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haemonchus contortus: new data on its genetic constitution. 19751126417
failure to vaccinate lambs against haemonchus contortus with functional metabolic antigens identified by immunoelectrophoresis. 19751140881
the anthelmintic efficacy of fenbendazole against a mixed nematode infection in sheep.fenbendazole (methyl-5-(phenylthio)-2-benzimidazole carbamate) at dose rates of 5 mg/kg and above was 100 per cent effective in eliminating a naturally acquired dictyocaulus filaria infection in sheep. the drug was 100 per cent effective in eliminating concurrent infections of adult trichostrongylus axei, haemonchus contortus, haemonchus placei, ostertagia circumcincta, ostertagia ostertagii, cooperia oncophora, cooperia mcmasterii, nematodirus spathiger, neumatodirus filcollis, oesophagostomum ...19751153893
the effect of ageing on the antigenicity of haemonchus contortus larvae.viable haemonchus contortus larvae used as a source of antigen in complement fixation tests showed a decrease in antigenic potency following storage for approximately two months at 5 degrees c. in contrast, larvae killed by freezing and stored at --15 degree c showed no such decline over a similar period. it is suggested that this loss of potency with ageing may be partly responsible for increased worm populations in sheep in spring.19751153895
age group interaction of haemonchus contortus in premunized lambs.lambs premunized with a relatively less pathogenic (rlp) isolate of haemonchus contortus were challenge exposed each day with 500 3rd-stage larvae (l3) of a normally pathogenic isolate of the same worm, starting on day 9 of the premunition-induced infection. in 6-month-old lambs, there was a fourfold decrease in egg production by the premunizing rlp isolate with challenge exposure compared with egg production in lambs given only the premunizing rlp isolate and not challenge exposed. premunized l ...19751155835
effect of cambendazole, thiabendazole, and levamisole on fumarate reductase in cambendazole-resistant and -sensitive strains of haemonchus contortus. 19751165565
cross-resistance to other anthelmintics in an experimentally produced cambendazole-resistant strain of haemonchus contortus in lambs. 19751165566
the use of disophenol in studies of the pathogenicity of the arrested fourth-stage larvae of haemonchus contortus in the sheep.disphenol was administered to sheep infected with haemonchus contortus in order to prevent the development of populations of adult worms, and studies were made of the pathogenicity of the arrested fourth-stage larvae which remained. the treated sheep showed elevated plasma pepsinogen and abomasal ph, predominantly negative dry-matter balance, and evidence of greater fluid loss, including plasma, into the gastro-intestinal tract. it was concluded that arrested larvae may cause damage to the aboma ...19751166136
inhibited development in haemonchus contortus.inhibited development of haemonchus contortus was studied in single experimental infections of worm-free lambs. chilling of the infective larvae at +4 degrees c was without effect on the percentage of larvae subsequently becoming inhibited and a period of exposure to autumnal conditions was unnecessary to induce a high rate of inhibition. it was concluded that seasonal inhibition of h. contortus in east anglia is brought about primarily by an environmental stimulus acting upon the preparasitic s ...19751187184
field studies on inhibition of haemonchus contortus.the epidemiology of haemonchus contortus was studied in north east england in lambs reared under field conditions with infected ewes. the parasite population was monitored by pasture larval counts, faecal egg counts and lamb postmortems. from 25 june to 11 november, eight lambs were slaughtered each month, together with eight worm-free tracer lambs. postmortem worm counts showed that on 25 june, small numbers of adult h. contortus were present but no inhibited larvae. however, subsequently the n ...19751187186
observations on the development of haemonchus contortus in young sheep given a single infection.worm free lambs 2-4 months old were given a single infection of 50,000 haemonchus contortus larvae. the changes in packed red cell volume were compared with those of uninfected sheep and the infected sheep were divided into two groups according to the rate of change of packed cell volume. in group 1, packed cell volume fell sharply from the 10th day of infection and the sheep eventually died. in group 2, the fall was less marked and the packed cell volume returned to normal after about 40 days. ...19751202415
the resistance of a field strain of haemonchus contortus to five benzimidazole anthelmintics in current use.using artificially infected sheep, the response of a laboratory strain of haemonchus contortus, which had not been subjected to anthelmintics for three years, was compared with that exhibited by a parbendazole resistant field strain following treatment with each of seven anthelmintics, the laboratory strain proved fully susceptable to thiabendazole, parbendazole, cambendazole, mebendazole, fenbandazole, levamisole and haloxon, in contrast to the field strain which showed a moderate to marked res ...19751223291
micrometeorological factors involved in development and survival of free-living stages of the sheep nematodes haemonchus contortus and trichostrongylus colubriformis. a review. 19751232063
relationship of pasture rotation to acquisition of gastrointestinal nematodes by sheep.in a study of the relationship between pasture rotation in illinois and acquisition of nematodes (mostly haemonchus contortus) and body weight gains by lambs grazing with their ewes, 2 pasture rotation systems were tested. (1) lambs and ewes were rotated through a series of 12 alfalfa-bromegrass-lespedeza pastures, each pasture being grazed for 3 to 4 days and rested for 5.5 weeks; 4 complete rotations were done during a 168-day grazing season. (2) lambs and ewes were moved every 2 days, and 3 c ...19751238039
