Publications

the influence of breed on the susceptibility of sheep of haemonchus contortus infection in kenya.	the relative resistance of six breeds of sheep to haemonchus contortus infection was investigated under field conditions on two stations situated in a semi-arid zone in kenya. as judged by faecal egg counts, monitored throughout a two-year period, it was found that there were consistent differences between the breeds. the breeds studied in order of increasing susceptibility were red masai, blackhead persian, merino, dorper, corriedale and hampshire. post mortem findings confirmed that the differ ...	1979	262593
the influence of haemoglobin phenotype on the susceptibility of sheep to haemonchus contortus infection in kenya.	two flocks of merino sheep were set-stocked on pastures known to be endemic for haemonchus contortus. both flocks included sheep with the three common haemoglobin types (hbaa, hbab, hbbb). the results of regular monitoring over a two-year period showed a clear relationship between haemoglobin types and susceptibility to haemonchosis. the hbaa sheep experienced fewer deaths, had consistently lower egg counts and exhibited a more frequency and effective self-cure than the hbab or the hbbb types. p ...	1979	262594
termination of arrested development of the trichostrongyles of sheep in northern nigeria.	monthly worm counts of groups of ewes and lambs that grazed continuously and tracer lambs revealed that under the conditions existing in northern nigeria, most of the haemonchus contortus in sheep between november and march were arrested larvae. during the months of april and may, almost equal proportions of adults, developmental stages and arrested larvae were recovered and, by june, only adults and developmental stages were recovered in high numbers. the proportion of arrested larvae had dimin ...	1979	262601
field observations on the epidemiology of abomasal parasites in young sheep during winter and spring.	a flock of spring born lambs was continuously exposed to natural parasite infection from birth until selected for slaughter in groups of two or three, at monthly intervals throughout winter and spring for abomasal worm counts. meteorological data were recorded and regular estimates of infective pasture larval availability were made. parasite population changes and inhibition patterns for ostertagia spp, haemonchus contortus and trichostrongylus axei were recorded. ostertagia spp were found to su ...	1979	262603
haemonchus contortus: some factors influencing the degree of resistance of sheep immunized with attenuated larvae.		1979	422768
[helminth fauna of syrian cattle].	in this work the stomach and the small intestine of 34 and the large intestine of 4 more cattle were examined. 91,17% of the examined cattle (31 in 34 animals) had infected the stomach and/or the small intestine by parasites. 14 kinds of nematodes were found. the average intensity of infection of the stomach was higher than that of the small intestine. with the exception of higher infection in 3 stomachs and 2 small intestines the intensity of infection in all other cases was from small to mediu ...	1979	453633
parasites of domestic and wild animals in south africa. xii. artificial transmission of nematodes from blesbok and impala to sheep, goats and cattle.	sheep were successfully infested artificially with the larvae of haemonchus contortus, trichostrongylus axei, trichostrongylus falculatus and impalaja nudicollis, cultured from the faeces of blesbok naturally infested with these nematodes. haemonchus placei, longistrongylus sabie, trichostrongylus colubrifomis, t. falculatus, impalaia tuberculata and cooperia hungi likewise became established in sheep, goats and calves dosed with larvae cultured from the faeces of infested impala. sheep and goat ...	1979	460820
oxfendazole--anthelmintic activity in egyptian goats artificially infected with gastrointestinal nematodes.	the recently developed benzimidazole anthelmintic, oxfendazole, was tested against artificial nematode infestations in egyptian goats using oral dosing at 4.5 and 2.8 mg/kg. a 100% clearance of mature and immature haemonchus contortus, trichostrongylus axei, ostertagia circumcincta, coopera curticei, bunostomum trigonocephalum and chabertia ovina was obtained at the 4.5 mg/kg level. very high levels of clearance against the mature worms were obtained at 2.8 mg/kg but the drug was less effective ...	1979	462559
