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1.
The use of natural plant anthelmintics was suggested as a possible alternative control of gastrointestinal nematodes (GIN) in ruminants. Direct anthelmintic effects of tannin-containing plants have already been shown in sheep and goat GIN. These anthelmintic properties are mainly associated with condensed tannins. In the present study, we evaluated possible in vitro effects of three tannin-containing plants against bovine GIN. Effects of Onobrychis viciifolia, Lotus pedunculatus and Lotus corniculatus condensed tannin (CT) extracts on Cooperia oncophora and Ostertagia ostertagi were determined by a larval feeding inhibition assay (LFIA) and a larval exsheathment assay (LEA). In the LFIA, all three plant extracts significantly inhibited larval feeding behaviour of both C. oncophora and O. ostertagi first stage larvae in a dose-dependent manner. The L. pedunculatus extract, based on EC(50) (effective concentration for 50% inhibition), was the most effective against both nematodes, followed by O. viciifolia and L. corniculatus. The effect of CT extracts upon larval feeding behaviour correlates with CT content and procyanidin/prodelphidin ratio. Larval exsheathment of C. oncophora and O. ostertagi L3 larvae (third stage larvae) was also affected by CT extracts from all three plants. In both in vitro assays, extracts with added polyvinylpolypyrrolidone, an inhibitor of tannins, generated almost the same values as the negative control; this confirms the role of CT in the anthelmintic effect of these plant extracts. Our results, therefore, indicated that tannin-containing plants could act against cattle nematodes.  相似文献   

2.
A series of experiments was carried out to examine the effects of two different isolates of the nematode-trapping fungus Duddingtonia flagrans to reduce the number of free-living larvae of the bovine lungworm, Dictyocaulus viviparus. A laboratory dose-titration assay showed that isolates CI3 and Troll A of D. flagrans significantly reduced (P < 0.05 to P < 0.001) the number of infective D. viviparus larvae in cultures at dose-levels of 6250 and 12,500 chlamydospores/g of faeces. The larval reduction capacity was significantly higher for Troll A compared to CI3 when lungworm larvae were mixed in faecal cultures with eggs of Cooperia oncophora or Ostertagia ostertagi and treated with 6250 chlamydospores/g of faeces. Both fungal isolates showed a stronger effect on gastrointestinal larvae than on lungworm larvae. Two plot trials conducted in 1996 and 1997 involved deposition of artificial faecal pats containing free-living stages of D. viviparus and C. oncophora on grass plots. Herbage around the pats was collected at regular intervals and infective larvae recovered, counted and identified. These experiments showed that both D. flagrans isolates reduced the number of gastrointestinal as well as lungworm larvae in faecal pats. During both plot trials, the transmission of C. oncophora larvae, but not D. viviparus, from faecal pats to the surrounding herbage was clearly affected by climatic conditions. After collection of faecal pats from the grass plots one month after deposition, the wet and dry weight of pats as well as organic matter content were determined. No differences were found between the fungus-treated and non-treated control pats. This indicated that the rate of degradation of faeces was not affected by the addition of the fungus.  相似文献   

3.
The reindeer husbandry range of Scandinavia overlaps with sheep, goat, and cattle pastures. The aim of this study was to determine whether reindeer are suitable hosts for ovine or bovine nematode parasites, and thus may spread these parasites into the reindeer husbandry regions. To render worm-free, twelve 4-month-old male reindeer calves, six lambs, and six bovine calves were given ivermectin at 200 microg/kg body weight. Five weeks post-treatment, six reindeer calves were each artificially dosed with 10,000 third-stage larvae (L3) of gastrointestinal nematodes derived from sheep, and an additional six reindeer with L3 derived from cattle. Lambs and bovine calves received the same dose of ovine and bovine larvae as reindeer, from the same larval source, respectively. Faecal samples collected on five occasions after the larval dosing revealed that by the fourth week, all reindeer calves, lambs, and bovine calves were infected. Animals were slaughtered on days 40 (reindeer) or 47 (lambs and bovine calves) after the larval dosing. Reindeer calves were most susceptible to L3 derived from sheep. The overall mean intensity of Haemochus contortus, Trichostrongylus axei, and Teladorsagia circumcincta, did not differ between reindeer and sheep; however, early fourth-stage larvae of H. contortus were more abundant in reindeer (p = 0.002). The establishment of bovine-derived Ostertagia ostertagi was similar in reindeer (62%) and bovine calves (57%), but larval inhibition was much higher in reindeer (91%, p < 0.001) than in cattle (31%). Very poor establishment of bovine derived Cooperia oncophora was recorded in reindeer calves (2%) compared with bovine calves (59%). These results show that young reindeer are susceptible hosts to the important gastrointestinal parasites of sheep (T. circumcincta, H. contortus) and cattle (O. ostertagi), as well as being a suitable host for T. axei.  相似文献   

