Publications

glucose metabolism of haemonchus contortus adults: effects of thiabendazole on susceptible versus resistant strain.	analyses of the in vitro glucose metabolism of haemonchus contortus adults have confirmed a complex series of end-products: ethanol, n-propanol, propionate, acetate, and co2 as the major end-products of catabolism. no difference in end-product accumulation was seen between the cambendazole sensitive (bpl) and cambendazole resistant (cr) strains. thiabendazole (5 mm) in vitro depressed ethanol, propanol, acetate, and propionate accumulation by approximately 42% in the bpl strain. however, in the ...	1982	6813445
changes in optical path difference in the oesophageal region and the excretory cells during exsheathment in haemonchus contortus.		1982	6819242
haemonchus contortus: immunodiffusion patterns of antigens from phenotypically different females.		1982	6800835
quantitative studies of ovine haemonchosis. 2. relationship between total worm counts of haemonchus contortus, haemoglobin values and bodyweight.	the relationships between haemonchus contortus burdens, haemoglobin levels and bodyweight, were examined in 50 commercial merino sheep, 9-18 months of age, in south-east queensland where haemonchosis was endemic. worm counts and haemoglobin levels were predictable (p less than 0.001, r = 0.68) from the equations log worm count = b.wt. x 0.06942 + log worm count x (-2.18896) + 12.51557. bodyweight was not predictable from either worm counts or haemoglobin levels. although bodyweight was represent ...	1982	7201195
quantitative studies of ovine haemonchosis. 3. the interpretation and diagnostic significance of the changes in serial egg counts of haemonchus contortus in a sheep flock.	an examination of the level and distribution of egg counts of h. contortus within an extensively managed flock of merino sheep in south-east queensland was carried out on three occasions over a ten week period. during this time the geometric mean egg count increased from 527 to 1331 eggs per gram, and although 26.3% of the flock were responsible for this increase, clinical evidence of haemonchosis was not observed. examination of the distribution of counts supported the hypothesis that counts fo ...	1982	7201196
comparison of changes in resistance of haemonchus contortus eggs following withdrawal of thiabendazole selection.	two strains of haemonchus contortus with different levels of thiabendazole resistance were developed from the same parent strains by being subjected to different selection intensities. these two strains were each subdivided into two; one selected by thiabendazole in each generation, the other unselected for four generations. levels of thiabendazole resistance were monitored in each generation by an in vitro egg hatch technique. during this time the unselected strain with the higher level of resi ...	1982	7201152
changes in water content and volume accompanying exsheathment of haemonchus contortus.		1982	6279531
worm burdens in cows. ii. an analysis of the population of nematodes in the abomasa of adult dairy cows.	over a period of one year, from february 1979-february 1980, the abomasa of four dairy cows were examined each week for the presence of parasitic nematodes. based on the identification of adult male worms, ostertagia ostertagi (94%) and trichostrongylus axei (75%) were the most prevalent species, and haemonchus contortus was absent. total worm burdens varied from zero (one cow) to 100,890. the geometric mean total number was 3011. the geometric mean number of arrested larval stages was 685. of t ...	1982	6890273
haemonchus contortus: egg laying influenced by abomasal ph in lambs.		1982	6891337
gastro-intestinal nematodes in sheep in kashmir.	examination at necropsy of the abomasum and intestinal tract of 62 sheep (including both sexes) of karnah breed, aged one to two years over a period of one year was conducted at handwara, situated in the north-west of kashmir valley. the following species of nematodes were found: haemonchus contortus, trichostrongylus axei, trichostrongylus colubriformis, bunostomum trigonocephalum, chabertia ovina, nematodirus spathiger, skrjabinema ovis and trichuris ovis. infections with trichostrongylus axei ...	1982	6891858
seasonal incidence of helminths in sheep and goats in south mozambique.	the seasonal fluctuations in faecal worm egg counts were studied at monthly intervals for over a year in 20 male sheep and goats on extensive grazing tracts at a farm near maputo, mozambique. larval differentiation from faecal cultures showed that haemonchus contortus and oesophagostomum columbianum were the most prevalent worm species. trichostrongylus colubriformis, cooperia spp., strongyloides papillosus, moniezia spp., paramphistomum spp. and trichuris spp. also occurred. after the onset of ...	1982	6892176
strongyle infections of small ruminants in nigeria.	a survey of strongyle infections was conducted in sheep and goats reared in a traditional extensive husbandry system in two ecological zones of nigeria. one zone had a seasonal pattern of infection. the majority of animals had faecal worm parasite egg counts of below 500 eggs per gram. kids, and lambs younger than 3 months did not carry strongyle worm burdens, and the highest infection rate was found in the 7-12 month age group. a high proportion of small ruminants shed strongyle eggs during the ...	1982	6892178
morphological changes in trichostrongylid eggs after treatment with fenbendazole.	the influence of daily doses of 0.05-0.1 mg fenbendazole/kg body weight on egg development was tested in twenty-seven lambs artificially infected with haemonchus contortus plus trichostrongylus colubriformis or ostertagia circumcincta, as well as in two additional sheep naturally infected with nematodirus spp. atypical eggs were detected before a reduction in the number of eggs. atypical eggs had blastomeres of different sizes and shapes; knot-like, crater-like or bubble-like. in isolated cases ...	1982	6892181
efficacy of ivermectin against naturally acquired and experimentally induced nematode infections in sheep.	the activity of ivermectin against common nematode parasites of sheep was examined in 2 experiments. in the 1st experiment, 14 sheep with naturally acquired infections were assigned to 2 groups of 7 sheep each. sheep in 1 group were treated with 200 micrograms of ivermectin/kg of body weight and the remainder served as nontreated controls. in the 2nd experiment, 15 sheep with experimentally supplemented infections (including a benzimidazole-resistant strain of haemonchus contortus) were assigned ...	1982	7041712
