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1.
A 12-month study was conducted to assess and monitor gastrointestinal tract nematodes and liver fluke in cohorts of cattle on a Scottish organic dairy farm. Various diagnostic markers for helminth parasites of cattle from different age groups were assessed monthly from April 2007 to March 2008. First season grazing stock were subjected to significant challenge from Ostertagia ostertagi nematodes as reflected in serum pepsinogen concentrations, which rose markedly in the second half of the grazing season. In addition, plasma albumin concentrations decreased and faecal egg counts (FEC) increased moderately, indicating exposure to both O ostertagi and probably Cooperia oncophora. Second season grazing animals had a peak FEC early in the grazing period, suggestive of a potential carry-over of Ostertagia species infection ('Type 2') during housing. All classes of cattle showed evidence of fluke (Fasciola hepatica) infection. Adult cow exposure to O ostertagi and fluke was estimated via the use of ELISA testing to detect antibodies to O ostertagi and F hepatica and the high levels detected suggested a significant exposure response. Despite low stocking densities and sympathetic grazing management, there was a significant challenge to all grazing stock from gastrointestinal nematodes and liver fluke.  相似文献   

2.
The present study investigated whether abomasal mucus from calves naturally infected with gastrointestinal nematodes possessed larval migration inhibition (LMI) activity in vitro, and whether LMI activity was greater in mucus from previously immunised animals, compared to primary infected and uninfected calves. LMI activity was also assessed in serum from calves during both natural and artificial Ostertagia ostertagi infections, in an attempt to monitor the development of acquired immunity. Both abomasal mucus and serum exhibited larval paralysing activity. Although the LMI capacity of the abomasal mucus was very variable, the highest paralysing activity was consistently observed in mucus from previously immunised calves. LMI activity in serum increased significantly during both artificial and natural Ostertagia infections. After a challenge infection, sera from immunised animals showed a significantly higher LMI capacity, compared to previously uninfected calves. Moreover, serum LMI activity was significantly negatively correlated with Ostertagia worm counts after the challenge infection. The present results suggest that LMI activity in serum and/or abomasal mucus reflects a protective immune response against O. ostertagi in the abomasal mucosa.  相似文献   

3.
Daily changes in serum gastrin and pepsinogen concentration have been studied during two types of infection with Ostertagia ostertagi in calves. In a first experiment two calves were trickle infected (10 times 10,000 L3 Ostertagia) and two animals received a single infection of 100,000 L3 Ostertagia. Gastrin and pepsinogen changes are discussed in relation to adult wormburdens. The second experiment involved 8 calves and was designed to investigate pepsinogen and gastrin changes following a challenge infection in previously sensitized calves. The high dosed group was infected with 5,000 L3 O. ostertagi during 30 days, the low dosed group received 500 L3 O. ostertagi and group 3 served as uninfected control. At day 41 post infection all animals were treated with oxfendazole and on day 61 challenged with 100,000 L3 O. ostertagi. Only in the high dosed group a distinct pepsinogen and gastrin reaction was noticed. Both parameters dropped to almost preinfection levels after treatment. Two days post challenge a moderate rise (+/- 1,000 mU tyr) of the pepsinogen concentration was observed in the previously infected animals and gastrin showed a temporary slight increase in several animals 8 to 10 days post challenge. The effect of treatment and challenge infection is discussed in relation to gastrin and pepsinogen changes and immunity.  相似文献   

4.
Two trials with stabled milking cows were carried out. In the first trial, cows were either experimentally infected with Ostertagia ostertagi larvae or served as naturally-infected controls. In the second trial, cows were treated the same as in the first trial, but in addition half of the number of cows of each group were treated with oxfendazole before the trial started. The results showed that experimental infection influenced Ostertagia egg output, host serum pepsinogen levels and anti-Ostertagia antibody titres. The influence on egg output consisted of an initial decrease 1 week after infection, followed by an increase 3-7 weeks after infection. The pepsinogen level was significantly elevated after one week. The antibody titres increased from 3 weeks p.i. onwards. No influence on the milk production could be demonstrated. Naturally-infected controls also showed a rise in pepsinogen level and antibody titres, probably due to the existing worm burden. The egg output appeared to be influenced by the partus. Naturally-infected cows, treated with oxfendazole, showed no changes in any of the parameters during the trial.  相似文献   

