Publications

changes in response of a benzimidazole resistant strain of haemonchus contortus from sheep after passing through calves.	a benzimidazole resistant strain of haemonchus contortus was passaged through lambs only or from lambs to calves and back into lambs. changes in response to thiabendazole were monitored by using an egg hatch test at each animal passage and by a controlled experiment on adult worms at the final passage in lambs. an increased level of resistance was shown for the isolate during its passage through calves by the egg hatch test, although this was not supported on the adult worms in sheep using a sin ...	1981	7255904
anthelmintic efficacy of low-dose phenothiazine against strains of sheep nematodes susceptible or resistant to thiabendazole, levamisole and morantel tartrate: effect on patent infections.	the anthelmintic efficacy of low-dose phenothiazine therapy, administered as a 1:40 phenothiazine: molasses mixture, was tested against patent infections of strains of haemonchus contortus, trichostrongylus colubriformis and ostertagia spp susceptible or resistant to thiabendazole (an other benzimidazoles), levamisole and morantel tartrate. phenothiazine reduced faecal egg output for both susceptible and resistant strains of all three nematodes. in daily doses of 0.25 g per sheep per day and abo ...	1981	7255906
anthelmintic efficacy of low-dose phenothiazine against strains of sheep nematodes susceptible or resistant to thiabendazole, levamisole and morantel tartrate: efficiency against sequentially administered infections.	low-dose daily phenothiazine therapy, administered as a 1:40 phenothiazine:molasses mixture, was tested against sequential infections of strains of haemonchus contortus. trichostrongylus colubriformis and ostertagia spp susceptible or resistant to thiabendazole, levamisole and morantel tartrate. phenothiazine at a dose rate of 0.5 g per sheep per day significantly reduced the numbers of worm eggs per gram of faeces in both susceptible and resistant strains by an average of 48 per cent and 60 per ...	1981	7255907
the isolation of a field strain of haemonchus contortus in queensland showing multiple anthelmintic resistance.	following the apparent failure of levamisole to control infections of haemonchus contortus in sheep at lawes in south eastern queensland, a strain of this parasite was isolated at the animal research institute, yeerongpilly. this strain was used to infect sheep at yeerongpilly and the merrindale research station, victoria where four experiments to classify the resistance pattern of the parasite were carried out. resistance to thiabendazole was first suspected in 1969, and these experiments confi ...	1981	7259650
the epizootiology of nematode parasites of sheep in a high-rainfall area of zimbabwe.	fifty-two untreated lambs from a contaminated flock were slaughtered at regular intervals throughout the year, and their gastro-intestinal tracts were examined for the presence of nematode parasites. haemonchus contortus and oesophagostomum columbianum were found to be of major importance. the incidence of haemonchus rose to a peak and remained at a high level throughout the winter through the fourth larval stages of the parasite predominated at this stage. oesophagostomum columbianum was recove ...	1981	7265099
nippostrongylus brasiliensis and haemonchus contortus: function of the excretory ampulla of the third-stage larva.		1981	7274368
infection with gastrointestinal helminths. effect of lactation and maternal transfer of immunity.	lactation in sheep and mice was associated with a marked increase in susceptibility to newly acquired infection with haemonchus contortus and nematospiroides dubius, respectively. in sheep this increased susceptibility to infection with h. contortus occurred in late pregnancy and during lactation and was seen when the ewes were infected with both a single large dose of infective larvae and a "trickle" infection of 200 and 400 infective larvae of h. contortus given weekly for 14 weeks. nonlactati ...	1981	7281902
changes in blood leukocytes, bone marrow and lymphoid organs in sheep infected with haemonchus contortus.		1981	7287297
hybridization of australian haemonchus placei (place, 1893), haemonchus contortus cayugensis (das & whitlock, 1960) and haemonchus contortus (rudolphi, 1803) from louisiana.		1981	7287298
inheritance of cambendazole resistance in haemonchus contortus.	fourth-molt larvae (m4) of cambendazole-resistant (cbz-r) and cambendazole-susceptible (bpl) strains of haemonchus contortus were recovered from donor lambs and inoculated orally into source lambs to effect mating in 2nd lamb. eggs produced by these parasitic matings were collected, cultured, and inoculated into lambs to compare the anthelmintic activity of cambendazole (cbz), given at a dose rate of 20 mg/kg, against the f1 adults with its activity against the 2 parenteral strains (cbz-r and pb ...	1981	7294466
effect of haemonchus contortus extracts on coagulation of ovine plasma.		1981	7299587
immunity acquired by sheep from an experimental infection with haemonchus contortus.		1981	7309338
a residual anthelmintic 2,6-diiodo-4-nitrophenol (disophenol). methods of testing its anthelmintic efficacy.	a subcutaneous injection of 2,6-diiodo-4-nitrophenol (disophenol) at 10 mg/kg sheep leaves a residue bound to serum albumin which is lethal to haemonchus contortus for 3 months after treatment. in the larval anthelmintic test, susceptible worm free sheep are dosed so that either third stage larvae (l3), or fourth stage larvae (l4) or 5th and adult stages are present on the day of treatment but slaughter is delayed to allow these larval stages to develop to adults because the larger worms are mor ...	1981	7310790