[changes in the serum proteins in lambs experimentally infected with haemonches contortus].infected were experimentally eight lambs with larvae of haemonchus contortus. the test lambs were divided into two groups and were given each, by groups, 2500 and 5000 h. contortus larvae. prior to infection and on the 10th, 20th, 30th, 40th and 50th day following it electrophoretic studies on the blood serum were performed. results showed that certain quantitative changes in the protein fractions took place. they consist in the drop of the albumin and the rise of the globulin fractions.19751239856
the efficacy of thiabendazole against the arrested larvae of some trichostrongylidae and chabertia ovina in sheep.the activity of thiabendazole at 100 mg/kg was tested against the arrested larvae of ostertagia spp, haemonchus contortus, trichostrongylus axei, nematodirus spp and chabertia ovina in natural infections, in 10-month-old lambs. the result, assessed by means of worm counts, showed the treatment to be very effective.19761257622
the ecology of the free-living stages on haemonchus contortus. 19761260414
the passive transfer of humoral immunity from sows infected with hyostrongylus rubidus (hassal and stiles, 1892), the red stomach worm, to their offspring and its significance in the conferring of protective immunity.sows repeatedly infected with large single doses of third stage infective hyostrongylus rubidus larvae show an anamnestic circulating agglutinin response to the parasite as detected by the passive haemagglutination reaction. at farrowing the circulating antibody level dropped, whereas the colostral agglutinating antibody level increased for a period of a few hours. the predominant class of immunoglobulin which had agglutinating activity against h. rubidus was igg. offspring which had suckled the ...19761262052
haemonchus contortus infection in ewes: blastogenic responses of peripheral blood leukocytes to third stage larval antigen. 19761262125
influence of potassium ion and osomtic pressure on development of haemonchus contortus in vitro.development of infective larvae of haemonchus contortus to the fourth stage in vitro was impaired if the concentration of potassium ion in the medium was 0.26 mm or less. at or below 0.015 mm, development was almost completely stopped. high concentrations of potassium, in solutions with a ratio of sodium to potassium from 150 down to 1.3, were all equally favorable for development, but solutions composed only of salts of potassium were unfavorable. development was impaired by osmotic pressures b ...19761263034
effect of desiccation on the survival of infective haemonchus contorus larvae under laboratory conditions.when stored in water at 4 and 20 c, respectively, 42 and 36% of free 3rd-stage, infective larvae of haemonchus contortus were alive after 256 days. when stored at -95 c, 73% of the free, desiccated larvae died during the 1st half hour and 80% during the 1st half day; thereafter no more died for 255 days, the duration of the experiment. desiccation protected the larvae against death on storage at temperature below freezing, but it was harmful at temperatures above freezing. h. contortus larvae do ...19761263035
efficacy of p-toluoyl chloride phenylhydrazone against gastrointestinal helminths in ovines.a new anthelmintic candidate, p-toluoyl chloride phenlylhydrazone, was administered to lambs in a paste formulation. the efficacy of this drug was determined at dose rates of 20, 30, 40, and 50 mg of active ingredient per kilogram of body weight. helminths expelled by these dosages included haemonchus contortus, ostertagia circumcicta, trichostrongylus colubriformis, t. axei, nematodirus filicollis, cooperia curticei, strongyloides papillosus, oesophagostomum columbianum, bunostomum trigoncephal ...19761263040
a possible relationship between haemonchosis and haemoglobin polymorphism in merino sheep in kenya.it is known that sheep show polymorphism for haemoglobin in that three phenotypes (hba, hbb and hbab) are normally found. since it has been suggested, on the basis of haematological values, that hba type sheep are more able to survive in haemonchus contortus endemic environments, a preliminary study was conducted on the performance of set-stocked merino ewes and lambs in relation to their haemoglobin phenotypes. the results provided some evidence that, in merino sheep at least, those with hba ...19761265360
resistance of selected lines of haemonchus contortus to thiabendazole, morantel tartrate and levamisole. 19761279076
[clinical examination of the blood of red deer (cervus elaphus l.) naturally infested with parasites].in six animals hunted and four immobilized animals of red deer (cervus elaphus l.) of both sexes and of different age, kept at three game preserves in bohemia, the psychological values were ascertained: the number of erythrocytes and leucocytes, the hemoglobin content, the hematocrit, mcv, mch, mchc, the white blood count, the total serum protein, the fractions: albumin, alpha-, beta- and gamma-globulin, the activity of sgot, and sgpt, the alkaline phosphatase and the metabolism of calcium, phos ...1976820034
zinc as a co-factor for an enzyme involved in exsheathment of haemonchus contortus. 1976821874
efficacy of albendazole against haemonchus, nematodirus, dictyocaulus, and monieza of sheep.albendazole was highly efficacious in the removal of monospecific and mixed infection of haemonchus contortus, nematodirus spathiger, and dictyocaulus filaria from sheep. a dose level of 5 mg/kg removed nearly all gastrointestinal nematodes, and 10 mg/kg removed all lungworms. tapeworms of the genus moniezia were completely removed by a dose level of 10 hg/kg.1976136914
