Publications

immunological unresponsiveness of lambs to infection with haemonchus contortus. effect of infection in the ewe on the subsequent responsiveness of lambs.	specific antigen-induced lymphocyte transformation in vitro and haemagglutinating antibody responses were absent from lambs infected with haemonchus contortus. however, when lambs were injected with soluble third stage larval antigen of h. contortus, given on five occasions during the first 6 weeks of life, specific antigen-induced lymphocyte transformation and haemagglutinating antibodies were induced to the antigen. in particular, a periparturient increased susceptibility to infection and the ...	1984	6720033
control of hypobiotic and benzimidazole-resistant nematodes of sheep.	in studies comprising a total of 117 naturally infected crossbred lambs, it was found that lambs turned out to spring pasture were exposed to immediate infection with overwintered ostertagia, nematodirus, and trichostrongylus spp, but did not acquire haemonchus contortus infection until july. with all species, there appeared to be only one major disease-producing generation of worms per year; it was responsible for serious worm burdens and clinical disease from july onward. high frequencies of h ...	1984	6725108
haemonchus contortus: lipid biosynthesis from c14-labelled acetate and glucose.		1984	6730798
respiratory metabolism and thiabendazole susceptibility in developing eggs of haemonchus contortus.		1984	6735578
glutathione-s-transferase, a possible drug-metabolizing enzyme, in haemonchus contortus: comparative activity of a cambendazole-resistant and a susceptible strain.		1984	6735580
the relevance of in vitro anthelmintic screening tests employing the free-living stages of trichostrongylid nematodes.	the response of the free-living stages of nippostrongylus brasiliensis, nematospiroides dubius, haemonchus contortus, trichostrongylus colubriformis and ostertagia ostertagi to a wide variety of antiparasitic agents in vitro was investigated. all the major broad spectrum veterinary anthelmintics showed good activity against each of these worms with ec50 values varying from about 0.0002 mg/l for certain benzimidazoles and ivermectin to about 6.5 mg/l for febantel. of 22 known narrow spectrum anth ...	1984	6747252
the helminths of various antelope species from natal.	helminth parasites were collected from 2 bushbuck, tragelaphus scriptus, 2 red duiker, cephalophus natalensis, 1 oribi, ourebia ourebi, and 4 reedbuck, redunca arundinum, that died or were culled in various parts of natal. one trematode genus, 1 cestode genus and 12 nematode species were recovered. haemonchus contortus. ostertagia harrisi, trichostrongylus capricola, trichostrongylus vitrinus, cooperia rotundispiculum and setaria scalprum are new parasite records for the red duiker. trichostrong ...	1984	6241958
effect of ph and temperature on four dehydrogenase enzymes of haemonchus contortus.		1984	6242277
anthelmintic efficacy of mebendazole suspension against induced helminth infections in south african sheep and cattle.	critical controlled tests were performed in 157 sheep (8 experiments) and 34 cattle (2 experiments) to evaluate the anthelmintic activity of mebendazole suspension, administered intraruminally via a stomach tube at a dosage rate of 15 mg of mebendazole/kg of body weight, against induced infections of immature and adult stages of commonly encountered nematode parasites in south africa. in the sheep, the controlled efficacy of mebendazole suspension was good to excellent (90.1% to 100%) against al ...	1984	6375485
haemonchus contortus: effect of ph and temperature on some dehydrogenases.		1985	2940824
efficacy of ivermectin against induced gastrointestinal nematode infections in goats.	the efficacy of ivermectin (0.08 per cent w/v oral solution) at different dose levels was evaluated against induced infections of adult haemonchus contortus (21 days old) and trichostrongylus colubriformis (21 days old) and fourth stage larvae of oesophagostomum columbianum (17 days old), ostertagia circumcincta (five days old) and strongyloides papillosus (five days old). twenty-five boergoats (mutton goats) were randomly allocated by bodyweight within each sex to an untreated control group and ...	1985	3840299
potentiation of the anthelmintic activity of oxfendazole by parbendazole.	the ability of parbendazole (pbz) to potentiate co-administered oxfendazole (ofz) was investigated. administration of a range (1.35-36.0 mg/kg) of doses of pbz with 4.53 mg ofz/kg demonstrated that significant potentiation occurred at 4.5 mg pbz/kg. at 4.5 mg pbz/kg, the area under the plasma ofz concentration curve was about twice that obtained from oral administration of ofz alone. when tested against benzimidazole-resistant haemonchus contortus and trichostrongylus colubriformis, the mixture ...	1985	3840535
anthelmintic activity of ivermectin against immature gastrointestinal nematodes of sheep.	twenty-four lambs of mixed breeding with mixed experimental infections of haemonchus contortus, ostertagia circumcincta, trichostrongylus axei, and t colubriformis were allotted to 4 groups. one group (control) was given the vehicle propylene glycol, and the others were given 100, 200, or 300 micrograms of ivermectin/kg of body weight by mouth. twelve days after treatment, the sheep were necropsied. the compound was greater than 99% effective against immature stages of 4 nematode species at all ...	1985	3840965
[haemonchus contortus and ostertagia circumcincta: expulsion of parasites and restoration of the integrity of the abomasal mucosa after intraabomasal administration of arachidonic acid to the experimentally infested sheep].		1985	3935475
haemonchus contortus and ostertagia circumcincta: fenbendazole treatment and abomasal permeability changes in sheep.	effects of fenbendazole (7.5 mg/kg of body weight infused during 90 minutes) on abomasal transmural potential difference (pd), ph, and ionic concentrations were determined in 8 lambs fitted with permanent abomasal cannulae. four sheep were treated before inoculation and on day 28 after inoculation, with 200,000 3rd-stage ostertagia circumcincta larvae and 4 others were similarly inoculated with 15,000 3rd-stage haemonchus contortus larvae. in worm-free lambs, the unique effect was an increase in ...	1985	3970427