studies on cross-transmission and pathogenicity of haemonchus contortus in white-tailed deer, domestic cattle and sheep.	experiments were conducted to compare the relative pathogenicity and infectivity of deer- and cattle-derived haemonchus contortus for three hosts, viz., white-tailed deer, cattle and domestic sheep. parameters evaluated for all animals were: general physical condition, basic hematologic values, fecal egg counts and parasite infectivity rates. clinical signs attributable to h. contortus infections were not observed in any of the experimental animals. deer harboring h. contortus burdens greater th ...	1981	7310944
prolonged anthelmintic effect of closantel and disophenol against a thiabendazole selected resistant strain of haemonchus contortus in sheep.	two long-acting anthelmintics, closantel and disophenol, were tested by treatment 90, 60 and 30 days before challenge with a thiabendazole selected laboratory strain of haemonchus contortus. the sheep were slaughtered 28 days after infection for total worm counts. a significant reduction in the number of adults remaining at autopsy was recorded after treatment with both anthelmintics 30 and 60 days before challenge but there was zero efficacy when the animals were treated 90 days before challeng ...	1981	7313310
resistance to reinfection with haemonchus contortus in lactating and barren ewes following a single infection with larvae conditioned for inhibited development.	ewes were infected in november 1977 with third stage larvae of haemonchus contortus which were conditioned for inhibited development at +15 degrees c for 35 days. worm counts in december and may and weekly faecal egg counts revealed that the high burdens of inhibited larvae present in december virtually disappeared during winter, while the faecal egg counts remained low. this happened whether the ewes were pregnant or not. indications of a slight postpartum rise in faecal egg counts, however, we ...	1981	7314814
efficiency and sensitivity of techniques for recovering nematode eggs from bovine feces.	haemonchus contortus eggs were extracted from sheep feces and known numbers were added to helminthologically sterile bovine feces to provide samples with seven, 30 and 60 eggs per gram (epg). at 60 epg, dilution techniques (modified cornell-mcmaster and modified mcmaster) tended to overestimate the number of eggs and more eggs were recovered (mean of 121 and 88% respectively) with these techniques than with centrifugal concentration procedures (modified cornell-63% and wisconsin- 69%). at 30 epg ...	1981	7340910
the similarity between arrested development in parasitic nematodes and diapause in insects.	the similarities between arrested development in parasitic nematodes and diapause in insects are discussed. particular attention is paid to the similarity between arrested development in haemonchus contortus and diapause in oestrus ovis in sheep. factors inducing arrested development and influencing resumed development and measures to control arrested nematodes in ruminants are discussed.	1981	7341780
a field strain of haemonchus contortus showing slight resistance to rafoxanide.		1981	7341786
efficiency of oxfendazole administered as a single dose or in a controlled release capsule against benzimidazole-resistant haemonchus contortus, ostertagia circumcincta and trichostrongylus colubriformis.	laboratory strains of haemonchus contortus and ostertagia circumcincta selected for thiabendazole resistance were found to have a strong side resistance to a single dose of oxfendazole. the ld50 and ld95 in mg of drug per host liveweight were respectively 4.28 and 18.46 mg/kg for h contortus and 3.61 and 11.20 mg/kg for o circumcincta. a field strain of trichostrongylus colubriformis that had not been selected with thiabendazole for seven years also had a strong side resistance to oxfendazole wi ...	1981	7342223
haemonchus contortus third stage larvae in sheep: kinetics of arrival into the abomasum and transformation during rumino-omasal transit.	the kinetics of passage of haemonchus contortus third stage larvae through the omasoabomasal orifice were analysed in sheep for six hours after their administration by the nasooesophageal route. the larvae moved into the abomasum more slowly than the liquid phase of the ruminal contents. they arrived in three different forms: sheathed, exsheathed or coiled. a very small number of exsheathed larvae seemed to be necessary for inducing early modifications in permeability of the abomasal mucosa.	1981	7342230
passive transfer of immunity to trichostrongyle species infections in sheep. investigations of specificity and limitations of 'transfer factor' activity with trichostrongylus axei infections.	the ability of transfer factor (tf) preparations to transfer resistance to challenge with trichostrongylus axei in sheep and to correct partially the immune immaturity of young lambs was confirmed. non-dialysed tf consistently transferred resistance but dialysed tf frequently failed, perhaps demonstrating a loss of activity during tf preparation procedures. specificity of transfer was demonstrated when t. axei tf transferred resistance to t. axei challenge but haemonchus contortus tf failed to d ...	1981	7342416
circulating antigens in ovine haemonchosis.	we have developed a sandwich enzyme linked immunosorbent assay (sandwich elisa), which allows the sensitive assay of haemonchus contortus antigens. using this test we have attempted to detect h. contortus circulating antigens in the serum, urine and milk of experimentally infected ewes. the results of this study indicate that circulating antigens may not be a general feature in ovine haemonchosis.	1981	7342821
immune response of sheep to haemonchus contortus: serum antibodies against cross reacting antigens between parasites.	normal and h. contortus infected sera were studied by elisa technique against different stages of the parasites. in all cases antibody activity was detected. this activity in serum is partially eliminated after absorption with an adult worm extract of n brasiliensis. n. brasiliensis and h. contortus antigens were analysed by tciep with a rabbit anti-n. brasiliensis serum to examine shared antigens of h. contortus. a minimum of seven cross reacting antigens were detected. h. contortus adult worm ...	1981	7342831
