, r4 elements do not appe ... | 1995 | 8524653 |
| amplification and characterization of cysteine proteinase genes from nematodes. | in order to isolate proteinase genes from parasitic nematodes by polymerase chain reaction (pcr) techniques, we employed a pair of consensus oligonucleotide primers designed to anneal to the active site cysteine (primer ncpc) and asparagine (primer ncpn) coding regions of cysteine proteinases. the primers were biased toward the nucleotide and codon usages of cysteine proteinase genes of nematodes and were based on the consensus nucleotide sequences flanking the active site residues of genes from ... | 1995 | 8525283 |
| experimental study of survival strategy of haemonchus contortus in sheep during the dry season in desert areas of the mauritania. | the survival of the most common worm of sheep and goats of desert areas, haemonchus contortus, during the dry season is of the utmost importance. it may be achieved through long survival of adult worms that may preserve their ability to excrete viable eggs or to inhibited development in host and survival as a larval stage. twelve lambs were experimentally infected with larvae obtained at the end of the rainy season. the resulting adult worms were able to survive and maintain their ability to pro ... | 1995 | 8544042 |
| the effect of molybdenum and sulphur on anthelmintic resistant haemonchus contortus in sheep. | 1995 | 8544158 | |
| the persistence of the efficacy of injectable or oral moxidectin against teladorsagia, haemonchus and trichostrongylus species in experimentally infected sheep. | the persistence of the efficacy of moxidectin was evaluated against experimental gastrointestinal nematode infections in 55 lambs randomly allocated to 11 equal groups and infected on day 0. moxidectin 1 per cent injectable solution was administered at a dose rate of 0.2 mg moxidectin/kg bodyweight to five of the groups on days -42, -35, -28, -21 and -14; five other groups were treated with moxidectin 0.1 per cent oral drench at the same dose rate on days -35, -28, -21, -14 and -7, and the 11th ... | 1995 | 8545937 |
| isolation of af2 (kheylrfamide) from caenorhabditis elegans: evidence for the presence of more than one fmrfamide-related peptide-encoding gene. | numerous fmrfamide-related peptides (farps) have been isolated and sequenced from extracts of free-living and parasitic nematodes. the most abundant farp identified in ethanolic/methanolic extracts of the parasitic forms, ascaris suum and haemonchus contortus and from the free-living nematode, panagrellus redivivus, was kheylrfamide (af2). analysis of the nucleotide sequences of cloned farp-precursor genes from c. elegans and, more recently, caenorhabditis vulgaris identified a series of related ... | 1995 | 8554607 |
| actin isoforms in the parasitic nematode haemonchus contortus. | actin proteins in the parasitic nematode haemonchus contortus were partially purified by a new method based on precipitation with podophyllotoxin and dimethylsulfoxide. two-dimensional gel electrophoresis of partially purified actin proteins revealed differences in isoform composition between adults and third-stage larvae. the significance of this finding is possibly related to the existence of differential functional or developmental characteristics between these two life-cycle stages. | 1995 | 8570588 |
| heat-shock and stress response of the parasitic nematode haemonchus contortus. | before and after a stress treatment, larval stages and adult worms of haemonchus contortus were tested for the induction and expression of heat-shock proteins (hsps) using immunoblot analysis with hsp70-and hsp65-specific monoclonal antibodies. stress treatment or heat shock did not alter the signals obtained with these antibodies, but the amount of hsp70 differed between the successive stages. in addition, the different stages were metabolically labeled with [35s]-methionine during a temperatur ... | 1995 | 8570590 |
| [anthelmintics resistance in gastrointestinal nematodes in domestic animals]. | in belgium benzimidazole resistance has been reported in 28% of the sheep farms and 29 to 50% of the studs. in several member states of the european union the prevalence of anthelmintic resistance (ar) is even higher than in belgium, although ar is nearly absent in some countries of southern europe. ar is particularly widespread in certain nematodes of sheep, goats and horses in europe, whereas only sporadic cases of ar have been reported in helminths of cattle. in belgium only one case of ar ha ... | 1995 | 8571668 |