haemonchus contortus: abomasal transmural potential difference and permeability changes associated with experimental infection in sheep.		1982	7060704
[haemonchosis in lambs and the prophylactic effect of anthelmintic treatment; consequences of sub-therapeutic dosage and the presence of strains of haemonchus contortus resistant to benzimidazoles in the netherlands (author's transl)].		1982	7064137
[observations on the spring rise of faecal strongyle egg counts in goats (author's transl)].	examination of the faeces at regular intervals during the period from february to june 1980 in a group of multiparous dairy goats produced the following results: (a) a marked increase in faecal strongyle egg-counts, (b) haemonchus contortus was the worm mainly causing this increase, (c) differences in faecal egg-counts between dutch white (saanen) goats and toggenburger goats or between groups of goats of different ages were not observed, (d) no differences in faecal egg-counts were observed in ...	1982	7064140
gastro-duodenal motor and transit disturbances associated with haemonchus contortus infection in sheep.	abomasal and duodenal motility was investigated by electromyography in 4 lambs fitted with permanent abomasal and duodenal cannulae and infected twice with 25,000 haemonchus contortus larvae at an interval of 39 days. in addition, abomasal and duodenal ph, flow rate of digesta of the duodenum, and faecal water content were determined. the 80-90 min cycles of antral contractions were shortened for at least 3 weeks after infection. this was accompanied by a 26% increase in the number of duodenal m ...	1982	7070846
benzimidazole resistance in a field strain of haemonchus contortus in the netherlands.		1982	7072124
changes in the flow and composition of gastric lymph in sheep given a primary infection of 10,000 haemonchus contortus.	some aspects of the local immune response to a primary infection with 10,000 haemonchus contortus were studied in five sheep by monitoring changes in the flow and composition of gastric lymph continuously sampled for up to 34 days from the start of infection. increases in lymph flow rates were recorded in four animals at varying times after the start of infection. these were usually associated with an increase in the protein content of the lymph and were considered to be a consequence of inflamm ...	1982	7079599
attempts to immunise sheep against ostertagia circumcincta with irradiated larvae.	mature sheep immunised with two doses of 10,000 irradiated ostertagia circumcincta larvae were only slightly resistant to challenge with a single dose of 10,000 larvae. this slight resistance was abolished if the 'vaccine' worm population was removed one week before challenge. in contrast, seven of eight sheep immunised with irradiated haemonchus contortus larvae were highly resistant to homologous challenge. evidence of some cross protection against challenge with o circumcinta was observed in ...	1982	7089372
evaluation of the cornell-wisconsin centrifugal flotation technique for recovering trichostrongylid eggs from bovine feces.	several variables in the cornell-wisconsin centrifugal flotation technique were studied using helminthologically sterile bovine feces to which known numbers of haemonchus contortus eggs had been added. neither mode of mixing (levigation versus conventional), volume (15-60 ml) of water used for making the feces water suspension nor specific gravity (1.20-1.33) of the sucrose flotation solution affected egg recovery. optimal times for centrifugation at 264 x g of first the feces water and then the ...	1982	7093809
the pathogenesis of a single challenge dose of haemonchus contortus in lambs under six months of age.		1982	7096969
origin of the early digestive disturbances induced by haemonchus contortus infection in lambs.		1982	7103200
studies on haemonchus contortus. vi. attempts to stimulate immunity to abomasal trichostrongylids in merino sheep.	two doses of infective larvae of 20 000 trichostrongylus axei, dosed to merino lambs at an interval of 14 days and subsequently challenged with ostertagia circumcincta, caused a significant reduction (p less than 0.01) in the establishment of 5th and adult stages of the latter. t. axei was unable to protect merino sheep against homologous challenge nor was haemonchus contortus a successful vaccine against challenge with the same species. the vaccinated group showed a reduction (p less than 0,025 ...	1982	7122063
studies on haemonchus contortus. vii. the effect of treatment of trichostrongylus axei prior to challenge with h. contortus.	four-month-old worm-free merino lambs were dosed with 20 000 infective larvae of trichostrongylus axei on day 0 and again on day +14. on day +83 they were treated with mebendazole at 15 mg/kg. all lambs in this group and a further group of 11 worm-free merino control lambs were challenged with 50 000 infective larvae of haemonchus contortus dosed from day +90-day +92. at necropsy 27 and 28 days later there was no significant difference between the worm burdens of the 2 groups. t. axei must be pr ...	1982	7122068
effect of anthelmintic treatment of ewes at parturition and lambs at weaning on the build up of haemonchus contortus populations in lambs in the netherlands.	in two groups of ewes and lambs, grazing pastures which were used respectively by calves and sheep in the previous year, infection with haemonchus contortus was virtually prevented by a single treatment of the ewes with fenbendazole before turning out. in another group, grazing a pasture which was not grazed in the previous year, a delay of approximately eight weeks in the build up of high h contortus burdens in lambs was obtained by this treatment, compared with a group of untreated ewes grazin ...	1982	7134638
effect of removing anthelmintic selection pressure on the benzimidazole resistance status of haemonchus contortus and trichostrongylus colubriformis in sheep.		1982	7134649
time of onset and target of immune reactions in sheep with acquired immunity against haemonchus contortus.		1982	7141783