[immune response in sheep experimentally infected with haemonchus contortus, comparative study in male and female (author's transl)].	merino breed sheep eight months old at the beginning of the experiment and carriers of hemaglobin a were used. they were infected one or more times with h. contortus larvae and then challenged with 500 or 5000 larvae l3. self-cure was reproduced and animals were found immune after infectation. self-cure was more evident in females than in males and immunity was also better and appeared earlier in females than in males.	1981	7342835
the interaction of trypanosoma congolense and haemonchus contortus infections in 2 breeds of goat. 1. parasitology.		1981	7343578
the interaction of trypanosoma congolense and haemonchus contortus infections in 2 breeds of goat. 2. haematology.		1981	7343579
the role of absorbed drug in the efficacy of oxfendazole against gastrointestinal nematodes.	comparisons were made of the relative efficacy of ozfendazole (ofz), administered to sheep at 5 mg/kg either as an oral drench, single intravenous injection or 12 and 24 divided intravenous injections over 24 and 48 hours, against benzimidazole-resistant haemonchus contortus and trichostrongylus colubriformis. a single intravenous injection was at least equally potent as the oral drench whilst the divided dose intravenous regimes significantly increased ofz efficacy against both parasite species ...	1981	7344270
studies on haemonchus contortus. iv. the effect of trichostrongylus axei and ostertagia circumcincta on challenge with h. contortus.	worm-free merino yearlings were dosed with either a mixture of infective larvae of trichostrongylus axei and ostertagia circumcincta or with o. circumcincta only, and challenged 90-93 days later with infective larvae of haemonchus contortus. neither of these methods protected sheep against challenged and slight protection was afforded sheep predosed with t. axei and o. circumcincta and challenged with a trickle dose of h. contortus.	1981	7345390
studies on haemonchus contortus. v. chemoprophylaxis and its effect on worm egg counts and the haematocrit.	a group of 12 10-month-old, worm-free merino lambs were given a single injection of disophenol at 10 mg/kg. this group and another group of 12 worm-free lambs were infested with infective larvae of haemonchus contortus 1-3 times a week with a maximum dose of 4000/week from 0-91 days. from 95-168 days the dose was increased to a maximum of 6000/week. every 7 days faeces were examined for worm eggs and blood samples for haematocrit (ht). worm egg counts in the controls rose from 21-56 days, fluctu ...	1981	7345391
the response of awassi sheep to re-infection with haemonchus contortus larvae.	the response of awassi sheep to primary infection with 10 000 haemonchus contortus larvae and subsequent challenge with 20 000 larvae was studied. two types of response to re-infection were observed. the first, characterized by a sharp decline in egg counts, progressive improvement in packed cell volume (pcv) and a marked loss of adult worms and challenge larvae, was considered as self-cure and protection. in the second type of response there was a temporary decline in egg counts, no improvement ...	1980	7367038
lateral migration of haemonchus contortus larvae on pasture.		1980	7369613
efficacy of albendazole and levamisole in sheep against thysanosoma actinioides and haemonchus contortus from the edwards plateau, texas.	lambs naturally infected with thysanosoma actinioides and naturally and experimentally infected with haemonchus contortus were used in a controlled experiment to determine the anthelmintic activity of albendazole as compared with levamisole. the lambs were given 10,000 h contortus larvae 25 to 35 days before treatment, were slaughtered 7 to 9 days after treatment, and were housed on concrete from the time of treatment until slaughter. in lambs given doses of 7.5 mg or 3.8 mg of albendazole/kg or ...	1980	7369618
efficacy of oxfendazole against nematodirus battus and inhibited stages of sheep nematodes.	oxfendazole administered at a dose rate of 5 mg/kg was 100 per cent effective against artificially acquired seven-day-old and 23-day-old infections of nematodirus battus in lambs. at the same dose rate it was 100 per cent effective against naturally acquired infections of adult trichostrongylus spp, adult and arrested early fourth stage larvae of haemonchus contortus and nematodirus spp. efficacy against ostertagia spp was 99 to 100 per cent against adults and 100 per cent against inhibited larv ...	1980	7375726
observations on epidemiological and clinical aspects of gastrointestinal helminthiasis of sheep in northern nigeria during the rainy season.	during the rainy season of 1976 severe gastrointestinal helminthiasis was observed in yankassa sheep grazing unimproved pasture in northern nigeria. until mid august high mortality from acute haemonchosis was mainly in lambs. later, lambs and ewes died from haemonchosis combined with trichostrongylosis but the course of the disease was less rapid. animals surviving until the end of october showed combined symptoms of chronic haemonchosis and of trichostrongylosis. a rapid turnover rate of adult ...	1980	7375733
resistance of haemonchus contortus to oxfendazole.		1980	7406781
emergence of haemonchus contortus resistant to thiabendazole.		1980	7406782
diagnostic exercise. haemonchus contortus infection.		1980	7431863
haemonchus contortus resistance in straightbred and crossbred barbados blackbelly sheep.	resistance to haemonchus contortus infection was studied in two experiments conducted with 52 lambs of widely different genetic background. breed groups compared were: dorset (d), barbados blackbelly (b), dorset x blackbelly (d x b), suffolk x blackbelly (s x b), suffolk x dorset x blackbelly (s x d x b,[1/4 b]) and nonblackbelly (nb, d and s). in each experiment, lambs were raised on concrete from birth and were essentially parasite free until infective larvae were administered. in exp. 1, d x ...	1980	7440430