| humoral and cellular responses following local immunization with a surface antigen of the gastrointestinal parasite haemonchus contortus. | a purified, larval specific antigen of the abomasal parasite haemonchus contortus was used to immunize sheep. in an attempt to induce a local immune response in the abomasum, the antigen was injected twice into the abomasal wall after one peripheral immunization. serum antibody responses were boosted by each intra-abomasal immunization but not by the challenge infection given 3.5 weeks after the last immunization. examination of the specific antibody secreting cells (asc) recirculating in the pe ... | 1995 | 8578690 |
| moisture and temperature requirements in faeces for the development of free-living stages of gastrointestinal nematodes of sheep, cattle and deer. | isolates from eight gastrointestinal nematode species parasitic in sheep, cattle and deer were maintained in sheep, to provide eggs in similar faecal environments and to compare temperature and moisture requirements for their development. faecal cultures were processed at different temperatures (for four species) and moisture contents (for the eight species). at 60% of faecal moisture content (fmc), maximal rates of development (expressed as l3/100 hatchable eggs estimated by an extraction techn ... | 1995 | 8583130 |
| microclimatic effect on vertical migration of haemonchus contortus and haemonchus placei third-stage larvae on irrigated kikuyu pasture. | the influence of microclimate on numbers of third-state larvae of haemonchus contortus and haemonchus placei in four strata of irrigated kikuyu pasture was assessed. on 36 different, interspersed days three replicates of pasture samples were collected on three occasions per day from 1990-1992 for larval recovery and the log10 mean counts of the larvae recovered were analysed by use of anova models. because the ground-surface area from which herbage was collected was standardized, estimated larva ... | 1995 | 8600435 |
| alveolar mastocytosis and eosinophilia in lambs with naturally acquired nematode infections of protostrongylus rufescens and haemonchus contortus. | specific-pathogen-free dorset and st. croix lambs were placed on pasture contaminated with haemonchus contortus third stage larvae and slugs carrying third stage larvae of protostrongylus rufescens for an entire grazing season to evaluate breed differences in acquired resistance to these nematodes. lambs were evaluated for clinical signs, clinical pathology and histopathologic lesions associated with these infections. both breeds acquired natural infections with h. contortus and lungworm when al ... | 1995 | 8746699 |
| dietary protein for young grazing sheep: interactions with gastrointestinal parasitism. | effects of protein supplementation and of nematode control on production responses in young grazing sheep and on nematode population dynamics were assessed. young merino wether sheep (n = 270) were allocated to one of three supplementation (su) treatments and one of three regimes of nematode control (drench, dr) in a factorial design. each of the nine treatments was replicated three times in a randomised complete block. animals received no supplement (su0) or were given supplements at a level eq ... | 1995 | 8747911 |
| evidence for multiple anthelmintic resistance in sheep and goats reared under the same management in coastal kenya. | four experiments, two with sheep and two with goats, were carried out to determine the efficacy of ivermectin, fenbendazole, levamisole, closantel and some of their combinations by faecal egg count reduction tests. in the first experiment, injectable ivermectin, oral ivermectin, fenbendazole and levamisole were tested in 6-month-old lambs, and their reduction percentages were 77%, 13%, 42% and 92%, respectively. in the second experiment, with yearling sheep, the reduction percentages were 35% fo ... | 1995 | 8747913 |
| studies on multispecific resistance of gastrointestinal nematodes to benzimidazoles on dairy-goat farms. | multispecific resistance to benzimidazoles was studied in three selected farms. these farms had bred dairy goats for more than 15 years. the helminths were introduced with the goats at the establishment of the farms which afterwards remained isolated. nematode resistance could then be related to their own management practices. faecal egg count tests and egg hatch assays were performed to assess intensity of resistance. the generic (infective larvae in faecal cultures) and specific richness (adul ... | 1995 | 8747916 |