4.
OBJECTIVE: To evaluate efficacy of topically administered doramectin against eyeworms, lungworms, and gastrointestinal nematodes of cattle. ANIMALS: 400 cattle (20 cattle in each of 20 trials). PROCEDURE: Trials were conducted in North America; natural and experimentally induced infections were used. In each trial, cattle were allocated randomly to control (placebo [saline [0.9% NaCl] solution at 1 ml/10 kg of body weight] or untreated; n = 10) or doramectin-treated (500 microg/kg of body weight; 10) groups. Treatments were applied in a single passage along the midline of the back, from the withers to the tailhead. Cattle were euthanatized > or =14 days after treatment, and worm burdens were determined by use of standard techniques. RESULTS: Efficacy of doramectin was > or =95.3% against adults of Thelazia gulosa, T skrjabini, Dictyocaulus viviparus, Haemonchus contortus, H placei, Ostertagia lyrata, O ostertagi, Trichostrongylus axei, Bunostomum phlebotomum, Capillaria spp, Cooperia oncophora, C pectinata, C punctata, C spatulata, C surnabada, Nematodirus spathiger, Strongyloides papillosus, T colubriformis, Oesophagostomum radiatum, and Trichuris spp. Efficacy was 95.1% against fourth-stage larvae of D viviparus, H placei, O lyrata, O ostertagi, T axei, C oncophora, C punctata, C spatulata, C surnabada, N helvetianus, T colubriformis, O radiatum, and Trichuris spp. In addition, efficacy against inhibited fourth-stage larvae of O ostertagi and Ostertagia spp was > or =98.1%. CONCLUSIONS AND CLINICAL RELEVANCE: A single topical application of doramectin pour-on was efficacious against a broad range of nematode species in cattle.  相似文献   

5.
The main objective of the present study was to evaluate the accuracy of the faecal egg count reduction test (FECRT) to assess the resistance status of ivermectin (IVM)-resistant isolates of the cattle nematodes Ostertagia ostertagi and Cooperia oncophora, using the controlled efficacy test (worm counts) as a reference. The second objective was to investigate whether both IVM-resistant isolates showed side-resistance against moxidectin (MOX) under controlled conditions. Thirty male Holstein calves were experimentally infected with 25,000 L3 of an IVM-resistant O. ostertagi isolate and 25,000 L3 of an IVM-resistant C. oncophora isolate. Twenty-eight days later the calves were randomly divided into 2 treatment groups and 1 untreated control group. Animals in groups 1 and 2 received MOX (Cydectin(?) 1%, Pfizer) and IVM (Ivomec(?) 1%, Merial) respectively, by subcutaneous injection at a dose rate of 0.2mg/kg bodyweight. Faecal samples were collected 7 and 14days after treatment and animals were necropsied 14/15days post-treatment. Both the FECRT and the controlled efficacy test demonstrated that the O. ostertagi and C. oncophora isolates were resistant against IVM, with efficacies below 90%. The IVM-resistant O. ostertagia isolate was still susceptible to MOX treatment, as shown by over 99% reduction in egg counts and worm burden. The FECRT suggested borderline resistance against MOX in the IVM-resistant C. oncophora isolate, with egg count reductions between 97% (95% CI: 76; 100) at day 7 and 86% (95% CI: 49; 96) at day 14. However, the controlled efficacy test clearly showed MOX-resistance, with a decrease of only 31% (95% CI: -12; 57) in C. oncophora worm numbers. After MOX treatment, a significantly lower number of eggs per female C. oncophora worms was counted compared to the control group (43% reduction). Due to this reduced fecundity, the FECRT may fail to detect MOX-resistance.  相似文献   