studies on haemonchus contortus. iii. titration of trichostrongylus axei and explusion of h. contortus.	groups of merino weaners were dosed with infective larvae of trichostrongylus axei in numbers ranging from 20 000-50 000 and challenged 3 months later with 50 000 infective larvae of haemonchus contortus. when the dose of infective larvae of t. axei was given on day 0 and the balance on day + 14, efficacy against h. contortus was > 60% in > 60% of sheep (p < 0, 1). a single dose of 40 000 or 50 000 infective larvae of t. axei was > 80% effective against h. contortus in > 80% of sheep (p < 0, 01) ...	1980	7454233
haemonchus contortus: attempts to immunise lambs with irradiated larvae.	two doses of irradiated haemonchus contortus larvae stimulated firm resistance to challenge in adult worm-free sheep but not in two-month-old lambs. parenteral administration of larval antigens in adjuvant together with the two doses of irradiated larvae did not reduce the susceptibility of the lambs. however four doses of the attenuated larvae stimulated three of six lambs to resist the challenge. similar concentrations of serum igg and mucosal iga and igg antibodies were detected in the sheep ...	1980	7455354
use of disophenol for the control of haemonchus contortus in sheep in west java, indonesia.	the result of a field trial investigating the anthelmintic effect of disophenol against h. contortus in sheep raised under asian small farming practice is reported. it was clearly shown that a single injection of disophenol suppressed the numbers of h. contortus to very low levels for periods up to 3 months despite the presence of large populations of h. contortus infective larvae available on pasture and herbage grasses.	1980	7456119
anthelmintic activity of closantel against benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis in sheep.		1980	7458788
parasitic infection of camelus dromedarius from iran.	25 intestinal tract, 30 oesophagus and respiratory organs and 47 liver of arabian camel were examined. 35 species of nematodes two species of cestodes one immature trematode one cestodes larvae, one diptera larvae, one microfilaria of lung worm and two external parasites were found. this is a first report of helminths in camel from iran. the nematodes: physocephalus sexalatus, ascarops strongylina, haemonchus contortus, cooperia punctata, nematodirus oratianus, nematodirella longissimespiculata, ...	1980	7460130
haemonchosis in white-tailed deer in the southeastern united states.	haemonchosis concomitant with malnutrition has been a frequent parasitic disease observed in white-tailed deer (odocoileus virginianus) in the southeastern united states. typically, afflicted deer were fawns from the southeastern coastal plain, and most cases were submitted between october and march. a survey of deer from 14 areas along the atlantic coast revealed that fawns had significantly higher numbers of haemonchus contortus than adults and in some areas fawns harbored h. contortus burdens ...	1980	7463602
survival and development of larvae of the common nematodes of ruminants after long-term cryopreservation and investigation of different routes of infestation.	exsheathed infective larvae (l3) of 16 species of nematodes were tested for infectivity in either sheep or cattle after they had been frozen and stored in 0,09% nacl solution in the gas phase of liquid nitrogen for periods of up to 59 months. a mean of greater than 90% of the l3 of haemonchus contortus, ostertagia circumcincta, trichostrongylus axei, trichostrongylus colubriformis, nematodirus spathiger, oesophagostomum columbianum and chabertia ovina of sheep and haemonchus placei, ostertagia o ...	1980	7465164
a field strain of haemonchus contortus showing slight resistance to rafoxanide.	a field strain of h. contortus, already resistant to benzimidazole anthelmintics, was also found to be slightly resistant to rafoxanide. this is apparently the first report of resistance to rafoxanide in a field strain of h. contortus.	1980	7465165
benzimidazole-resistant haemonchus contortus--the effect of cryopreservation on the resistance of successive generations.	infective larvae (l3) of a strain of benzimidazole-resistant haemonchus contortus were stored in the gas phase of liquid nitrogen, thawed and used to infest worm-free sheep from which, in turn, larvae were cultured, frozen and thawed. this cycle was repeated 5 times. thereafter, the progeny of the cryopreserved larvae were compared with the progeny of the original untreated larvae for susceptibility to benzimidazole anthelmintics. repeated freezing of consecutive generations of l3 in liquid nitr ...	1980	7465166
a technique for the recovery of nematodes from ruminants by migration from gastro-intestinal ingesta gelled in agar: large-scale application.	a gelled-agar technique for worm recovery was adapted to facilitate the recovery of larval and adult nematodes from the total ingesta of large numbers of sheep. the technique was also used to recover nematodes from 4 calves. in one trial involving 120 sheep, 100% of 2013 4th stage larvae (l4) and 92,1% of 134,205 adult haemonchus contortus migrated from the agar preparations. highly significantly more male than female worms failed to migrate. using 1 x 1/10 aliquot to estimate the numbers of wor ...	1980	7465167
characterization and localization of cathepsin b proteinases expressed by adult ancylostoma caninum hookworms.	the hookworm ancylostoma caninum induces human eosinophilic enteritis (ee), probably via allergic responses to its secretions. cysteine and metallo-proteinases may be the components of these secretions that elicit hypersensitivity reactions. in order to characterize genes encoding cysteine proteinases (cp) secreted by a. caninum, an adult hookworm cdna library was constructed and screened with a cloned fragment of a hookworm cp gene. this fragment was obtained using consensus oligonucleotide, cp ...	1995	7477098
