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field evaluation of an albendazole intraruminal capsule against benzimidazole-resistant haemonchus contortus. 19921595176
growth and development of haemonchus contortus in jirds, meriones unguiculatus.growth and development of haemonchus contortus were examined in jirds and were compared to these processes in lambs. number, sex, size, and stage of development were determined for worms recovered at necropsy at various times postinoculation (pi) from immunosuppressed jirds inoculated with approximately 1,000 exsheathed infective larvae (l3) of h. contortus. in addition, gastric tissue samples from jirds were examined histologically. parallel studies were done in lambs inoculated with approximat ...19921597794
induction of tissue eosinophilia by platelet-activating factor in merino sheep.a study was undertaken on the capacity of platelet-activating factor (paf) to induce eosinophil accumulation in the mammary glands of non-lactating sheep. platelet-activating factor induced dose-dependent accumulation of eosinophils in mammary exudates 24 h after infusion. infection, by intraruminal injection of 20,000 infective trichostrongylus colubriformis larvae, did not modify the responsiveness of outbred sheep to intramammary infusion of paf. mature ewes from high and low responder lines ...19921604802
seasonal variations in the numbers of trichostrongylid nematode eggs and their larvae in the faeces of farmed goats in malaysia.faecal worm egg counts of goats from two farms in penang island, west malaysia, were monitored over a period of 14 months. the faecal egg count pattern followed that of total rainfall. the humid tropical environment was favourable for the development of various species of trichostrongylid nematodes, namely haemonchus contortus, trichostrongylus spp., oesophagostomum spp. and cooperia spp. generally, h. contortus was observed to be the predominant species, more so in the monsoon months of the yea ...19921615628
a microlarval development assay for the detection of anthelmintic resistance in sheep nematodes.a microlarval development test for the detection of anthelmintic resistance in nematodes is described. haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis eggs were cultured to third stage larvae in the presence of earle's balanced salt solution, yeast extract and bacteria in a total volume of 150 microliters. good dose-response data were obtained with thiabendazole, levamisole, pyrantel tartrate and ivermectin allowing the determination of the 50 per cent lethal c ...19921621342
the mortality and fecundity of haemonchus contortus in parasite-naive and parasite-exposed sheep following single experimental infections.parasite-exposed lambs and their parasite-naive controls were experimentally infected once only with 30,000 h. contortus larvae at 3, 9, 12, and 20 weeks following termination of a moderate immunizing infection of 30,000 h. contortus larvae. previously exposed lambs, challenged at 3 weeks, had a significant reduction in the total h. contortus worm burden as compared to parasite-naive controls. no difference in the total h. contortus worm burden was found between parasite-exposed or parasite-naiv ...19921639567
resistance to ivermectin by haemonchus contortus in goats and calves.efficacy of ivermectin on susceptible or resistant populations of the parasitic nematode haemonchus contortus was determined in cattle and goats held in a barn. goats were each infected with 3000 infective, ivermectin-susceptible or -resistant h. contortus larvae on day 0 and reinfected with 2000 infective larvae on day 24. goats were treated orally with 600 micrograms kg-1 ivermectin on day 31. no significant differences were detected in blood packed cell volume (pcv) or total protein (tp), pre ...19921639573
no adaptation of haemonchus contortus to genetically resistant sheep.a composite population of haemonchus contortus was established with larvae from seven diverse sources, then maintained in merino sheep bred to have either increased or decreased resistance to haemonchus. after five, seven and 14 parasite generations, the two resulting lines of parasites were used to infect sheep from the increased resistance line, an unselected control line and the decreased resistance line. line of sheep had a highly significant effect on average faecal egg counts 4 and 5 weeks ...19921639574
differential stability of the benzimidazole (bz)-tubulin complex in bz-resistant and bz-susceptible isolates of haemonchus contortus and trichostrongylus colubriformis.the binding of [3h]mebendazole ([3h]mbz) to tubulin from bz-susceptible (bz-s) and bz-resistant (bz-r) isolates of haemonchus contortus and trichostrongylus colubriformis was investigated using charcoal extraction and gel filtration techniques. the amount of [3h]mbz bound at infinite free ligand concentration (bmax) was significantly reduced for the bz-r isolate compared with the bz-s isolate in both species when assayed by charcoal extraction. however, bmax was increased to comparable levels fo ...19921639577
parasitological and immunological responses of genetically resistant merino sheep on pastures contaminated with parasitic nematodes.one hundred and twenty lambs were grazed continuously from weaning until 9 months of age on 12 plots contaminated with larvae of three nematode species (haemonchus contortus, trichostrongylus colubriformis and ostertagia circumcincta). the lambs were sired by either a genetically resistant ram or susceptible rams (determined by the response of previous progeny to artificial h. contortus infection). half the resistant and half the susceptible lambs were given strategic anthelmintic treatment and ...19921644517
systemic immunization of sheep with surface antigens from haemonchus contortus larvae.sheep immunized systemically with a surface extract from third-stage h. contortus larvae showed high serum antibody reactivity against surface antigens and whole, viable larvae. after a first infection, no significant difference was found between the mean egg counts of the vaccinates and controls although most vaccinated sheep seemed to show an increased susceptibility to infection. the local abomasal response was stimulated by giving both vaccinated and control sheep a large, abbreviated infect ...19921644531
survey for drug-resistant gastrointestinal nematodes in 13 commercial sheep flocks.the prevalence of drug-resistant ovine parasites in the united states has not been widely reported. thirteen flocks, typical of commercial sheep production units, were selected for survey. four anthelmintics (fenbendazole, ivermectin, pyrantel pamoate, and levamisole) were tested for their ability to reduce herd mean pretreatment fecal egg count. if a properly dosed and administered drug failed to reduce herd mean pretreatment fecal egg count by 80%, it was considered ineffective in that flock, ...19921644650
biochemical characterisation of the enzyme responsible for "activated l-serine sulphydrase" activity in nematodes.the biochemical properties of the enzyme responsible for nematode "activated l-serine sulphydrase" activity (l-cysteine + r-sh----cysteine thioether + h2s) have been investigated using primarily the gastro-intestinal nematodes nippostrongylus brasiliensis and haemonchus contortus. the activated l-serine sulphydrase enzyme was found to be cytosolic in origin and exhibited maximal activity at ph 9.0. enzyme activity was widely distributed amongst the major tissues of adult female ascaris suum but ...19921740180