the response of sheep to parenteral vaccination and immunizing infections against the abomasal nematode, haemonchus contortus.		1982	7141784
the use of faecal egg counts for estimating worm burdens in sheep infected with haemonchus contortus.	clun forest sheep, worm-free from birth, were given a single dose of 20 000 infective larvae of haemonchus contortus. the total number of eggs/day in the faeces was recorded for 21 infections and data on population size, sex ratio and individual worm development were collected from 76 sheep. the female to male ratio was 1.28 +/- 0.07 (s.e.). the relation between increase in worm size and uterine egg content was linear. the number of eggs present in the uteri was found to be an accurate measure o ...	1982	7145469
the effect of ethoxyzolamide, an analogue of insect juvenile hormone, nor-adrenaline and iodine on changes in the optical path difference in the excretory cells and oesophagus during exsheathment in haemonchus contortus.		1982	7160957
enhanced resistance to infection with haemonchus contortus in sheep treated with a corticosteroid.		1982	7160958
haemonchus contortus: the in vitro effects of dl-tetramisole and rafoxanide on glycolytic enzymes.		1982	7160961
the anthelmintic efficacy of artemisia herba-alba against haemonchus contortus infection in goats.	the anthelmintic activity of the powdered shoots of artemisia herba-alba was investigated in experimental haemonchosis in six nubian goats which had been infected with single doses of 800 to 1,000 infective haemonchus larvae. the clinical signs of caprine haemonchosis included inappetence, dullness and soft faeces and were correlated with the pathological findings. none of these changes were observed in four of the six goats following the treatment with 2, 10 or 30 g of artemisia shoots. this su ...	1982	7162537
the effects of treatment with transfer factor, parasitic antigen and precipitated immunoglobulin on the parasitological and histopathological responses in haemonchus contortus infection in lambs under six months of age.		1982	7166633
the trichostrongyloid parasites of sheep in south australia and their regional distribution.	the species of trichostrongyloid nematodes present in 376 sheep from different agricultural regions of the state of south australia were determined. parasites encountered in the abomasum were teladorsagia circumcincta, t. trifurcata, t. davtiani, camelostrongylus mentulatus, haemonchus contortus and trichostrongylus axei. t. circumcincta was the species most commonly encountered, but c. mentulatus was widespread in arid areas. h. contortus was present in a small number of sheep only, mainly in s ...	1982	7168719
gastrointestinal parasites and bacteria flora of wild animals in the borgu game reserve in nigeria.	faecal droppings from animals in the borgu game reserve were examined between the months of january and march 1981. these animals included buffalo, hartebeest, kob, roan antelope, genu cat, mangoose, warthog and monkey. haemonchus contortus was identified from the faeces of five buffalos, oesophagostomum species was identified from one warthog while strongyloides species was identified from two monkeys. no pathogenic bacteria was isolated in any of the faecal samples examined. the influence of w ...	1982	7174235
the seasonal incidence of helminth parasites and of oestrus ovis in karakul sheep in the kalahari region of south west africa, namibia.	the seasonal incidence of gastro-intestinal helminths and of oestrus ovis was determined by slaughter of successive groups of 4 tracer lambs, each exposed on pasture for 33 days. haemonchus contortus was present from march 1979 to early july 1979, with a generally increasing percentage of 4th stage larvae in each successive month. a "spring rise" in the egg count was seen in flock sheep in october 1978. oesophagostomum columbianum was recovered from tracers slaughtered in march 1979. apart from ...	1982	7177585
studies on haemonchus contortus. viii. attempts to protect suckling lambs against infestation with h. contortus.	a group of 12 merino lambs, 3,5 months of age, which were still suckling, were each dosed with 40 000 infective larvae of trichostrongylus axei on day 0. from day +62-day 64 each of these lambs and those of a 2nd group of 11 controls were dosed with 30 000 infective larvae of haemonchus contortus, and all the lambs of both groups were killed on day +90. attempts to use t. axei to protect them against subsequent challenge with h. contortus were unsuccessful.	1982	7177593
[effects of alternate grazing on faecal egg output of gastrointestinal nematodes and on the growth of calves and lambs].	during the period from 1975 to 1977, the faecal egg output of gastrointestinal nematodes and the gain in weight of a group of calves and a group of ewes with lambs on pastures alternately grazed by the two groups, were compared with the egg output and the gain in weight of a group of calves and a group of ewes with lambs not grazed alternately. the annual level of the egg output was identical in each comparable group. variations in larval differentiation were observed between the groups grazed a ...	1982	7179232
haemonchus contortus: the in vitro effects of anthelmintics on total glucose and glycogen contents, and total volatile fatty acids.		1982	7187820
slight resistance to the residual effect of closantel in a field strain of haemonchus contortus which showed an increased resistance after one selection in the laboratory.	on the strength of a complaint of suspected resistance to closantel, a field strain of haemonchus contortus was isolated from sheep on a farm near pretoria and tested for resistance to the remedy, both without exposure to closantel in the laboratory (designated the "unselected" substrain of the parasite) and after a single selection with closantel (called the "selected" substrain). for comparative purpose a few sheep were treated with rafoxanide to ascertain whether the efficacy of this drug was ...	1982	6764253
