[distribution of nematode parasites of the digestive system in sheep (ovis aries) and goats (capra hircus) of the piedmontese and valdostano alpine arc].a survey, carried out on gastro-intestinal nematodes of sheep and goats of piemonte and of valle d'aosta (87 sheep and 12 goats) has shown the presence of the following species in sheep, bunostomum trigonocephalum, chabertia ovina, cooperia curticei, haemonchus contortus, marshallagia marshalli, nematodirus abnormalis, nematodirus filicollis, nematodirus helvetianus, nematodirus spathiger, oesophagostomum venulosum, ostertagia circumcincta, ostertagia lyrata, ostertagia trifurcata, skrjabinema o ...1977572958
an evaluation of ethyl-6-ethoxybenzothiazole-2-carbamate (sch 18099) for anthelmintic activity in domestic animals.ethyl-6-ethoxybenzothiazole-2-carbamate (sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens. sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. at 15 mg/kg, efficacy against adult and larval oxyuris equi was 100% and 91% and against small strongyles it was 98%. efficacy levels were 95% against strongylus vulgaris and s. edentatus at the 20 mg/kg dosage. in two trials at 100 mg/kg efficacy against parascaris e ...1977864223
effects of dietary molybdenum on nematode and host during trichostrongylus vitrinus infection in lambs.the addition of molybdenum (0.05 mmol kg-1 dry matter) to the diet of lambs exposed for four weeks to a trickle (2500 third stage larvae per day) infection with trichostrongylus vitrinus reduced the number and length of adult worms retrieved from the small intestine 11 days later: both effects were particularly marked in female worms from female lambs (p less than 0.01). worms from lambs given molybdenum contained less proteinase enzyme activity and secreted less proteinases in culture irrespect ...19921316630
effect of genetic type, lactation and management on helminth infection of ewes in an intensive grazing system on irrigated pasture.a survey of helminth infection was conducted in a flock of 290 ewes distributed into romanov (r), merinos d'arles (m) and romanov x merinos (r x m) genetic types, grazing irrigated pasture in the south of france. faecal egg and larval counts were done seven times per year from 1981 to 1984 on homogeneous groups of ewes and then individually once to four times every autumn from 1985 to 1988. helminth fauna was diverse and more abundant during autumn. high levels of strongyle infection occurred in ...19921459785
interactions between teladorsagia circumcincta and trichostrongylus vitrinus infections in young lambs.groups containing six lambs that previously had been infected five times each week for four, eight or 12 weeks, either with 1000 trichostrongylus vitrinus third stage larvae (l3) or 1000 t vitrinus l3 and 2500 l3 teladorsagia (previously ostertagia) circumcincta were challenged, along with six worm-free control lambs, with 3000 75se-labelled t vitrinus l3. the lambs were killed 10 days after challenge. those given a dual infection for four and eight weeks had significantly lower total t vitrinus ...19921465511
comparison of an indirect haemagglutination assay and an elisa for diagnosing fasciola hepatica in experimentally and naturally infected enzyme-linked immunosorbent assay (elisa) with somatic (s) or excretory-secretory antigens (es) was compared with an indirect haemagglutination assay (iha) for ability to detect antibodies against fasciola hepatica in sheep. the specificity of both assays was determined by testing sera collected from sheep experimentally or naturally mono-infected with fasciola hepatica, haemonchus contortus, ostertagia circumcincta, cooperia curticei, taenia ovis, eimeria spp., trichostrongylus vitrinus, tri ...19921485406
effects of challenge with trichostrongylid nematode larvae on immunologically resistant grazing yearling sheep in south australia.paddocks near gawler, south australia, were grazed by newly weaned sheep which received either no anthelmintic treatment, regular 3-weekly treatment or a single treatment in february. a decline in the faecal egg count of untreated sheep in autumn associated with the ingestion of infective larvae indicated that the sheep had developed a resistance to reinfection. at the end of the experiment, 10 sheep were experimentally infected with trichostrongylus vitrinus larvae to demonstrate this resistanc ...19911858285
studies on the presence and release of proteolytic enzymes (proteinases) in gastro-intestinal nematodes of ruminants.the proteolytic activity of worm homogenates prepared from the third stage larval (l3) and adult stages of the ovine gastro-intestinal nematodes, nematodirus battus, ostertagia circumcincta, trichostrongylus colubriformis, trichostrongylus vitrinus and haemonchus contortus, and the rodent intestinal nematode, nippostrongylus brasiliensis, has been examined using the protein substrates azocasein, azocoll and elastin-orcein. activity detected in third stage larvae was usually higher than that obse ...19902185170
