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1.
Neutrophil function and mononuclear cell proliferative responses to mitogens were determined in healthy cattle and in cattle persistently infected with bovine viral diarrhea (BVD) virus. Uptake of [3H]thymidine by resting and mitogen-stimulated peripheral blood mononuclear cells was significantly lower in cattle persistently infected with BVD virus than in healthy cattle. Neutrophils from cattle persistently infected with BVD virus had significantly impaired capability to ingest Staphylococcus aureus, but were normal in respect to random migration under agarose, cytochrome C reduction, iodination, and antibody-dependent cell-mediated cytotoxicity. Impairment of neutrophil function in cattle persistently infected with BVD virus differs from impairment of neutrophil function reported in healthy cattle mounting an immune response to recent BVD virus infection.  相似文献   

2.
During the clinical phase of bovine spongiform encephalopathy (BSE), a significant decrease was observed in the ratio of muscle glycogen to plasma L-lactic acid concentrations in BSE infected field case and experimentally infected dairy cattle compared with healthy control cattle (P<0.001), this being due to changes in the concentration of both metabolites in the BSE infected cattle compared with the control group. Furthermore, the concentration of plasma alanine was significantly increased (P<0.05) in the infected animals. No significant difference was detected between these two groups in the ratio of hepatic glycogen to plasma lactate. We infer that BSE infected cattle exhibit signs of altered energy metabolism and when applied in conjunction with changes in other metabolite biomarkers these changes may be useful for discriminating BSE infected cattle from healthy cattle or those suffering with other disorders or diseases.  相似文献   

3.
Teneral tsetse flies infected with either Trypanosoma brucei or T. vivax were fed on healthy cattle. Blood samples collected daily from the cattle were examined by microscopy for the presence of trypanosomes, in thick smear, thin smear and in the buffy coat (BC). All the cattle fed upon by infected tsetse developed a fluctuating parasitaemia. DNA was extracted from the blood of these cattle and subjected to polymerase chain reaction (PCR) using oligonucleotide primers specific for T. brucei or T. vivax. The PCR products unique to either T. brucei or T. vivax were identified following amplification of DNA from the blood samples of infected cattle, whereas none was detectable in the DNA from the blood of the cattle exposed to non-infected teneral tsetse. In a concurrent set of experiments, one of the oligonucleotide primers in each pair was biotinylated for use in PCR-ELISA to examine all the blood samples with this assay. Both the PCR and the PCR-ELISA revealed trypanosome DNA in 85% of blood samples serially collected from the cattle experimentally infected with T. brucei. In contrast, the parasitological assays showed trypanosomes in only 21% of the samples. In the blood samples from cattle experimentally infected with T. vivax, PCR and PCR-ELISA revealed trypanosome DNA in 93 and 94%, respectively. Microscopy revealed parasites in only 63% of the BCs prepared from these cattle. Neither PCR nor PCR-ELISA detected any trypanosome DNA in blood samples collected from the animals in the trypanosome-free areas. However, both assays revealed the presence of trypanosome DNA in a number of blood samples from cattle in trypanosomosis-endemic areas.  相似文献   

4.
Blood samples from 78 cattle were tested for hemoplasma infection using molecular methods. PCR and sequence analysis revealed that 17 cattle were infected with Mycoplasma wenyonii, while 13 were infected with 'Candidatus Mycoplasma haemobos'. Four animals were infected with both species. This is the first study to report hemoplasma species infection among cattle in Japan.  相似文献   

5.
The serum antibody levels to Taenia saginata of three groups of cattle were assessed by an enzyme-linked immunosorbent assay (ELISA). The first group of cattle were from four farms which had a confirmed T saginata cysticercosis outbreak, all of which had cattle classed as infected by ELISA. The second group were from four farms where sewage sludge had been applied to pasture subsequently grazed by the cattle. One of these farms had cattle classed as infected by ELISA. The control cattle, which were all classed as uninfected by ELISA, came from five farms whose pasture had not been treated with sewage sludge. In a wider survey, involving sera from 47 additional farms, the majority could not be distinguished from the control farms in the earlier survey. However, samples from three of the farms had a similar number of positives to two of the known infected farms in the initial survey. Since the ELISA assay may indicate infected herds, farms such as these warrant further investigation.  相似文献   