5.
A sensitive limiting dilution analysis (LDA) was used to quantitate the local and systemic cellular immune response of cattle after immunization with keyhole limpet hemocyanin (KLH) and infection with Ostertagia ostertagi. The assay measures the proliferative response of bovine T-cells after in vitro stimulation with antigen. Interleukin 2 activity was supplied by supernates from mitogen-stimulated bovine peripheral blood lymphocytes (PBL) and accessory cell function was in the form of irradiated autologous PBL. The assay measures the response of a single cell and was most easily demonstrated in the lymph nodes draining the site of antigen inoculation. Comparison of cell frequencies and maximal responses generated in conventional proliferative assays showed several differences between the two assays. First, after antigen injection, the highest cell frequencies were seen in the draining lymph nodes within 3 days, and decreased by 10 days post-immunization. In contrast, in mass cultures maximal stimulation was not seen until 7-10 days after injection, but remained high up to 4 weeks after immunization. Second, at 17 days post-infection, a time of eruption of the parasite from the gastric glands, high frequencies of inducible cells were demonstrated by LDA in all lymphoid populations tested. In contrast, low levels of proliferation were seen in mass cultures. The reasons for these differences may include different sensitivities to suppression or more stringent requirements for specificity between the two assays. Finally, it was found that immunologically naive calves have relatively high frequencies of Ostertagia-specific cells in PBL, and that after infection these frequencies decrease. These results indicate either active suppression of the potential anti-Ostertagia response or an extra-vascularization of these cells to the site of infection.  相似文献   

6.
A blind-well chemotaxis chamber method was used to indicate migration stimulation of bovine neutrophil and eosinophil polymorphonuclear leukocytes and macrophages as related to ostertagiasis. Live exsheathed Ostertagia ostertagi 3rd-stage larvae (L3) and soluble L3 antigen (SLA), prepared by freeze thawing and sonic disruption of L3, enhanced cellular migration for eosinophils, but not for neutrophils and macrophages. Products of lymphocytes cultured with SLA for 3 to 6 hours were also examined, using lymphocytes from peripheral blood of helminth-free cattle and cattle infected with O ostertagi or Trichostrongylus axei. Lymphokines that enhanced cellular migration of neutrophils, eosinophils, and macrophages were present in culture supernatants of SLA-stimulated lymphocytes from O ostertagi-infected cattle, but not from cattle infected with T axei or helminth-free cattle. Seemingly, L3 and SLA were stimulants of eosinophil migration. Further, neutrophil, eosinophil, and macrophage migration was modulated by lymphokines produced by SLA-stimulated lymphocytes from cattle with ostertagiasis.  相似文献   