[dynamics of infestation with gastrointestinal strongyles of moors grazed by sheep in the mediterranean area].the dynamics of free-living stages of sheep nematodes was studied. the kinetics of infective larvae population was established during 16 months by sampling grass and faeces every 2 wk on an area frequently used by ewes on 3 out of 4 paddocks grazed by a flock. the periods at high risk for animal infection were autumn and spring, the moors being sterilized during summer by the dryness. teladorsagia circumcinta, trichostrongylus vitrinus, nematodirus filicollis and n. spathiger were the main speci ...19902288450
development of immunity to incoming radiolabelled larvae in lambs continuously infected with trichostrongylus vitrinus.infective third stage larvae (l3) of trichostrongylus vitrinus were radiolabelled with 75 selenium by a method which did not affect their viability. three groups of six-month-old lambs were infected daily with 1000 l3 for four, eight and 12 weeks, respectively. after each period, one of those groups (n = 5) and a group (n = 4) of worm-free controls were challenged with three consecutive daily doses of 1000 radiolabelled l3, killed 10 days after the first dose, and their worm burdens examined. af ...19892922501
susceptibility of the pre-parturient ewe to infection with trichostrongylus vitrinus and ostertagia circumcincta.during two successive years, groups of pregnant ewes and non-pregnant worm-free sheep were given anthelmintic, challenged one week later with 10,000 infective larvae of either trichostrongylus vitrinus or ostertagia circumcincta and killed two, four and six weeks after challenge. all of the ewes were killed within three days of their predicted lambing date. there was no annual variation in the response of the ewes to infection with either species. compared to adult naive animals, ewes expressed ...19883194590
influence of two levels of concurrent infection with ostertagia circumcincta and trichostrongylus vitrinus on the growth performance of lambs.groups of seven lambs were infected on five days each week for 11 weeks with either 1000 or 2000 trichostrongylus vitrinus larvae alone or concurrently with 1500 or 2500 ostertagia circumcincta larvae and their growth performance compared to that of worm-free controls. the cumulative liveweight gain of the infected groups was significantly lower than that of the controls but the gain of the concurrently infected lambs did not differ significantly from the respective t vitrinus group. there were ...19883212273
climate and the distribution of intestinal trichostrongylus spp. of sheep.the relative prevalences of trichostrongylus vitrinus, t. colubriformis and t. rugatus in sheep in south-west western australia were examined for evidence of associations with climatic conditions in different localities. the region has a mediterranean-type climate with hot, dry summers and cool, wet winters. the intestinal trichostrongylus spp. populations in sheep sampled comprised 50% t. vitrinus, 38% t. colubriformis and 12% t. rugatus. the prevalence of t. vitrinus was negatively correlated ...19883347988
the macroscopic appearance and associated histological changes in the enamel organ of hypoplastic lesions of sheep incisor teeth resulting from induced parasitism.twenty-one penned female sheep were infected with a high dose of nematodes (200,000 trichostrongylus vitrinus and 25,000 ostertagia circumcincta) during first incisor development when aged 7-8 months. three sheep were infected with 200,000 t. vitrinus only; 10 sheep were untreated. anorexia, lassitude and severe diarrhoea were seen in 14 of the infected sheep after 21-26 days. anthelmintic was given to sheep showing undue distress to end the infection and to all remaining sheep on day 33. animal ...19863467666
regulation of trichostrongylus vitrinus and t colubriformis populations in naturally infected sheep in the netherlands.during a study on the epidemiology of gastrointestinal helminth infections in sheep at the university of utrecht (1974 to 1977) information was obtained on the population regulation of small intestinal trichostrongylus species. comparison of the cumulative burdens in tracer lambs with those in flock lambs showed an accumulation of trichostrongylus species in the latter until autumn followed by an expulsion of worms. the dominating species, t vitrinus, was expelled earlier than t colubriformis. t ...19873616141
effect of concurrent infection with ostertagia circumcincta and trichostrongylus vitrinus on the performance of lambs.the interaction between ostertagia circumcincta and trichostrongylus vitrinus was investigated in lambs continuously infected over 12 weeks. four groups of seven lambs were given either zero, 1000 t vitrinus larvae per day, 2500 o circumcincta larvae per day or infected concurrently. overall liveweight gain was reduced by 17, 20 and 30 per cent in t vitrinus, o circumcincta and concurrent infection, respectively. t vitrinus infection significantly lowered serum phosphorus concentrations by week ...19863704343