identification of a novel brugia pahangi beta-tubulin gene (beta 2) and a 22-nucleotide spliced leader sequence on beta 1-tubulin mrna.we have examined the expression of beta-tubulin genes in the parasitic nematode, brugia pahangi. a genomic library was constructed and screened by hybridization with a haemonchus contortus beta-tubulin cdna fragment which recognizes several b. pahangi beta-tubulin sequences, including sequences which correspond to the previously characterized beta 1-tubulin gene. the b. pahangi beta 2-tubulin gene was isolated by selecting clones which hybridize to the h. contortus beta-tubulin gene but which do ...19921741015
cloning of a cdna encoding phosphoenolpyruvate carboxykinase from haemonchus contortus.biochemical and metabolic data have led to the conclusion that the enzyme phosphoenolpyruvate carboxykinase (pepck; ec 4.1.1.32) contributes to a critical point of divergence in energy conservation pathways between mammals and nematodes. to facilitate the determination of the molecular basis for host vs parasite differences in pepck, we have cloned a cdna encoding this enzyme from a parasitic nematode of ruminants, haemonchus contortus. h. contortus pepck was cloned by functional complementation ...19921741016
three beta-tubulin cdnas from the parasitic nematode haemonchus contortus.experimental evidence indicates that tubulin is the site of action of the anthelmintic benzimidazoles. furthermore, certain residues of beta-tubulin seem to be critical for this mechanism. although the benzimidazoles selectively affect nematode vs. mammalian beta-tubulin, the molecular basis for this differential action is not known. to enhance our understanding of this phenomenon, and to provide the basis for investigating benzimidazole resistance in parasitic nematodes, we undertook the clonin ...19921741017
an evaluation of an oral formulation of moxidectin against selected anthelmintic-resistant and -susceptible strains of nematodes in lambs.the efficacy of an oral formulation of the newly developed parasiticide, moxidectin, was tested against benzimidazole-resistant haemonchus contortus, trichostrongylus colubriformis, and nematodirus spathiger, levamisole-resistant ostertagia circumcincta, and susceptible cooperia curticei infections in weaned lambs. thirty-two lambs were experimentally infected with mixed doses of the above strains of nematodes. they were allocated into four treatment groups by stratified randomisation using live ...199216031668
development of a vaccine against haemonchus contortus.haemonchus contortus is an economically important nematode parasite of sheep and the occurrence worldwide of strains resistant to anthelmintic chemicals has emphasized the need to develop a vaccine against it. here, ed munn describes the approach to this problem adopted in his laboratory. the principle developed should be applicable to other gastrointestinal parasites.199315463800
a search for associations between major histocompatibility complex restriction fragment length polymorphism bands and resistance to haemonchus contortus infection in sheep.polymorphic bands were detected within the dqb and drb regions of the ovine major histocompatibility complex by probing taqi digested dna from three large sheep half-sib families derived from a highly resistant ram. all animals were phenotypically assessed for haemonchus contortus resistance by faecal egg counts and associations with rflp bands and haplotypes were estimated using mixed model, best linear unbiased prediction statistical methods. although the highly resistant sire was homozygous a ...19937902040
monoclonal antibody to cd4+ t cells abrogates genetic resistance to haemonchus contortus in sheep.the roles of cd4+ and cd8+ t cells in genetically determined resistance of sheep to haemonchus contortus (a natural host-parasite relationship) was investigated by selectively depleting genetically resistant merino lambs of their cd4+ or cd8+ t cells by treatment with mouse monoclonal antibody (mab) specific for the appropriate determinant before and during challenge infection. administration of anti-cd4 mab to genetically resistant lambs completely abrogated their expression of genetic resistan ...19938094709
effect of selection for benzimidazole resistance in haemonchus contortus on beta-tubulin isotype 1 and isotype 2 genes.in vitro selection for benzimidazole (bz) resistance in the nematode haemonchus contortus, a parasite of sheep, suggested the involvement of beta-tubilin genes. two distinct beta-tubulin isotype classes were analyzed. selection with stepwise increased concentrations of bz showed for the first time that the increasing degrees of resistance correlate to a dual phase adaptation mechanism. at lower degrees of developing resistance, selection for a single beta-tubulin isotype 1 variant takes place. s ...19938096381
catecholamines during development of the parasitic nematode, haemonchus contortus.1. catecholamines from infective larvae of haemonchus contortus were extracted, separated on hplc, and measured on an electrochemical detector. doma 18 ng/100,000 larvae: ne 6 ng: e 1 ng: da 1 ng 2. levels of norepinephrine decreased below detection level rapidly after gassing with co2. 3. levels of 3,4-dihydroxymandelic acid (doma), a metabolite of norepinephrine, increased when exsheathment took place in tap water rather than buffer.19938098687
characterization and biological activities of anti-brugia pahangi tubulin monoclonal antibodies.three monoclonal antibodies (mab) specific to beta-tubulin were used to investigate the heterogeneity of tubulins from nematodes and mammals. western blot analysis of one-dimensional sds-page showed that anti-brugia pahangi tubulin mab 1b6 and p3d react with epitope(s) specific to nematode beta-tubulin and recognize tubulin from adults and microfilariae of b. pahangi, adult b. malayi and dirofilaria immitis, eggs of haemonchus contortus and adult ascaris suum. however, the same mab did not recog ...19938106183
the b cell dependence of haemonchus contortus antigen-induced lymphocyte proliferation.the proliferative responses of ovine lymphocytes to soluble antigens of third-stage larvae of haemonchus contortus (hcag) were examined in vitro. lymphocytes in mononuclear cell cultures responded consistently to hcag even if the lambs were naive to h. contortus. lymphocytes from sheep that were immune to reinfection with h. contortus also consistently responded to hcag with a response significantly greater than that recorded from naive lambs. when the responses of t cell or b cell enriched frac ...19938106184
detection of anthelmintic resistance by culture in vitro of parasitic stages of ovine nematodes.exsheathed l3 larvae of haemonchus contortus were cultured at 38.5 degrees c in a complex medium supporting growth to adult worms. although there was a clear difference in response between susceptible and benzimidazole/ivermectin/closantel resistant h. contortus using thiabendazole, the test failed to differentiate satisfactorily between the strains using ivermectin or closantel.19938128582