7.
Possible immunomodulation by low-level infection with Ostertagia ostertagi was studied in 4-month-old calves. Six groups of 4 calves each were subjected to the following regimens: group 1--nonparasitized controls; group 2--nonparasitized, but challenge exposed at day 64 with Brucella abortus strain 19 vaccine (BA) and at day 78 with IV administration of a soluble third-stage larval (L3) antigen preparation of O ostertagi (OAG); group 3--nonparasitized, but challenge exposed at day 78 with 75 x 10(3) L3 of O ostertagi; group 4--continuously parasitized by weekly dosing with 30 x 10(3) L3 of O ostertagi; group 5--continuously parasitized by weekly dosing with 30 x 10(3) L3 of O ostertagi, then challenge exposed on day 64 with BA and on day 78 with IV inoculation of OAG; and group 6--continuously parasitized by weekly dosing with 30 x 10(3) L3 of O ostertagi, then challenge exposed on day 78 with 75 x 10(3) L3 of O ostertagi. Over the initial 10 weeks of the study, nonparasitized calves, (groups 1, 2, and 3) had higher body weight, blood lymphocyte (BL) response to phytohemagglutinin (PHA), and significantly (P less than 0.05) higher feed consumption and lymphocyte numbers, whereas parasitized calves (groups 4, 5, and 6) had higher BL responses to pokeweed mitogen (PWM) and significantly (P less than 0.05) higher neutrophil and eosinophil numbers, plasma pepsinogen (PP) values, and BL response to OAG.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
Calves infected orally with third stage larvae of Ostertagia ostertagi or infected with adult O ostertagi by direct transplantation into the abomasum had raised plasma pepsinogen activity, as did four-year-old dairy cattle challenged with O ostertagi third stage larvae on five occasions. Using fast protein liquid chromatography two forms of pepsinogen; pepsinogen 1 (PG1) and pepsinogen 2 (PG2) were identified in each of the parasitic infection regimes.  相似文献   

9.
Yearling cattle in Louisiana were examined at monthly intervals for abomasal nematode burdens and histological lesions over a year. Tracer calves were grazed for 3 to 4 weeks and removed from pasture for 2 to 3 weeks, then slaughtered; a few animals were killed in extremis shortly after removal from pasture. Histological changes were correlated with worm burdens and characterized according to the type of Ostertagia ostertagi infection present. In cattle with acute Type I ostertagiasis, changes varied from eosinophil infiltration to glandular dilation and slight mucous cell hyperplasia with submucosal edema. During the summer months the cattle had worm burdens that were primarily early 4th stage larvae (EL4), with changes characterized by minimal glandular dilation and mucous cell metaplasia and moderate lymphoid cell proliferation and with intramucosal migration of EL4. In the autumn, the maturation of EL4 produced the Type II syndrome with severe glandular changes, prominent mucosal hyperplasia and marked lymphoid cell accumulation. With increased duration of the pre-Type II interval, there was greater development of the subepithelial lymphoid tissue and increased frequency of epithelial globule leukocytes. The lymphoproliferation which occurred during the prolonged pre-Type II interval appeared to be related to the increased severity and mortality seen with the Type II ostertagiasis syndrome.  相似文献   

10.
In separate experiments, the immune status of six matched pairs of yearling heifers from a field trial in which both parasitic gastroenteritis and husk had occurred in control animals, was tested with a single massive challenge of either Dictyocaulus viviparus or Ostertagia ostertagi. The clinical responses of untreated controls and animals that had carried an oxfendazole pulse release intraruminal device (OPRB) were in all cases similar (with the exception of one lung-worm-challenged control that succumbed to a fulminating pulmonary hypersensitivity reaction), indicating that both groups possessed comparable degrees of protection. Faecal larval/egg-output data and serum gastrin levels, however, suggested that larger worm populations had established in the OPRB cattle.  相似文献   

11.
The efficacy of fenbendazole (Panacur, Hoechst-Roussel) against inhibited early fourth-stage larvae of Ostertagia ostertagi and other nematodes of the abomasum and intestinal tract was investigated in naturally infected, yearling cattle in April 1978. The time when peak levels of inhibited larvae occurred was determined by epizootiologic study which began in November 1977. All animals were removed from pasture and maintained free from further helminth infection until slaughter (19 to 21 days). The fenbendazole liquid suspension was administered as an oral drench at dose level of 10 mg/kg to 10 animals and then at dose level of 15 mg/kg to an additional 10 animals at 10 days after removal from pasture. Eleven animals were maintained as untreated controls. In cattle given the dose of 10 mg/kg, the following reductions were observed: O ostertagi adults--100%, developing stages--80%, and inhibited larvae--97%; other worm genera in the abomasum and nematodes of the intestinal tract--100%. In the cattle given the larger dose, the following reductions were observed: O ostertagi adults--100%, developing stages--98%, and inhibited larvae--99%; other worm genera in the abomasum and nematodes of the intestinal tract--100%.  相似文献   