the distribution of the infective larvae of sheep gastro-intestinal nematodes in soil and on herbage and the vertical migration of trichostrongylus vitrinus larvae through the soil.from may 1982 until september 1983 samples of soil and herbage were collected from a paddock grazed from may to october 1982, and for two short periods between may and july 1983, by sheep infected with gastro-intestinal nematodes. few infective larvae were recovered from the soil although appreciable numbers of larvae were recovered from the herbage. infective larvae of trichostrongylus vitrinus in faeces buried in the soil of grass plots, at a depth of 10 cm, each month from april 1982 until ma ...19854031451
observations on the bionomics of the free-living stages of trichostrongylus vitrinus.eggs of trichostrongylus vitrinus in faecal pellets deposited on grass plots each month from april 1981 to march 1982 developed into infective larvae. from october to march development was slow and mortality of the pre-infective stages was very high. from april to september development was more rapid. the weather was generally dry and mortality of the pre-infective stages was high on plots with short herbage but was lower on most of the plots with long herbage, especially in july and august. in ...19846538891
effect of phosphorus intake on growth rate, food intake and quality of the skeleton of growing lambs infected with the intestinal nematode trichostrongylus vitrinus.the performance of growing lambs dosed daily for 12 weeks with 2500 trichostrongylus vitrinus larvae (i) or given no larvae (control, c) was compared at two levels of phosphorus intake; 2.75 gp/kg dry matter (normal, np) and 1.88 pgp/kg dry matter (low, lp). both low phosphorus and t vitrinus infection reduced dry matter intake and growth rate and the combined effect of low phosphorus and infection were additive. plasma hypophosphataemia (less than 60 mg per litre) occurred in groups clp, ilp an ...19836635343
alternative pathway activation of complement in fetal lamb serum by trichostrongylus vitrinus larvae.fetal lamb serum (fls) complement activated by incubation with trichostrongylus vitrinus larvae was deposited on the larval surface and its presence was demonstrated by leucocyte and erythrocyte adherence reactions and by analysis of antisera from guinea-pig immunized with the larvae. the complement activation proceeded in the apparent absence of antibody and in the presence of ethylene glycol tetracetic acid (egta) or mg++-egta but not ethylenediamine tetracetic acid (edta). fls heated to 50 de ...19816798533
development of morphological changes in the small intestine of lambs continuously infected with trichostrongylus vitrinus.groups of three-month-old worm-free suffolk cross lambs were given 2500 trichostrongylus vitrinus larvae on five days each week for four, six, eight and 13 weeks and killed one week later. severe villous atrophy, epithelial erosion and cellular infiltration were common features in the duodenum and the following 2 to 3 m of intestine of lambs killed at weeks 5 and 7. there was evidence of intestinal recovery in the lambs killed at weeks 9 and 14; five of the seven lambs had large areas of intesti ...19836878880
changes in the intestinal enzyme activity of lambs during chronic infection with trichostrongylus vitrinus.the pathology and enzymology of the intestinal mucosae of lambs dosed daily with 2500 trichostrongylus vitrinus larvae and killed at five, nine or 14 weeks were compared with worm-free animals. the proximal small intestines of the infected lambs exhibited extensive mucosal damage at five and nine weeks, but only isolated lesions were found at 14 weeks. activities of the brush border enzymes alkaline phosphatase, leucine amino-peptidase, maltase and glycyl-l-leucine dipeptidase were all significa ...19827100647
the trichostrongyloid parasites of sheep in south australia and their regional distribution.the species of trichostrongyloid nematodes present in 376 sheep from different agricultural regions of the state of south australia were determined. parasites encountered in the abomasum were teladorsagia circumcincta, t. trifurcata, t. davtiani, camelostrongylus mentulatus, haemonchus contortus and trichostrongylus axei. t. circumcincta was the species most commonly encountered, but c. mentulatus was widespread in arid areas. h. contortus was present in a small number of sheep only, mainly in s ...19827168719