effects of time, from collection to processing, on the recovery of haemonchus contortus third-stage larvae from herbage.being able to obtain accurate estimates for the number of haemonchus contortus third-stage larvae (l3) on pasture is essential to any type of strategy intended for control. the objective of this experiment was to study the effect of the time, from collection to processing, on the recovery rate of h. contortus l3 from herbage. separate herbage samples were inoculated with two treatments of a known amount of larvae on day 1 and then samples were processed from day 1 to day 30. this simulated infec ...19938128590
detection of haemonchus contortus surface antigen in faeces from infected sheep.an antigen capture enzyme-linked immunosorbent assay (elisa) has been developed that could identify haemonchus contortus antigens in dilute suspensions of worm homogenates and in faeces from sheep naturally infected with moderate burdens of the parasite. the elisa is based on a polyclonal (rabbit or sheep) antibody coated solid-phase that captures parasite antigen from a suspension of worms or faeces. the captured antigen is detected by a mouse monoclonal antibody (mab e2) that is reactive with ...19938128591
[the behavior of hematological parameters (hemoglobin, hematocrit, leukocyte count) and clinicochemical values in plasma (glucose, total proteins, alpha-amino-n, urea, pepsinogen, ascorbic acid, fe, cu, zn) and the content of ascorbic acid in liver, spleen and adrenal glands in healthy lambs and lambs infected with haemonchus contortus and trichostrongylus colubriformis].in 8 healthy, noninfected lambs with an initial body weight (b. w.) of 24.79 +/- 1.16 kg as well as in 3 groups of lambs (n = 8 per group) of a similar body weight after an inoculation with 3rd stage larvae of haemonchus contortus (2500) and trichostrongylus colubriformis (10,000) analyses of the blood plasma were performed for 45 days thereafter. on the 37th day after infection ivermectin (0.2 mg/kg b. w.) was administered per os respectively subcutaneously to the lambs of 2 groups. after 7 and ...19938129699
expression of cloned beta-tubulin genes of haemonchus contortus in escherichia coli: interaction of recombinant beta-tubulin with native tubulin and mebendazole.two distinct beta-tubulin cdna isotypes (beta 8-9 and beta 12-16) from haemonchus contortus were expressed for the first time in escherichia coli and characterised by their specific mebendazole (mbz) binding and polymerization properties. beta-tubulin was expressed without translational fusion to an e. coli sequence under the regulation of the tryptophan promoter in the ptrp2 vector. beta-tubulin was produced in large amounts in insoluble 'inclusion bodies'. the inclusion bodies were purified an ...19938139621
consequences of dose-dependent immunosuppression by progesterone on parasitic worm burdens in lambs.eighteen female lambs with prior exposure to haemonchus contortus infections were ovariectomized and assigned to 1 of 3 replacement regimens: 0, 25, or 250 mg of progesterone/d delivered im. after 3 weeks of hormonal treatment, all lambs were inoculated with 100,000 infective larvae of h contortus. after 8 weeks of hormonal treatment, a blastogenic assay was performed on blood lymphocyte populations, and the abomasum from each lamb was obtained for larval and adult worm recoveries of h contortus ...19938214899
irrigation, faecal water content and development rate of free-living stages of sheep trichostrongyles.the effect of irrigation by flooding the pastures on the ability of the eggs of sheep trichostrongyles to develop into infective larvae (l3) was estimated in outdoor conditions by depositing parasitised faeces on plots, without irrigation or submerged, at different times and durations. the rates of development of teladorsagia circumcincta, trichostrongylus vitrinus and chabertia ovina were very low in spring and summer in dry plots but proportional to the duration of submersion in the irrigated ...19938220500
haemonchus contortus: identification of proteases with diverse characteristics in adult worm excretory-secretory products.host tissue penetration and feeding by helminth parasites may be mediated by both mechanical processes and histolytic products released by the parasites. to investigate potential histolytic products released by adult haemonchus contortus worms, proteases in excretory-secretory (es) products were analyzed. the optimum activity of es proteases was at ph 5.0, although activity was observed over a wide range of ph tested (ph 3.0-9.0). four protease bands were observed on gelatin-containing polyacryl ...19938224091
an in vitro assay utilising parasitic larval haemonchus contortus to detect resistance to closantel and other anthelmintics.a new assay for detecting resistance to anthelmintics in vitro is described. the assay uses a simple culture system in which the ability of anthelmintics to kill or inhibit the migration of parasitic third and fourth stage haemonchus contortus larvae through a 50 microns aperture mesh is assessed. the assay detects 2-10-fold resistance to closantel. resistance to benzimidazoles, levamisole and ivermectin can also be detected.19938225759
comparative kinetic disposition of oxfendazole in sheep and goats before and during infection with haemonchus contortus and trichostrongylus colubriformis.the kinetic disposition of [14c]-oxfendazole (ofz) and its metabolites, fenbendazole (fbz) and fenbendazole sulphone (fbz.so2), in plasma and abomasal fluid were determined in merino sheep and angora goats before and during infection with trichostrongylus colubriformis and haemonchus contortus. the systemic availability (area under the plasma curve, auc) of ofz was significantly lower in goats (13.5 micrograms.h/ml) than in sheep (22.2 micrograms.h/ml) and was reduced with infection in goats (5. ...19938230395
activity of morantel citrate against strains of benzimidazole-resistant nematodes of sheep in the united kingdom.the activity of morantel citrate (5.94 mg/kg base) was determined in laboratory tests against field isolates of benzimidazole-resistant nematodes. its efficacies against adult and seven-day-old worms were 100 per cent and 100 per cent for cooperia curticei, 95.1 per cent and 69.8 per cent for haemonchus contortus and 100 per cent and 82 per cent for ostertagia circumcincta. morantel citrate was 100 per cent effective against benzimidazole-susceptible nematodirus battus and trichostrongylus vitri ...19938236701
efficacy of doramectin against field nematode infections of cattle in latin america.two studies were conducted, one in argentina and one in brazil, to evaluate the therapeutic efficacy of doramectin administered subcutaneously at a dose rate of 200 micrograms kg-1 (1 ml per 50 kg) to cattle harboring mixed field infections of gastrointestinal nematodes. in each trial, 20 heifers were randomly allocated to a control or treated group of ten animals each, on the basis of fecal egg counts. animals in the treated and control groups received an injection of doramectin or saline in th ...19938236736
ivermectin-resistant haemonchus contortus in australia. 19938240179
lamb serum recognition of infective larvae and adult haemonchus contortus antigens.sixteen- to eighteen-week-old lambs were infected with 2500 3rd stage larvae (l-3) of haemonchus contortus or kept as uninfected controls. two months later all animals were challenged with 5000 l-3 of this parasite. soluble antigens of h. contortus l-3 and adult worms were analyzed by sds-page and western blotting during experimental infection and challenge. antigens from both sources, particularly of low molecular weight under reducing conditions, were recognised by the pooled sera of infected ...19938249249