effect of temperature on survival of free-living stages of haemonchus contortus.one percent or more unembryonated eggs of haemonchus contortus survived in sheep fecal pellets less than 0.5 hour at -95 c, 2 hours at -28 c, 1 hour at -10 c, 4 days at 4 c, and 1 hour at 45 c. one percent or more embryonated eggs survived 1 hour at -95 and -28c, 12 hours at -10 c, 64 days at 4 c, and 12 hours at 45 c. over half the unembryonated and embryonated eggs survived only 1 and 4 days, respectively, at 4 c. one percent or more 1st-stage larvae did not survive 0.5 hour at -95 c but did s ...1976949128
the anthelmintic efficacy of fenbendazole against thiabendazole-resistant strains of haemonchus contortus and trichostrongylus colubriformis in sheep.the anthelmintic efficacy of fenbendazole (methyl 5-(phenylthio)-2-benzimidazole carbamate) was tested in sheep against standardised strains of hcaemonchus contortus and trichostrongylus colubriformis, known to be resistant to thiabendazole (ld90 for thiabendazole against h ontortus was 200 mg/kg bodyweight and against t colubriformis was 150 mg/kg). fenbendazole at dose rates of 5, 10 and 20 mg/kg per os reduced total worm counts in h contortus infected sheep by 66, 90 and 100 per cent respecti ...1976968192
response of haemonchus contortus cayugensis to a change in the ratio of smooth to linguiform.the equilibrium of vulvar phenotypes in haemonchus contortus cayugensis was changed by infecting lambs with either a selected strain of smooth or of linguiform worms. subsequently the lambs grazed the same pasture and observations were made on changes in worm populations in the lambs, and on pasture it appeared that the seasonal change in the relative frequencies of a and b linguiform worms was related to density-dependent factors in the host. in the spring, when lambs first become infected, the ...1976980542
biological controls in mixed trichostrongyle infections.the parasite reaction phenotype of 80 lambs was determined with natural infection on pasture. these lambs were then assigned to outcome groups and randomized into treatment groups. developing some simple but unusual analytical techniques it was possible to demonstrate that mixed natural infections of trichostrongyles with the chief biomass component haemonchus contortus cayugensis protected against superinfections with 35000 infective larvae but protected against superinfections with 1000 infect ...1976985666
changes in the hatch rate of haemonchus contortus eggs between geographic regions.vulvar phenotypes and the rate of development of eggs over a range of temperatures were used to compare haemonchus contortus populations in new york state and ohio. these parameters indicated that the westernmost boundary of the subspecies haemonchus contortus cayugensis is the chautauqua valley in new york. the haemonchus ecotype in ohio had a vulvar phenotype formula similar to that described for the subspecies haemonchus contortus contortus. the relationship between slope and intercept of the ...1976988532
the ageing process in infective larvae of the roundworms haemonchus contortus and nippostrongylus brasiliensis: carbohydrate content.trehalose, glycogen and traces of glucose were the only anthrone sensitive carbohydrates identifiable. the variation of 13-22% of the dry weight in different populations of haemonchus contortus l3 is shown to be due to their capacity to synthesize glycogen during ageing. this contrasts with the larvae of nippostrongylus brasiliensis in which a low level of carbohydrate remains constant with time. it is suggested that h. contortus can convert lipid to carbohydrate as is the case for several other ...1976988680
experimentally induced haemonchus contortus infections in the rabbit.haemonchus contortus originally derived from an ontario field strain was used to infect laboratory rabbits. both enshealthed and artificially exsheathed larvae were given at doses of up to 10 million larvae per rabbit. only artifically exsheathed larvae were infective and a dose of at least 50,000 was required to produce a significant level of infection. h. contortus completed its development in the rabbit, but at a slower rate than in the sheep. although a few fecund females were found 35 days ...1976993571
efficacy of albendazole against gastrointestinal nematodes of cattle.forty-five calves with artificial and pasture-acquired nematode infections were medicated with albendazole at dose levels of 0, 2.5, 5.0, or 10 mg/kg of body weight. a dose level of 2.5 mg/kg removed at least 99% of adult trichostrongylus axei, trichostrongylus colubriformis, cooperia oncophora, and bunostomum phlebotomum. burdens of haemonchus contortus, strongyloides papillosus, and ostertagia ostertagi were reduced 79, 88, and 97%, respectively. at a dose level of 5.0 mg/kg, at least 95% of a ...1976999077
nematodes parasitizing domestic ruminants in afghanistan.a total of 12 nematode species were determined in the collection recovered from domestic ruminants in afghanistan. ten of them were found for the first time in this region: trichocephalus globulosus, trichostrongylus probolurus, cooperia bisonis, nematodirus spathiger, n. abnormalis, thelazia rhodesi, bunostomum phlebotomum, haemonchus contortus, dictyocaulus filaria and oesophagostomum radiatum. morphological and metrical characteristics of t. globulosus, t. skrjabini and c. bisonis, based on o ...19761034588
histochemical studies on the body wall of nematodes: haemonchus contortus (rud., 1803) and xiphinema insigne loos, 1949.histochemical studies on the body wall of haemonchus contortus (rud.) and xiphinema insigne loos have been made. in h. contortus, the cuticle is mainly proteinous in nature. the lipids and pas-postive materials are only present in cortical layers. in addition, haemoglobin and acid phosphatase are also present. the hypodermis shows the presence of glycogen, lipids, rna, acid and alkaline phosphatases. the oval dense body is composed of keratinous and collagenous proteins associated with acid muco ...1977140550