anthelmintic resistance survey in new zealand.	the prevalence and level of thiabendazole resistance of sheep nematodes in the north island of new zealand was investigated by means of an in vitro egg-hatch technique; samples from sheep on 52 properties in six country areas were examined. resistance of haemonchus contortus and trichostrongylus spp. was identified on the basis of egg hatch in 0.1 ppm thiabendazole. evidence of resistance was obtained on 11(21.2%) of the properties. ld 50's and resistance ratios were calculated for the resistant ...	1982	16030902
therapeutic and prophylactic efficacy of morantel when administered directly into the rumen of cattle on a continuous basis.	the efficacy of morantel tartrate when administered on a continuous basis directly into the rumen/reticulum of cattle, either by a cannula or from a specially designed device, was evaluated against gastrointestinal parasites under laboratory conditions. in two experiments the continuous infusion of morantel at rates between 0.26 and 1.04 mg/kg body weight per day using a peristaltic pump was highly efficacious in both preventing the establishment of infections and removing established infections ...	1983	6225238
infectivity of haemonchus contortus in sheep after freezing for ten years over liquid nitrogen.		1983	6827445
development of benzimidazole resistance in a haemonchus contortus strain in the netherlands following fenbendazole treatment of ewes at parturition.	in contrast to observations in former years treatment of ewes after parturition with 5 to 7.5 mg/kg fenbendazole was not fully effective in removing haemonchus contortus. comparison of the h contortus populations in the lambs of these ewes and those of untreated ewes later in the year revealed that the treatment resulted in fenbendazole resistance and also in side resistance to other benzimidazoles. though the faecal egg counts of the treated ewes were low, the prophylactic effect of the treatme ...	1983	6836180
changes in resistance in mixed infections of susceptible and benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis passaged in sheep.	benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis were each diluted with equal numbers of their respective susceptible genotypes and passaged in separate worm-free sheep. the progeny of the mixed susceptible and resistant infections were diluted with equal numbers of susceptible genotypes before passaging on two further consecutive occasions in worm-free sheep. in h contortus the amount of thiabendazole required to prevent a 50 per cent egg hatching (lc50 ...	1983	6836181
seasonal fluctuations and hypobiosis of gastro-intestinal nematodes of awassi lambs in iraq.	the results of an epidemiological study involving the estimation of worm counts of gastro-intestinal nematodes of lambs, during the period december 1978 to november 1979, in the baghdad area are reported. ostertagia spp. and trichostrongylus spp. were the most abundant nematodes in the weaned lambs used in this study. ostertagia spp. infection was present throughout the period of observation, the level of infection being the highest during early summer (may-june). trichostrongylus spp. infection ...	1983	6856333
observations on the fumarate reductase system in haemonchus contortus and their relevance to anthelmintic resistance and to strain variations of energy metabolism.	fumarate reductase activity in a thiabendazole-resistant strain of haemonchus contortus was found to be significantly lower than that from a susceptible strain. however, the fumarate reductase activity in a mebendazole-resistant strain did not differ from that in the susceptible strain, even though it was cross-resistant to thiabendazole. published reports of fumarate reductase activity in strains of h. contortus susceptible or resistant to benzimidazoles were reassessed. a second, unrelated aus ...	1983	6877276
ribonucleotide levels in six nematodes, a cestode and a trematode.	the levels of ribonucleotides in the nematodes haemonchus contortus, ostertagia circumcincta, trichostrongylus colubriformis, nippostrongylus brasiliensis, ascaris suum and stephanurus dentatus, the cestode moniezia expansa and the trematode fasciola hepatica were measured by high pressure liquid chromatography. the adenylate charge, atp and total adenine nucleotide levels were in general agreement with those determined enzymatically and with published data. udp and guanine nucleotide levels wer ...	1983	6877282
[resistance to nematodes to anthelmintics].	resistance of nematodes to anthelmintics is being increasingly observed throughout the world in recent years. benzimidazole-resistance of haemonchus contortus is also observed in the netherlands. there are a number of methods to detect resistance to anthelmintics of which only the in vitro techniques can be used to detect resistance in the field. factors such as dosage, frequency of treatment and the time of treatment may affect resistance.	1983	6879576
[observations on the effect of some measures for preventing gastrointestinal helminth infections in sheep].	prophylactic anthelmintic treatment of ewes about parturition has only a negligible effects on the most important species of helminths when the ewes and their lambs are not grazed on clean pasture. haemonchus contortus infections were completely prevented in some cases but usually severe infections occurred. as the build-up of these heavy infections in lambs was slightly delayed in comparison with that in the lambs of untreated ewes, treatment about parturition should still be regarded as useful ...	1983	6879577
pharmacokinetic behaviour and anthelmintic efficacy of 1-n-butyl carbamoyl oxfendazole given by intramuscular injection.	oxfendazole (ofz) was chemically modified to 1-n-butyl carbamoyl ofz (c4-ofz) in an attempt to improve the solubility of ofz and enable it to be administered by injection. after intramuscular injection to sheep and cattle, c4-ofz was metabolised to ofz which resulted in higher plasma ofz concentrations that persisted for a considerably longer period than those observed following administration of ofz orally. the anthelmintic efficacy of injected c4-ofz was tested, in sheep, against strains of tr ...	1983	6880009
a comparison of the effects of dialysed and non-dialysed transfer factor preparations on haemonchus contortus infections in young lambs.	significant reductions in worm burdens were achieved in lambs treated with dialysed transfer factor and challenged with 10,000 haemonchus contortus larvae, when compared with challenged control animals. non-dialysed transfer factor, from the same leucocyte pool, produced no protection, but was successful in reducing worm burdens when given after a primary infection of 1,000 h. contortus larvae with subsequent challenge of 10,000 larvae. while the results confirmed the previously reported inconsi ...	1983	6880013