influence of dietary protein on the pathophysiology of ovine haemonchosis in finn dorset and scottish blackface lambs given a single moderate infection.	two experiments were conducted to examine the influence of dietary protein on the pathophysiology of haemonchus contortus in lambs of two breeds, namely finn dorset and scottish blackface. erythrokinetic and metabolic studies using 51cr-red cells, 59fe-transferrin and 125i-albumin, and digestive efficiency and nitrogen balance measurements were conducted between four and six weeks after infection. identical radioisotopic and nutritional studies were also conducted on pair-fed control lambs of bo ...	1985	3975482
influence of dietary protein on parasite establishment and pathogenesis in finn dorset and scottish blackface lambs given a single moderate infection of haemonchus contortus.	an experiment was conducted to examine the influence of dietary protein on parasite establishment and pathogenesis of haemonchus contortus in lambs of two breeds. finn dorset and scottish blackface. the lambs were introduced to high protein (170 g crude protein (cp) kg-1 dry matter (dm) or low protein (88 g cp kg-1 dm) diets at three months old and infected one month later with 125 larvae (kg bodyweight)-1. blood and faecal samples were collected for analysis and bodyweights recorded weekly. the ...	1985	3975483
resistance of exotic and domestic lambs to experimental infection with haemonchus contortus.		1985	3980138
the contribution of a partial tricarboxylic acid cycle to volatile end-products in thiabendazole-resistant and susceptible trichostrongylus colubriformis.	acetate, propionate, ethanol and propanol were the predominant end-products released during incubation of a thiabendazole resistant and a susceptible strain of trichostrongylus colubriformis. the parasites in all the incubations appeared to be deficient in reducing equivalents if the end-products arose from the classical catabolic pathway through fumarate reductase (ec 1.3.1.6). possible alternative pathways for accounting for redox balance, including beta-oxidation, the pentose phosphate pathwa ...	1985	3990706
the seasonal prevalence of inhibited development of haemonchus contortus in sheep in senegal.	throughout a period of 13 months, the abomasa of 1024 sheep, living in a sahelian region, were examined for adult haemonchus contortus and their inhibited l4 larvae. of these 796 (78%) were found harbouring h. contortus, but with low worm burdens (geometric mean 37). significant numbers of inhibited larvae appeared early in the dry season (november) and they represented 49% of the total in december. a similar proportion of inhibited larvae were present until april and after that their number dec ...	1985	3992869
cuticular carbohydrates of three nematode species and chemoreception by trichostrongylus colubriformis.	the cuticle of haemonchus contortus, nippostrongylus brasiliensis and trichostrongylus colubriformis contained n-acetylgalactosamine and n-acetylglucosamine, based on the binding of fluorescein-labelled lectins. binding of the lectins varied between the sexes and body regions of the nematodes. treatment of male t. colubriformis with the lectin lens culinaris agglutinin (lca) reduced the feeding by helminths that was stimulated by histamine and the male's response to their female's pheromone, bas ...	1985	3998961
study of gastro-intestinal strongylosis in a sheep flock on permanent pasture 2. sheep parasitism in 1978-1979.	the epidemiological study carried out in 1977 in the limousin region of france was continued for the next two years. eighty-five lambs were slaughtered at the rate of five animals every weeks: sixty were slaughtered from may 1978 to march 1979 and twenty-five from may to september 1979. total parasite counts and coprological examinations were carried out. in spring the infestation of the lambs was early and heavy, and revealed that certain free-living stages can survive in low temperatures. the ...	1985	4014986
effects of season and physical condition on the gastrointestinal helminth community of white-tailed deer from the texas edwards plateau.	eighty-six adult female white-tailed deer, odocoileus virginianus (zimmermann), collected over a 12-mo period in the texas edwards plateau, harbored six species of nematodes (haemonchus contortus, gongylonema pulchrum, oesophagostomum venulosum, ostertagia ostertagi, cooperia sp., and apteragia odocoilei), and two cestodes (moniezia sp. and taenia hydatigena). the patterns of distribution of the three common species of gastrointestinal helminths (h. contortus, o. venulosum, and g. pulchrum) were ...	1985	4032624
haemonchus contortus: qualitative and quantitative analysis of lipids.		1985	4050203
anthelmintic resistance in nematode parasites of goats.	cases of anthelmintic resistance on 3 goat farms in gippsland were investigated. on the first farm haemonchus contortus, trichostrongylus colubriformis and ostertagia (teladorsagia) circumcincta were found to be resistant to fenbendazole, but the first 2 species were fully susceptible to levamisole. on the second farm a population of t. colubriformis, resistant to concurrent full doses of levamisole and a benzimidazole, was found to retain this resistance when transferred to sheep. on the third ...	1985	4051913
enhancement of resistance of lambs to haemonchus contortus by previous infection with ostertagia circumcincta.	two experiments were performed to determine whether previous infection of young lambs with ostertagia circumcincta increased their resistance to the development of haemonchus contortus and to explore alterations in the microenvironment of the abomasum related to the interaction. the parasitic infections were monitored with periodic fecal egg counts and by recovery and enumeration of parasites at necropsy of the lambs. alteration of the microenvironment was examined by measurement of serum gastri ...	1985	4062019
regulation of haemonchus contortus populations in sheep exposed to continuous infection.		1985	4066146
