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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
resistance to haemonchus contortus in sheep given repeated daily doses of 10 000 infective larvae. 197826700
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
[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
helminth parasitisms among intermingling insular populations of white-tailed deer, feral cattle, and feral swine.helminth infections among free-ranging, intermingling populations of white-tailed deer (odocoileus virginianus), cattle (bos taurus), and swine (sus scrofa) on an island off the georgia coast were studied. of 39 species of helminths collected, 19 were found in deer, 17 in cattle, and 13 in swine. of 28 species of helminths recovered from ruminants, 8, viz, capillaria bovis, cooperia punctata, dictyocaulus viviparus, gongylonema pulchrum, g verrucosum, haemonchus contortus, moniezia benedeni, and ...1975123523
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
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
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
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
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
the influence of breed on the susceptibility of sheep of haemonchus contortus infection in kenya.the relative resistance of six breeds of sheep to haemonchus contortus infection was investigated under field conditions on two stations situated in a semi-arid zone in kenya. as judged by faecal egg counts, monitored throughout a two-year period, it was found that there were consistent differences between the breeds. the breeds studied in order of increasing susceptibility were red masai, blackhead persian, merino, dorper, corriedale and hampshire. post mortem findings confirmed that the differ ...1979262593
the influence of haemoglobin phenotype on the susceptibility of sheep to haemonchus contortus infection in kenya.two flocks of merino sheep were set-stocked on pastures known to be endemic for haemonchus contortus. both flocks included sheep with the three common haemoglobin types (hbaa, hbab, hbbb). the results of regular monitoring over a two-year period showed a clear relationship between haemoglobin types and susceptibility to haemonchosis. the hbaa sheep experienced fewer deaths, had consistently lower egg counts and exhibited a more frequency and effective self-cure than the hbab or the hbbb types. p ...1979262594
termination of arrested development of the trichostrongyles of sheep in northern nigeria.monthly worm counts of groups of ewes and lambs that grazed continuously and tracer lambs revealed that under the conditions existing in northern nigeria, most of the haemonchus contortus in sheep between november and march were arrested larvae. during the months of april and may, almost equal proportions of adults, developmental stages and arrested larvae were recovered and, by june, only adults and developmental stages were recovered in high numbers. the proportion of arrested larvae had dimin ...1979262601
field observations on the epidemiology of abomasal parasites in young sheep during winter and spring.a flock of spring born lambs was continuously exposed to natural parasite infection from birth until selected for slaughter in groups of two or three, at monthly intervals throughout winter and spring for abomasal worm counts. meteorological data were recorded and regular estimates of infective pasture larval availability were made. parasite population changes and inhibition patterns for ostertagia spp, haemonchus contortus and trichostrongylus axei were recorded. ostertagia spp were found to su ...1979262603
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
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
[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
haemonchus contortus: some factors influencing the degree of resistance of sheep immunized with attenuated larvae. 1979422768
[helminth fauna of syrian cattle].in this work the stomach and the small intestine of 34 and the large intestine of 4 more cattle were examined. 91,17% of the examined cattle (31 in 34 animals) had infected the stomach and/or the small intestine by parasites. 14 kinds of nematodes were found. the average intensity of infection of the stomach was higher than that of the small intestine. with the exception of higher infection in 3 stomachs and 2 small intestines the intensity of infection in all other cases was from small to mediu ...1979453633
parasites of domestic and wild animals in south africa. xii. artificial transmission of nematodes from blesbok and impala to sheep, goats and cattle.sheep were successfully infested artificially with the larvae of haemonchus contortus, trichostrongylus axei, trichostrongylus falculatus and impalaja nudicollis, cultured from the faeces of blesbok naturally infested with these nematodes. haemonchus placei, longistrongylus sabie, trichostrongylus colubrifomis, t. falculatus, impalaia tuberculata and cooperia hungi likewise became established in sheep, goats and calves dosed with larvae cultured from the faeces of infested impala. sheep and goat ...1979460820