specific identification of strongyle eggs in small samples of sheep faeces.a method for the specific identification of strongyle eggs in small samples of sheep faeces based on dimensional and biological characteristics is described. more than 90 per cent of the eggs of ostertagia spp and of trichostrongylus vitrinus can be positively identified. for other species supporting information from larval cultures may be needed but this need will vary according to the composition of the sample.19827201151
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.) ...19957660570
a comparison of the mast cell and eosinophil responses of sheep and goats to gastrointestinal nematode infections.the mucosal mast cell and eosinophil responses of goats and sheep to a mixed gastrointestinal nematode infection were compared. groups of eight does and nine ewes, previously maintained on pasture and treated with anthelmintic when they were housed and five worm-free lambs were challenged with 10,000 trichostrongylus vitrinus third stage larvae (l3) and 10,000 teladorsagia circumcincta l3. eleven days after challenge, the ewes had significantly (p < 0.001) lower burdens of abomasal and intestina ...19957709060
a middle-repetitive dna sequence element in the sheep parasitic nematode, trichostrongylus colubriformis.a novel repetitive dna sequence in the sheep parasitic nematode trichostrongylus colubriformis was cloned and sequenced. a 1.1 kb repetitive sequence (tc15) which hybridized with dna from t. colubriformis but not with dna from two other parasitic nematodes, haemonchus contortus and ostertagia circumcincta, or sheep was further characterized. southern blot analysis showed that the repeat hybridized to a range of fragments in restriction digested t. colubriformis dna and existed in multiple copy n ...19947970890
efficacy of moxidectin against gastrointestinal nematode infections in sheep.the efficacy of moxidectin against gastrointestinal nematode infections was studied in 30 fleischschaf x rasa aragonesa male lambs aged 3 months at the beginning of the experiment. the lambs were distributed in three groups of 10 animals each and experimentally infected with a mixture of an equal number of infective (l3) larvae from each of the following species: haemonchus contortus (2000), ostertagia circumcincta (2000), trichostrongylus colubriformis (2000) and trichostrongylus vitrinus (2000 ...19948171833
irrigation, faecal water content and development rate of free-living stages of sheep trichostrongyles.the effect of irrigation by flooding the pastures on the ability of the eggs of sheep trichostrongyles to develop into infective larvae (l3) was estimated in outdoor conditions by depositing parasitised faeces on plots, without irrigation or submerged, at different times and durations. the rates of development of teladorsagia circumcincta, trichostrongylus vitrinus and chabertia ovina were very low in spring and summer in dry plots but proportional to the duration of submersion in the irrigated ...19938220500
activity of morantel citrate against strains of benzimidazole-resistant nematodes of sheep in the united kingdom.the activity of morantel citrate (5.94 mg/kg base) was determined in laboratory tests against field isolates of benzimidazole-resistant nematodes. its efficacies against adult and seven-day-old worms were 100 per cent and 100 per cent for cooperia curticei, 95.1 per cent and 69.8 per cent for haemonchus contortus and 100 per cent and 82 per cent for ostertagia circumcincta. morantel citrate was 100 per cent effective against benzimidazole-susceptible nematodirus battus and trichostrongylus vitri ...19938236701
the efficacy and persistent anthelmintic effect of ivermectin in sheep.the direct efficacy and the long-term persistent anthelmintic effect of an oral suspension and an injectable formulation of ivermectin at a dose rate of 0.2 mg kg-1 was studied in sheep. lambs were infected experimentally with haemonchus contortus, trichostrongylus vitrinus and cooperia curticei. after 3 weeks they were treated with an oral suspension or with an injection, and reinfected with the same dose of larvae 3, 6 or 10 days after treatment. post-mortem worm counts showed no persistent ef ...19938291186
nematode burdens and immunological responses following natural challenge in romney lambs selectively bred for low or high faecal worm egg count.breeding lines of romney sheep, selected as lambs for consistently low or high faecal nematode egg count (fec) following periods of natural challenge, have been maintained at wallaceville for some years. in order to determine the extent to which fecs in low and high genotypes reflected their ability to resist the establishment of gastro-intestinal nematode burdens, we investigated the infection status and immune responses in 8- to 9-month-old progeny of selected rams from low and high fec breedi ...19968720563