studies on the abomasal pathology of immunized and non-immunized sheep infected with haemonchus contortus.	five adult ewes and five lambs were repeatedly immunized with weekly doses of 10,000 irradiated haemonchus contortus l3 before challenge with 100,000 and 10,000 normal larvae respectively. two groups of non-immunized ewes and lambs were similarly challenged and one animal from each of the four groups killed on days 3, 5, 7, 10 and 24 post-challenge. the cellular changes in the abomasal mucosa were less marked in the non-immunized groups than in the immunized animals and appeared later in the lam ...	1985	4093592
a strain of haemonchus contortus resistant to thiophanate.	the occurrence of a field strain of haemonchus contortus resistant to thiophanate is reported for the first time in new zealand. in a controlled anthelmintic trial with experimentally infected animals, thiophanate at 50-100 mg/kg had no appreciable effect on the haemonchus burden. albendazole reduced faecal strongylate egg counts by 95% in animals with naturally acquired 59 infections.	1985	16031158
the persistence of the anthelmintic activity of ivermectin in sheep.	the persistent anthelmintic effect of subcutaneously and orally administered ivermectin given at a dose rate of 0.2 mg/kg was evaluated against experimentally induced infections of haemonchus contortus, ostertagia spp., trichostrongylus spp. and cooperia curticei in sheep. while both ivermectin treatments apparently resulted in some reduction in the establishment of most of the parasite species examined, only for c. curticei were these reductions statistically significant. for c. curticei, stati ...	1986	16031290
non-confirmation of anthelmintic resistance in ostertagia spp.	an investigation was undertaken to confirm the existence of a mebendazole-resistant strain of ostertagia spp. on a ram-breeding property in taihape. the results indicated that while a strain of haemonchus contortus from this farm was highly resistant to mebendazole, an isolate of ostertagia spp. was fully susceptible. possible reasons for the discrepancy between previous and present findings are briefly discussed.	1986	16031304
haemonchus contortus: lipid biosynthesis from 14c-labelled palmitic acid and sodium bicarbonate.		1986	3034005
incorporation of carbon from 14c-labelled precursors into major chemical fractions of haemonchus contortus in vitro.		1986	3034006
[haemonchus contortus: inhibition of prostaglandin synthesis by the abomasal mucosa promotes the development of the parasite].		1986	3943589
pathologic changes in lambs with ostertagia circumcincta infections associated with decreased infectivity of haemonchus contortus.	two experiments were done to examine the severity and type of abomasal lesions induced by moderate infections of ostertagia circumcincta in young lambs and to examine the differences in pathologic changes in lambs with monospecific and combined infections of o circumcincta and haemonchus contortus. observations included descriptions of gross and microscopic changes in the abomasums, as well as quantitative analysis of the thickness of the mucosa, numbers of mucus-containing cells, and inflammato ...	1986	3954209
control of helminthosis in lambs by strategic treatment with closantel and broad-spectrum anthelmintics.	treatment of ewes with broad-spectrum anthelmintic in august (pre-lambing) and early november, and of lambs in early november and early february, was effective in controlling infections with trichostrongylus spp in lambs reared on contaminated pastures under set-stocked conditions. it was ineffective in controlling infections with haemonchus contortus; 82% of lambs had to be withdrawn from the experiment because of severe haemonchosis. treatment with closantel (7.5 mg/kg) at the same times was v ...	1986	3954695
resistance to benzimidazole of haemonchus contortus utkalensis in sheep on martinique.		1986	3962103
control of trichostrongylid pasture infestation in spring by the periparturient anthelmintic treatment of housed ewes prior to or at the time of turn out.	ewes, housed in late november and lambing in late february and march, were divided into three groups of eight, six and eight animals, and received a single treatment with ivermectin (approximately 200 micrograms kg-1) in late february (group i), on 15 april (group ii), or on 1 may (group iii), respectively. the egg output of the ewes and, subsequently, of eight lambs (group iv) was measured at 2-weekly intervals by counting and identifying the larvae after culture. group i showed a small rise in ...	1986	3962158
effect of cool storage of faecal samples containing haemonchus contortus eggs on the results of an in vitro egg development assay to test anthelmintic resistance.	an in vitro egg development assay was used to test the resistance of eggs from a benzimidazole susceptible and a resistant strain of haemonchus contortus to four benzimidazoles. storage of eggs contained in faecal samples at 4 degrees c for four, 24 or 72 hours did not appear to impair the results from the in vitro egg development assay or alter the ld50. storage for one week, however, proved to be lethal for the eggs. the average ld50 values for thiabendazole, albendazole, mebendazole and cambe ...	1986	3704322
the effect of dietary protein on the pathogenesis of acute ovine haemonchosis.	two experiments were conducted to examine the influence of dietary protein on parasite establishment and pathogenesis in finn dorset/dorset horn lambs infected with haemonchus contortus. the lambs were introduced to high (169 g) or low (88 g crude protein (cp) kg-1 dry matter (dm)) protein diets at 3 months of age and infected 1 month later with 350 larvae kg-1 body weight (bw). blood and faecal samples were collected for analysis and body weights recorded weekly. in the first experiment some of ...	1986	3716173
the effect of dietary protein on the pathophysiology of acute ovine haemonchosis.	an experiment was conducted to examine the effect of dietary protein on the pathophysiology of acute haemonchosis in finn dorset/dorset horn lambs. erythrokinetic and metabolic studies using 51cr-red cells, 59fe-transferrin and 125i-albumin and digestive efficiency and nitrogen balance measurements were conducted between 19 and 39 days after infection. identical radioisotopic and nutritional studies were conducted later on pair-fed control lambs. the results demonstrated that lambs on a low prot ...	1986	3716174