parasites of domestic and wild animals in south africa. iv. helminths in sheep on irrigated pasture on the transvall highveld.the seasonal incidence of helminth infestation in sheep on newly established irrigated pastures was determined by the slaughter of pairs of tracer lambs exposed for periods of approximately 33 days from october 1968--july 1970 and of sets of 3 lambs from march 1971--may 1973. it took several months for the infestation to become established on the pasture, but thereafter, of the various species present; haemonchus contortus was most prevalent. in general, peak burdens of this species were recover ...1977148623
development of haemonchus contortus in vitro and the stimulus from the host.infective larvae of haemonchus contortus which have been exposed for about 9 hr to relatively high partial pressures of carbon dioxide at near-neutral ph, as they might be in the rumen, develop slowly to the fourth stage or not at all. but following this treatment, exposure to lower partial pressures of carbon dioxide and higher concentrations of hydrogen ions, such as might be encountered in the abomasal mucosa, brings about development at a rate comparable with that in the sheep.197716106
the mechanism of hatching of eggs of haemonchus contortus. 1977558173
resistance of nematode eggs to the ovicidal activity of benzimidazoles.eggs of benzimidazole-resistant haemonchus contortus and trichostrongylus colubriformis are resistant to the ovicidal activity of benzimidazoles. the possiblity is raised of using this as a simple screen for detection of resistance in nematodes of domesticated animals.1977560037
cryopreservation of the infective larvae of the common nematodes of ruminants.exsheathed infective larvae (l 3) of 19 species of nematodes were tested for infectivity in either sheep or cattle after they had been frozen in 0,9% nacl solution, stored for a relatively short time in the gas phase of liquid nitrogen and subsequently thawed. in addition, 13 of these species were tested after similar storage for up to 18 months. in sheep, haemonchus contortus, ostertagia circumcincta, trichostrongylus axei, trichostrongylus colubriformis, nematodirus spathiger and oesophagostom ...1977566412
anthelmintic efficacy of albendazole in cattle: comparison of critical and controlled tests.twelve calves were experimentally inoculated with 6 species of gastrointestinal nematodes and the liver fluke, fasciola hepatica. six calves were administered albendazole at 10 mg/kg of body weight, and the drug efficacy was determined by critical and controlled tests. albendazole was only 74% effective against haemonchus contortus (cambendazole-resistant strain), 99 to 100% effective against ostertagia ostertagi, trichostrongylus colubriformis, cooperia oncophora, and oesophagostomum radiatum, ...1977334003
[effectiveness of fenbendazole (panacur) in cattle invaded by gastrointestinal and pulmonary nematodes].the effectiveness of the new anthelmintic fenbendazole (panacur) produced by hoechst, w. germany, was tested in cattle naturally invaded by gastro-intestinal and pulmonary nematodes. the single dose of 5.7 mg per kg or 7.5 mg per kg body weight administered either in the form of a 10% suspension or in pellets containing 1.5% of the active substance gave 100% intenseffectiveness and 100% extenseffectiveness in the control of dictyocaulus viviparus, haemonchus contortus, trichostrongylus spp., ost ...1977408961
serum and mucus antibodies in sheep immunised with larval antigens of haemonchus contortus.inoculation of sheep with larval antigens in adjuvant stimulated a marked serum and mucus igg antibody response. however no mucus iga antibodies were stimulated and no protection against challenge infection was observed.1977841197
epidemiological studies on gastro-intestinal nematode parasites of sheep: the seasonal number of generations and succession of species.monthly post mortem worm counts were carried out from june to september on grazing lambs, in association with faecal egg counts and pasture larval counts. similar patterns were recorded by all three methods, and egg counts proved to be a reliable reflection of worm burden over this period. a succession of species was recorded, in particular ostertagia spp and nematodirus spp in june; haemonchus contortus in july; trichostrogylus virinus in august; t axei, t colubriformis and cooperia curticei in ...1977841205
"spring rise" in fecal nematode egg counts in sheep in maine.a "spring rise" in fecal nematode egg counts occurred in maine sheep housed under conventional conditions during 2 years. nematodes causing this increase were haemonchus contortus in one year and ostertagia sp in the other. the increase in egg counts was greater in sheep that lambed than in unbred sheep. most of the eggs in the spring rise were probably produced by worms that passed the winter in developmental arrest in the sheep. some of the female worms probably came from contaminated bedding ...1977851288
genetics of vulvar morph types in haemonchus contortus: haemonchus contortus cayugensis from the finger lakes region of new york. 1977858660
haemonchus contortus: effects of compounds with juvenile hormone activity on the in vitro development of infective larvae. 1977862711
an evaluation of ethyl-6-ethoxybenzothiazole-2-carbamate (sch 18099) for anthelmintic activity in domestic animals.ethyl-6-ethoxybenzothiazole-2-carbamate (sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens. sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. at 15 mg/kg, efficacy against adult and larval oxyuris equi was 100% and 91% and against small strongyles it was 98%. efficacy levels were 95% against strongylus vulgaris and s. edentatus at the 20 mg/kg dosage. in two trials at 100 mg/kg efficacy against parascaris e ...1977864223