6.
Interactions between the predacious hyphomycete Arthrobotrys oligospora and third-stage larvae of nine animal-parasitic nematodes were tested in vitro. The trap-inducing capabilities of the ruminant trichostrongylus Cooperia oncophora, C. curticei, Haemonchus contortus and Ostertagia ostertagi and of equine cyathostomes were almost comparable to those of free-living soil nematodes, and significantly higher than those of the porcine Oesophagostomum dentatum and Oe. quadrispinulatum and of the murine Nematospiroides dubius. The trap-forming potential of Dictyocaulus viviparus was poor. All animal-parasitic nematodes were rapidly captured when fungal traps had been pre-induced in high numbers. The possible influence of predacious fungi on animal-parasitic nematode populations under natural conditions in the field is discussed.  相似文献   

7.
Trichostrongylid burdens in 1 to 2-year-old dairy heifers were estimated after they grazed with a dairy herd for up to 12 months. Ostertagia ostertagi, Trichostrongylus axei and Cooperia oncophora represented 79.5, 12.7 and 7.8% respectively of all trichostrongylids recovered. The largest burden was 97,000 trichostrongyles with less than 20,000 being the typical burden. Clinical disease was not observed. The strain of O. ostertagi present was capable of inhibition and was not necessarily controlled by anthelmintics. Availability of infective larvae increased with the onset of spring when "modified tracer" calves accumulated up to 30,000 trichostrongyles over intervals of one month. From July to September each year, up to 80% of the Ostertagia burden in these animals were inhibited larvae. Faecal strongyloid egg counts fell from less than an average of 60 eggs per gram to 10 eggs per gram when the heifers were one and 2 years old, respectively. Mature cows continually passed few eggs in their faeces.  相似文献   

8.
The influence of a priming infection with gastrointestinal nematodes on the subsequent establishment of lungworms was studied. Repeated inoculations of calves with Ostertagia ostertagi and Cooperia oncophora during 3, 5 or 7 weeks resulted in an establishment of lungworms that was 191% of the establishment found in na?ve controls. The higher take was associated with a higher faecal output of lungworm larvae and with lower weight gains of calves. The effect was not significantly influenced by the duration of the primary infections or by the actual presence or absence of worms in the gastrointestinal tract.  相似文献   

9.
Albendazole, methyl 5-propylthio-1H-benzimidazol-2-yl carbamate, was given as a bolus (7.68 to 8.18 mg/kg of body weight) to cattle naturally infected with gastrointestinal nematodes and lungworms in a controlled trial. Over 99% of adult Ostertagia ostertagi, Trichostrongylus longispicularis, Cooperia oncophora, Nematodirus helvetianus, and Dictyocaulus viviparus were removed by the treatment. Efficacy against immature O ostertagi, early fourth-stage O ostertagi, and Oesophagostomum radiatum was 95.2%, 86.6%, and 96.7%, respectively. In a field trial, the same compound administered in a paste formulation (at approximately 7.5 mg/kg) eliminated over 99% of strongylin and Moniezia eggs from feces of treated cattle.  相似文献   