the helminth parasites of various artiodactylids from some south african nature reserves.	the helminth species composition and helminth burdens of 4 grey duikers, 12 bushbuck, 2 nyala, 2 giraffe, a steenbok, an oribi, a waterbuck and a tsessebe from the kruger national park (knp); of a steenbok and a greater kudu from the farm riekerts laager, transvaal; of a single blue duiker from the tsitsikama forest national park, and of a blue wildebeest, a red hartebeest, a gemsbok and 2 springbok from the kalahari gemsbok national park (kgnp) were collected, counted and identified. new parasi ...	1986	3725333
cultivation of haemonchus contortus (nematoda: trichostrongylidae) from infective larvae to the adult male and the egg-laying female.	the parasitic nematode haemonchus contortus was cultured in vitro to the adult male and the egg-laying female. gastric contents from 2 cannulated calves and 2 sheep as well as extracts of stomach mucosa from both hosts were added to a mixture of api-1 culture medium and fildes' reagent (a pepsin digest of defibrinated bovine blood) adjusted to ph 6.4 for the first week and ph 6.8 thereafter. the gas phase was 85% n2:5% o2:10% co2. best results were obtained when api-1 culture medium plus fildes' ...	1986	3734999
effect of ph and temperature on lipase and phospholipase of adult haemonchus contortus (nematoda: trichostrongylidae).		1986	3735000
the effect of triflumuron (sir8514) on the free-living stages of sheep nematodes.	studies both in vitro and in vivo showed that the insect growth regulator, triflumuron, exhibited potent larvacidal effects against the free-living stages of trichostrongylus colubriformis. effects were not as marked on the closely related nematodes, haemonchus contortus and ostertagia circumcincta. nevertheless, these findings suggest that growth regulators may be used to develop novel methods of nematode control, and thus offer alternatives or adjuncts to conventional anthelmintic therapy and ...	1986	3739204
the comparative efficacy of oxfendazole administered as bolus and suspension to naturally infected sheep in greece.	in a flock of 20 ewes naturally infected with those parasites of sheep most common in greece, and kept indoors during the whole trial, oxfendazole at the dose rate of approximately 2.9 and 2.8 mg/kg body-weight was tested as a 4 g bolus containing 112 mg active ingredient and a 2.265% suspension. the evaluation of its efficacy was based on the necropsy findings which were also supported by faecal egg counts. no differences in efficacy were noticed between the two formulations of the drug. both b ...	1986	3745877
interactions of benzimidazoles (bz) with tubulin from bz-sensitive and bz-resistant isolates of haemonchus contortus.	the binding of tritiated benzimidazoles (bzs)-albendazole, parbendazole, oxibendazole, mebendazole, oxfendazole and fenbendazole-to crude tubulin extracts from bz-susceptible and -resistant haemonchus contortus has been examined. for all bzs, the binding was substantially lower in the resistant isolate. the extent of this reduction was dependent on the structure of the bz, with mebendazole demonstrating superior binding to the resistant isolate than the other bzs. enrichment of the crude tubulin ...	1986	3755220
activity of ivermectin against natural infections by abomasal nematodes in lambs in controlled tests: evaluation of equine and bovine injectable formulations administered intraorally.	the efficacy of 2 injectable formulations of ivermectin, administered intraorally at the dosage of 200 micrograms/kg of body weight, was evaluated against naturally occurring infections by abomasal nematodes in lambs in 2 controlled tests. one test (a) included 17 lambs treated with the equine formulation and 16 nontreated lambs. for the other test (b), 14 lambs were treated with the bovine formulation, and 12 were nontreated. in controlled test a, only mature nematodes were recovered, and remov ...	1986	3755309
efficacy of repeated doses of levamisole, morantel, fenbendazole, and ivermectin against gastrointestinal nematodes in ewes.	levamisole, morantel, fenbendazole, or ivermectin was administered at 2-week intervals from may 1 through sept 14, 1985, to breeding ewes (20 ewes/drug) infected with various gastrointestinal nematodes. all ewes had fewer gastrointestinal nematode eggs per gram of feces (epg) after 2 treatments, compared with pretreatment epg counts. ewes administered ivermectin continued to have a low mean epg (0 to 3) throughout the study. the mean epg counts of ewes treated with levamisole increased from 3 to ...	1986	3755877
changes in serum pepsinogen and haemoglobin concentrations in calves infected with haemonchus contortus.	in four calves given haemonchus contortus larvae, the serum pepsinogen concentration rose quickly to reach a mean of 3.5 iu tyrosine on day 14 after infection. the mean concentration dropped to 1.8 iu tyrosine by day 23 and remained around 2.0 iu tyrosine until an anthelmintic was given on day 57, when concentrations returned to preinfection values.	1986	3764097
in vitro demonstration of in utero larval development in an oviparous parasitic nematode: haemonchus contortus.	the life-cycle of haemonchus contortus, a pathogenic stomach nematode of sheep, is typical of those of the other members of the superfamily trichostrongyloides, all of which require a period of development outside the definitive host. classically, gravid h. contortus, known as strictly oviparous, releases her eggs into the abomasal lumen. the eggs are passed out in the faeces in which they hatch into the 1st-stage larvae and then develop into the infective 3rd-stage larvae. we have developed a m ...	1986	3785975
haemonchus contortus and other trichostrongylid infections in parturient, lactating and dry ewes.	from autumn (april) to spring (november), groups of pregnant and dry merino ewes grazed pasture contaminated with infective larvae of haemonchus contortus, ostertagia circumcincta and trichostrongylus colubriformis. a periparturient rise in faecal egg counts occurred in the pregnant ewes, following the maturation in early spring of arrested fourth-stage larvae of h. contortus and failure of pregnant ewes to expel the resulting adult worms. peak egg counts were seen in september, just before lamb ...	1986	3788026