avermectins, new family of potent anthelmintic agents: efficacy of the b1a component.	when given to sheep as a single oral dose at 0.1 mg/kg, the b(1a) component of the avermectins caused a reduction of >95% in the numbers of haemonchus contortus, ostertagia circumcincta (including inhibited l(4) larvae), trichostrongylus axei, trichostrongylus colubriformis, cooperia oncophora, and oesophagostomum columbianum. when given to cattle as a single oral dose at 0.1 mg/kg, avermectin b(1a) was >95% effective in reducing the numbers of haemonchus placei, ostertagia ostertagi (including ...	1979	464563
thiabendazole resistance in field populations of haemonchus contortus.	six populations of h. contortus were selected for a study of thiabendazole resistance from a collection of 40 populations made during a survey of the efficiency of thiabendazole on the northern tablelands of new south wales. based on survey results, 3 of these populations were considered susceptible and the remaining 3 were considered resistant. however, when these populations were compared with a known susceptible strain on the ability of their eggs to hatch in a solution containing thiabendazo ...	1979	464936
the inheritance of thiabendazole resistance in haemonchus contortus.	haemonchus contortus worm populations isolated from naturally infected sheep at the pastoral research laboratory, armidale, n.s.w., were found to contain approximately 20% of worms resistant to a 50 mg/kg dose of thiabendazole. following 3 generations of selection with 50 mg/kg thiabendazole the number of worms removed by the anthelmintic was too small to detect differences between treated and control groups. after more than 15 generations of selection, matings between males from the selected st ...	1979	471531
inhibited development of trichostrongylids of sheep in northern nigeria.	worm counts from yankassa ewes, lambs and tracer lambs grazing unimproved pasture at zaria were obtained each month during the rainy season of 1976. in june and july up to 14 per cent of the haemonchus contortus populations consisted of early fourth stage larvae (l4). in august this increased to more than 55 per cent and in october to more than 95 per cent. from june to august most of the abundant late l4 contained rodlike crystals. more than 95 per cent of the haemonchus contortus populations o ...	1979	472478
the possible fate of crystal harbouring larvae of haemonchus contortus.	an examination of the occurrence of crystalline inclusions in the intestinal cells of fourth and fifth stage haemonchus contortus revealed that a high percentage of inhibited early fourth stage larvae (l4) and developing l4 and a lower percentage of early fifth stage larvae (l5) harboured these crystals. before the fourth moult crystals were falling into pieces, indicating that worms harbouring crystals can develop further. the presence of crystals may be associated with a retardation of develop ...	1979	472480
the effect of single and divided dose administration on the efficacy of fenbendazole against adult stages of benzimidazole resistant sheep trichostrongylids.	sheep infected with benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis were used to compare the anthelmintic efficacy of fenbendazole given as a single dose or administered in a divided dose regime over five days. statistical analysis showed no significant difference between the two methods of administration for h contortus. on the other hand, divided dose fenbendazole was significantly less effective than single doses against adult t colubriformis at dose ...	1979	472493
the anthelmintic efficacy of albendazole against fasciola hepatica and benzimidazole resistant strains of haemonchus contortus and trichostrongylus colubriformis in sheep.	the anthelmintic efficacy of albendazole (methyl [5-(propylthio) - 1h - benzimidazole -2 -yl] carbamate) against immature and adult fasciola hepatica and against standardised strains of benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis was evaluated in experimentally infected sheep. a single intrarumenal treatment of dose rates of 3.8 and 7.6 mg/kg was ineffective against immature (six weeks old) f hepatica. dose rates of 5.7 and 7.6 mg/kg reduced the number of matu ...	1979	472494
in vitro variation of glycogen content in three sheep nematodes.	in vitro variation of glycogen content under aerobic conditions was measured on fresh weight basis in 3 sheep nematodes inhabiting different niches; haemonchus contortus, oesophagostomum columbianum and trichuris ovis. the parasites were saparated into species and then sexes and starved for varying periods of time up to 24 h in glucose-free physiological saline. the differences between females and males and among the species with respect to glycogen content and its rate of change with time are d ...	1979	481912