the development of haemonchus contortus, a nematode parasite of the ovine abomasum, in the laboratory rabbit.the development and growth of haemonchus contortus was studied in the stomach of the laboratory rabbit. less than 1% of the ensheathed infective larvae given to rabbits became established, whereas after exsheathment in vitro under physiological conditions, 20-30% of the larvae administered developed to the 4th stage. following doses of up to 10000 larvae, nearly all worms were lost from the 16th to the 21st day after infection, but after doses of 50000 larvae considerable numbers of 4th-stage la ...1977876680
anti-larval antibodies in the serum and abomasal mucus of sheep hyperinfected with haemonchus contortus.a radioimmunoassay technique was used to follow the anti-larval antibody response in the serum of sheep subjected to repeated dosing with haemonchus contortus. the response was found to develop slowly and seemed to decline as soon as the sheep stopped receiving larvae. no immunological memory was observed after the sheep were challenged with 4000 larvae nine weeks after daily dosing was stopped. examination of abomasal mucus collected from the sheep at slaughter revealed the presence of iga and ...1977877429
developmental arrest of haemonchus contortus larvae in lambs given larval inoculum exposed to different temperatures and storage conditions.the temperature (15 or 30 c) at which haemonchus contortus larvae were allowed to develop to the infective (3rd) stage and the temperature at which they were subsequently stored (4, 15, or 30 c) had no effect on the occurrence of developmental arrest (larval impasse) of the larvae in infected lambs. if a large inoculating dose (10,000 larvae) was given to the lambs, a smaller percentage of nematodes was retained (14.2%) then if a small dose (1,000 larvae, 25.8% retention) was given, but the perc ...1977879578
a helical, polymeric extracellular protein associated with the luminal surface of haemonchus contortus intestinal cells.the structure of the intestinal cells of the parasitic nematode haemonchus contortus is described. the cells have numerous microvilli about 0-09 micron in diameter; most being 5-5-7-5 micron in length. the microvillar (plasma) membrane is coated with a layer of amorphous material (glycocalyx) about 60 a thick which is electron dense in sectioned preparations. associated with the surface of this material, and filing the spaces between the microvilli, are filaments in the form of helices about 400 ...1977898175
haematological observations on the helminthiasis caused by haemonchus contortus in nigerian dwarf sheep. 1977906083
development and survival of haemonchus contortus larvae on pastures in ibadan.the development and survival of the eggs of haemonchus contortus on pasture at ibadan were studied by spreading faeces containing eggs on grass plots from october 1973 to october 1974. development of the eggs to the infective larvae took place within one week in may, june, july, september and october. larvae were not recovered in the other months. their survival times were 28, 42, 42, 35, 63 and 49 days respectively in october 1973. may, june, july, september and october 1974. rainfall was the m ...1977906089
recovery of infective 3rd stage larvae of haemonchus contortus and ostertagia ostertagi by migration in agar gel. 1977910655
degree-day concept in development of infective larvae of haemonchus contortus and trichostrongylus colubriformis under constant and cyclic conditions. 1977911077
a light and electron microscopic study of the dorsal buccal lancet of haemonchus contortus. 1977915615
development of haemonchus contortus to the fourth stage in an abnormal host, the laboratory mouse. 1977915636
the effects of photoperiod during development and of storage on maturation of haemonchus contortus larvae. 1977915637
anthelmintic activity of albendazole against gastrointestinal nematodes in calves.anthelmintic activities of albendazole were evaluated in a controlled experiment. forty calves experimentally infected with gastrointestinal nematodes were allotted to 4 groups. calves in group 1 were used as nonmedicated controls; calves in groups 2, 3, and 4 were given (by oral route) a suspension containing albendazole at dose concentrations of 2.5, 5.0, and 7.5 mg/kg of body weight on the 35th day after administration of infective nematode larvae. in groups 2, 3, and 4 calves, average overal ...1977921039
[distribution of nematode parasites of the digestive system in sheep (ovis aries) and goats (capra hircus) of the piedmontese and valdostano alpine arc].a survey, carried out on gastro-intestinal nematodes of sheep and goats of piemonte and of valle d'aosta (87 sheep and 12 goats) has shown the presence of the following species in sheep, bunostomum trigonocephalum, chabertia ovina, cooperia curticei, haemonchus contortus, marshallagia marshalli, nematodirus abnormalis, nematodirus filicollis, nematodirus helvetianus, nematodirus spathiger, oesophagostomum venulosum, ostertagia circumcincta, ostertagia lyrata, ostertagia trifurcata, skrjabinema o ...1977572958
the effect of route of administration on the anthelmintic efficacy of benzimidazole anthelmintics in sheep infected with strains of haemonchus contortus and trichostrongylus colubriformis resistant or susceptible to thiabendazole.observations of erratic anthelmintic activity of fenbendazole against known standardised thiabendazole-resistant strains of haemonchus contortus and trichostrongylus colubriformis in sheep were investigated. fenbendazole at a dose rate of 10 mg/kg body weight was administered by oral, intra-ruminal or intra-abomasal routes, and was most effective against both resistant strains following intra-ruminal administration. in addition thiabendazole, oxibendazole, fenbendazole, parbendazole and mebendaz ...1977577045