laboratory selection for ivermectin resistance in haemonchus contortus.a strain of haemonchus contortus, susceptible to ivermectin (ivm), was submitted to a selection procedure using ivm at 0.02 mg kg-1 during nine successive passages in lambs. treatment reduced worm egg counts (epg) by more than 99% up to the seventh passage, but thereafter there was no significant reduction in epg. the efficacy of ivermectin against the ninth selected generation compared with the original susceptible strain was assessed. the results showed that animals infected with the selected ...19938249250
parasite spectrum and seasonal epidemiology of gastrointestinal nematodes of small ruminants in the gambia.one hundred and four post mortem examinations of randomly selected sheep (52) and goats (52) were carried out weekly from march 1990 to february 1991. gastrointestinal parasites were identified and counted. a large spectrum of 16 helminth species was found in 101 (97%) infected animals. the nematodes infecting small ruminants were, in order of predominance: trichostrongylus colubriformis (96% of all animals), oesophagostomum columbianum (82%), haemonchus contortus (67%), strongyloides papillosus ...19938249251
the prevalence of concurrent trypanosome and gastrointestinal nematode infections in west african dwarf sheep and goats in nsukka area of eastern nigeria.the prevalence of concurrent nematode-trypanosome infections in traditionally reared west african dwarf sheep and goats in eastern nigeria was monitored over a 12-month period during 1987-1988. the most prevalent nematodes were haemonchus contortus and trichostrongylus colubriformis, which usually occurred together in all nematode infected animals. their combined prevalence rates ranged from 90 to 100% throughout the year and they accounted for 66 to 98% of the total monthly worm burdens. of the ...19938249254
factors affecting the prevalence and severity of footrot in a merino flock selected for resistance to haemonchus contortus.an outbreak of virulent footrot occurred in three lines of sheep selected for different levels of resistance to haemonchus contortus, providing an opportunity to examine the factors affecting footrot severity. the selection lines did not differ significantly in average footrot score, but various other factors were found to have an effect. in breeding ewes, the average score was 10.2 (maximum possible score 20) and the prevalence of footrot was 96%. there was a significant age effect, with averag ...19938257313
benzimidazole resistance of haemonchus contortus in goats in malaysia. 19938279113
acute or chronic administration of prolactin alters ovine infections of haemonchus contortus.prolactin has been implicated as a modulator in the phenomenon of periparturient egg rise during ovine nematodiasis. in the first experiment, lambs (4 months of age) with patent infections (10,000 infective larvae) of haemonchus contortus were injected daily (days 28-39 post-inoculation (pi)) with prolactin (20 or 200 iu) or saline. fecal egg concentrations and total daily egg production were monitored for each lamb. after 12 days, lambs injected with the lower dose of prolactin had the highest ...19938291185
the efficacy and persistent anthelmintic effect of ivermectin in sheep.the direct efficacy and the long-term persistent anthelmintic effect of an oral suspension and an injectable formulation of ivermectin at a dose rate of 0.2 mg kg-1 was studied in sheep. lambs were infected experimentally with haemonchus contortus, trichostrongylus vitrinus and cooperia curticei. after 3 weeks they were treated with an oral suspension or with an injection, and reinfected with the same dose of larvae 3, 6 or 10 days after treatment. post-mortem worm counts showed no persistent ef ...19938291186
comparison of the effects on milk production of concurrent infection with haemonchus contortus and trichostrongylus colubriformis in high- and low-producing dairy goats.the impact of nematode parasitism of the digestive tract on milk output and milk quality was examined in dairy goats. in addition, the consequences of worm infection were compared in goats with different lactation performance (ie, with initial high or low milk production). forty-eight goats in the second month of lactation were allotted equally to 2 groups. the first group was given 5,000 haemonchus contortus and 20,000 trichostrongylus colubriformis larvae. the 24 additional goats remained free ...19938291768
acetylcholinesterase in infective-stage larvae of haemonchus contortus, ostertagia circumcincta and trichostrongylus colubriformis resistant and susceptible to benzimidazole anthelmintics.the amounts of acetylcholinesterase (ache) in homogenates of infective-stage larvae of strains, from different countries, of haemonchus contortus, ostertagia circumcincta and trichostrongylus colubriformis resistant or susceptible to benzimidazole (bz) anthelmintics, were compared using a rapid colorimetric assay. the levels of ache were much greater in those strains which were bz-resistant than in bz-susceptible populations. the larvae of susceptible and resistant h. contortus contained less ac ...19938295794
rejection of heterologous nematodes by sheep immunized with larval or adult trichostrongylus colubriformis.sheep immunized by truncated larval infections or by the adoptive transfer of adult trichostrongylus colubriformis were subsequently challenged with single infections of t. colubriformis, nematodirus spathiger, haemonchus contortus or ostertagia circumcincta or combinations of the parasites. sheep vaccinated with larval infections were > 90% protected by 4 days after challenge (dac) against t. colubriformis l3 given in a single or combined infection, whereas no significant protection was exhibit ...19938314366
kinetics of expulsion of haemonchus contortus from sheep and jirds after treatment with closantel.experiments were conducted in sheep after intramuscular treatment with closantel and in jirds after oral treatment with closantel to determine when expulsion of established h. contortus commences. expulsion starts at about 8 h in sheep and coincides with the onset of reduced motility in worms recovered from the abomasum. in jirds, expulsion starts by 2 h after treatment. experiments also conducted in jirds showed that infective larvae are first killed by circulating closantel 3 days after infect ...19938314373
characterization of proteinases in extracts of adult haemonchus contortus, the ovine abomasal nematode.the degradation of several protein substrates, including the blood proteins haemoglobin, albumin and fibrinogen, by proteinases present in extracts of adult haemonchus contortus was examined over a broad ph range. these proteinases were further characterized on the basis of substrate specificity, inhibitor sensitivity and molecular size by spectrophotometric and substrate gel analysis. the majority of the proteinases capable of degrading the blood proteins tested were active at acidic ph and cou ...19938316437