12.
The present study reports on the development of a copro-antigen capture ELISA for detecting Ostertagia ostertagi infections in cattle. The ELISA was based on polyclonal rabbit antibodies, which recognize O. ostertagi excretory/secretory antigens (ES). ES antigens are released by the metabolic active stages of the parasite in the abomasum, and passed in the faeces of the host. The detection limit of pure ES material was 30 ng ml(-1) in sample buffer and 125 ng ml(-1) in faecal extract. The test was evaluated using a follow up from six artificially infected calves. Elevated levels of Ostertagia coproantigens could be measured from 21 days after infection, indicating that only the presence of adult parasites can be detected. To evaluate the capacity of the assay to measure levels of infection, three groups of cattle were tested: 38 artificially infected calves, 17 naturally infected first grazing season calves and 16 naturally infected adult dairy cows. Optical densities were significantly correlated to the worm burdens of the animals and the ELISA had an overall sensitivity of 91% and a specificity of 45%. The test gave negative readings for faeces of animals carrying patent mono-infections with Cooperia oncophora.  相似文献   

13.
Two groups of yearling cattle which had been treated with ivermectin either three and eight, or three, eight and 13 weeks after turn out to trichostrongyle contaminated pasture in their first grazing season were exposed in the following season to natural challenge with helminth parasites. To assess their immunity to this challenge each group shared a pasture with parasite naive first season calves. No anthelmintic treatments were administered at any time during the year. Throughout the grazing period the yearlings showed normal respiratory rates, negative faecal lungworm larval counts, and, relative to the calves, low faecal trichostrongyle egg counts. All the first season calves developed patent lungworm infections and on one occasion the mean respiratory rates of each group of calves were significantly greater than those of the yearling cattle. At the end of the grazing period, from early May until late September or October 1986, the cattle were removed from pasture and together with parasite naive controls challenged with either 10 or 22 third stage larvae of Dictyocaulus viviparus/kg bodyweight and necropsied between 18 and 23 days later. Although the experimental challenge resulted in relatively heavy lungworm infection of the naive controls, none of the yearlings and only three of the 11 calves which had been at pasture were found to be infected. However, large numbers of arrested fourth stage larvae of Ostertagia ostertagi were present in all the naturally infected yearlings and calves.  相似文献   

14.
Parasite-free, 4-month-old-calves were inoculated with Ostertagia ostertagi and/or Trichostrongylus axei, followed 6 weeks later by inoculation with increasing doses of O ostertagi for 8 weeks in the 2 groups (n = 4) of calves that had been given O ostertagi. Gastrin immunoreactivity concentration in serum was measured before and after infection and was correlated with changes in mucosal thickness. Gastrin immunoreactivity concentration in preinoculation control sera ranged from 95.2 to 287.1 pg/ml, and increased values were measured in all parasitized calves after 15 weeks. Significantly (P less than 0.05) increased serum gastrin immunoreactivity concentration compared with the preinfection value, was found in calves infected with O ostertagi or T axei, and highly significant (P less than 0.01) values were observed in calves infected with both parasites. Abomasal mucosal hyperplasia was observed in all parasitized calves; increased mucosal thickness and mucosal cross-sectional area were most prominent in calves infected with O ostertagi and T axei.  相似文献   

15.
The duration of the anthelmintic activity of abamectin administered by subcutaneous injection at 200 microg/kg was determined using induced infections of Haemonchus placei, Ostertagia ostertagi, Cooperia spp., and Oesophagostomum radiatum in cattle. Twenty-four Friesian calves, raised under worm-free conditions, were assigned to four groups of six animals using a randomised block design based on bodyweight. One group acted as untreated controls and the other three were treated with abamectin 14, 10 or 7 days before infection. At slaughter, 50-52 days after treatment (36-38 days after infection), efficacy was greater than 98-99% against all the parasite species for the groups challenged 10 and 7 days after treatment, whereas no significant activity could be demonstrated 14 days after treatment.  相似文献   