dietary protein for young grazing sheep: interactions with gastrointestinal parasitism.effects of protein supplementation and of nematode control on production responses in young grazing sheep and on nematode population dynamics were assessed. young merino wether sheep (n = 270) were allocated to one of three supplementation (su) treatments and one of three regimes of nematode control (drench, dr) in a factorial design. each of the nine treatments was replicated three times in a randomised complete block. animals received no supplement (su0) or were given supplements at a level eq ...19958747911
the influence of stocking rate on gastrointestinal nematode infections of sheep over a 2-year grazing period.six groups of four ewes with twin lambs grazed six paddocks during two consecutive seasons from may to september in a two-factorial study on stocking rate (9, 13 and 17 ewes ha-1) and infected (designated i-low, i-medium and i-high) versus clean pasture (c-low, c-medium and c-high). all animals were treated with anthelmintic at turn-out and the c-groups were further treated fortnightly. the two sets of paddocks received 0, 80 and 160 kg n fertilizer ha-1 annually with increasing stocking rate. e ...19969017869
effects of the excretory/secretory products of six nematode species, parasites of the digestive tract, on the proliferation of ht29-d4 and hgt-1 cell lines.the excretory/secretory (es) products of the nematode parasite trichostrongylus colubriformis have been found to increase the in vitro proliferation of the epithelial cell line ht29-d4. to assess the specificity of this effect, es products from other trichostrongyle species were tested on colonic (ht29-d4) and gastric (hgt-1) tumour cell lines. adult worms of six different nematode species, parasites of the stomach or the small intestine of ruminants, were incubated in vitro in dulbecco's modifi ...19959439903
a comparison of the first internal transcribed spacer of ribosomal dna in seven species of trichostrongylus (nematoda: trichostrongylidae).the first internal transcribed spacer (its-1) of the ribosomal dna of seven species of trichostrongylus was sequenced. the length of its-1 in the different species varied from 387 to 390 bases. the g + c content of the its-1 sequences were approximately 42%. little or no intraspecific variation was detected in the three species. trichostrongylus axei, trichostrongylus colubriformis and trichostrongylus vitrinus, for which multiple isolates from different geographical regions were sequenced. in c ...19989762572
the pathogenesis and control of diarrhoea and breech soiling in adult merino sheep.diarrhoea and soiling of the breech with faeces ('winter scours') is a serious problem in adult merino sheep grazing improved pastures in south-eastern australia during winter and spring. this occurs even on farms where gastro-intestinal nematodes are effectively controlled. it was shown that winter scours was associated with the ingestion of trichostrongylid larvae, and that host factors were important in determining susceptibility to this syndrome. no differences were detected in the protectiv ...199910480726
the relationship between the rate of intake of trichostrongylid larvae and the occurrence of diarrhoea and breech soiling in adult merino sheep.a hypersensitive inflammatory response, associated with the ingestion of trichostrongylid larvae, is a major cause of diarrhoea and soiling of the breech with faeces in adult merino sheep ('hypersensitivity scours'). this response is characterised by an infiltration of eosinophils and altered lymphocyte populations in the gut of affected sheep. the objective of this study was to investigate the numbers of ostertagia circumcincta and trichostrongylus vitrinus infective larvae that were needed to ...200010736672
effectiveness of grazing management in controlling gastrointestinal nematodes in weaner lambs on pasture in denmark.a dose and move to clean pasture strategy for nematode control in weaner sheep was compared to a move only strategy. sixteen ewes with twin lambs (2-3 weeks old) were turned out on infected pasture on 4 may 1999. on 1 july, the lambs were allocated to four groups of eight and weaned on to clean pasture. two groups (dm1+2) were treated with anthelmintics, while the other two (m1+2) were not treated. each group was allocated to a separate paddock and set stocked until 27 september when all the ani ...200111445152
direct anthelmintic effects of condensed tannins towards different gastrointestinal nematodes of sheep: in vitro and in vivo vitro and in vivo studies were conducted to determine possible direct anthelmintic effects of condensed tannins towards different ovine gastrointestinal nematodes. a larval development/viability assay was used to investigate the effect of a condensed tannin extract (quebracho) towards larvae of haemonchus contortus, teladorsagia circumcincta and trichostrongylus vitrinus. the development to infective larvae and their viability was assessed in all three species and ld 50 values were calculated ...200111502368