model predictions for anthelmintic resistance amongst haemonchus contortus populations in southern brazil.a computer model developed to study ostertagia circumcincta resistance to anthelmintics in uk sheep flocks has been adapted for use with haemonchus contortus under southern brazilian conditions. the model simulates the effect of different anthelmintic control regimens on the year-to-year pattern of resistance in breeding ewes. the nematode control regimen most used by brazilian sheep farmers was found to increase the frequency of genes which confer resistance from approximately 3% to 14% in an h ...19938333136
the ecology of animal parasitic nematodes in endemic areas of jos, nigeria.a survey involving 3418 faecal samples collected from three areas of heavy human and animal activities in jos, nigeria showed that 2354 (68.9%) of the samples harboured various parasitic nematodes of man and animals. altogether, twelve species of parasitic nematodes were encountered. five of these, namely: ascaris lumbricoides, ancylostoma duodenale, necator americanus, trichuris trichiura and strongyloides stercoralis infect man while five others: trichostrongylus probolurus, t. colubriformis, ...19938334456
immune responsiveness of lambs selected for resistance to haemonchosis.several parameters of immune competence were measured in lambs with genetic resistance to haemonchus contortus and in lambs with average susceptibility to h contortus (random-bred). increase in skinfold thickness following intradermal injection was greater in resistant lambs for concanavalin a and to a lesser extent for phytohaemagglutinin. both mitogens induced infiltration of superficial and deep dermis by eosinophils, cd4+, cd8+ and t19+ lymphocytes, though the responses did not differ betwee ...19938337484
haemonchus contortus: ivermectin-induced paralysis of the pharynx.how the avermectins cause the elimination of gastrointestinal nematodes from host animals has not yet been clearly identified. using visual and radiometric parameters to measure oral ingestion in haemonchus contortus, we showed that ivermectin (ivm) rapidly inhibited ingestion at concentrations > or = 10(-10) m. motility, monitored quantitatively with an automated motility meter, was unaffected by ivm at concentrations < or = 10(-8) m, while atp levels were unaffected at concentrations < or = 10 ...19938344410
haemonchus contortus: a challenging parasite from immunological point of view. 19938346663
the effect of feed intake on the rate of flow of digesta and the disposition and activity of oxfendazole in sheep.within 3 h of intra-ruminal (ir) administration oxfendazole (ofz) was extensively associated with digesta particulate material. this association appeared to be a passive adsorption/desorption since sheep given dose equivalent ofz which was contained solely in rumen particulate digesta (obtained from ofz treated donor sheep) exhibited similar ofz disposition to the ir treated animals. the association of ofz with rumen particulate digesta is a major determinant of the pharmacokinetic behaviour of ...19938354599
longistrongylus curvispiculum (nematoda: trichostrongyloidea) in free-ranging exotic antelope in texas.longistrongylus curvispiculum was recovered from free ranging sable (hippotragus niger), addax (addax nasomaculatus) and biesa oryx (oryx beisa) on two ranches in central texas (usa). these nematodes represented a small portion of the total abomasal worm burden dominated by haemonchus contortus. female l. curvispiculum easily could be confused with other ostertaginae, but the spicules of the males were diagnostic.19938355363
in vitro activity of paraherquamide against the free-living stages of haemonchus contortus, trichostrongylus colubriformis and ostertagia circumcincta.paraherquamide, an oxindole alkaloid recently reported to have potent nematocidal activity, was shown to have a marked inhibitory effect on the motility of the free-living larval stages of h. contortus, t. colubriformis and o. circumcincta. the effect of paraherquamide on larval motility could be distinguished from that caused by levamisole and the avermectins. after 72 h exposure, the concentration of paraherquamide required to inhibit the motility of 50% of l3 larvae present was 0.033, 0.058 a ...19938359986
an outbreak of haemonchosis associated with anthelmintic resistance in sheep.an outbreak of haemonchosis associated with anthelmintic resistance was recorded in a flock of 150 crossbred lambs. closantel and ivermectin were 100% effective against haemonchus contortus while fenbendazole and morantel reduced faecal egg counts by 87 and 29%, respectively. levamisole showed an efficacy of 95%. at double the recommended dose (10 mg kg-1), fenbendazole had an efficacy of 99% against h. contortus infection. this appears to be the first report of an outbreak of haemonchosis assoc ...19938359992
species-specific pcr for the parasitic nematodes haemonchus contortus and trichostrongylus colubriformis.reliable species determination of gastrointestinal nematode parasites from sheep is usually carried out on third-stage larvae (l3) by visual differentiation. the culturing of l3 takes about 1 week so a reliable method that could use eggs for the determination would accelerate the procedure. we developed a polymerase chain reaction (pcr), using very small amounts of parasite dna and an oligonucleotide set according to parts of the dna sequence of a beta-tubulin gene from haemonchus contortus, tha ...19938359994
demonstration of co-resistance of haemonchus contortus to ivermectin and moxidectin.studies were conducted to determine whether organisms which are resistant to ivermectin are also resistant to moxidectin. the mechanisms of action of moxidectin and ivermectin were compared by measuring the changes in membrane conductance they induced in leg muscle fibres of the common shore crab (pachygrapsus crassipes) by using standard micro-electrode techniques. meriones unguiculatus (jirds) were infected with ivermectin-resistant or -susceptible strains of haemonchus contortus, treated with ...19938362470
molecular characterisation of beta-tubulin genes present in benzimidazole-resistant populations of haemonchus contortus.a beta-tubulin isotype 1 gene, gru-1, from a benzimidazole (bz)-resistant population of the nematode parasite, haemonchus contortus, was cloned and sequenced. the predicted gene organisation showed 10 exons and 9 introns, one of which was h. contortus specific. using probes and restriction sites selected from this sequence, restriction maps were constructed from and around beta-tubulin genes of 3 bz-susceptible and 7 bz-resistant populations. there was a reduction in beta-tubulin isotype 1 genes ...19938366887
systemic responses to challenge infection with haemonchus contortus in immune merino sheep.some systemic responses to single-dose infection with 10,000 haemonchus contortus infective larvae were examined in sheep already shown to have protective immunity against the parasite. the major haematological finding was a neutrophil leukocytosis that occurred after the infections became patent but not during the pre-patent period. there was no definitive eosinophilia and no discernible change in the erythrocyte parameters. systemic hyperthermia was not conclusively evident during the pre-pate ...19938367936