experimental transmission of gastro-intestinal nematodes between sheep (ovis aries) and thomson's gazelles (gazella thomsonii).	experimental cross-transmission of gastro-intestinal nematodes between merino sheep (ovis aries) and thomson's gazelles (gazella thomsonii) from similar but separate grazing habitats in kenya was studied. cross-transmission did occur with some species but the faecal egg counts of sheep were higher than the gazelles' following infection with larvae isolated from either sheep or gazelles. of the 11 gastro-intestinal nematodes which became established in gazelles following infection with larvae cul ...	1979	501844
gastro-intestinal helminths in white-tailed deer (odocoileus virginianus) of illinois.	two deer populations, one in northern illinois the other in southern illinois, were examined by necropsy (n = 44 and 40 respectively) for helminth parasites of the gastro-intestinal tract and abdominal cavity. both herds were parasitized by apteragia odocoilei, haemonchus contortus, gongylonema pulchrum, setaria yehi, trichuris ovis, and moniezia benedeni. nematodirus sp. was found only in deer of northern illinois. ostertagia mossi, capillaria sp., cooperia sp., and oesophagostomum sp. were fou ...	1979	501845
the efficacy of fenbendazole and albendazole against immature and adult stages of benzimidazole-resistant sheep trichostrongylids.	the efficacy of two recently introduced benzimidazole anthelmintics, albendazole and fenbendazole, was determined for six-day, 10-day and adult stages of resistant strains of haemonchus contortus and trichostrongylus colubriformis. albendazole, at 3.8 mg/kg reduced h contortus worm counts by 92.4, 70.8 and 67.1 per cent while fenbendazole, at 5.0 mg/kg, reduced worm burdens by 51.7, 95.5 and 93.4 per cent against six-, 10- and 25-day-old parasites respectively. for t colubriformis, the correspon ...	1979	504798
the anthelmintic efficacy of oxfendazole and haloxon against arrested haemonchus contortus larvae in sheep.	in a controlled trial with natural infection of haemonchus contortus, oxfendazole at 4.53 mg/kg body weight was highly effective against arrested larvae, developmental stages and adult helminths. haloxon at 40 mg/kg significantly reduced helminth burdens.	1979	504805
the response of awassi and merino sheep to primary infection with haemonchus contortus.	the possible existence of breed differences in the response of sheep to primary infection with haemonchus contortus was examined by comparing worm establishment and pathogenic effects of the parasite in awassi and merino sheep of haemoglobin type b infected with 500 third stage h. contortus larvae per kg body weight. the results showed that the merino sheep had lower faecal egg counts and worm burdens and suffered less severe clinical disturbances than sheep of the awassi breed. this suggests th ...	1979	505590
the activity of levamisole against benzimidazole resistant haemonchus contortus and trichostrongylus colubriformis.		1979	516343
efficiency of rafoxanide and naphthalophos against inhibited haemonchus contortus.		1979	518438
resistance of haemonchus contortus to oxfendazole.		1979	518439
investigation of haemonchus contortus infections in sheep. comparison of irradiated larvae and transfer factor treatment.	a comparison is made between the resistance conferred to haemonchus contortus challenge by irradiated larval treatment and transfer factor (tf) treatment in four-month-old lambs and seven-month-old lambs. as in previous investigations the irradiated larval treatment failed to confer resistance to the four-month-old lambs challenged with 10,000 third stage larvae while similar irradiated larval treatment in seven-month-old lambs reduced the worm burdens by 40 per cent compared to controls. the tf ...	1979	523821
anthelmintic activities of b1a fraction of avermectin against gastrointestinal nematodes in calves.	anthelmintic activities of the b1a fraction of avermectin were evaluated in a controlled experiment. twenty 12-week-old calves artificially infected with gastrointestinal nematodes were allotted to four groups. calves in group 1 were used as nonmedicated controls; other calves in groups 2, 3, and 4 were given (orally) b1a avermectin at dosage levels of 50, 100, and 200 microgram/kg of body weight, respectively. these treatments were given 35 days after calves were inoculated with infective nemat ...	1979	525922