immune responses of texel sheep to excretory/secretory products of adult haemonchus contortus.	the excretory/secretory (e/s) products of adult haemonchus contortus comprise of at least 15 polypeptides with molecular weights ranging from 10 to > 100 kda. these e/s products induce an immune response in infected texel sheep, as demonstrated by specific igg1 levels and a significant lymphocyte proliferation index. moreover, immunoblotting analysis revealed that sera of primary h. contortus-infected sheep specifically recognize a 24 kda e/s product. in addition, sera of challenged sheep react ...	1994	7517519
cloning of a putative inhibitory amino acid receptor subunit from the parasitic nematode haemonchus contortus.	a cdna, hgl, encoding an inhibitory amino-acid receptor subunit has been cloned from a mixed egg population of the parasitic nematode haemonchus contortus. the predicted amino-acid sequence of the subunit shows 24% to 32% homology with other vertebrate and invertebrate gabaa and glycine receptor subunits and has all the expected motifs for a member of the ligand-gated ion channel superfamily. when expressed in xenopus oocytes hgl gives a small response to 1 mm glycine, but not to 1 mm gaba, glut ...	1994	7525001
the sensitization of mucosal mast cells during infections with trichostrongylus colubriformis or haemonchus contortus in sheep.	responses of isolated mucosal mast cells (mmc) during infections with either trichostrongylus colubriformis or haemonchus contortus were examined by measuring the release of sheep mast cell protease (smcp) in a degranulation assay. mmc from sheep immune to t. colubriformis released maximal amounts of smcp and histamine within 0.5h of incubation with larval antigen whereas maximum secretion of leukotrienes occurred 3h after addition of antigen. it was only after 8 weeks of a primary t. colubrifor ...	1995	7544771
genetic factors affecting antibody responses to four species of nematode parasite in romney ewe lambs.	serum levels of antibodies (ab) and immunoglobulin g1 (igg1) to the larval (l3) stage of the internal parasites cooperia curticei and trichostrongylus colubriformis and levels of ab to the l3 stages of haemonchus contortus and ostertagia circumcincta were determined in 1432 romney ewe lambs which were born on one farm in 1990 and 1991 and were the progeny of 63 rams. the objectives were to estimate heritabilities of, and genetic correlations among, the serum concentrations in newly weaned lambs ...	1995	7558568
vaccination of sheep against haemonchosis with h11, a gut membrane-derived protective antigen from the adult parasite: prevention of the periparturient rise and colostral transfer of protective immunity.	pregnant ewes were immunised with a fraction highly enriched in the membrane glycoprotein antigen h11, isolated from the intestinal brush border of adult haemonchus contortus. immunity induced by immunisation was able to abolish almost completely (98-99%) the worm egg output from pregnant ewes challenged with ca. 10,000 infective larvae of h. contortus during the last trimester. furthermore, lambs born and reared on vaccinated ewes had substantial antibody levels to h11 derived from maternal tra ...	1995	7558570
immune responses of sheep to microdissected parts of haemonchus contortus.	adult specimens of haemonchus contortus were microdissected into four body fragments: oesophagus, cuticle of oesophagus, gut and cuticle with adjacent muscle layer. the antigenicity of these different body fragments was analysed in comparison to total (whole) worm extracts with immunoblotting and elisa using sera of h. contortus-infected sheep. in particular, oesophagus-derived antigens appeared to be specifically recognized and may prove valuable in diagnostic assays.	1995	7558573
efficacy of pyrantel tartrate against experimental infections with haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis in goats.	the efficacy of pyrantel tartrate was evaluated in goats against induced infections with haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis. all the strains were of sheep origin and tested for susceptibility to pyrantel tartrate in sheep at the standard dose rate (20 mg kg-1) prior to the infection of goats. fifteen french alpine female goats were inoculated with the three nematode species. on day 25 post-infection, goats were randomized into an untreated control ...	1995	7571339
anthelmintic profile of the cyclodepsipeptide pf1022a in in vitro and in vivo models.	a novel cyclodepsipeptide of fungal origin, pf1022a, recently was reported to have anthelmintic activity. to supplement published reports and determine potential utility of pf1022a as a ruminant anthelmintic, the compound was examined in in vitro and in vivo models. assays used measured motility of haemonchus contortus (intrinsic drug potency), atp levels (parasite death), and activity against h. contortus, ostertagia ostertagi, and trichostrongylus colubriformis in the jird (spectrum, potency, ...	1995	7592027
levamisole resistance in haemonchus contortus selected at different stages of infection.	resistance to the anthelmintic levamisole is common amongst most genera of trichostrongylid nematodes of sheep, but is relatively rare in the species haemonchus contortus. the level of resistance in at least one strain of this species varies during the life cycle. investigation of this phenomenon, especially in parasitic stages of the parasite may reveal information on resistance mechanisms and factors affecting the selection of resistance. compared with adult worms of the same resistant strain, ...	1995	7601592
bafilolides, potent inhibitors of the motility and development of the free-living stages of parasitic nematodes.	three streptomyces isolates were identified as producing macrolide antibiotics of the bafilomycin or leucanicidin types during an evaluation of australian actinomyces for the production of inhibitors of larval development in the parasitic nematode, haemonchus contortus. bafilomycins a1, b1, c1, and d were obtained from culture a239 and the 2-o-methyl-l-rhamnosyl derivative of bafilomycin a1, leucanicidin, from cultures a223 and a240. all these 'bafilolides' gave similar patterns of inhibition ty ...	1995	7601593