ascaris suum: cloning of a cdna encoding phosphoenolpyruvate carboxykinase.a cdna encoding phosphoenolpyruvate carboxykinase (pepck) from ascaris suum was cloned by complementation of a strain of escherichia coli deficient in pepck and malic enzyme. the product of this cdna was enzymatically similar to a recombinant pepck obtained from haemonchus contortus by the same method. comparison of the predicted amino acid sequence of a. suum pepck with other pepcks showed that this enzyme is most closely related to the h. contortus enzyme. the two nematode enzymes share consid ...19938375484
evaluation of aspects of the protection afforded to sheep immunised with a gut membrane protein of haemonchus contortus.experiments were undertaken to evaluate the type of protection conferred against haemonchus contortus by immunising sheep with h11, a 'hidden' integral gut membrane protein isolated from this parasite. a serial kill experiment showed that worms began to be lost from immunised lambs between seven and 14 days after challenge with a single dose of larvae and adult female worms were more susceptible than male worms. seven-day-old juveniles survived immunisation even though their intestinal cells bec ...19938378601
protection in lambs immunised with haemonchus contortus gut membrane proteins.substantial protection against haemonchus contortus was induced in lambs by hyperimmunising them with an integral membrane extract of intestines dissected from adult worms. the procedure was effective in young growing animals but did not afford any cross protection against either ostertagia circumcincta or nematodirus battus. a serum transfer experiment suggested that the effector mechanism was serum antibody which bound to the brush border membrane of the parasites intestinal cells. sheep which ...19938434155
efficacy of abamectin against nematodes in cattle.eight controlled trials were conducted, using 96 cattle of european breeds, to evaluate the efficacy of abamectin against natural and artificially acquired infections of adult and fourth-stage larvae of all the economically important gastrointestinal nematodes and lungworms in germany and the united kingdom. half the animals were treated on one occasion with abamectin at a dose of 200 micrograms/kg bodyweight given subcutaneously while the other half remained untreated. worms were counted 14 or ...19938442334
isotype-specific antibody responses to haemonchus contortus in genetically resistant sheep.the kinetics of anti-haemonchus antibody responses in serum and faecal extracts of pasture-reared, genetically resistant and random-bred sheep infected with haemonchus contortus were examined using an isotype-specific elisa. anti-haemonchus antibodies of iga, igg1, igg2 and igm isotypes were detected in serum and faecal extracts of both resistant and random-bred sheep after challenge infection. serum igg1 and iga levels in resistant sheep were significantly higher than in random-bred sheep betwe ...19938446465
effect of subclinical coccidiosis in kids on subsequent trichostrongylid infection after weaning.seven-week-old female kids of the murciana-granadina breed naturally infected with coccidia were superinfected with a multispecific eimeria inoculum (300,000 oocysts) or treated to control the coccidial infection with amprolium (50 mg kg-1 liveweight day-1; 4 days every 14 days); 80 days later both animal groups received 2500 third-stage larvae of a sheep-derived mixture of trichostrongylus colubriformis (50%), teladorsagia circumcincta (40%) and haemonchus contortus (10%). kids experimentally s ...19938447060
the ecology of haemonchus contortus in a winter rainfall region in australia: the development of eggs to infective larvae.the seasonal pattern of development of haemonchus contortus eggs to infective larvae was investigated on the south coast of western australia. sheep faeces containing h. contortus eggs were deposited on pasture plots at intervals over a 3-year period, and pasture grass and faeces were sampled periodically for infective larvae (l3). the maximum recoveries occurred in late autumn and in late spring, when adequate moisture coincided with warm temperatures. larval development was low and sporadic ov ...19938447070
the ecology of haemonchus contortus in a winter rainfall climate in australia: the survival of infective larvae on pasture.at sites near albany, on the south coast of western australia, sheep faecal pellets containing either eggs or infective larvae (l3) of haemonchus contortus were deposited onto natural pasture plots at intervals over 3 years. faecal and pasture samples were collected periodically and processed to detect l3. on annual pasture plots, l3 were recovered for from 10 to over 20 weeks from depositions made between autumn and early spring, at which time temperatures were mild or low, rainfall was frequen ...19938447071
survival and development of ivermectin-resistant or susceptible strains of haemonchus contortus under field and laboratory conditions.the free-living development of three strains of haemonchus contortus was studied in two experiments. day 21 faecal samples were collected from lambs infected with either a susceptible strain, a laboratory-selected ivermectin (ivm) resistant strain or a south african field strain showing multiple anthelmintic resistance, which included ivm. no eggs hatched in samples cultured at 4 or 10 degrees c. at 22 degrees c the laboratory-selected strain showed the highest rate of development while at 27 de ...19938460253
the same fractions of haemonchus contortus soluble antigen induce lymphocyte responses in naive lambs and immune sheep.soluble antigen extracted from third stage larvae of haemonchus contortus was divided into fractions based on molecular weight by sodium dodecyl sulphate polyacrylamide gel electrophoresis and electrotransferred to nitrocellulose. infection immunised adult sheep and h contortus naive lambs were used to examine the lymphocyte responses to these fractions in vitro. the results demonstrate that the same two fractions induced the strongest responses in both groups of animals.19938460267
efficacy of closantel against fenbendazole and levamisole resistant haemonchus contortus in small ruminants.sheep infected with a fenbendazole resistant strain of haemonchus contortus and goats with a levamisole resistant strain of the same parasite were used to evaluate the anthelmintic efficacy of closantel. closantel at the rate of 10 mg/kg body weight was 100% effective against the 2 resistant strains of the parasite as indicated by faecal egg count and worm reduction. the efficacy of fenbendazole in sheep and of levamisole in goats was 56.68 and 76.90%, respectively.19938465440
ecdysteroids during development in the ovine parasitic nematode, haemonchus contortus.1. samples of embryonating eggs, infective larvae, fourth-stage larvae, young adults, and male and female mature adults of haemonchus contortus were collected for steroids analysis; lipids were extracted, partially purified, fractionated with hplc, and analyzed for ecdysteroids by radioimmunoassay. 2. free ecdysone and 20-hydroxyecdysone were detected in all samples; maximal concentrations occurred in the fourth-stage larvae and young adults. 3. conjugated ecdysone and 20-hydroxyecdysone were de ...19938472534