osteopenia and reduced serum alkaline phosphatase activity in grazing lambs naturally infected with gastrointestinal nematodes.the effect of gastrointestinal nematode infections on bone development was investigated in growing sheep on pasture. forty-five weaned lambs from six groups in a two-factorial design incorporating stocking rate (sr; low, medium and high) and presence or absence of infection on pasture were sampled in the late grazing season. worm counts were performed at slaughter, and the left metacarpal bones were excised for bone assessment. faecal egg counts and worm burdens, primarily of ostertagia circumci ...200111578136
variation among merino sheep in susceptibilty to lice (bovicola ovis) and association with susceptibility to trichostrongylid gastrointestinal parasites.sheep of two bloodlines of merino were artificially infested with equal numbers of lice (bovicola ovis) and the resulting louse populations were monitored over the following 20 months. the sheep were shorn 6 and 17 months after infestation and, for analysis, the louse counts considered in 3 years separated by shearings. nematode faecal egg counts (fecs) were assessed on faecal samples collected on five occasions, three times following natural challenge and twice after artificial challenge with 4 ...200211777614
efficacy of eprinomectin pour-on against gastrointestinal nematode infections in sheep.two field trials were conducted in two farms (farms a and b) in southern italy, to assess the efficacy of eprinomectin applied topically at the dose rate of 500 micro g/kg to sheep with naturally occurring infections of gastrointestinal nematodes (gin). the nematode population determined by necropsy consisted of teladorsagia circumcincta, haemonchus contortus, trichostrongylus vitrinus, t. capricola, nematodirus sp., and chabertia ovina in sheep from farm a, and of t. circumcincta, t. vitrinus, ...200312591196
profiling of gender-specific gene expression for trichostrongylus vitrinus (nematoda: strongylida) by microarray analysis of expressed sequence tag libraries constructed by suppressive-subtractive hybridisation.gender-specific gene expression in trichostrongylus vitrinus (order strongylida) was investigated by constructing male- and female-specific gene archives using a suppressive-subtractive hybridisation approach, sequencing of expressed sequence tags from these archives, comparison with genes of caenorhabditis elegans and other organisms, and expression profiling of a representative subset of 716 expressed sequence tags by microarray and macroarray analysis. of these t. vitrinus expressed sequence ...200415064128
serpin expression in the parasitic stages of trichostrongylus vitrinus, an ovine intestinal nematode.members of the genus trichostrongylus, such as t. vitrinus, being endemic in northern europe, are among the principal causative nematodes which contribute to parasitic gastro-enteritis in sheep world-wide, inhabiting the proximal small intestine and causing damage to the mucosa. this results in impaired nutrient absorption as well as a pronounced inflammatory response with cellular infiltration of the mucosa, including a pronounced mast cell response. these mast cells release serine proteinases ...200515796018
real time pcr for the diagnosis of benzimidazole resistance in trichostrongylids of sheep.this report describes a new molecular method for the diagnosis of benzimidazole susceptibility or resistance in three main species of trichostrongylids of sheep (haemonchus contortus, teladorsagia circumcincta and trichostrongylus vitrinus). this assay is based on the use of real time polymerase chain reaction (pcr) to detect mutations of residue 200 on isotype 1 of beta-tubulin. the technique allows calculation of the proportion of each allelic variant as it combines kinetic (real time quantita ...200515845285
variation among faecal egg counts following natural nematode infection in scottish blackface lambs.faecal egg counts were examined in 2 flocks of naturally infected scottish blackface sheep in southern and central scotland. the distribution of mean counts was right skewed and similar to a gamma distribution. the counts varied with month, with mean counts rising from may to july, then falling but rising again in october, although data within each year did not always show such a clear pattern. there was no significant difference in mean egg count between the 2 farms examined. the distribution o ...200616209724
gastrointestinal nematode species burdens and host mortality in a feral sheep population.every few years a large proportion of the feral sheep on hirta, st kilda die due to food shortage. the effects of malnutrition are exacerbated by gastrointestinal nematodes. as found in sheep flocks in mainland britain, teladorsagia circumcincta has long been considered the predominant and most pathogenic nematode species in all age classes of soay sheep. previous research indicated that intensity of this species showed a negative association with host age and comprised 75% of the entire gastroi ...200616817995