the effect of haemonchus contortus infection on the pregnant and lactating ewe.		1983	6618756
investigation with dexamethasone of the processes which moderate immunity against the nematode, haemonchus contortus, in sheep.	treatment of sheep with the corticosteroid, dexamethasone, was used to investigate some properties of the immunoregulatory process which dampens the expression of protective responses against the abomasal nematode, haemonchus contortus, and which may occur as an adaptation for evasion of host immunity by this parasite. the protective responses released by giving dexamethasone early in infection operated during a series of superimposed infections. accordingly, they may also operate during field e ...	1983	6626053
morphology and histochemistry of the spicules and gubernaculum of haemonchus contortus (nematoda: trichostrongylidae).	a study has been made of the morphological, histological and histochemical characteristics of spicules and gubernaculum in haemonchus contortus (rud., 1803). the correlation coefficients of body length and left and right spicule lengths, left and right spicule lengths, and the distance of barb from the distal end of left and right spicule ends have been found to be statistically significant while the correlation coefficient of body length and gubernaculum length has been found to be non-signific ...	1983	6629205
haemonchus contortus from the vaal ribbok, pelea capreolus, and the bontebok, damaliscus dorcas dorcas, in the bontebok national park.	during a survey of the parasites of antelope in the bontebok national park, swellendam, cape province, specimens of haemonchus contortus with exceptionally long spicules were recovered from 5 out of 8 bontebok, damaliscus dorcas dorcas, and 3 out of 5 vaal ribbok, pelea capreolus, but not from 4 springbok, antidorcas marsupialis. typically, h. contortus has spicules 0,466 +/- 0,085 mm long, but those recovered from vaal ribbok had spicules 0,581 +/- 0,02 mm long and were recovered in large numbe ...	1983	6646659
population dynamics of haemonchus contortus and trichostrongylus spp. in sheep.		1983	6654581
observations on the self-cure reaction and other forms of immunological responsiveness against haemonchus contortus in sheep.		1983	6654583
erythrocyte potassium concentration: a simple parameter for erythropoiesis in sheep infected with haemonchus contortus.	a number of haematological parameters were monitored in eight-month-old merino wethers, six infected with 10,000 haemonchus contortus and 13 controls. blood loss caused by infection was reflected in a decrease in packed cell volume (r = -0.78; p less than 0.001), and was correlated with faecal egg excretion (r = 0.89; p less than 0.001). infected animals showed a decline of serum iron content and increased serum transferrin levels. erythrocyte potassium concentration showed a high correlation wi ...	1983	6665309
stimulatory effects of prostaglandin f2 alpha on faecal egg production in haemonchus contortus infected sheep.	the effect of prostaglandin f2 alpha on the pattern of faecal egg count was tested in 10- to 12-month-old sheep infected with 20,000 haemonchus contortus larvae. prostaglandin was infused intravenously 25, 50 and 75 days after infection for four hours at a rate of 5 micrograms/kg/minute and the egg counts in the faeces were determined daily for 110 days. treatment on days 50 and 75 was followed by a significant rise in egg count lasting 19 and 12 days respectively. this observed rise seems to be ...	1983	6665312
immune exclusion, a mechanism of protection against the ovine nematode haemonchus contortus.	the fate of exsheathed haemonchus contortus larvae injected directly into the abomasal lumen was studied in groups of naive and hyperimmune sheep. within 48 hours of challenge, more than 90 per cent of the larvae were lost from hyperimmune sheep. the larvae had a propensity to associate with the superficial mucus in both groups and, in naive sheep, approximately 50 per cent of the larvae entered glandular tissue within four hours of challenge. by contrast, although initially associated with the ...	1983	6665320
radiolabeling of infective larvae of haemonchus contortus (nematoda: trichostrongyloidea) with 75se-methionine and their performance as tracers in sheep.	haemonchus contortus infective larvae incorporated between 5 and 12 pci/larva for each muci of 75se-methionine added per gram of fecal sediment. thorough admixture of 75se-methionine and fecal sediment was necessary to obtain approximately normal distribution and low variance of individual larval radioactivities. ecdysis induced by treatment with 0.025% hclo in vitro resulted in loss of approximately 40% of the 75se label of infective larvae. loss of 75se by parasitic larvae and adult h. contort ...	1983	6672167
epidemiology of gastrointestinal parasites of awassi sheep in iraq.	studies on the epidemiology of gastrointestinal nematodes of sheep, conducted at two different farms in the baghdad area, in 1979, revealed two peaks in worm egg counts in ewes, one in spring and the other in autumn; the latter coincided with the lambing season. similarly in lambs, two peaks of infection were apparent, but the spring peak was not so well defined. during the hot and dry summer months of iraq, helminthic infection was at a low level. faecal culture for larvae and their identificat ...	1983	6683037
endotube-brush border complexes dissected from the intestines of haemonchus contortus and ancylostoma caninum.	a procedure for the blunt dissection of the syncytial intestine of haemonchus contortus to separate the endotube-brush border complex is described. a similar complex can be obtained from the partially cellular intestine of ancylostoma caninum. the structural features of the complexes from the two sources are compared. the main differences are in the retention of terminal bars by the endotube from a. caninum and in the extent and organization of the microfilaments associated with the basal side o ...	1983	6684761