vaccination of merino lambs against haemonchosis with membrane-associated proteins from the adult parasite.groups of south african, farm-reared merino lambs about 4 months old were vaccinated with extracts of adult haemonchus contortus enriched with h11, an integral membrane protein from the parasite's intestinal microvilli, or with proteins soluble in tween 20. the lambs were challenged with 5000 infective 3rd-stage larvae. compared to the adjuvant-injected controls, lambs vaccinated with 350 micrograms/kg liveweight of the h11-enriched extract showed an 89% reduction in parasite egg production and ...19938479802
biochemistry of the nematode cuticle: relevance to parasitic nematodes of livestock.the cuticle of nematodes is a thin, flexible outer covering composed primarily of protein with trace amounts of lipid and carbohydrate. there has been considerable recent interest in the biochemistry, immunology and molecular biology of the cuticle of parasitic nematodes because of its role as an interface between parasite and host. the cuticle consists of: (1) collagen-like proteins that form the medial and basal layers; (2) non-collagen proteins that form the epicuticular and external cortical ...19938484203
the role of inhibited development in the epidemiology of ostertagia infections.seasonal patterns of inhibited larval development have been described for ostertagia spp. from many parts of the world; winter inhibition is found in areas where transmission of infections occurs mainly in summer and summer inhibition in areas where transmission is mainly from autumn to spring. there is no fixed regional seasonal inhibition pattern. depending on weather and farm management, the timing and level of inhibition will vary from year to year. moreover, differences in the propensity fo ...19938484216
a key to the identification of arrested gastrointestinal nematode larvae of sheep in britain.a simple key is presented for the identification of arrested larval nematodes recovered from the gastrointestinal tract of sheep slaughtered in britain. the parasites included in this key are those species which are most commonly seen to undergo arrested development in sheep. they include teladorsagia (ostertagia) spp., haemonchus contortus, trichostrongylus axei, intestinal trichostrongylus spp., nematodirus battus, nematodirus filicollis, and cooperia spp. easily identifiable morphological fea ...19938493769
the potential value of integral membrane proteins in the vaccination of lambs against haemonchus contortus.an extract of adult haemonchus contortus enriched in the parasite's intestinal microvillar membrane protein h11 and other integral membrane proteins but free of the protein contortin was evaluated as a potential vaccine in two breeds of sheep. the worm burdens of clun forest sheep injected with the extract and challenged with 25,000 infective larvae were reduced 89% by weight compared to the average for the controls. the worm burdens of dorset sheep (challenged with 10,000 infective larvae) were ...19938496009
purification and evaluation of the integral membrane protein h11 as a protective antigen against haemonchus contortus.a detergent extract of adult haemonchus contortus enriched in the integral membrane protein h11, previously shown to give protective immunity against the parasite, was fractionated by lectin and ion-exchange chromatography. the fractions were evaluated for their ability to immunize clun forest and dorset horn sheep against experimental haemonchosis. most of the protective activity was associated with h11. used in an approximately 95% pure form it gave a mean reduction in parasite egg output of 9 ...19938496010
efficacy of moxidectin against internal parasites of sheep.the efficacy of injectable and oral formulations of moxidectin, at a dosage of 0.2 mg kg -1 live mass was evaluated by the non-parametric method (npm) against the most common internal parasites of sheep in 9 trials involving a total of 201 sheep. both formulations obtained an a classification (more than 80% effective in more than 80% of the treated animals) against the third (l3) and fourth (l4) larval and adult stages of haemonchus contortus, teladorsagia circumcineta, trichostrongylus colubrif ...19938496891
the pattern of faecal egg output in lambs infected with a multiple resistant strain of haemonchus contortus after treatment with albendazole.worm-free lambs (n = 6) were infected with 5,000 l3 of an ivermectin/benzimidazole/closantel resistant strain of haemonchus contortus. on day 21 post infection animals were allocated, according to worm egg counts, to 2 groups of 3 animals each and on day 29 one group was treated with albendazole at 3.8 mg kg-1, while animals in the other group remained untreated as controls. all animals were slaughtered on day 44 when the treated group was found to have 2,083 +/- 1,718 worms and the controls 2,7 ...19938496892
efficacy of moxidectin against a strain of haemonchus contortus resistant to ivermectin, a benzimidazole and a salicylanilide.the efficacy of moxidectin at 0.2 mg kg-1 live body mass against the multiple anthelmintic resistant white river krtz strain of h. contortus was determined and compared to that of ivermectin, a benzimidazole, a salicylanilide and levamisole. moxidectin and levamisole were effective against this strain of h. contortus and reduced the arithmetic mean burdens of this parasite in the sheep by 99.98% and 99.59%, respectively, while the efficacy of ivermectin, albendazole and closantel was only 29.1%, ...19938496899
controlled tests of activity of several antiparasitic compounds against natural infections of haemonchus contortus and other helminths in lambs from a flock established in 1962.antiparasitic activity of several compounds was evaluated over a long period (about 25 years) in the same flock of sheep. haemonchus contortus was of special interest, including its relation to drug resistance, especially to thiabendazole and other benzimidazoles, in addition to phenothiazine. eleven compounds were evaluated in 15 controlled tests, done between 1966 and 1989 in naturally infected lambs (n = 145) born and raised on the same pasture. sheep were first placed on the pasture in 1962, ...19938498743
selection for a strain of haemonchus contortus that exhibits periparturient egg rise in sheep.periparturient egg rise (ppr) is a principal means for some nematode parasites to survive over winter and to provide transmission of infective larvae from ewes to lambs during the spring. routine laboratory propagation techniques probably have selected for those characteristics that would not promote ppr in conventional laboratory strains of haemonchus contortus. an established isolate of h. contortus (bpl) was the source of the initial inoculum to select for a strain that readily exhibits chara ...19938501597
protective immunity to haemonchus contortus induced by immunoaffinity isolated antigens that share a phylogenetically conserved carbohydrate gut surface epitope.whole gut homogenates of the blood-sucking nematode haemonchus contortus induce protective immunity in goats, and some of these gut ag are conserved among related parasitic nematode species. to identify gut ag that induce protective immunity and have phylogenetically conserved epitopes, mab were made to gut-surface ag of h. contortus. forty-nine mab reacted with microvilli of the parasite gut. two of these mab (42/10.6.1 and 42/53.3.5) were analyzed here. both of the mab bound to the microvillar ...19937693812