10.
Interactions between gastrointestinal worms (Ostertagia ostertagi, Cooperia oncophora) and lungworms (Dictyocaulus viviparus) in calves were studied by assessing the effect of primary infections with either group of worms on the development of homologous or heterologous challenge infections. Primary infections with lungworms resulted in some degree of resistance to challenge with gastrointestinal worms, but this resistance was lower than that found after homologous infection. Primary infections with gastrointestinal worms did not confer any resistance to challenge with lungworms. On the contrary, an indication was found of some enhancing effect of previous gastrointestinal worm infection on the establishment of lungworms. The highest degree of resistance against lungworm challenge was found where calves have been primarily infected with lungworms. Lungworm infections produced some elevation of serum pepsinogen levels. Gastrointestinal worms evoked a rise in circulating eosinophils, although this rise was smaller and occurred later than in lungworm-infected calves. Under the conditions of the experiment, the effect of 6000 infective lungworm larvae on weight gain was larger than the effect of 100,000 L3 of Ostertagia ostertagi and 100,000 L3 of Cooperia oncophora.  相似文献   

11.
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 nematode larvae. In groups 2, 3, and 4, overall reductions (based on geometric means) were 98.6%, 98.7%, and 98.4%, respectively. These reductions were highly significantly different (P less than 0.01) from the control calves. Nematodes in the calves were Haemonchus contortus. Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia oncophora, C punctata, and Oesophagostomum radiatum.  相似文献   

12.
The residual effect of treatment with ivermectin after experimental reinfection in calves was tested. Twenty-four calves were divided into 6 groups of 4 calves each. All calves received a primary infection of 50,000 larvae of both Ostertagia ostertagi and Cooperia oncophora and 1000 Dictyocaulus viviparus larvae. Calves of group 1 remained untreated, and all other calves were treated 21 days after primary infection (0.2 mg/kg injected subcutaneously). Calves of groups 1 and 2 were slaughtered 7 days later. Calves of groups 3-6 were reinfected with the same number of larvae 3 days, 1, 3 and 6 weeks after treatment respectively. Slaughter was 21 days after reinfection. Based on post-mortem worm counts the efficacy of ivermectin after primary infection was 99.7% for O. ostertagi, 95.1% for C. oncophora and 100% for D. viviparus. A residual effect was present for at least one week, but could not be observed 3 weeks after treatment.  相似文献   

13.
Exsheathed infective larvae (L 3) of 19 species of nematodes were tested for infectivity in either sheep or cattle after they had been frozen in 0,9% NaCl solution, stored for a relatively short time in the gas phase of liquid nitrogen and subsequently thawed. In addition, 13 of these species were tested after similar storage for up to 18 months. In sheep, Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Nematodirus spathiger and Oesophagostomum columbianum were viable after 2 years of cryopreservation, a mean of greater than 90% of the L 3 being alive when thawed after this period. Similar results were obtained with Chabertia ovina L 3 after 18 months and with Marshallagia marshalli, Trichostrongylus falculatus and Dictyocaulus filaria, after a short period of freezing. On the other hand, Gaigeria pachyscelis and Strongyloides papillosus survived freezing for up to 7 months but neither was viable at the end of this period, nor was exsheathed G. pachyscelis viable without freezing. Most of these infestations were established by inoculating the infective larvae into the abomasum and/or duodenum. M. marshalli, T. falculatus and C. ovina also proved infective after oral dosing. D. filaria, the only other species tested by this route, was not infective when dosed per os after thawing. The infective larvae of the bovine nematodes, Haemonchus placei, Ostertagia ostertagi, Nematodirus helvetianus, Oesophagostomum radiatum, Cooperia pectinata and Cooperia punctata survived freezing for a mean of 26 months, greater than 90% being alive on thawing, but infectivity was generally lower than with the same genera in sheep. Even when not frozen, exsheathed Bunostomum phlebotomum was non-infective. When Cooperia spp. after thawing were tested for infectivity by the oral route, more worms developed in one calf infested orally than in another infested by inoculation into the duodenum. Ova of H. contortus, M. marshalli, O. circumcincta, T. colubriformis, T. falculatus, N. spathiger, C. ovina, H. placei, O. ostertagi, Cooperia spp. and N. helvetianus were recovered from the faeces of animals infested with cryopreserved L 3. No ova of O. columbianum or O. radiatum were recovered from faeces, because differential larval counts were performed before they were patent. Nevertheless, gravid females were obtained post-mortem. Frozen L 3 of N. helvetianus were used to re-establish a pure strain in calves, 2,3 million ova being recovered from infestations with 10 670 L 3 frozen for 26 months. The infectivity of the progeny of frozen L 3 was tested with M. marshalli and C. ovina. In both instances infectivity was high and the worms which developed also produced ova, thus completing the cycle. This appears to be the first report of infective larvae of parasitic nematodes retaining their infectivity after being frozen in liquid nitrogen (gas phase) for longer than 2 years. This is also apparently the first time that M. marshalli T. colubriformis, T. falculatus, T. axei, N. spathiger, C...  相似文献   