| multiple anthelmintic resistance in haemonchus contortus on a sheep farm in india. | multiple resistance to benzimidazoles (fenbendazole, albendazole and mebendazole) in a strain of haemonchus contortus in sheep was detected on a farm where fenbendazole resistance had already been identified. following a faecal egg count reduction test, this was confirmed by both critical and controlled anthelmintic tests. different groups of sheep infected naturally or given an experimental infection with the fenbendazole-resistant strain were treated with the recommended doses of various anthe ... | 1995 | 8747919 |
| duration of the persistent activity of moxidectin against haemonchus contortus in sheep. | weaned lambs were infected with haemonchus contortus 35, 28, 21, 14 and 7 days after treatment with moxidectin at 0.2 mg/kg and 35 and 14 days after treatment with ivermectin at the same dose rate. worm counts 14 days after infection showed that moxidectin prevented the establishment of over 99% of infective larvae for 28 days and reduced the establishment rate at 35 days by 96%, relative to ivermectin. there was no difference in the protective efficacy of ivermectin at 14 or 35 days. the persis ... | 1995 | 8929185 |
| introduction to symposium on recent research on haemonchus contortus. | 1995 | 8635878 | |
| progress on vaccination against haemonchus contortus. | control of haemonchus contortus at present is largely by the use of anthelmintics, assisted in some regions by management programs. widespread development of resistance, particularly in south africa and australia, and concerns associated with the manufacture and use of chemicals have led to increasing interest in vaccination as an alternative means of control. vaccination strategies basically fall into 2 categories, 'hidden' antigens (usually derived from the gastrointestinal tract of the adult ... | 1995 | 8635880 |
| the immunogenetics of resistance to trichostrongylus colubriformis and haemonchus contortus parasites in sheep. | three possible immunogenetic markers for resistance to intestinal parasites in sheep have been studied. allotypes of the major histocompatibility complex (mhc) of the sheep have been investigated as markers, using serological typing or gene probes, for associations between allotypes and resistance to parasites in selected high responder and low responder lines of sheep. only the serologically-determined class i ovine leucocyte antigen (ola) types sy 1a and sy 1b have been found to be consistentl ... | 1995 | 8920110 |
| the fmrfamide-like neuropeptide af2 is present in the parasitic nematode haemonchus contortus. | peptides belonging to the fmrfamide family are widely distributed amongst invertebrates. we report here on the isolation of the fmrfamide neuropeptide af2 (lys-his-glu-tyr-leu-arg-phe-nh2) from the parasitic nematode haemonchus contortus. immunocytochemical techniques showed that fmrfamide-like material was distributed in several regions of these organisms including nerve cords and cell bodies of the central nervous system. af2 was isolated using a method that employed 6 steps of reverse-phase h ... | 1995 | 11023415 |
| effects of the excretory/secretory products of six nematode species, parasites of the digestive tract, on the proliferation of ht29-d4 and hgt-1 cell lines. | the excretory/secretory (es) products of the nematode parasite trichostrongylus colubriformis have been found to increase the in vitro proliferation of the epithelial cell line ht29-d4. to assess the specificity of this effect, es products from other trichostrongyle species were tested on colonic (ht29-d4) and gastric (hgt-1) tumour cell lines. adult worms of six different nematode species, parasites of the stomach or the small intestine of ruminants, were incubated in vitro in dulbecco's modifi ... | 1995 | 9439903 |
| management of anthelmintic resistance: inheritance of resistance and selection with persistent drugs. | resistance to the benzimidazole (bz) anthelmintics is inherited as an incomplete dominant/ incomplete recessive trait and is now widespread in populations of gastrointestinal nematode parasites of sheep. unlike benzimidazole resistance, which is common in haemonchus contortus, trichostrongylus colubriformis and ostertagia circumcincta, resistance to levamisole is relatively rare in h. contortus, although common in the other 2 species. one explanation for the slow spread of resistance to levamiso ... | 1996 | 8923146 |