levels of benzimidazole resistance in haemonchus contortus and trichostrongylus colubriformis recorded from an egg hatch test procedure.a method of using commercially available benzimidazole anthelmintics in an egg hatch test, to record levels of resistance is described. the test shows that a side-resistance is present to all the benzimidazole anthelmintics tested against both haemonchus contortus and trichostrongylus colubriformis after selection with thiabendazole. additional selection on the field resistant strain of h contortus with thiabendazole showed increased levels of resistance to all the compounds tested while similar ...1978581912
the dose response of several benzimidazole anthelmintics against resistant strains of haemonchus contortus and trichostrongylus colubriformis selected with thiabendazole.dose response lines for eight benzimidazole anthelmintics and thiophanate were determined, using standardised strains of thiabendazole selected and resistant haemonchus contortus and trichostrongylus colubriformis. against h contortus, thiophanate, thiabendazole, parbendazole and oxibendazole were inactive. mebendazole was inactive at dose rates of 6.26 and 12.5 mg/kg, although significant activity occurred at 25 mg/kg. fenbendazole, cambendazole, oxfendazole and albendazole demonstrated signifi ...1978581913
leucine aminopeptidase in exsheathing fluid of north american and australian haemonchus contortus. 1978631980
the anthelmintic efficacy of non-benzimidazole anthelmintics against benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis in sheep.the anthelmintic efficacy of 6 non-benzimidazole compounds and thiabendazole against standardised, benzimidazole resistant strains of h. contortus and t. colubriformis in sheep was determined using a controlled test. all compounds were administered intraruminally at their recommended therapeutic dose rates and 4 of the compounds were also assessed at half their recommended therapeutic dose rates. levimisole at a dose of 6.4 mg/kg body weight, morantel at 4.4 mg/kg and 8.8 mg/kg, naphthalophos at ...1978655966
the induction of slelctive immunological unresponsiveness in cells of blood and lymphoid tissue during primary infection of sheep with the abomasal nematode, haemonchus contortus. 1978666670
genetic resistance to helminths. comparison of the development of ostertagia circumcincta infections in scottish blackface sheep of different haemoglobin type.over the years a number of investigators have reported that sheep with haemoglobin a are more resistant to haemonchus contortus than animals of the same breed with haemoglobin b. the experiment described here was an attempt to ascertain whether a similar association might exist between haemoglobin type and resistance to non-haematophagic parasites. the results indicate that such a relationship might exist, since scottish blackface sheep with hba showed milder biochemical and pathophysiological c ...1978674855
anthelmintic activity of fenbendazole against gastrointestinal nematodes in calves.anthelmintic activities of fenbendazole were evaluated in a controlled experiment. forty calves artificially infected with gastrointestinal nematodes were allotted to 4 groups. calves in group 1 were used as nonmedicated controls; the other calves were given (orally) fenbendazole at the dose level of 5 mg/kg in the forms of a suspension (group 2), medicated feed to individual calves (group 3), and medicated feed to the group (group 4). these treatments were given on day 35 after calves were inoc ...1978677528
thiophanate as a low daily dosage anthelmintic in sheep.thiophanate administered daily at low dosages reduced nematode faecal egg output, egg hatchability and parasitic worm burdens in treated lambs and ewes. six daily doses of 1 or 3 mg per kg thiophanate (approximately 1/25th to 1/75th of the median therapeutic dose), given to lambs experimently infected with trichostrongylus colubriformis, were partially effective in suppressing faecal egg output and egg hatchability. six doses of 5 mg per kg per day were effective in lambs infected with haemonch ...1978695254
parasites of domestic and wild animals in south africa. v. helminths in sheep on dryland pasture on the transvaal highveld.the seasonal incidence of helminth infestation on a farm in the transvaal highveld was determined by the slaughter of tracer lambs exposed on pasture for periods of approximately 6 weeks. haemonchus contortus, the most prevalent nematode, was recovered in the greatest numbers from january--may 1974. peak counts of ostertagia circumcincta were made during march and april 1974 and in january 1975, while trichostrongylus spp. were mainly encountered from march--june. cooperia spp. were generally re ...1978704040
recovery of nematodes from ruminants by migration from gastro-intestinal ingesta and mucosa gelled in agar: preliminary report.when gastro-intestinal ingesta and mucosa containing larvae or adult haemonchus contortus, ostertagia circumcincta. trichostrongylus colubriformis, strongyloides papillosus, nematodirus spathiger, gaigeria pachyscelis, oesophagostomum columbianum or chabertia ovina were suspended in 0,75--1,00% agar gel and incubated in physiological saline, a mean of 93,6% of the helminths migrated from the agar-ingesta or agar-mucosa into the physiological saline. the lowest suitable concentration of agar was ...1978704042
genetic resistance to helminths. the influence of breed and haemoglobin type on the response of sheep to primary infections with haemonchus contortus. 1978704147