14.
Paraherquamide, an oxindole alkaloid metabolite of Penicillium paraherquei and Penicillium charlesii, was tested against the adult stages of nine common gastrointestinal and lung nematodes of calves at single, oral dosages of 0.5, 1.0, 2.0 or 4.0 mg kg-1. At dosages 1.0-4.0 mg kg-1 there was 95% or more removal of Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, Trichostrongylus colubriformis, Cooperia oncophora, Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus. Cooperia punctata, the dosage-limiting species, was virtually unaffected by any dosage except the highest, which produced an efficacy of 89%. The 0.5 mg kg-1 dosage was 95% or more efficacious against H. placei, O. ostertagi, C. oncophora, and D. viviparus, but weaknesses were evident against the other five species. No adverse reaction was observe in any calf.  相似文献   

15.
Twelve Holstein calves were used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. Two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. Group-1 calves served as nonmedicated controls. Each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. Third-stage nematode infective larvae were given to the calves on posttreatment days 28 and 42. The calves were euthanatized 77 or 78 days after treatment. Ivermectin was 100% effective (P less than 0.05) in preventing the establishment of infection by Haemonchus placei, Ostertagia ostertagi, Cooperia spp (C punctata, C oncophora, C surnabada), Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus and was greater than 99% effective against Trichostrongylus axei. Incidental infection by Trichuris spp was reduced by 94% (P = 0.08).  相似文献   

16.
Efficacy of ivermectin in a topical formulation was evaluated in cattle against adult gastrointestinal and pulmonary nematode infections (experiment 1, n = 24), the 2nd- and 3rd-stage larvae of Hypoderma spp (experiment 2, n = 12), and the biting louse Damalinia bovis (experiment 3, n = 12). Nematode infections were induced and grubs and lice were naturally acquired. Treatments consisted of a single dose of ivermectin in a topical formulation of 200, 500, or 1,000 micrograms/kg of body weight in experiment 1 or 500 micrograms/kg in experiments 2 and 3. At 1,000 micrograms/kg, ivermectin was 100% effective against Ostertagia ostertagi, Trichostrongylus colubriformis, Oesophagostomum radiatum, Nematodirus helvetianus, Haemonchus placei, and Dictyocaulus viviparus and was greater than 99% effective against Cooperia oncophora, C punctata, and T axei. At 500 micrograms/kg, the efficacy was 100% against C oncophora, C punctata, O ostertagi, T axei, Oes radiatum, N helvetianus, Haem placei, and Dict viviparus and greater than 99% against T colubriformis. At 200 micrograms/kg, the efficacy was 100% against Oes radiatum, Haem placei, and Dict viviparus, greater than 99% for O ostertagi, 96% for C oncophora, 86% for C punctata, 90% for T axei, 85% for T colubriformis, and 71% for N helvetianus. At 500 micrograms/kg, ivermectin was highly effective against the grubs Hypoderma bovis and H lineatum and eliminated the louse Damalinia bovis.  相似文献   