developmental arrest of haemonchus contortus in sheep treated with a corticosteroid.		1986	3804575
[microecological characterization of parasitic nematoda present in goats of arid zones of venezuela].	goats from the venezuelan northern arid zones were found infested by the following nematodes: haemonchus contortus, trichostrongylus axei, t. colubriformis, cooperia curticei, oesophagostomum columbianum, skrjabinema ovis y trichuris globulosa. the shannon-weaver index of diversity values oscillated between 0.045 and 1.73 bits (means = 1.16 +/- 0.24 bits). the maximum value of montly diversity ranged from 1 to 2.80 bits (means = 2.49 +/- 0.28 bits) and the equitability ranged from 0.045 to 0.67 ...	1986	3587000
effects of anthelmintics on haemonchus contortus (nematoda: trichostrongylidae).	the review summarizes and evaluates recent information about the effects of anthelmintics on haemonchus contortus. the topic is discussed under the headings effects of drugs on the absorptive surfaces, effects of drugs on metabolism, effects of drugs on the neuromuscular system, effects of drugs on developmental stages, anthelmintic efficacy, and resistant strains. possible future lines of work are suggested in the conclusions.	1986	3511606
evaluation of three formulations of fenbendazole (10% suspension, 0.5% pellets, and 20% premix) against nematode infections in cattle.	anthelmintic efficacies of 3 formulations of fenbendazole were evaluated in cattle naturally parasitized with nematodes: a 10% oral suspension, 0.5% pellets as a top dressing on feed, and a 20% premix. all formulations of fenbendazole were greater than 99% effective in removing adults of haemonchus contortus, ostertagia spp, cooperia spp, and oesophagostomum radiatum. fenbendazole was greater than 96% effective in removing adults of strongyloides papillosus and greater than 85% effective in the ...	1986	3516024
the periparturient rise in fecal egg counts in three strains of florida native ewes and its value in predicting resistance of lambs to haemonchus contortus.		1986	3528003
transcuticular solute movement in parasitic nematodes: relationship between non-polar solute transport and partition coefficient.	the rate constants (k) for steroid transport across the isolated cuticle of ascaris suum were, linearly related to partition coefficients (p) of steroids in model solvents. the slope of log p vs log k for an isolated cuticle was closest to unity for the more polar solvents, octanol and ether, suggesting that the barrier to steroid movement across the cuticle has partition properties similar to these solvents. the transcuticular movement of steroids into intact adult a. suum and infective larvae ...	1986	2874926
the physiology of infection with nematodes: the role of intracellular ph in the development of the early parasitic stage.	1. h2co3, the host's signal which induced (less than 25 min) the ca2+-dependent development of the first parasitic stage of haemonchus contortus, produced a diphasic change in the phi (less than 30 min), measured with 5,5-dimethyl-2,4-oxazolidinedione, in the infective stage. the intensity of the diphasic change was related to the [h2co3] and so to the efficiency of the stimulus for development. 2. mes and hepes buffers induced a rapid rise in phi of infective stages in step with pho. ortho-and ...	1987	2890466
[benzimidazole resistance in haemonchus contortus in a south german sheep herd].		1987	3297604
two field strains of haemonchus contortus resistant to rafoxanide.	two field strains of haemonchus contortus, one from pretoria on the highveld and the other from white river in the lowveld of the transvaal, showed pronounced resistance to rafoxanide at a dosage rate of 7.5 mg/kg live mass per os. both of these strains originated from kikuyu pastures under irrigation. resistance in south africa to rafoxanide and other anthelmintics, namely, closantel, ivermectin and the benzimidazoles is reviewed. it is concluded that apart from avoiding farming practices where ...	1987	3306550
comparison of inhibition of polymerisation of mammalian tubulin and helminth ovicidal activity by benzimidazole carbamates.	the correlation between the inhibition of hatching of haemonchus contortus eggs and inhibition of mammalian tubulin polymerisation by benzimidazole carbamates has been investigated. the hatching process was observed to be independent of the biomass (eggs plus debris) over a 6-fold range and the early (e1-e3) stages of egg development, but was dependent on the concentration of co-solvent (dmso) and time of incubation. benzimidazole carbamates with strong inhibitory activity against mammalian tubu ...	1987	3564338
changes in lipids and free fatty acid fractions in adult haemonchus contortus during incubation in vitro.	adult haemonchus contortus (rud., 1803) has been investigated for its ability to utilize lipids with regard to the total lipids, sterols, free fatty acids, acylglycerols and phospholipids produced during incubation in vitro. all these components exhibit extensive fluctuations, decreasing at some times and increasing at others, thus indicating both biosynthesis and utilization. also, changes in fatty acid components of total lipids have been analyzed by gas liquid chromatography. these observatio ...	1987	3564346
comparison of ivermectin and thiabendazole for treatment of naturally occurring nematode infections of goats in kenya.	the anthelmintic activity of thiabendazole (tbz) at 88 mg kg-1 and ivermectin at 0.2 mg kg-1 was examined in goats with naturally-acquired nematode infections. in one experiment, a herd of 450 does was treated with tbz or ivermectin at 4-week intervals for 9 months and efficacy was measured by reduction in faecal egg counts after each treatment. in a second experiment, 100 kids were treated with ivermectin and effectiveness measured at 2 and 4 weeks after treatment by comparison of their egg cou ...	1987	3564349