susceptibility of two crossbreeds of sheep to haemonchus contortus.studies were conducted on 20 crossbred lambs of 4-5 months old. ten lambs were nali x corriedale cross (hisardale) and the other 10 were nali x lohi cross (munjal). seven lambs each of both crossbreeds were infected with 10,000 infective larvae of haemonchus contortus. three lambs of each crossbreed served as uninfected controls. clinicopathological examinations were done before and after infection and all the lambs were necropsied 28 days post-infection. the body weight gain, haemoglobin and pa ...19938300294
persistence of acquired immunity to trichostrongylus colubriformis in sheep after termination of infection.lambs were infected with 6000 trichostrongylus colubriformis l3 per week for 18, 12 or 6 weeks, beginning at ages 14, 20 and 26 weeks, respectively. at the end of the primary infection subgroups had geometric mean adult worm burdens of 5000, 15,000 and 18,000, respectively. in the remaining sheep the worm population was removed with anthelmintic, and sheep had no further larval intake until challenged with t. colubriformis 1, 6, 12, 18 or 24 weeks later. in the groups given 18 or 12 weeks primar ...19938300297
new morphological characters for identifying individual specimens of haemonchus spp. (nematoda: trichostrongyloidea) and a key to species in ruminants of north america.the large stomach worms haemonchus contortus, haemonchus placei, and haemonchus similis are important pathogens of cattle and sheep. this paper describes characteristics of surface cuticular ridges (synlophe), which for the first time provide morphological criteria for identifying individual adult specimens of either sex. the diagnostic patterns of the synlophe on the anterior half of specimens can be observed at 400x in temporary mounts on glass slides. the synlophe can be studied in cleared pr ...19948308643
evolution of cysteine proteinases in eukaryotes.phylogenetic analyses of the major family of cysteine proteinases of eukaryotes revealed that this family has been characterized by numerous gene duplications, several of which occurred very early in eukaryote evolutionary history. for example, certain cysteine proteinases from plants and animals are homologous to each of the two cysteine proteinases of the protist dictyostelium discoideum, indicating that these genes duplicated prior to the divergence of dictyostelium, plants, and animals. all ...19947697189
reduction of haemonchus contortus infective larvae by three nematophagous fungi in sheep faecal cultures.the reduction of haemonchus contortus (l3) infective larvae in sheep faecal cultures caused by the action of three nematophagous fungi conidia was evaluated in vitro. addition of 20,000 conidia of monacrosporium eudermatum, arthrobotrys oligospora and arthrobotrys robusta per gram of faeces caused a reduction of 95.7%, 98.3% and 10.1%, respectively, compared with the control group. a 97.4% reduction was observed when combined conidia of the three fungi were used. total reduction of the larval po ...19947879378
resistance to benzimidazole anthelmintics by haemonchus contortus in goats in peninsular malaysia.a previous study had suggested that local strains of goat trichostrongyles, comprising largely haemonchus contortus, might have developed resistance to benzimidazole anthelmintics. a trial involving 18 goats was conducted to confirm this. there was a significant (p < 0.01) reduction in worm burdens in goats given levamisole, but this was not so for those animals given albendazole, fenbendazole, oxfendazole and mebendazole (p > 0.05).19947886916
multiple and multigeneric anthelmintic resistance on a sheep farm in malaysia.the anthelmintic efficacy of benzimidazoles, levamisole, closantel, ivermectin and moxidectin was evaluated on an institutional farm in malaysia using faecal egg count reduction tests, controlled slaughter trials and an in vitro egg hatch assay. the results of this study indicated simultaneous resistance of haemonchus contortus against benzimidazoles and ivermectin and of trichostrongylus colubriformis against benzimidazoles and levaminsole on the same farm. moxidectin was effective against the ...19947886917
helminth and arthropod parasites of indigenous goats in the northern transvaal.helminth and arthropod parasites of 60 female indigenous goats of three age groups on a farm in the northern transvaal were collected, identified and counted. anoplocephalid tapeworms were present in the two younger groups of goats, while larvae of taenia hydatigena were recovered from all three groups. eight species and two genera of nematodes were found in the youngest goats, five species and three genera in the middle group and six species and two genera in the oldest goats. strongyloides pap ...19947898893
differential expression of two succinate dehydrogenase subunit-b genes and a transition in energy metabolism during the development of the parasitic nematode haemonchus contortus.the carbohydrate metabolism of free-living and parasitic stages of the sheep nematode haemonchus contortus was studied, and it was demonstrated that during development a switch occurred from krebs-cycle activity towards a more fermentative metabolism. during this switch a transition might take place in complex ii of the respiratory chain. in the free-living (l3) and early parasitic (xl3) stages, complex ii catalyses the oxidation of succinate to fumarate via the krebs cycle, whereas in adults co ...19947808477
isolation of an ivermectin-resistant strain of haemonchus contortus from sheep in malaysia. 19947817517
identification and analysis of a cuticular collagen-encoding gene from the plant-parasitic nematode meloidogyne incognita.the vast majority of proteins in the nematode cuticle are collagens. cuticular collagen-encoding genes (col) have been described for the animal parasites ascaris suum and haemonchus contortus and for the free-living caenorhabditis elegans. the proteins encoded by all these genes seem to have the same basic structure, indicating that there is a conserved subfamily of cuticular col in these nematodes. in this paper, we describe the identification and characterization of a cdna (lemmi 5) which corr ...19947828882
vaccination against gastrointestinal nematodes of sheep using purified secretory acetylcholinesterase from trichostrongylus colubriformis--an initial pilot study.purified secretory acetylcholinesterase (sache) from trichostrongylus colubriformis was used as a candidate vaccine against mixed t. colubriformis, haemonchus contortus and c. oncophora challenge infections of sheep. cross species protection was achieved with an average reduction in worm burden of all species of 31%, rising to 58% in individual cases. there was no consistent reduction in faecal egg counts and increases in anti-t. colubriformis sache igg antibody levels following vaccination were ...19947838599
access to the abomasum of sheep via a rumen fistula for follow-up studies during trichostrongylid infections.a technique is described for the examination of the abomasum of adult sheep via a rumen fistula. the size of the fistula allowed a manual exploration of the rumen which was necessary to achieve an access to the abomasum. in four adult sheep, two of them infected with haemonchus contortus, fibreoptic endoscopy was used to investigate the abomasal mucosa macroscopically as well as histopathologically and ultrastructurally by means of mucosal biopsy specimen. the acidity of the abomasal contents wa ...19947839744
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