the effects of transfer factor, parasitic antigen and precipitated immunoglobulin treatments in lambs infected with haemonchus contortus.	significant reductions in adult worm burdens in lambs less than six months old infected with 5000 third stage haemonchus contortus larvae were achieved following the combination of a single transfer factor treatment with multiple parenteral treatments of adult parasitic antigen and precipitated immunoglobulin. specific cellular responses in the abomasa associated with individual treatments were discernible in all the experimental groups and quantitative differences in these responses reflected t ...	1983	6684825
a survey of seasonal changes in nematode faecal egg count levels of sheep and goats in senegal.	a survey of the gastro-intestinal nematodes in domestic sheep and goats of the sahelian zone of senegal was undertaken. their prevalence and the egg production were estimated by faecal egg count in 2234 sheep and 577 goats slaughtered at the dakar slaughterhouse during a 12 month period. the highest prevalence (%) and highest mean egg counts (epg) were recorded at the end of the wet season. amongst the species of nematodes encountered there are two of potential importance: haemonchus contortus a ...	1983	6686379
the effects of dl-tetramisole and rafoxanide on tricarboxylic acid cycle enzymes of haemonchus contortus, in vitro.	various enzymes of the tricarboxylic acid cycle (tca) viz., aconitase (e.c. 4.2.1.3), isocitrate dehydrogenase (e.c. 1.1.1.42), succinate dehydrognease (e.c. 1.3.99.1), fumarate reductase (nadh: fumarate oxido-reductase), fumarase (e.c. 4.2.1.2) and maltate dehydrogenase (e.c. 1.1.1.37) were detected in adult haemonchus contortus (nematoda: trichostrongylidae), in vitro. low activities of aconitase and isocitrate dehydrogenase suggested that the tca cycle has a minor function and the pathway of ...	1983	6686386
in vitro activity of various anthelmintic compounds against haemonchus contortus larvae.	twenty-five known anthelmintic compounds were evaluated in vitro against the highly motile exsheathed non-feeding third-stage of haemonchus contortus larvae. activity was based on lack of motility or death of larvae after 24 h of chemical exposure. six compounds (avermectins, closantel, levamisole, morantel, phenylhydrazone and ticarbodine) were active at a concentration of 100 micrograms cm-3 or less. the most active compounds were avermectins and levamisole. when higher in vitro concentrations ...	1983	6686387
antiparasitic efficacy of ivermectin in naturally parasitized sheep.	sixteen sheep harboring naturally acquired parasitisms were allocated to 1 of 2 treatment groups: (i) sheep given ivermectin in an oral solution at the dosage rate of 200 micrograms/kg of body weight, and (ii) those given the vehicle at a dosage rate of 0.25 ml/kg. all animals were necropsied at 2 weeks after treatment. parasites and percentages of parasitic reductions, as demonstrated in this trial, were: dictyocaulus filaria (99.4%), oestrus ovis first stage instars (100%), trichuris ovis (98. ...	1983	6689112
reversal of order of ecdysis in haemonchus contortus (nematoda).	exposure of haemonchus contortus infective larvae to carbon dioxide under specific conditions is believed to activate a succession of events that ultimately control both exsheathment and subsequent development to the fourth stage. rarely at ph 6, but always at ph 2, worms fail to exsheath yet develop to the fourth stage surrounded by cuticles two and three. failure to exsheath is probably a consequence of inactive enzymes in exsheathing fluid, because exposure to edta, which inactivates exsheath ...	1983	6406659
partial biochemical and serological characterization of exsheathing fluid and somatic extracts of infective larvae and adult females of haemonchus contortus.	exsheathing fluid from infective larvae of haemonchus contortus may contain antigens which induce protective immunity upon infection in sheep. in this study, a rapid method of preparing exsheathing fluid was used to determine its biological activity, purity and antigenic complexity. protein in exsheathing fluid ranged from 21-59.5 micrograms/ml and no carbohydrate was detected. gel filtration showed a single broad peak which retained biological activity and polyacrylamide gel electrophoresis dem ...	1984	6426763
energy metabolism of adult haemonchus contortus in vitro: a comparison of benzimidazole-susceptible and -resistant strains.	in vitro biochemical characteristics of three strains of haemonchus contortus, benzimidazole-susceptible, mebendazole-resistant and thiabendazole-resistant isolates, were investigated. steady-state pool sizes of glucose and metabolic intermediates, including adenine nucleotides and end-products revealed no differences between adult worms resistant or susceptible to benzimidazoles in 30-60 min incubations. possible regulatory steps in the glycolytic pathway are identified as those involving the e ...	1984	6427605
studies on haemonchus contortus. ix. the effect of trichostrongylus axei in merinos on natural pasture.	four groups of 6-7-month-old merino lambs were each dosed with 40 000 infective larvae of trichostrongylus axei on 2 november 1976 and subsequently exposed to challenge with haemonchus contortus on natural grazing at the university of pretoria's experimental farm in the eastern suburbs of pretoria. one of these groups and one group of controls were killed every 8 weeks from the end of december 1976-june 1977. predosing with t. axei was greater than 50% effective against 5th stage and adult h. co ...	1984	6462631
studies on haemonchus contortus. x. the effect of trichostrongylus axei in merinos on artificial pastures.	a recently established eragrostis curvula pasture 1,1 ha in size at hennops river in the transvaal highveld was contaminated from 6 october 1976 until 20 may 1977 by 30 weaned merinos, each infested with 7 000 infective larvae of h. contortus. on 2 november 1976 3 groups of weaned merinos and again on 10 january 1977 a further group of merinos were infested with 40 000 infective larvae of trichostrongylus axei. from 19 november a single group of sheep, predosed with t. axei, and a control group ...	1984	6462632