partial protection of lambs against haemonchus contortus by vaccination with a fractionated preparation of the parasite.	florida native lambs, less than 6 months of age, were successfully vaccinated against haemonchus contortus with a high mol. wt fraction (greater than 30,000 daltons) derived from a somatic extract of h. contortus larvae (sel) and excretions and secretions (es) of larvae isolated during in vitro development from the infective 3rd to 4th stage. a 59% reduction in adult worm numbers was obtained in vaccinates compared to naive lambs following challenge. the protection in vaccinated lambs was simila ...	1987	3564350
repeatability of ovine faecal egg counts and blood packed cell volumes in haemonchus contortus infections.		1987	3583550
parasites as stressors: plasma cortisol responses of goats infected with the stomach worm haemonchus contortus to exogenous corticotropin (acth).	ten male, juvenile pigmy goats of similar age and weight were allocated randomly to two groups. goats in one group were each inoculated with 20,000 infective larvae of haemonchus contortus. the other group served as uninfected controls. goats were housed together, and precautions were taken to avoid the creation of differential, between group, stressogenic circumstances. body weights, nematode egg production, hematocrits, and clinical signs were monitored over a 61-day period following inoculati ...	1987	3031870
the genetics of resistance and resilience to haemonchus contortus infection in young merino sheep.		1987	3429127
lipid biosynthesis from 14c-glycerol in haemonchus contortus (nematoda: trichostrongylidae), in vitro.		1987	3434509
the anthelmintic efficacy of netobimin against naturally acquired gastrointestinal nematodes in sheep.	the broad-spectrum anthelmintic efficacy of netobimin (sch 32481, schering corporation) was evaluated using 30 cross-bred spring lambs with naturally acquired infections of gastrointestinal nematodes. three groups of 10 animals each were allotted into either control (given a tap water drench as a placebo) or 7.5 and 20 mg kg-1 dosage groups (given the netobimin as an oral drench). seven to fourteen days post-treatment, animals were necropsied and nematodes recovered by standard techniques. exami ...	1987	3439008
further investigation of the primary mechanism of benzimidazole resistance in haemonchus contortus.		1987	3440696
changes in the response of haemonchus contortus eggs to the ovicidal activity of thiabendazole during the course of infection.	hatching rates and susceptibility to thiabendazole were studied on haemonchus contortus eggs collected after either a single, a challenge or a trickle infection of sheep with a non-resistant strain. considerable changes were observed both in hatching rates and lc50 values for thiabendazole during the course of infection. peaks in lc50 suggested that a susceptible strain can produce eggs at least tolerant and perhaps slightly resistant at some days pi even without any previous contact with anthel ...	1987	3451681
systemic release of a mast cell proteinase following nematode infections in sheep.	an enzyme-linked immunosorbent assay (elisa) for sheep mast cell proteinase (smcp) has been developed. concentrations of smcp in homogenates of abomasal tissue from parasite-immune sheep (341 micrograms smcp/g tissues) were raised when compared to those in normal (non-infected) abomasa (0.145 micrograms smcp/g tissue). smcp was not detected in sera from normal animals challenged with haemonchus contortus but was present (less than 1.0 ng smcp/ml) in sera from 8/11 immune sheep 2 h after intra-ab ...	1987	3479741
[ecoepidemiology of haemonchus contortus bahiensis, ecotype present in sheep of arid zones of venezuela].	the frequency distribution of female haemonchus contortus bahiensis grisi, 1974 in sheep from venezuelan arid zones is 15.32% for the type with vulvar flap, 51.6% for the vulvar-knob and 33.07% for smooth type. a shannon-weaver diversity index corresponding to 1.44 bits was calculated for these forms with similarities in the general size, egg-size and in the number of the longitudinal cuticular ridges. an aggregated kind of distribution in the host population according to the k parameter of a ne ...	1987	3507572
parasites in sheep grazing on kikuyu (pennisetum clandestinum) pastures in the winter rainfall region.	regular worm counts were done post-mortem on sheep that had grazed on kikuyu pastures at the elsenburg research station near stellenbosch, a winter rainfall region. major species were trichostrongylus colubriformis, trichostrongylus axei, while ostertagia circumcincta was usually present in large numbers. minor species were haemonchus contortus, nematodirus spathiger, dictyocaulus filaria, oesophagostomum venulosum, trichuris spp., chabertia ovina and larvae of the arthropod oestrus ovis. muelle ...	1987	3587925
vaccination of young lambs by means of a protein fraction extracted from adult haemonchus contortus.	lambs aged 48-150 days which had been injected with extracts enriched in a functional antigen (contortin) obtained from adult haemonchus contortus developed specific circulating antibodies and were less susceptible to haemonchosis when challenged 1 month later with a single dose of 20,000-25,000 infective 3rd-stage larvae. sera from 18 out of a total of 19 lambs injected with the extract contained precipitating antibodies to 2-5 components of the extract. none of these lambs died. the one extrac ...	1987	3588016
epidemiology of gastrointestinal nematodes of sheep and goats in haryana, india.	epidemiological studies on some gastrointestinal nematodes of sheep and goats in karnal, ambala and rohtak districts of haryana (india) revealed that haemonchus contortus and trichostrongylus spp. were responsible for parasitic gastroenteritis in these hosts. the adult parasites persisted in the host throughout the year and there was no indication of hypobiosis. the maintenance of the parasite population depended on a continuous cycle of infection between the host and the pasture. the agroclimat ...	1987	3590608
[benzimidazole-resistant haemonchus contortus in sheep in west germany].		1987	3593194