the role of inhibited larvae in the epidemiology of ovine haemonchosis.	three paddocks were contaminated with haemonchus contortus eggs from early spring to mid summer by yearling sheep. in paddock 1, all contamination was derived from worms that had been previously inhibited in their development. the contamination in paddock 2 was produced only by infections recently acquired from pasture, and in paddock 3 contamination was attributable to both sources. when the yearling sheep were replaced in mid-summer by newly weaned lambs, severe outbreaks of haemonchosis occur ...	1979	539940
the incidence of thiabendazole resistance in field populations of haemonchus contortus on the northern tablelands of new south wales.	a survey was undertaken to assess the incidence of thiabendazole resistance in field populations of h. contortus in sheep flocks on 40 farms distributed throughout the sheep grazing area of the northern tablelands of new south wales. treatment with thiabendazole at 66 mg/kg reduced h. contortus ova output by 96-100% in 18 flocks while in the remaining 22 there was a range of responses down to levels where the anthelmintic was without apparent effect. factors which may contribute to the high inci ...	1979	543833
study of gastro-intestinal stronglyosis in a sheep flock on permanent pasture. 1. sheep parasitism in 1977.	an epidemiological study aimed at defining gastro-intestinal parasitism in sheep qualitatively and quantitatively was carried out in the limousin area in france. five lambs were sacrificed regularly every 4 weeks from may till january of the following year. complete parasite counts were performed on these animals as well as measurements of the plasma level of pepsinogen. in order to define the influence of parasitism on the growth of the animals, the weight gains of lambs treated regularly and u ...	1979	547822
studies on haemonchus contortus. ii. the effect of abomasal nematodes on subsequent challenge with h. contortus.	fifty-thousand infective larvae of trichostrongylus axei dosed to 7-9-month-old merinos protected them against a subsequent challenge with 50 000 infective larvae of haemonchus contortus. protection varied with the period between an initial dosage of t. axei and challenge with h. contortus as follows: after 90 days it was more than 80% effective in more than 80% of sheep; at 119 and 180 days there was still a significant reduction in the numbers of h. contortus recovered (p < 0,05 and p < 0,001, ...	1979	551369
effect of anthelmintic treatment on the performance of awassi sheep in iraq.	studies are reported on the effect of anthelmintic treatment on the body weight gain and wool growth of ewes with subclinical helminth infections. the parasites involved were fasciola gigantica and ostertagia spp., together with some haemonchus contortus, trichostrongylus spp., and dictyocaulus filaria. in 1 group, 5 sheep, which were treated twice with tetramisole at an interval of 4 weeks to remove gastro-intestinal nematodes and lungworms, showed an increase of 41% in weight gain and 3.2% in ...	1979	552676
the efficiency of oxfendazole against four field populations of benzimidazole resistant haemonchus contortus.		1979	556191
oxfendazole: anthelmintic activity in sheep artificially infected with nematodes. results of trials against nine species including benzimidazole-resistant haemonchus contortus.	in a series of 11 trials, in which 281 lambs were artificially infected with 9 species of nematodes, larval anthelmintic tests were carried out to assess the activity of a dose of 5 mg/kg oxfendazole against all 3 parasitic stages of each species. an efficacy of over 99,4% was obtained against all stages of haemonchus contortus, ostertagia circumcincta, trichostrongylus colubriformis, nematodirus spathiger, gaigeria pachyscelis, chabertia ovina and oesophagostomum columbianum with the exception ...	1980	7005443
the role of carbon dioxide in the metabolism of adult haemonchus contortus, in vitro.	adult haemonchus contortus worms simultaneously excrete and fix co2. their initial content of co2 was measured as 4.55 mumoles/100 mg wet weight and their excretion rate in air as 1 mumol/100 mg wet weight/h for at least 4 h. when the worms were incubated either aerobically or anaerobically with 14co2 most of the metabolized radioactivity was associated with propan-1-ol and propionate but small amounts were found in succinate and lactate. no radioactivity was associated with ethanol or acetate, ...	1980	6770322