effects of weaning, supplementation and gender on acquired immunity to haemonchus contortus in lambs.	this study was designed to investigate whether delaying the age of weaning, or feeding a protein-rich supplement alters the rate at which lambs develop immunity to haemonchus contortus and whether there is any interaction between nutrition, stress of weaning, and gender and the development of this immunity. ninety-six merino lambs were allocated to one of four treatment groups: supplemented-unweaned; supplemented-weaned; unsupplemented-unweaned; unsupplemented-weaned. there were approximately si ...	1995	7601597
the residual anthelmintic efficacy of moxidectin against selected nematodes affecting sheep.	determination of the residual anthelmintic efficacy in sheep of an oral formulation of moxidectin at a dosage rate of 0.2 mg kg-1 was evaluated 27-29 (mean: 28) d after dosing and that of the injectable formulation of moxidectin at a dosage rate of 0.2 mg kg-1 at 27-29 (mean: 28) and 34-36 (mean: 35) d post-treatment. the injectable formulation was more than 80% effective in more than 80% of treated sheep against a third larval stage challenge of haemonchus contortus, teladorsagia (ostertagia) c ...	1994	7602570
developmentally regulated secretion of cathepsin l-like cysteine proteases by haemonchus contortus.	cysteine protease activity was present in media collected after 24 hr in vitro culture of adult haemonchus contortus. the released cysteine protease hydrolyzed the fluorogenic 7-amino-4-trifluoromethyl coumarin (afc)-substituted synthetic peptides z-phe-arg-afc and z-ala-arg-arg-afc, but not z-arg-arg-afc or z-arg-afc, characterizing this activity as cathepsin l-like. within the parasite, cysteine protease activity was highest in extracts of intestinal tissue. secreted cysteine protease inhibite ...	1995	7623189
bilateral, perivulval cuticular pores in trichostrongylid nematodes.	a new hypodermal gland was discovered in female nematodes of the family trichostrongylidae. because the new structure appears to be associated with the vulva, it was named the perivulval pore. it is similar, based on light and scanning electron microscopy, to phasmids that are located laterally on the tails of nematodes of the class secernentea. like phasmids, perivulval pores are paired and bilateral, with cuticular ducts to the surface in the areas of the lateral chords. they are located sligh ...	1995	7623208
avermectin inhibition of larval development in haemonchus contortus--effects of ivermectin resistance.	avermectin (avm) inhibition of the development of the free-living stages of haemonchus contortus has been quantified in an assay in which nematode eggs are placed on an agar matrix containing serial dilutions of a drug in the wells of a microtitre plate. development is allowed to proceed for 6 days by which time larvae in control wells (no drug) have reached the infective, third (l3) stage. at high concentrations (> 30 nm) ivermectin (ivm) paralyses l1 larvae soon after hatching, however, much l ...	1995	7635622
the epidemiology of helminth infections of growing sheep in argentina's western pampas.	seasonal population trends of helminth parasites of growing lambs were investigated over 4 years. successive worm-free lambs were grazed together with untreated lambs for 20-30 days and then slaughtered for helminth counts 2 weeks after their removal from pasture. likewise untreated lambs from the same flock were slaughtered from 2 to 15 months of age for worm counts in the same way as tracer lambs. the predominant parasites were haemonchus, nematodirus and trichostrongylus. haemonchus contortus ...	1995	7635625
interaction between ostertagia circumcincta and haemonchus contortus infection in young lambs.	twenty-one-week-old, worm-free, pen-reared lambs were infected with either 6000 o. circumcincta l3 per week, or 3000 h. contortus l3 per week, or both (9000 l3 per week). egg counts were monitored throughout the experiment, and worm burdens and larval establishment rates of both worm species were estimated after 4, 7, 10 and 13 weeks of infection. after 10-13 weeks of infection with h. contortus only, establishment of o. circumcincta was lower than in previously uninfected controls, demonstratin ...	1995	7635626
protection against multiply drug-resistant and geographically distant strains of haemonchus contortus by vaccination with h11, a gut membrane-derived protective antigen.	h11 is a "hidden antigen" derived from adult haemonchus contortus which is capable of conferring a high degree of protection against subsequent challenge. to be commercially useful, any vaccine based on this antigen must protect against field strains and drug-resistant worms. the results show that vaccination with h11 affords high levels of protection against the multiply drug-resistant (mdr) lawes strain of haemonchus contortus. moreover, there was no difference in protection whether the h11 wa ...	1995	7635627
analysis of proteins related to conditioning for arrested development and differentiation in haemonchus contortus by two-dimensional gel electrophoresis.	the abundance of the majority of proteins of infectious third-stage larvae (l3) of haemonchus contortus, conditioned for arrested development, remained unaltered. only seven proteins showed quantitative differences as observed by two-dimensional gel electrophoresis. these differences were also observed in a laboratory strain which has lost the ability for arrested development. the abundance of two of these proteins increased dramatically during conditioning of larvae for 5-10 weeks. this coincid ...	1995	7635634
variation in immune responsiveness of sheep to the antigens of intestinal nematodes and blowfly larvae.	the total and igg1 antibody responses to the intestinal nematode parasites haemonchus contortus and trichostrongylus colubriformis were measured in the serum of 160 lambs, 4 months of age. these antibodies had developed as the result of natural exposure to the parasites on pasture. three sires were examined and strong sire effects on half-sib progeny were found. plotting of elisa antibody results in two dimensions revealed clustering of responses within sire groups. bimodal antibody distribution ...	1995	7635641