17.
This study was carried out to examine the survival of infective Ostertagia ostertagi larvae (L(3)) on pasture under different simulated conditions of grazing, i.e. mixed grazing of cattle and nose-ringed sows, or grazing by cattle alone. Standardised pats of cattle faeces containing O. ostertagi eggs were deposited on three types of herbage plots, which were divided into zone 1: faecal pat; zone 2: a circle extending 25cm from the edge of the faecal pat; zone 3: a circle extending 25cm from the edge of zone 2. For "tall herbage" (TH) plots, the herbage in zone 2 was allowed to grow naturally, while the herbage in zone 3 was cut down to 5-7cm fortnightly, imitating a cattle-only pasture. For "short herbage" (SH) plots, the herbage in both zones 2 and 3 were cut down to 5-7cm fortnightly, imitating mixed grazing of cattle and sows. The grass in the "short herbage and scattered faeces" (SH/SF) plots were cut as for SH plots, and the faeces were broken down 3 weeks after deposition and scattered within zone 2, imitating the rooting behaviour of co-grazing sows. Five faecal pats from each plot group were collected on monthly basis, along with the herbage from zones 2 and 3 cut down to the ground. Infective larvae were then recovered from both faeces and herbage. The numbers of L(3) recovered from zone 1 were higher in the TH plots than in the other two groups and, furthermore, the larval counts from SH plots were always higher than from SH/SF plots. The three groups followed a similar pattern during the season regarding numbers of L(3) in zone 2, and no clear patterns between plot types were obtained. The presence of L(3) in zone 3 was almost negligible. Important differences were seen throughout the study from the biological point of view; more L(3) were able to survive in faeces on the TH plots, presumably reflecting a better protection from heat and desiccation compared to those in the other plots. The overall results support the idea that mixed grazing of cattle and pigs favour the reduction of O. ostertagi larval levels in pasture. This reduction is mainly due to the grazing behaviour of pigs, which by grazing up to the very edge of the cattle faeces, will either expose the larvae in faeces to adverse environmental summer conditions or ingest cattle parasite larvae, or both.  相似文献   

18.
Twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of Ostertagia ostertagi. The calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a steady rate was given orally. After treatment, the 2 groups were housed in separate pens with concrete flooring. Twenty-eight days after treatment, all calves were euthanatized and necropsied. The ivermectin-treated calves had no larval or adult Ostertagia spp and significantly (P less than 0.01) fewer adult Trichostrongylus axei and adult Cooperia (C oncophora, C punctata and C surnabada) than control calves. Efficacy of ivermectin was greater than 99% for Cooperia spp, and 100% for other parasites. Drug-related adverse reactions were not observed.  相似文献   

19.
Summary The activity of albendazole against gastrointestinal helminths in naturally infected calves in the Netherlands was tested. The calves were in their fist grazing season and kept in two groups of ten. One of these groups was grazed alternately with sheep. Five out of each group were drenched with albendazole (7.5 mg/kg) on the day they were housed (November 1). Before and 2, 14, and 28 days after treatment individual faecal samples were taken from all calves and larval cultures were made. Ten calves, six treated and four untreated, were killed for post mortem studies 14 days after treatment The remaining calves were slaughtered 14 days later. The drug was highly effective in reducing the egg output, measured as the number of larvae cultured per gram of faeces. Compared with the untreated calves, the reduction was more than 99% two days after treatment, 100% at 14 days, and 99% after 28 days. It was shown that egg output 28 days after treatment came from worms which had developed from arrested larvae of Ostertagia ostertagi that had survived treatment. Post mortem results showed an efficacy of 100% against adult O. ostertagi, of almost 100% against Trichostrongylus axei, and 100% against adult and larval Cooperia oncophora. Twenty-eight days after treatment, the reduction of arrested early fourth stages of O. ostertagi was 85% in comparison with the untreated calves. Apparently less effect was found against Trichuris ovis at the given dose rate.  相似文献   

20.
The antigenic differences among the life cycle stages of Cooperia oncophora were studied by SDS-gel electrophoresis and Western blotting. Sodium dodecylsulphate polyacrylamide gel electrophoresis of the different life cycle stages of C oncophora revealed a complex protein pattern with a decreasing number of protein bands towards the adult stages. Several bands of the fourth stage larvae were in common with both the third stage and the adult nematode. Western blotting with sera from C oncophora monoinfected calves showed that the antigens of the fourth stage larvae were recognised predominantly and the presence of stage specific antigens in all stages. Strong cross reactivity was demonstrated when serum from Ostertagia ostertagi infected calves was used.  相似文献   

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