oxfendazole--anthelmintic activity in egyptian goats artificially infected with gastrointestinal nematodes.the recently developed benzimidazole anthelmintic, oxfendazole, was tested against artificial nematode infestations in egyptian goats using oral dosing at 4.5 and 2.8 mg/kg. a 100% clearance of mature and immature haemonchus contortus, trichostrongylus axei, ostertagia circumcincta, coopera curticei, bunostomum trigonocephalum and chabertia ovina was obtained at the 4.5 mg/kg level. very high levels of clearance against the mature worms were obtained at 2.8 mg/kg but the drug was less effective ...1979462559
avermectins, new family of potent anthelmintic agents: efficacy of the b1a component.when given to sheep as a single oral dose at 0.1 mg/kg, the b(1a) component of the avermectins caused a reduction of >95% in the numbers of haemonchus contortus, ostertagia circumcincta (including inhibited l(4) larvae), trichostrongylus axei, trichostrongylus colubriformis, cooperia oncophora, and oesophagostomum columbianum. when given to cattle as a single oral dose at 0.1 mg/kg, avermectin b(1a) was >95% effective in reducing the numbers of haemonchus placei, ostertagia ostertagi (including ...1979464563
thiabendazole resistance in field populations of haemonchus contortus.six populations of h. contortus were selected for a study of thiabendazole resistance from a collection of 40 populations made during a survey of the efficiency of thiabendazole on the northern tablelands of new south wales. based on survey results, 3 of these populations were considered susceptible and the remaining 3 were considered resistant. however, when these populations were compared with a known susceptible strain on the ability of their eggs to hatch in a solution containing thiabendazo ...1979464936
the inheritance of thiabendazole resistance in haemonchus contortus.haemonchus contortus worm populations isolated from naturally infected sheep at the pastoral research laboratory, armidale, n.s.w., were found to contain approximately 20% of worms resistant to a 50 mg/kg dose of thiabendazole. following 3 generations of selection with 50 mg/kg thiabendazole the number of worms removed by the anthelmintic was too small to detect differences between treated and control groups. after more than 15 generations of selection, matings between males from the selected st ...1979471531
inhibited development of trichostrongylids of sheep in northern nigeria.worm counts from yankassa ewes, lambs and tracer lambs grazing unimproved pasture at zaria were obtained each month during the rainy season of 1976. in june and july up to 14 per cent of the haemonchus contortus populations consisted of early fourth stage larvae (l4). in august this increased to more than 55 per cent and in october to more than 95 per cent. from june to august most of the abundant late l4 contained rodlike crystals. more than 95 per cent of the haemonchus contortus populations o ...1979472478
the possible fate of crystal harbouring larvae of haemonchus contortus.an examination of the occurrence of crystalline inclusions in the intestinal cells of fourth and fifth stage haemonchus contortus revealed that a high percentage of inhibited early fourth stage larvae (l4) and developing l4 and a lower percentage of early fifth stage larvae (l5) harboured these crystals. before the fourth moult crystals were falling into pieces, indicating that worms harbouring crystals can develop further. the presence of crystals may be associated with a retardation of develop ...1979472480
the effect of single and divided dose administration on the efficacy of fenbendazole against adult stages of benzimidazole resistant sheep trichostrongylids.sheep infected with benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis were used to compare the anthelmintic efficacy of fenbendazole given as a single dose or administered in a divided dose regime over five days. statistical analysis showed no significant difference between the two methods of administration for h contortus. on the other hand, divided dose fenbendazole was significantly less effective than single doses against adult t colubriformis at dose ...1979472493
the anthelmintic efficacy of albendazole against fasciola hepatica and benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis in sheep.the anthelmintic efficacy of albendazole (methyl [5-(propylthio) - 1h - benzimidazole -2 -yl] carbamate) against immature and adult fasciola hepatica and against standardised strains of benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis was evaluated in experimentally infected sheep. a single intrarumenal treatment of dose rates of 3.8 and 7.6 mg/kg was ineffective against immature (six weeks old) f hepatica. dose rates of 5.7 and 7.6 mg/kg reduced the number of matu ...1979472494