the use of chicory for parasite control in organic ewes and their lambs.the aim of the present study was to investigate the potential benefits of grazing lactating ewes and their lambs on chicory (cichorium intybus). fifty-six certified organic twin-rearing ewes were either drenched with an anthelmintic or not, within 2 days after parturition and were grazed upon either grass/clover or chicory pastures. around 12 weeks after parturition a subset of 12 lambs per treatment was slaughtered for worm number and parasite species determination. the faecal egg counts of lam ...200717032469
trichostrongylus vitrinus (nematoda: strongylida): molecular characterization and transcriptional analysis of tv-stp-1, a serine/threonine phosphatase gene.a full-length cdna (tv-stp-1) encoding a serine/threonine protein phosphatase (tv-stp-1) was isolated from trichostrongylus vitrinus (order strongylida), an economically important parasitic nematode of small ruminants. the uninterrupted open reading frame (orf) of 951 nucleotides encoded a predicted protein of 316 amino acids (aa), containing the characteristic motif [livmn]-[kr]-g-n-h-e. comparison with other sequences in non-redundant databases showed that tv-stp-1 had significant identities/s ...200717490653
metazoan-protozoan parasite co-infections and host body weight in st kilda soay sheep.for hundreds of years, the unmanaged soay sheep population on st kilda has survived despite enduring presumably deleterious co-infections of helminth, protozoan and arthropod parasites and intermittent periods of starvation. important parasite taxa in young soay sheep are strongyles (trichostrongylus axei, trichostrongylus vitrinus and teladorsagia circumcincta), coccidia (11 eimeria species) and keds (melophagus ovinus) and in older animals, teladorsagia circumcincta. in this research, associat ...200818215336
arrested development of sheep strongyles: onset and resumption under field conditions of central europe.two tracer tests were conducted between august 2004 and march 2007 at an ecological farm in western bohemia. the first tracer test was performed for the summer-autumn grazing period (onset of arrested development), the second for spring (resumption of arrested development). in the first tracer test, the percentage of nematodes arresting development over the winter months reached 87.7% for teladorsagia circumcincta, 66.7% for haemonchus contortus, 89.9% for nematodirus filicollis, 21.6% for trich ...200818454350
molecular and phylogenetic characterization of cytochromes c from haemonchus contortus and trichostrongylus vitrinus (nematoda: trichostrongylida).although cytochrome c genes (cyt c) and proteins (cyt c) have been relatively well studied in mammals, very little is known about them in parasitic helminths. in the present study, we investigated this group of molecules in haemonchus contortus (barber's pole worm) and trichostrongylus vitrinus (black scour worm), two parasitic nematodes of small ruminants. the cyt c gene (512 bp) of h. contortus had one intron and encoded a transcript of 345 nucleotides, whilst that of t. vitrinus (792 bp) had ...200818718861
dose determination studies for monepantel, an amino-acetonitrile derivative, against fourth stage gastro-intestinal nematode larvae infecting sheep.monepantel is the first compound from the recently discovered amino-acetonitrile derivative (aad) class of anthelmintics to be developed for use in sheep. three dose determination studies were conducted in australia and switzerland to identify the minimum therapeutic dose of monepantel when formulated for the oral treatment of sheep to control fourth stage (l4) gastro-intestinal nematode larvae. in each study, sheep infected with the target nematodes (selected from haemonchus contortus, teladors ...200818760536
linear distribution of nematodes in the gastrointestinal tract of tracer lambs.forty-eight tracer lambs were killed in 2004-2007. the abomasum, duodenum, small intestine (jejunum and ileum), colon and caecum were collected and processed for parasites enumeration and identification-mucosal scrapings of both abomasums and intestines were digested. out of 48 gastrointestinal tracts examined, all were found to be positive for nematode infection. seventeen species of gastrointestinal nematodes were recovered: bunostomum trigonocephalum, cooperia curticei, haemonchus contortus, ...200818766377
cross-species utility of microsatellite markers in trichostrongyloid nematodes.the development of microsatellite markers for parasitic nematodes has been hampered by technical difficulties in isolation and pcr amplification. we have investigated the potential for circumventing these problems using microsatellites from 3 trichostrongyloid species on a panel of 7 species. ten of the 22 pcr primer pairs tested amplified in species other than the target species, usually in closely related species, and 2 new variable loci were discovered in the sheep parasite trichostrongylus v ...200918817456