isolation of a larval surface glycoprotein from haemonchus contortus and its possible role in evading host immunity.		1995	7637698
characterisation of an avermectin resistant strain of australian haemonchus contortus.	a strain of haemonchus contortus (cavr) isolated in australia was found to be resistant to ivermectin (ivm) with 0.4 mg kg-1 of the anthelmintic failing to significantly reduce worm burdens. resistance to ivm was sex-influenced in the cavr strain with adult males showing a greater sensitivity to ivm. cross resistance to moxidectin was evident with approximately 15% of the population surviving a dose of 0.1 mg kg-1. the free-living stages of the cavr isolate had a reduced sensitivity to avermecti ...	1995	7657454
influence of supplementation with dietary soyabean meal on resistance to haemonchosis in hampshire down lambs.	the influence of dietary protein supplementation on resistance to haemonchosis was examined in hampshire down lambs fed either a basal diet or a diet supplemented with soyabean. at seven months of age the lambs were challenged with an initial loading dose of haemonchus contortus, followed by a trickle infection three times a week. blood and faecal samples were collected three times a week and bodyweights were recorded weekly. after 10 weeks the lambs were slaughtered and their worm burdens and c ...	1995	7659847
comparison of two enzyme immunoassays for the detection of haemonchus contortus infections in sheep.	two enzyme-linked immunosorbent assays (elisa) using either excretory/secretory (es) products or crude somatic antigens (csa) of adult haemonchus contortus were compared for their ability to detect antibodies against h. contortus in sheep. serum samples obtained from a group of 32 h. contortus mono-infected sheep were tested in the two elisas and the obtained data were compared with the results of the faecal examinations of these sheep. the first sheep became patent 3 weeks post infection (p.i.) ...	1995	7660570
seasonal changes and inhibited development of the abomasal nematodes of sheep and goats in saudi arabia.	from august 1991 to july 1992, a total of 48 abomasa from sheep and 48 from goats were examined at the jeddah abattoir for the presence of adult and larval nematodes. twenty-three of the sheep (47.9%) and 21 of the goats (43.8%) were infected with nematodes, a total of eight species being found. haemonchus contortus and marshallagia marshalli appeared to be the most important parasites. other species were less prevalent: trichostrongylus axei, camelostrongylus mentulatus, parabronema skrjabini, ...	1995	7676605
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 ...	1993	7693812
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 ...	1994	7697189
use of random amplified polymorphic dna for identification of ruminant trichostrongylid nematodes.	the aim of this work was to evaluate random amplified polymorphic dna (rapd) as a source of markers for species identification and phylogenetic analysis of ruminant trichostrongylid nematodes. as these nematodes are often polymorphic, species identification may be difficult. we tested eight species and several of their morphs: haemonchus contortus (three vulvar morphotypes: flap, smooth, and knobbed), teladorsagia circumcincta, ashworthius gagarini, spiculopteragia boehmi, ostertagia leptospicul ...	1995	7724508
anthelmintic resistance in goats in peninsular malaysia.	ninety-six randomly selected farms, located throughout peninsular malaysia, were surveyed for goat nematodes resistant to benzimidazoles (bz). on 33 farms bz resistance was demonstrated by means of an egg hatch assay. haemonchus contortus was found to be the main species involved in anthelmintic resistance. there was a positive association between the frequency of anthelmintic treatments on a farm and the presence of benzimidazole resistance. to assess the value of the egg hatch assay, faecal eg ...	1994	7725626
ivermectin resistant haemonchus contortus in louisiana lambs.	fifteen weaned crossbred (suffolk x louisiana native) lambs were treated with albendazole (10 mg kg-1) to remove existing nematode infections. they were inoculated with haemonchus contortus infective larvae from a residual population surviving treatment with the oral formulation of ivermectin (0.2 mg kg-1). one group of five lambs remained untreated, another group of five was treated with the injectable formulation of ivermectin (0.2 mg kg-1), and a third group of five was treated with the oral ...	1994	7725627
strongyle infections in sheep and goats under the traditional husbandry system in peninsular malaysia.	faecal egg counts were used to study patterns of trichostrongyle infections in sheep and goats according to season, age, pregnancy and lactation on traditional farms in west malaysia. haemonchus contortus and trichostrongylus spp. were the most important strongyles in sheep and in goats, h. contortus, trichostrongylus spp. and oesophagostomum spp. were most prevalent. the faecal egg counts of sheep and goats were apparently not influenced by the small seasonal climatic variations. strongyle infe ...	1995	7732637
dry areas: an example of seasonal evolution of helminth infection of sheep and goats in southern mauritania.	a total of 647 faecal egg counts and 53 necropsies were performed on sheep and goats originating from three sites of a sahelian region of mauritania (gorgol) over a period of 2 years (1990-1992). haemonchus contortus, oesophagostomum columbianum and stilesia globipunctata were the most prevalent species. the seasonal pattern was characterized by long survival of adults and high percentages of arrested fourth-stage larvae in the dry season, suggesting that two different strategies were used to su ...	1995	7732638