studies on haemonchus contortus. xi. the effect of a bovine strain of trichostrongylus axei in merinos on natural pastures heavily infested with h. contortus.	sheep grazed on natural pastures heavily infested with infective larvae of haemonchus contortus. sixty-eight weaned merinos were divided into 6 groups on day 0 (23 november 1977), and on day +14 (7 december) 79 merinos were divided into 7 groups. there were 2 groups of undosed controls and other groups were either dosed with infective larvae of trichostrongylus axei (bovine strain) only on days 0 and +14, or in combination with h. contortus, or with subsequent doses of h. contortus, 28 days late ...	1984	6462634
studies on haemonchus contortus. xii. effect of trichostrongylus axei in dorper lambs on natural pasture lightly infested with h. contortus.	weaned dorper lambs on natural pasture were predosed with 40 000 infective larvae (l3) of trichostrongylus axei, irradiated (0,3 kgy) l3 of t. axei or closantel at 10 mg/kg either in september or november 1978 and were compared with merino yearlings predosed with 40 000 l3 of t. axei in november 1977. the following summer (december-march) only 178,6 mm of rain fell and very few h. contortus were present on pastures. artificial challenge with 20 000 l3 of haemonchus contortus with the local strai ...	1984	6462635
effect of cimetidine on abomasal ph and haemonchus and ostertagia species in sheep.	cimetidine, a histamine h2-receptor blocking agent which reduces gastric acid flow in simple stomach animals was administered directly into the abomasum of sheep at 100 mg kg-1 twice daily for five consecutive days and again on the eighth day. the drug caused a significant increase in the ph values of the abomasal contents and was highly effective in reducing the adult population of haemonchus contortus (100 per cent) and ostertagia circumcincta (70 per cent) in the abomasum of sheep. the possib ...	1984	6463375
prevalence of anthelmintic resistant nematodes in sheep in south-east england.	the prevalence of anthelmintic resistant nematodes among 52 commercial flocks in south-east england was investigated by comparing the faecal egg counts of groups of lambs before, and seven days after, treatment with thiabendazole and levamisole. evidence of thiabendazole resistance was found on seven farms. in each case haemonchus contortus was the only species of nematode involved. in vitro egg hatch assays carried out for isolates from these farms gave ed50 estimates of 0.065 to 0.332 microgra ...	1984	6464318
the effect of anaerobiosis on adenosine triphosphate levels in larval nippostrongylus brasiliensis and haemonchus contortus.	the adenosine triphosphate (atp) content of the pre-parasitic stages of nippostrongylus brasiliensis, haemonchus contortus (l1, l2 and l3) and the adults of the free-living nematode, panagrellus redivivus, have been measured by bioluminescent photometry in aerated or near-anoxic conditions. the atp content of the l1 and l2 stages of both parasitic species was unaltered by a lack of oxygen over a 90-min period. however, the l3 stage of both species and the adults of p. redivivus showed a signific ...	1984	6506845
studies on the pathophysiology of chronic ovine haemonchosis in merino and scottish blackface lambs.	an experiment was conducted to examine, under laboratory conditions, the pathophysiology of chronic ovine haemonchosis. in the present study, groups of merino and scottish blackface lambs were maintained on a low plane of nutrition and infected with 50 haemonchus contortus larvae/kg live weight. the parasitized lambs along with respective breed controls were examined over a 27-week period. in addition to the body weight, haematological and parasitological parameters, erythrokinetic, metabolic, d ...	1984	6514383
the effect of transfer factor treatment on two challenge infections of haemonchus contortus in immuno-competent 7-month-old lambs.	a number of immuno-competent blackface lambs were infected with 10,000 haemonchus contortus third stage larvae and were later challenged with a second dose of 10,000 h. contortus third stage larvae. one group of lambs was treated with dialysed transfer factor prior to the second challenge dose. histological changes in the abomasal wall, reductions in abomasal worm burdens at slaughter and faecal egg counts monitored throughout the experiment suggested the presence in some animals of an innate re ...	1984	6516210
stocking rate effects on the worm burdens of angora goats and merino sheep.	worm egg counts of yearling angora or merino wethers grazing in mixed flocks at either 4/ha or 8/ha were observed over a 5 month period. based on faecal egg counts infection levels in the sheep increased for the first 3 months and then decreased as the animals developed resistance. egg counts in the goats did not decrease during the experiment. post mortem worm counts indicated that there was a significant host species--stocking rate interaction on worm burdens of haemonchus contortus adults and ...	1984	6517775
the structure of excretory system of the infective larva of haemonchus contortus.		1984	6526575
effects of bovine heme on development of haemonchus contortus in vitro.		1984	6527196
[kinetics of the population of worms in various developmental stages, haemonchus contortus in sheep after a single experimental infection] experimental infection].	this work was performed to study, in 147 month-old male lambs experimentally infected with 14000 haemonchus contortus infective larvae and slaughtered at 6, 12, 18 and 24h and at 2, 6, 8, 11, 15 and 39 days post-infection (pi): 1, the importance, localisation and nature (with or without sheath) of the worms during the first 24 h pi; 2, the kinetics of the total worm population and of each evolutionary stages from the first to the 39th day pi: 3, the period of emergence of the fourth-stage larvae ...	1984	6529116
the anthelmintic efficacy of d.l. tetramisole against haemonchus contortus infection in goats.		1984	6531494
serum and abomasal antibody response of sheep to infections with haemonchus contortus.	serum and abomasal iga, igg and igm antibody response against adult worm, l3 and egg antigens of haemonchus contortus was monitored by the elisa technique after one or two infections with this nematode. following the first infection, antibody levels in serum did not change materially. after administration of a challenge dose of infective larvae, antibodies of the three immunoglobulin classes in infected animals rose slightly, but this rise appeared later than the fall in the faecal egg counts. i ...	1984	6538719