the contribution to the epidemiology of gastrointestinal nematodes of sheep with special focus on the survival of infective larvae in winter conditions.tracer tests conducted over a 3-year period were aimed at measuring the level and species nematode composition of survival on pastures with a special focus on winter months. the survival of infective larvae in chilly conditions is not significantly affected by trichostrongylus axei, trichostrongylus colubriformis, trichostrongylus vitrinus and chabertia ovina. on the contrary, the number of teladorsagia circumcincta and nematodirus filicollis significantly increased in milder winter conditions. ...200919031086
availability of gastro-intestinal nematode larvae to sheep following winter contamination of pasture with six nematode species on the northern tablelands of new south wales.this experiment was designed to determine the infective consequences of winter pasture contamination by sheep infected with 6 species of trichostrongylid gastro-intestinal nematode (gin) at armidale in the new england region of nsw. ten helminthologically inert pasture plots were contaminated using 'donor' sheep harbouring artificial infections of haemonchus contortus, trichostrongylus colubriformis, trichostrongylus vitrinus, trichostrongylus axei, nematodirus spathiger and teladorsagia circumc ...200919070435
dose confirmation studies for monepantel, an amino-acetonitrile derivative, against fourth stage gastro-intestinal nematode larvae infecting sheep.monepantel is the first compound from the recently discovered amino-acetonitrile derivative (aad) class of anthelmintics to be developed for use in sheep. nine dose confirmation studies were conducted in australia, new zealand and switzerland to confirm the minimum therapeutic oral dose of monepantel to control fourth stage (l4) gastro-intestinal nematode larvae in sheep (target species were haemonchus contortus, teladorsagia (ostertagia) circumcincta, teladorsagia trifurcata, trichostrongylus a ...200919135310
re-establishment of nematode infra-community and host survivorship in wild soay sheep following anthelmintic treatment.compared to mainland britain, where there has been decades of anthelmintic use, the natural host-parasite relationship of the wild soay sheep on the remote archipelago of st. kilda has remained undisturbed. small-scale anthelmintic bolus experiments on the island have previously shown that the removal of gastrointestinal nematodes can improve over-winter survival of young and male sheep in high host density years. this study, in which two-year-old sheep were treated, is the first to examine patt ...200919150178
the relative contributions of t. colubriformis, t. vitrinus, t. axei and t. rugatus to sheep infected with trichostrongylus spp. on the northern tablelands of new south wales.this survey was designed to determine the spatial and temporal distribution and the relative contributions of trichostrongylus colubriformis, trichostrongylus vitrinus, trichostrongylus axei and trichostrongylus rugatus to sheep infected with trichostrongylus spp. on the northern tablelands of nsw. thirty completed larval cultures were collected from a commercial parasitology laboratory servicing the northern tablelands of nsw between june and december 2007. cultures were selected at random from ...200919632782
in vitro effect of condensed tannin extract from acacia (acacia mearnsii) on gastrointestinal nematodes of sheep.the aim of this study was to determine the inhibitory effects of condensed tannin extract from acacia on the feeding of first-stage larvae (l1) of haemonchus contortus, trichostrongylus vitrinus and teladorsagia circumcincta. the experiment was developed such that the inhibition of feeding for each of the nematode species could be evaluated. l1 recovered from fecal samples from a donor with monospecific infection was incubated in several dilutions of acacia extract (ae). the ld50 was determined ...200820059834
efficacy of a combined oral formulation of derquantel-abamectin against the adult and larval stages of nematodes in sheep, including anthelmintic-resistant strains.derquantel (dql), a semi-synthetic member of a novel anthelmintic class, the spiroindoles, in combination with abamectin (aba) [as the combination product startect(-«)] is a new entry for the treatment and control of parasites in sheep. the 19 studies reported herein were conducted in australia, new zealand, south africa and the united kingdom to demonstrate the efficacy of derquantel-abamectin (dql-aba) against a broad spectrum of gastrointestinal and respiratory nematodes of sheep, and to supp ...201121684691
Displaying items 1 - 63 of 63