parasites of domestic and wild animals in south africa. ix. helminths in blesbok.four blesbok culled in the rietvlei nature reserve during may 1972 were each infested with trichostrongylus axei and impalaia nudicollis. some of these animals also harboured haemonchus bedfordi, haemonchus contortus, trichostrongylus falculatus, skrjabinema alata and avitellina centripunctata. thirty-two blesbok were culled in pairs at approximately 4-5 week-intervals in the percy fyfe nature reserve from july 1972 to november 1973. adult h. contortus were recovered in fair numbers from buck sl ...1978714392
haemonchus contortus infections in targhee and targhee-barbados black-belly cross lambs.targhee and targhee-barbados black-belly cross lambs that were raised helminth-free were experimentally infected with 10,000 or 25,000 infective larvae of haemonchus contortus. there were no significant (p = less than 0.05) differences in results of weight gain, packed cell volumes, numbers of eggs per gram of feces, or numbers of helminths between the 2 groups of lambs.1978727591
[haemonchus contortus infection in sheep]. 1978734642
the influence of breed on the susceptibility of sheep and goats to a single experimental infection with haemonchus contortus.four breeds of sheep and three breeds of goats, maintained on both high and low planes of nutrition were given a single infection of 350 haemonchus contortus larvae per kg. although animals on a low protein diet had much higher faecal egg counts than those on the high protein diet the pattern of relative susceptibility was similar in both cases. it would appear that the nutritional status of the host influences its resistance to h contortus infection. of the breeds studied the indigenous red mas ...1978741614
efficacy of oxfendazole against an ovine isolate of benzimidazole resistant haemonchus contortus.eighteen parasite-free sheep were each infected with 6000 +/- 25 infective larvae of the ah-2, benzimidazole-resistant strain of haemonchus contortus on each of experimental days -27, -15, -8 and -1. the sheep were subsequently randomized into 3 groups of 6 sheep each. group 1 served as untreated controls; groups 2 and 3 were treated orally with oxfendazole at dose levels of 5 mg/kg and 10 mg/kg body weight, respectively. at both dosage levels, oxfendazole was 100% effective against third, fourt ...1978743042
haemonchus contortus: local and serum antibodies in sheep immunised with irradiated larvae. 1978748210
leucine aminopeptidase and exsheathing activity in preparations from haemonchus contortus. 1978748217
the energy metabolism of adult haemonchus contortus, in vitro.a comparison was made of the major excretory products when adult haemonchus contortus worms were incubated with d-[u-14c]glucose under aerobic and anaerobic conditions. catabolites measured were propan-1-ol, acetate, n-propionate and co2 and the only major difference was that nearly twice as much co2 both in terms of quantity and radioactivity was excreted under aerobic than anaerobic conditions. the worms were also much more physically active under aerobic conditions. when worms were incubated ...1978748835
in vitro and in vivo studies on the ovicidal activity of fenbendazole.the in vitro ovicidal activity of fenbendazole against eggs of ostertagia ostertagi, haemonchus contortus and trichostrongylus colubriformis was observed using different concentrations of active principle. the optimum concentration for ovicidal activity is evidently 0.5 ppm fenbendazole. a further increase in concentration results in a decrease in activity which is probably due to physical causes. ovicidal activity of the product is assessed by the proportion of non embryonated eggs as well as e ...1978749077
the efficacy of febantel on gastrointestinal nematodes in sheep.febantel (bay h 5757, rintal) is a broad-spectrum anthelmintic of a new type. a single oral dose of 5 mg/kg is fully effective against larval and adult stages of haemonchus contortus, trichostrongylus colubriformis, oesophagostomum columbianum, ostertagia circumcincta and bunostomum trigonocephalum in sheep.1978749080
physiological characteristics of free-living and parasitic stages of strains of haemonchus contortus, susceptible or resistant to benzimidazole anthelmintics.the effect of changes in genetic constitution (associated with developing benzimidazole resistance) on the physiological characteristics of haemonchus contortus was investigated. benzimidazole resistant h contortus were significantly more infective for sheep (20 per cent) than benzimidazole susceptible strains. pathological changes were more severe in sheep infected with resistant h contortus as measured by packed cell volume, plasma protein concentration and haemoglobin levels. faecal egg outpu ...1978749089
anthelmintic activity of albendazole in white-tailed deer.albendazole at dose rates of 11 to 54 mg/kg (mean of 25 +/- 11 sd) of body weight was highly effective (greater than 99%) against haemonchus contortus, ostertagia odocoilei, o mossi, trichostrongylus askivali and nematodirus odocoilei in 22 white tailed deer (odocoileus virginianus) in southern texas. it was 38% effective against mature and immature deer liver flukes (fascioloides magna). toxicoses associated with treatment were not observed. large numbers of abomasal nematodes (mean of 2,949 +/ ...1978749572
[efficacy of mebendazole in sheep experimentally invaded with larvae of haemonchus contortus and trichostrongylus colubriformis in relation to the results of clinical examination].a group of six lambs at the age of two months and of the average weight of 13 kg were invaded with the larvae haemonchus contortus and trichostrongylus colubriformis; the course of invasion was compared with that in a group of four control lambs. in regular ten-day intervals, some hematological indices, proteinemia. sgot and sgpt activities, glucose level, sodium and potassium were studied in blood samples; at the same time egg elimination was observed in excrement samples. the invasion intensit ...1978416548