in vitro variation of glycogen content in three sheep nematodes.in vitro variation of glycogen content under aerobic conditions was measured on fresh weight basis in 3 sheep nematodes inhabiting different niches; haemonchus contortus, oesophagostomum columbianum and trichuris ovis. the parasites were saparated into species and then sexes and starved for varying periods of time up to 24 h in glucose-free physiological saline. the differences between females and males and among the species with respect to glycogen content and its rate of change with time are d ...1979481912
experimental transmission of gastro-intestinal nematodes between sheep (ovis aries) and thomson's gazelles (gazella thomsonii).experimental cross-transmission of gastro-intestinal nematodes between merino sheep (ovis aries) and thomson's gazelles (gazella thomsonii) from similar but separate grazing habitats in kenya was studied. cross-transmission did occur with some species but the faecal egg counts of sheep were higher than the gazelles' following infection with larvae isolated from either sheep or gazelles. of the 11 gastro-intestinal nematodes which became established in gazelles following infection with larvae cul ...1979501844
gastro-intestinal helminths in white-tailed deer (odocoileus virginianus) of illinois.two deer populations, one in northern illinois the other in southern illinois, were examined by necropsy (n = 44 and 40 respectively) for helminth parasites of the gastro-intestinal tract and abdominal cavity. both herds were parasitized by apteragia odocoilei, haemonchus contortus, gongylonema pulchrum, setaria yehi, trichuris ovis, and moniezia benedeni. nematodirus sp. was found only in deer of northern illinois. ostertagia mossi, capillaria sp., cooperia sp., and oesophagostomum sp. were fou ...1979501845
the efficacy of fenbendazole and albendazole against immature and adult stages of benzimidazole-resistant sheep trichostrongylids.the efficacy of two recently introduced benzimidazole anthelmintics, albendazole and fenbendazole, was determined for six-day, 10-day and adult stages of resistant strains of haemonchus contortus and trichostrongylus colubriformis. albendazole, at 3.8 mg/kg reduced h contortus worm counts by 92.4, 70.8 and 67.1 per cent while fenbendazole, at 5.0 mg/kg, reduced worm burdens by 51.7, 95.5 and 93.4 per cent against six-, 10- and 25-day-old parasites respectively. for t colubriformis, the correspon ...1979504798
the anthelmintic efficacy of oxfendazole and haloxon against arrested haemonchus contortus larvae in sheep.in a controlled trial with natural infection of haemonchus contortus, oxfendazole at 4.53 mg/kg body weight was highly effective against arrested larvae, developmental stages and adult helminths. haloxon at 40 mg/kg significantly reduced helminth burdens.1979504805
the response of awassi and merino sheep to primary infection with haemonchus contortus.the possible existence of breed differences in the response of sheep to primary infection with haemonchus contortus was examined by comparing worm establishment and pathogenic effects of the parasite in awassi and merino sheep of haemoglobin type b infected with 500 third stage h. contortus larvae per kg body weight. the results showed that the merino sheep had lower faecal egg counts and worm burdens and suffered less severe clinical disturbances than sheep of the awassi breed. this suggests th ...1979505590
the activity of levamisole against benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis. 1979516343
efficiency of rafoxanide and naphthalophos against inhibited haemonchus contortus. 1979518438
resistance of haemonchus contortus to oxfendazole. 1979518439
investigation of haemonchus contortus infections in sheep. comparison of irradiated larvae and transfer factor treatment.a comparison is made between the resistance conferred to haemonchus contortus challenge by irradiated larval treatment and transfer factor (tf) treatment in four-month-old lambs and seven-month-old lambs. as in previous investigations the irradiated larval treatment failed to confer resistance to the four-month-old lambs challenged with 10,000 third stage larvae while similar irradiated larval treatment in seven-month-old lambs reduced the worm burdens by 40 per cent compared to controls. the tf ...1979523821
anthelmintic activities of b1a fraction of avermectin against gastrointestinal nematodes in calves.anthelmintic activities of the b1a fraction of avermectin were evaluated in a controlled experiment. twenty 12-week-old calves artificially infected with gastrointestinal nematodes were allotted to four groups. calves in group 1 were used as nonmedicated controls; other calves in groups 2, 3, and 4 were given (orally) b1a avermectin at dosage levels of 50, 100, and 200 microgram/kg of body weight, respectively. these treatments were given 35 days after calves were inoculated with infective nemat ...1979525922