efficacy of fenbendazole-medicated feed blocks against gastrointestinal nematode infections in calves.	an anthelmintic trial was conducted to determine the efficacy of fenbendazole (fbz) incorporated into two types of feed blocks given daily for 3 or 10 days to calves naturally parasitized with gastrointestinal nematodes. each treated calf consumed 5 mg of fbz/kg of body weight. the fbz was greater than 99% effective in removing adults of haemonchus contortus, ostertagia ostertagi, o lyrata, cooperia punctata, c pectinata, c onchophora, trichostrongylus axei, bunostomum phlebotomum, and oesophago ...	1987	3605803
physiological and microbiological changes in the abomasum of sheep infected with large doses of haemonchus contortus.	the ph, po2 and the number of viable bacteria per ml of abomasal fluid were recorded before and after administering large doses of infective larvae of h. contortus to sheep. highly significant increases were observed in the ph, in numbers of viable bacteria and in the proportion of oxygen-sensitive bacteria in the abomasal fluid during the first 10 to 14 days of infection. at the same time a decrease in the abomasal fluid po2 was recorded. subsequently a slow recovery of ph, po2 and bacterial nu ...	1987	3611432
changes in lc50 in an in vitro egg development assay during the patent period of haemonchus contortus in sheep.	using an in vitro egg development assay with thiabendazole as anthelmintic the lc50 of eggs produced by two sheep infected with either a susceptible or a resistant strain of haemonchus contortus was followed during the patent period from 22 days to 77 days after infection. in both sheep the lc50 followed the same pattern. at the start of the patent period the average values for the susceptible and the resistant strain were, respectively, 0.05 and 0.21 micrograms ml-1 thiabendazole, after 40 to 6 ...	1987	3616153
the pathogenicity of haemonchosis in sheep and goats in iraq: 1. clinical, parasitological and haematological findings.	the response of awassi sheep and the local breed of iraqi goats to primary infection with a prevalent trichostrongylid nematode, haemonchus contortus, was compared by examining their worm burden and the pathogenic effects of the parasite on these hosts following experimental infection. the results showed that the goats had lower worm burdens and had suffered less severe clinical and haematological disturbances than the awassi sheep. the worm counts in sheep were higher than in goats but the coun ...	1987	3617428
detecting in vitro anthelmintic effects with a micromotility meter.	an in vitro target parasite anthelmintic assay utilizing a micromotility meter has been developed and validated. haemonchus contortus, an economically important ruminant helminth with worldwide distribution, was the parasite used in the model. four commercially available ruminant anthelmintics (albendazole, ivermectin, levamisole hydrochloride and coumaphos) were initially evaluated at concentrations of 200, 150, 100 and 50 micrograms ml-1. all four significantly affected helminth motor activity ...	1987	3617429
prevalence of benzimidazole resistance of nematodes in sheep in the netherlands.	a survey was carried out in the netherlands to determine the prevalence of benzimidazole resistance in sheep nematodes. it was shown that 47 per cent of the 59 investigated flocks harboured trichostrongylid populations with resistance to benzimidazoles, as demonstrated by an ld50 value of 0.12 micrograms ml-1 thiabendazole or higher in an in vitro egg hatch assay. on these farms haemonchus contortus was found to be the dominant species. in two flocks resistant ostertagia and, or, trichostrongylu ...	1987	3628978
development and survival of haemonchus contortus larvae on pasture in iraq.	the survival of haemonchus contortus infective larvae on pasture and soil was studied over a period of 12 months in the baghdad area. infective larvae were found on herbage and soil at all times except in the summer months. during autumn and winter infective larvae in pasture survived for periods of up to 32 weeks. little larval migration into soil was observed during this study and larvae did not survive for long in the faecal pellets during the summer.	1987	3629723
evaluation of an antigenic fraction of taenia hydatigena metacestode cyst fluid for immunodiagnosis of bovine cysticercosis.	an antigenic fraction (thfas) isolated from taenia hydatigena metacestode cyst fluid was used in an elisa to detect antibodies to t saginata in experimentally and naturally infected cattle. in 10 calves given 1,000 to 100,000 t saginata eggs (20% to 60% viability), igg and igm antibodies were detected in all the calves by post-inoculation week 3. immunoglobulin g antibody values remained increased until calves were slaughtered at post-inoculation weeks 13 to 26. six naturally infected calves (de ...	1987	3631707
protection of lambs with a purified metabolite of exsheathed third-stage haemonchus contortus larvae.	helminth-free lambs (approx 4 months old) were inoculated sc with a purified metabolite of exsheathed third-stage haemonchus contortus larvae. the metabolite was obtained from in vitro cultivation and was identified as xl3fa1. after 3 periodic xl3fa1 inoculations, lambs were challenge exposed with h contortus. multiple vaccinations with xl3fa1 did not inhibit the development of worm populations in the lambs; however, worm egg production seemed to be inhibited.	1987	3631713
efficacy of levamisole and netobimin against haemonchus contortus in lambs in louisiana.	efficacy of levamisole was evaluated in a suspected levamisole-resistant population of haemonchus contortus in the louisiana state university sheep flock. the efficacy of netobimin also was evaluated against this population of haemonchus. in trial 1, 5 lambs naturally infected with h contortus were given 8 mg of levamisole/kg of body weight as a drench, and 5 lambs were not treated (controls). nematode recovery after slaughter indicated 0% efficacy against h contortus. in trial 2, 30 nematode-fr ...	1987	3662209
haemonchus contortus resistance to ivermectin.		1987	3681886