isotype-specific serum antibody responses of sheep to haemonchus contortus antigens.	in total, 19 8-month-old texel sheep were used to study the isotype-specific serum antibody responses against infective larvae and adult worms of haemonchus contortus. group group 1 sheep (n = 7) were infected with 20,000 l3 larvae (week 0), treated with ivermectin 6 weeks post-infection and subsequently challenged at week 10 of the experiment. this challenge consisted of a trickle infection of 10,000 l3 larvae per week for 5 weeks. group 2 sheep (n = 7) received a single infection at week 10 of ...	1995	7732639
[epidemiology of gastrointestinal helminthiasis in small ruminants in the tree-cropping pasture zone in senegal].	an epidemiological survey on gastrointestinal helminthiasis in 51 sheep and 51 goats was held in the tree-cropping pasture region in senegal from october 1990 to september 1991. all the animals examined were infected with at least 1 helminth species. three trematodes (fasciola gigantica, schistosoma bovis, amphistomatids), 2 cestodes (moniezia expansa, cysticercus tenuicollis) and 9 nematodes were identified. the most important parasite in sheep was haemonchus contortus while trichostrongylus co ...	1995	7735304
high energy phosphate metabolites observed by nmr in infective larvae of haemonchus contortus.	phosphorus resonances consistent with phosphoarginine and atp were observed in the in vivo 31p-nuclear magnetic resonance (nmr) spectra of infective larvae of haemonchus contortus. the level of phosphoarginine quickly declined when nematode suspensions were purged with nitrogen and was restored upon return to aerobic conditions. saturation transfer nmr demonstrated forward and reverse exchange of phosphorus between phosphoarginine and atp.	1995	7776130
characterization of local antibody responses to the gastrointestinal parasite haemonchus contortus.	the ability to identify antigens associated with an infection has generally relied on the use of serum antibodies produced by infected or previously exposed individuals. a major drawback with the use of serum is that it does not necessarily reflect the local antibody response at mucosal tissue sites. this study describes an approach that allows the use of antibodies generated close to the infection site to detect the transient expression of stage-specific antigens during infection with the gastr ...	1995	7790042
the effect of reduced feed intake on the efficacy of oxfendazole against benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis in sheep.	within 12 h of reducing the daily intake of a 50:50 lucerne and wheaten hay ration from 800 to 400 g, there was an increase in digesta marker concentration indicating a reduction in the flow rate of digesta fluid and particulates through the abomasum of sheep. the efficacy of the recommended dose of oxfendazole (ofz) was then tested against benzimidazole resistant trichostrongylus colubriformis and haemonchus contortus in sheep whose feed intake was halved 36 h before and after drug treatment. i ...	1995	7797375
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 ...	1994	7808477
isolation of an ivermectin-resistant strain of haemonchus contortus from sheep in malaysia.		1994	7817517
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 ...	1994	7828882
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 ...	1994	7838599
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 ...	1994	7839744
parasite control in transhumant situations.	transhumance is defined as 'seasonal moving of livestock to regions of different climate'. it is an integral part of livestock production in many parts of the world and takes several forms including moving of livestock from lowland to mountainous pastures or from dry to humid areas. the impact of transhumance on parasite populations of livestock and on parasite control is described, mainly using examples from europe. the epidemiology of trichostrongylidosis of cattle, mainly caused by ostertagia ...	1994	7846845
anthelmintic resistance.	anthelmintic resistance is widespread in nematode parasites of sheep, goats and horses. resistance is also developing in nematode parasites of cattle and has been detected in pig parasites. benzimidazole, levamisole/morantel and ivermectin resistances occur in nematodes of sheep and goats and closantel resistance has been found in haemonchus contortus. anthelmintic resistance is likely to develop wherever anthelmintics are frequently used and be detected if it is investigated. worm count or egg ...	1994	7846855
ingestion of host immunoglobulin by three non-blood-feeding nematode parasites of ruminants.	host immunoglobulin was detected in homogenates of adult worms or fourth stage larvae of haemonchus contortus, ostertagia ostertagi, o circumcincta and dictyocaulus viviparus, but not in preparasitic third stage larvae of h contortus. all the worms had been washed in detergent before being homogenised to remove any immunoglobulin adhering to the cuticle. this procedure, the concentrations of immunoglobulin detected and observations on sections of the worms stained with fluorescent anti-sheep imm ...	1994	7871262
beta-tubulin genes from the parasitic nematode haemonchus contortus modulate drug resistance in caenorhabditis elegans.	resistance to antimitotic chemotherapeutics in pathogenic nematodes, fungi and mammalian cells is closely associated with structural changes in cytoskeletal beta-tubulin. we investigated the possibility of using the well-characterised free-living nematode caenorhabditis elegans as a model for studying the mechanism of resistance against benzimidazole (bz) drugs in the parasitic nematode haemonchus contortus. functional analysis of a conserved beta-tubulin isotype (tub-1) mutation near gtp-bindin ...	1995	7877171
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 ...	1994	7879378
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).	1994	7886916
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 ...	1994	7886917
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 ...	1994	7898893