the role of inhibited larvae in the epidemiology of ovine haemonchosis.three paddocks were contaminated with haemonchus contortus eggs from early spring to mid summer by yearling sheep. in paddock 1, all contamination was derived from worms that had been previously inhibited in their development. the contamination in paddock 2 was produced only by infections recently acquired from pasture, and in paddock 3 contamination was attributable to both sources. when the yearling sheep were replaced in mid-summer by newly weaned lambs, severe outbreaks of haemonchosis occur ...1979539940
the incidence of thiabendazole resistance in field populations of haemonchus contortus on the northern tablelands of new south wales.a survey was undertaken to assess the incidence of thiabendazole resistance in field populations of h. contortus in sheep flocks on 40 farms distributed throughout the sheep grazing area of the northern tablelands of new south wales. treatment with thiabendazole at 66 mg/kg reduced h. contortus ova output by 96-100% in 18 flocks while in the remaining 22 there was a range of responses down to levels where the anthelmintic was without apparent effect. factors which may contribute to the high inci ...1979543833
study of gastro-intestinal stronglyosis in a sheep flock on permanent pasture. 1. sheep parasitism in 1977.an epidemiological study aimed at defining gastro-intestinal parasitism in sheep qualitatively and quantitatively was carried out in the limousin area in france. five lambs were sacrificed regularly every 4 weeks from may till january of the following year. complete parasite counts were performed on these animals as well as measurements of the plasma level of pepsinogen. in order to define the influence of parasitism on the growth of the animals, the weight gains of lambs treated regularly and u ...1979547822
studies on haemonchus contortus. ii. the effect of abomasal nematodes on subsequent challenge with h. contortus.fifty-thousand infective larvae of trichostrongylus axei dosed to 7-9-month-old merinos protected them against a subsequent challenge with 50 000 infective larvae of haemonchus contortus. protection varied with the period between an initial dosage of t. axei and challenge with h. contortus as follows: after 90 days it was more than 80% effective in more than 80% of sheep; at 119 and 180 days there was still a significant reduction in the numbers of h. contortus recovered (p < 0,05 and p < 0,001, ...1979551369
effect of anthelmintic treatment on the performance of awassi sheep in iraq.studies are reported on the effect of anthelmintic treatment on the body weight gain and wool growth of ewes with subclinical helminth infections. the parasites involved were fasciola gigantica and ostertagia spp., together with some haemonchus contortus, trichostrongylus spp., and dictyocaulus filaria. in 1 group, 5 sheep, which were treated twice with tetramisole at an interval of 4 weeks to remove gastro-intestinal nematodes and lungworms, showed an increase of 41% in weight gain and 3.2% in ...1979552676
the efficiency of oxfendazole against four field populations of benzimidazole resistant haemonchus contortus. 1979556191
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
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
[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
[clinical examination of the blood of roe deer (capreolus capreolus l.) and fallow deer (dama dama l.) naturally invaded by parasites].roe-deer (capreolus capreolus l. -- five animals) and fallow deer (dama dama l. -- eleven animals) of both sexes and at different age were subject to blood examination. the deer were killed in several preserves in bohemia during autumn and winter shootings in two years. the following blood values were determined: erythrocyte count, leucocyte count, hemoglobin content, hematocrit values, mcv, mch, mchc, white blood picture, total protein, its fractions (albumin, alpha-, beta-, and gamma-globulin) ...1975809892
[effect of fenbendazole (panacur) in sheep naturally invaded by gastrointestinal and lung nemtaodes].the paper presents the results of the clinical tests of fenbendazole (panacur, produced by hoechst, f. r. g.), a new antihelminthic preparation. the tests were performed in sheep naturally invaded by gastrointestinal and lung nematodes. helminthological dissection performed 7 days after the application of 5 mg of fenbendazole per 1 kg of sheep weight proved 100% effectiveness on lungworms (dictyocaulus filaria) and on the following gastrointestinal helminths: ostertagia ostertagi, haemonchus con ...1975812246
[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
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
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