instability of benzimidazole resistance in nematode eggs.the resistance of the eggs of benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis is not stable and will decrease in the absence of drug challenge. dosing animals harbouring resistant h contortus with either thiabendazole or mebendazole selects for nematodes producing thiabendazole resistant eggs. the eggs of a thiabendazole selected strain of h contortus were more resistant to thiabendazole, parbendazole and oxibendazole but less resistant to cambendazole and mebenda ...1978569353
the efficiency of various anthelmintics against field populations of haemonchus contortus resistant to thiabendazole. 1978570385
observations on crystals found in the intestinal cells of haemonchus contortus and in the intestinal lumen of ostertagia ostertagi. 1978204587
morphological, histochemical, and biochemical studies on the gut of haemonchus contortus rud., 1803).a study has been made on the structure and chemical composition of the gut of haemonchus contortus (rud., 1803). the oesophagus has typically a triradiate, cuticle-lined lumen. the intestinal epithelium is provided with a well-developed brush border which contains periodic acid-schiff-positive mucoproteins. the intestinal epithelium stores glycogen and lipids. it stains diffusely for phospholipids and general proteins and also for terminal-nh2 group. the presence of fe2+ and fe3+ containing pigm ...1978211748
resistance to haemonchus contortus in sheep given repeated daily doses of 10 000 infective larvae. 197826700
efficacy of febantel in sheep experimentally infected with five species of gastrointestinal nematodes.the anthelmintic activity of the guanidine derivative febantel was tested in a total of 76 experimentally infected lambs in two control tests. doses of 5.0 and 7.5 mg per kg body-weight were administered orally against fourth and pre-adult fifth or adult stages of haemonchus contortus, ostertagia circumcincta, trichostrongylus colubriformis, b unostomum trigonocephalum and oesophagostomum columbianum. the efficacy was between 98.5 and 100 per cent. the drug was well tolerated.1978155340
[helminthiases in newly established large-capacity breeding stations for cattle].invasions of gastrointestinal nematodes proved to be the most frequent helminthiases in new-established large-capacity herds of cattle according to the results of parasitary examinations of cattle in one locality in the tachov district. the nematodes, especially oesophagostomum spp., haemonchus contortus, cooperia spp., trichostrongylus spp., occurred in animals of all age categories. the ostertagia spp., chabertia ovina, nematodirus spp., bunostomum phlebotomum and trishuris spp. participated i ...197897836
genetic resistance to helminths. the influence of breed and haemoglobin type on the response of sheep to re-infection with haemonchus contortus.the influence of genetic factors on acquired resistance to haemonchus contortus infections in sheep was investigated. animals whose primary infections were terminated with an anthelmintic failed to develop any immunity against subsequent challenge as judged by worm numbers. nevertheless, all were better able to retard the development and reduce the fecundity and haematophagic activities of their parasite populations than animals undergoing primary infections. high levels of resistance, as judged ...1978309103
ostertagiosis in captive bison in new york state: report of nine cases.type ii ostertagiosis was found at necropsy in 9 american bison (bison bison) from 3 farms in new york. clinical signs included severe diarrhea, emaciation, unthrifty coats, anemia, and weakness. in severely affected animals, the macroscopic abomasal changes consisted of irregular thickening and edema of the mucosa, resulting in a pebbly or morocco-leather appearance. microscopically, many gastric pits and glands were dilated, lined by hyperplastic epithelium, and contained nematode sections or ...1979157257
efficacy of oxfendazole against natural infestations of nematodes and cestodes in sheep in egypt.oxfendazole liquid suspension (systamex; wellcome) was administered orally at the dose of 4.5 mg per kg to 800 indigenous egyptian sheep clinically affected with dictyocaulus filaria, moniezia expansa, haemonchus contortus, ostertagia circumcincta, nematodirus spp, trichostrongylus axei, cooperia curticei, trichuris ovis and oesophagostomum spp. a 100 per cent clearance was recorded for all parasites with the exception of t ovis which were markedly reduced in number.1979157586
antigens of hyostrongylus rubidus, the red stomach worm of pigs. analyses by means of passive haemagglutination and immediate hypersensitivity tests.antigens were prepared from different stages of worm development and adult worm antigens were fractionated by ion exchange and exclusion chromatography. the antigens, or fractions of them, were assessed for their activity in passive haemagglutination reactions or intradermal tests. the results of the passive haemagglutination reactions indicated that circulating agglutinins were more readily detected when adult stage specific antigens were used. antigen prepared from worms isolated when the popu ...197992802
phosphorylcholine antigens from nippostrongylus brasiliensis. ii.--isolation and partial characterization of phosphorylcholine antigens from adult worm.the phosphorylcholine antigens (c substance) were specifically isolated from nippostrongglus brasiliensis adult worms. they formed a gorup of fairly closely related molecules, but it was not possible to evidence that the carrier molecule was unique. an indirect immunoenzymatic test using immobilized lectins (concanavalin a, phytohaemagglutinin els, wheat germ agglutinin, recin types i and ii, peanut agglutinin) gave some light on the carbohydrate composition of the carrier molecules, whereas the ...197995087
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