placental transfer of specific antibodies during ovine congenital toxoplasmosis.	the passage of non-toxoplasma antibodies from dam to fetus through damaged placenta was studied in sheep inoculated with toxoplasma gondii. six ewes were inoculated with chicken globulins and leptospira bacterins 2 months before oral inoculation with toxoplasma gondii oocysts. ewes were euthanatized between 42 and 62 days after t gondii inoculation. antibody titers against chicken globulins, leptospira spp, haemonchus contortus, sarcocystis spp, and t gondii were measured in the maternal and fet ...	1987	3105371
the comparative efficacy of four broad spectrum anthelmintics against some experimentally induced trichostrongylid infections in sheep and goats.	a controlled slaughter trial was undertaken to compare the efficacies of oxfendazole (5 mg/kg), morantel citrate (10 mg/kg), levamisole (8 mg/kg) and ivermectin (0.2 mg/kg) against experimentally induced infections of adult haemonchus contortus, ostertagia spp., trichostrongylus colubriformis and cooperiacurticei in sheep and goats. ivermectin and oxfendazole achieved similar levels of efficacy in both hosts against all four worm genera as did levamisole and mortantel against h. contortus and c. ...	1987	16031344
removal of haemonchus contortus, ostertagia circumcincta and trichostrongylus spp. from goats, by morantel citrate, levamisole hydrochloride, fenbendazole, and oxfendazole.	young feral goats harbouring 3, 7 and 36 day old experimental infections of strains of gastrointestinal nematodes, known to be susceptible to anthelmintics in sheep, were dosed orally with commercially available anthelmintics at the manufacturers' recommended rates for sheep. the drugs and overall removals of ostertagia circumcincta and trichostrongylus spp. (t. colubriformis and t. vitrinus) respectively were: morantel citrate 69% and 68%; levamisole hydrochloride 55% and >99%; fenbendazole 98. ...	1987	16031353
genetic resistance to haemonchosis in sheep.	parasitic nematodes cause huge economic losses to the domestic livestock industry. control requires skilled farm management and heavy use of anthelmintics, but breeding for resistant animals has long been held a possibility. for about 20 years after world war ll, the genetics of association between sheep breeds and haemonchus contortus - the main parasite of importance in sheep - was studied in the usa and europe. since the early 1970s, however, such studies have received greater emphasis in aus ...	1987	15462974
the efficacy of albendazole against some gastrointestinal nematodes in goats.	on the basis of worm counts in naturally infected angora-x goats, albendazole at either 3.8 mg/kg repeated after 24 hours or as a single dose at 7.6 mg/kg, was >99% effective in removing adult ostertagia and trichostrongylus spp. small numbers of adult haemonchus contortus, cooperia sp. and chabertia ovina were present in control but not treated animals. the single dose of 7.6 mg/kg removed >99% of adult oesophagostomum venulosum whereas the repeated dose of 3.8 mg/kg removed only 96%.	1988	16031461
the effect of selenium supplementation on immunity, and the establishment of an experimental haemonchus contortus infection, in weaner merino sheep fed a low selenium diet.	immunity in 12 weaner merino sheep fed a low selenium (se) diet (low se sheep) was compared with that in 10 matching sheep fed the same diet but each given an intraruminal se pellet (high se sheep), while the sheep were housed in individual, sheltered pens. all sheep were challenged with killed brucella abortus cells (days 0 and 28), rabbit red blood cells (days 0, 7 and 28) and corynebacterium pseudotuberculosis toxoid (days 0 and 28), and serum antibody titres were measured weekly for 8 weeks ...	1988	3138968
the effect of dexamethasone on a single and a superimposed infection with haemonchus contortus in sheep.		1988	3170067
resistance of field strains of haemonchus contortus to ivermectin, closantel, rafoxanide and the benzimidazoles in south africa.	after a first description in 1975 of a strain of haemonchus contortus resistant to the benzimidazole anthelmintics in south africa, further strains of the same species developed resistance to rafoxanide and closantel, and a strain of ostertagia species became resistant to the benzimidazoles. recently five further strains of h contortus have been found which show resistance to these anthelmintics. of these, four showed varying degrees of resistance to ivermectin and one was resistant to three ant ...	1988	3176284
field observations on the control of ovine parasitic gastroenteritis in south-east england.	three worm control strategies, on a commercial farm in south east england, were monitored parasitologically for a grazing season. three peaks of larval infection in june, late august and late october/early november occurred on paddocks grazed by dosed ewes and lambs on a new ley (preventive strategy). lambs dosed and moved on to a hay aftermath in july (evasive strategy), had a mean egg count of 2090 by late august, attributable to infection with haemonchus contortus. three weekly drenching of l ...	1988	3188346
evaluation of haemonchus contortus infections in sexually intact and ovariectomized ewes.	three experiments were conducted to investigate experimentally the occurrence of periparturient nematode egg rise in ewes and the hormonal modulation of haemonchus contortus infections. in the first experiment, fall-bred and winter-bred pregnant (n = 4 and 14, respectively) and nonpregnant (n = 5 and 29, respectively) ewes were treated with anthelmintic and were pastured together on fields that were contaminated with h contortus. three weeks before lambing, all ewes were placed in concrete pens; ...	1988	3189989
haemonchosis in sheep and goats in sierra leone.	the incidence of haemonchosis in sheep and goats in sierra leone showed a seasonal variation with a high peak in the dry season (october to january) and a low one from march to may. mean relative densities were significantly higher in young hosts and showed two peaks, a high one from august to december and a low one from april to june while the mean relative densities of old hosts were low and exhibited an irregular seasonal pattern with no defined peaks. the peak seasons in young hosts coincide ...	1988	3192917