wool production of sheep chronically infected with haemonchus contortus.	a chronic infection was established in a group of twenty 18-month-old non-reproductive merino ewes by oral administration of 3000 infective h. contortus larvae twice weekly for 12 weeks. their live-weights and wool production were compared with those of 20 uninfected ewes grazing the same pasture. in the infected sheep, faecal egg counts increased over a period of 9 weeks to reach a mean of 5000 eggs per gram, accompanied by small, but significant effects on packed-cell volume and live-weight. t ...	1984	6541834
resistance to haemonchus contortus transferred between genetically histocompatible sheep by immune lymphocytes.	the pattern of faecal egg counts after infection with 10,000 haemonchus contortus larvae was similar within but not between, four pairs of monozygous twin sheep. transfer of whole lymph or washed lymph cells from three immune donor sheep to their identical co-twin recipients reduced the susceptibility of the recipients to challenge with 10,000 larvae as measured by faecal egg counts. cells from a nonimmune donor did not have this effect. in a final experiment, washed cells from an immune triplet ...	1984	6542246
some factors influencing the immunisation of sheep with irradiated haemonchus contortus larvae.	over the last 6 years a number of experiments in which sheep were successfully immunised with 2 doses of 10 000 haemonchus contortus larvae, irradiated at 60 krad in a gamma-source, have been reported by the authors. in this paper, the failure of such a regimen of immunisation, using the same strain of larvae, is reported together with an investigation of the possible causes. technical errors were eliminated as a cause, on the grounds that the failure occurred in 2 separate laboratories using di ...	1984	6542728
the abomasal histology of worm-free sheep given primary and challenge infections of haemonchus contortus.	the histological changes in the abomasal mucosa of pairs of worm-free ewes and lambs were compared at various stages after infection and reinfection with 350 haemonchus contortus l3 per kg bodyweight. in terms of worm burdens the ewes were relatively resistant to reinfection compared with the lambs and the histological changes in the abomasum at most stages after infection were more marked in the adult animals. these included increases in the numbers of mast cells, globule leucocytes, eosinophil ...	1984	6543052
anthelmintic efficacy of avermectin b1a and dihydroavermectin b1a against ovine gastrointestinal nematodes in 1977.	in a critical study, 40 female mixed-breed lambs with experimental infections of cooperia spp, trichostrongylus colubriformis, ostertagia circumcincta, t axei, and haemonchus contortus were allocated to 8 groups in 1977. groups 1 and 5 served as controls. groups 2 to 4 were treated orally with avermectin b1a at dosage levels of 25, 50, and 100 micrograms/kg of body weight, respectively. groups 6 to 8 were given oral dihydroavermectin b1a at dosage levels of 50, 100, and 200 micrograms/kg, respec ...	1984	6547280
efficacy of ivermectin against internal parasites of sheep.	ivermectin in an oral formulation was evaluated by the non-parametric method against a wide range of endoparasites of sheep in 15 trials involving a total of 297 sheep. ivermectin at 200 micrograms/kg was more than 80% effective in more than 80% of the treated animals (i.e. class a) against induced infestations of 3rd and 4th stage larvae and adults of chabertia ovina, dictyocaulus filaria, haemonchus contortus (including a benzimidazole-resistant strain), nematodirus spathiger, oesophagostomum ...	1984	6549472
amino acid biosynthesis in haemonchus contortus from c14-labelled precursors, in vitro.	adult haemonchus contortus (nematoda: trichostrongylidae) was investigated for its ability to utilize various c14-labelled precursors, i.e., glucose, acetate, co2 and palmitic acid, for amino acid biosynthesis. h. contortus has been demonstrated to be capable of synthesizing essential as well as non-essential amino acids. label from all the precursors was detected in aspartic acid, lysine, histidine, cystine, cysteine, glutamic acid, proline, arginine, tyrosine, alanine, glycine, serine, valine, ...	1984	6093333
nematoda: aerobic respiratory pathways of adult parasitic species.	aerobic respiratory pathways have been compared in adult parasitic nematodes, including trichostrongylus colubriformis, nippostrongylus brasiliensis, ostertagia ostertagi, cooperia oncophora, haemonchus contortus, oesophagostomum venulosum, chabertia ovina, dictyocaulus filaria, dictyocaulus viviparus, and ascaridia galli. respiration was measured in both whole worm or tissue homogenates and isolated mitochondrial fractions, and delineated into the mammalian type or alternative respiratory pathw ...	1984	6692887
use of coproantibody measurement to assess the influence of diet on local immune responses of sheep vaccinated against haemonchus contortus.	local antibody responses to challenge with 10,000 normal haemonchus contortus larvae were evaluated in vaccinated and control blackface sheep fed either a high or low protein diet. anti-parasite antibody activity was found in faecal extracts of both vaccinated and control animals after infection. the coproantibody levels showed some correlation with abomasal mucosa antibody levels and faecal antibody activity was mostly associated with iga. the low protein diet reduced local antibody responses i ...	1984	6718823
immunological unresponsiveness of lambs to infection with haemonchus contortus. modulation of responsiveness by exposure to soluble larval antigen.	the in vitro transformation of lymphocytes in the presence of antigen was used to assay the response of lambs to antigens of haemonchus contortus. neither uninfected lambs nor lambs infected with h. contortus up to 9 weeks of age developed in vitro lymphocyte responsiveness to antigen. a slight and transient increase in reactivity was demonstrable in some of the infected lambs when these were reinfected with h. contortus at 26 weeks of age. this lack of responsiveness could be modulated through ...	1984	6720032