an investigation of variables in a fecal flotation technique.	several variables in a standard vial fecal gravitational flotation technique were investigated. these were the specific gravity of the sodium nitrate flotation solution, duration of flotation and mesh sizes of strainers. the number of eggs which floated and adhered to a coverslip were counted and estimates of the number of eggs remaining in the strained fecal suspension and in the feces trapped on the strainer were made. eggs from hookworms, trichuris vulpis and toxocara canis in feces from dogs ...	1980	7190861
resistance of haemonchus contortus to thiophanate.	the occurrence of a field strain of haemonchus contortus which was resistant to thiophanate and susceptible to thiabendazole and levamisole is reported. the ld95 of thiophanate for the strain was found to be 156.1 mg/kg and its resistance factor was 6.7. in possessing specific thiophanate resistance it differed from previously reported thiophanate resistant strains of h contortus which have been benzimidazole resistant worms that have possessed cross resistance to thiophanate.	1980	7255897
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
relationship among particle size distribution, dissolution profile, plasma values, and anthelmintic efficacy of oxfendazole.	three mean particle sizes of oxfendazole raw material (1.65 micron, lot a; 3.2 micron, 10t b; 12.0 micron, lot c) were prepared and identically formulated as corresponding (a, b, and c) suspensions at 2.26% (w/v) concentration. studies involving microscopic examination, scanning electron microscope analysis, particle size distribution, and surface area measurement were carried out on raw materials. in vitro dissolution profiles were obtained for the suspensions. a comparative bioavailability stu ...	1980	7212443
thiabendazole-resistant strains of haemonchus and ostertagia in california lambs.	ten parasite-free experimental lambs were inoculated intraruminally with a mixed-larvae inoculum which contained approximately 5,000 haemonchus contortus infective larvae. five lambs were treated with thiabendazole (66 mg/kg of body weight) and 5 were untreated controls. all lambs were killed 35 days after inoculations were done, and parasites present were recovered. reduction in numbers of recovered haemonchus contortus (25.7%) and ostertagia spp (26.8%) were not significant (p greater than 0.0 ...	1980	7224297
inorganic elements in the adults of haemonchus contortus (nematoda: trichostrongylidae).		1980	7229318
effect of oesophageal groove closure on the pharmacokinetic behaviour and efficacy of oxfendazole in sheep.	direct intraabomasal oxfendazole (ofz) administration resulted in the peak plasma ofz concentration occurring sooner and the area under the plasma ofz concentration curve being reduced when compared with intraruminal administration. glucose given directly into the abomasum of fistulated sheep caused a substantially greater elevation of plasma glucose levels than did direct administration into the rumen. this difference was subsequently used to indicate rumen bypass, by oesophageal groove closure ...	1981	7244379
experiments on inhibited development of haemonchus contortus and ostertagia circumcincta in sheep in the netherlands.	inhibited development of haemonchus contortus and ostertagia spp was studied in sheep. exposure of infective haemonchus contortus larvae for five weeks to 15 degrees c or 16 degrees c very effectively induced inhibited development but exposure to lower temperatures was much less effective. infection with fresh larvae cultured for seven or 12 days at 25 degrees c in the dark resulted only in very low rates of inhibited development. this was not much influenced by the age of the host or the month ...	1981	7244384
experimental cross-infections with gastrointestinal nematodes of sheep and cattle.	five parasite-free lambs and five parasite-free calves were infected experimentally with 20,000 third stage gastrointestinal nematode larvae cultured from faeces of sheep from five different farms. in the same way five lambs and five calves were infected with larvae cultured from faeces of calves from five different farms. host specificity of the nematodes was determined using the following parameters: infection rate; number, size, and stage of the worms; their distribution within the gastrointe ...	1981	7245840
spermatogenesis in haemonchus contortus (nematoda: trichostrongylidae).	basic structure and development of spermatogonia, spermatocytes (primary and secondary), spermatids and spermatozoa have been studied in h. contortus (rud., 1803) with the aid of light microscopy.	1981	7227872