16.
Ivermectin as an antiparasitic agent in cattle   总被引：2，自引：0，他引：2  
In experimental trials on cattle, ivermectin given SC at 200 micrograms/kg had 95% or better efficacy against adult and immature GI and pulmonary nematodes, including inhibited fourth-stage larvae of Ostertagia ostertagi. Studies of efficacy against ectoparasites revealed nearly 100% efficacy against sucking lice, psoroptic and sarcoptic mange mites and cattle grubs. Safety trials revealed no adverse effects with the recommended dosage, including bulls and pregnant cows. A few grub-infested cattle died from acute esophagitis associated with a host-parasite reaction after ivermectin injection.  相似文献   

17.
Benzimidazole- and levamisole-resistant Ostertagia circumcincta from sheep have been reported from several countries, but there are no reports of anthelmintic-resistant O. ostertagi in cattle, where resistance has been confirmed in controlled trials. The reasons for this may include (1) the biology of the worm, (2) avoidance of drug action by inhibition, (3) host metabolism of drugs, (4) less anthelmintic used in cattle than in sheep, (5) high costs of controlled trials, (6) lack of adequate in vitro tests to detect resistant worms and (7) lack of reporting of anthelmintic failures. Reduced efficacy of the anthelmintics levamisole and thiabendazole to adult O. ostertagi and of modern benzimidazoles to the inhibited L4 larvae has been reported in cattle. This latter effect might, in part, represent a stage-specific expression of resistance. Although anthelmintic resistance in O. ostertagi is not known to be a problem at present, it could potentially become a serious issue.  相似文献   

18.
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   

19.
The anthelmintic efficacy of abamectin (avermectin B1) was evaluated against gastrointestinal nematodes, including Ostertagia ostertagi inhibited larvae and lungworm, in yearling crossbred beef heifers during late spring. The calves were grazed on contaminated pasture for 10 weeks and then held under conditions free of nematode infection for 3 weeks prior to allotment and treatment on 5 June. Thirteen calves were randomly assigned to two groups of six by restricted randomization on body weights; the extra lightest calf was assigned to the non-treated control group. Group 1 calves were treated with abamectin at 200 micrograms kg-1 body weight by s.c. injection and Group 2 calves were not treated; all were killed at 14 days after treatment. Ostertagia ostertagi was present in all controls; arithmetic mean numbers of adults, developing fourth stage larvae (L4) and inhibited EL4 were 7683, 605 and 36,102, respectively. Other nematode genera present in controls in sufficient numbers for the experiment were Haemonchus placei adults, Trichostrongylus axei adults, Cooperia spp. adults, Oesophagostomum radiatum adults, Bunostomum phlebotomum adults, Dictyocaulus viviparus adults and E5 (immature adults). Abamectin was highly effective (consistently greater than 99% efficacy and P less than 0.05) in removing all nematodes present in treated calves as represented in non-treated controls, including the primary target of Ostertagia ostertagi inhibited EL4. The lowest efficacy was 93.8%, against D. viviparus E5.  相似文献   

20.
Ostertagia ostertagi soluble antigens were prepared by gel electrophoresis and electrophoretic transfer onto nitrocellulose for enzyme-linked immunosorbent assays with serum probes. Serologic responses to L3-derived antigen of approximately 32 kDa may be unique and diagnostic for cattle harboring inhibited larvae, or pre-Type II ostertagiasis. Specificity was evaluated by comparing sera from pre-Type II cattle to sera from Type I, uninfected, Fascioloides magna infected, Fasciola hepatica infected or Cooperia oncophora infected cattle.  相似文献   

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