the impact of refugia on the development of thiabendazole resistance in haemonchus contortus.		1981	7228476
the development, composition and maintenance of experimental populations of haemonchus contortus in sheep.	clun forest sheep, aged between 3 and 18 months and worm-free from birth, were given a single dose of 25 000 infective larvae of the nematode haemonchus contortus. the host animals were killed between 4 and 100 days after infection and the nematode populations were examined to determine size and composition. the relation between worm body length, dry weight and age was studied and growth curves were constructed. variations in the sex ratio for infections of different ages were noted. no evidence ...	1981	7220086
five generations of selection with benzimidazole and non-benzimidazole anthelmintics against benzimidazole resistant strains of haemonchus and ostertagia spp in sheep.	benzimidazole resistant strains of haemonchus contortus and ostertagia spp were subjected to selection pressure over five laboratory generations with the recommended dose rates of either cambendazole, oxfendazole or morantel. a change in response, with larger residual worm burdens remaining after treatment at the fifth generation, was shown for both cambendazole and oxfendazole against both species of nematode. no change in response against either species are shown for morantel. the results are ...	1981	7255903
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
self-curve and immunity following infection and reinfection in ovine haemonchosis.	egg expulsion and post mortem examination were used to compare self-cure and resistance to reinfection with haemonchus contortus in female merino sheep, aa and bb hemoglobin types. animals were infected by 500 or 5000 larvae of h. contortus once, or several times, before being challenged by 500 (low dose) or 500 (high dose) larvae. in aa sheep infected once by 500 larvae self-cure was detected by a challenge of either 500 or 5000 larvae while in multi-infected sheep only a challenge of 5000 l, i ...	1981	7201184
the glucose metabolism of adult ostertagia circumcincta, in vitro.	adult ostertagia circumcincta from freshly killed sheep were incubated at 39 degrees c in a medium containing inorganic salts, antibiotics and d-[u-14c] glucose. the worms appeared healthy even after incubation for as long as 72 h. all the radioactivity was recovered either within the worms or in the incubation vessel in the form of metabolic products or unmetabolized glucose. incubations were carried out at low oxygen tension except for those in which co2 was measured. these were either aerobic ...	1981	6782539
anthelmintic efficacy of 22,23-dihydroavermectin b1 against gastrointestinal nematodes in calves.	anthelmintic activities of 22,23-dihydroavermectin b1 (comprised to greater than or equal to 95% 22,23-dihydroavermectin b1a and less than or equal to 5% 22,23-dihydroavermectin b1b) against gastrointestinal nematodes in calves were evaluated in 2 controlled experiments. infective larvae of haemonchus contortus, ostertagia ostertagi, trichostrongylus axei, t colubriformis, cooperia oncophora, and c punctate were given to 11-week-old calves and oesophagostomum radiatum had been given 21 days earl ...	1981	6895285
anthelmintic efficacy of ivermectin against immature gastrointestinal pulmonary nematodes of calves.	anthelmintic efficacy of ivermectin (greater than or equal to 80% 22,23-dihydroavermectin b1a and less than or equal to 20% 22,23-dihydroavermectin b1b) was evaluated in a controlled experiment against immature nematodes. twenty calves raised to about 8 weeks of age under nematode-free conditions were allocated into 4 groups. infective larvae of haemonchus contortus, ostertagia ostertagi, trichostrongylus axei, t colubriformis, cooperia oncophora, c punctata, oesophagostomum radiatum, and dictyo ...	1981	6896121
effects of two consecutive experimental haemonchus contortus infections on abomasal pepsin and electrolytes and serum pepsinogen and electrolytes of sheep.	pepsinogen, sodium, potassium and chloride concentrations in blood, and pepsin, ph and ionic concentrations in abomasal contents were measured in 4 lambs each fitted with a permanent abomasal cannula infected with 25 000 h. contortus larvae at intervals of 39 days. no significant change in blood sodium, potassium and chloride concentrations occurred after infections while the pepsinogen level increased rapidly to reaching a maximum (600% of control) 7-8 days after infection. this increase was as ...	1981	6805407