6.
A dot ELISA was developed for detection of antibodies to Mycobacterium paratuberculosis. The assay was evaluated by testing sera from cattle that were determined, by bacteriologic culturing of feces, to be infected with M paratuberculosis and were suspected of having clinical disease. Further evaluation involved testing sera from cattle in which M paratuberculosis had not been isolated from feces on several attempts. Results of the dot ELISA were positive for sera from 86 of 101 infected cattle, and results were negative for sera from 64 of 64 noninfected cattle. Results of conventional ELISA and agar gel immunodiffusion (AGID) tests were positive for 79 of 99 and for 51 of 101 infected cattle, respectively. The dot ELISA also was evaluated by comparing results of testing 708 sera with results of bacteriologic culturing of matched fecal samples from 262 cattle in 3 central Ohio dairy herds known to include cattle infected with M paratuberculosis. Results of the dot ELISA were positive for 25 of 39 sera from cattle with positive results on culturing of concurrently obtained fecal specimens. The dot ELISA results were negative for 661 of 669 sera from cattle with negative results to culturing of concurrently obtained fecal specimens. The 39 sera from cattle with positive results on bacteriologic culturing of matched fecal specimens had positive results for ELISA and the AGID test 25 and 14 times, respectively. The 669 sera from cattle with concurrently negative results on bacteriologic culturing of feces had negative results to ELISA and the AGID test 559 and 668 times, respectively.  相似文献   

7.
The first case of bovine spongiform encephalopathy (BSE) in Japan was found in September 2001. As a result, national BSE surveillance systems in slaughterhouses and farms were introduced between October 2001 and April 2004. All cattle, with the exception of those under 24 months of age that die at farms, now undergo compulsory testing when they die or are slaughtered. The removal of specified risk material (SRM) from all slaughtered cattle and a ban on the feeding of meat-and-bone meal to all farm animals were implemented in October 2001. However, infected cattle that died or were slaughtered before these measures were put into practice could have been a source of infection to other cattle through the rendering process. The slaughtered cattle could also have been a source of infection to humans via SRM that entered the food chain. The purpose of this study was to estimate the number of BSE-infected cattle that could have been a source of infection to cattle and humans before October 2001. Since all typical cases were dairy cattle, this study focused on the dairy cattle population. We developed a simulation model to obtain the year of death and the final disposition of infected cows born in each year from 1996 to 2001. In this model, the dairy cattle population was divided into birth cohorts, and parameters regarding its population dynamics were assumed to be constant. Using this model, the total number of infected cattle in each birth year was estimated by maximum likelihood estimation using data on the number of detected cases from 2002 to 2006. Finally, the number of infected cattle that died or were slaughtered each year was estimated by Monte-Carlo simulation using the same model with the total number of infected cattle estimated by maximum likelihood estimation. It was estimated that the majority of infected cattle that could have been sources of infection before 2001 were born in 1996. The total number born in 1996 was estimated to be 155 (95% confidence interval: 90-275). Of these 155 cattle, 56 died or were slaughtered before October 2001, after the accumulation of infectious agent in their bodies. Only 5 of these 56 cattle were estimated to have been slaughtered. Therefore, the number of infected cattle that could have served as a source of human infection would appear to have been a very limited subset of the BSE-infected cattle in Japan.  相似文献   

8.
OBJECTIVE: To evaluate the efficacy of a commercially available killed bovine viral diarrhea virus (BVDV) vaccine to protect against fetal infection in pregnant cattle continually exposed to cattle persistently infected with the BVDV. ANIMALS: 60 crossbred beef heifers and 4 cows persistently infected with BVDV. PROCEDURES: Beef heifers were allocated to 2 groups. One group was vaccinated twice (21-day interval between the initial and booster vaccinations) with a commercially available vaccine against BVDV, and the other group served as nonvaccinated control cattle. Estrus was induced, and the heifers were bred. Pregnancy was confirmed by transrectal palpation. Four cows persistently infected with BVDV were housed with 30 pregnant heifers (15 each from the vaccinated and nonvaccinated groups) from day 52 to 150 of gestation. Fetuses were then harvested by cesarean section and tested for evidence of BVDV infection. RESULTS: 1 control heifer aborted after introduction of the persistently infected cows. Bovine viral diarrhea virus was isolated from 14 of 14 fetuses obtained via cesarean section from control heifers but from only 4 of 15 fetuses obtained via cesarean section from vaccinated heifers; these proportions differed significantly. CONCLUSIONS AND CLINICAL RELEVANCE: A commercially available multivalent vaccine containing an inactivated BVDV fraction significantly reduced the risk of fetal infection with BVDV in heifers continually exposed to cattle persistently infected with BVDV. However, not all vaccinated cattle were protected, which emphasizes the need for biosecurity measures and elimination of cattle persistently infected with BVDV in addition to vaccination within a herd.  相似文献   

9.
Radioimmunoassay for Anaplasma marginale antibodies in cattle   总被引：2，自引：0，他引：2  
A radioimmunoassay is described for use in the detection of Anaplasma marginale antibodies in cattle sera. Optimal sensitivity and specificity were obtained by using 2 antigens, an A marginale antigen and a RBC antigen (obtained before infection was established) from the same calf. In addition, sera were preabsorbed with RBC from healthy cattle and with sonicated Babesia bovis. Of 86 sera obtained from cattle with A marginale infection (as determined by blood smear examination or by results of subinoculation of blood from such infected cattle into splenectomized calves), 85 had positive results by use of this test. Of 100 sera obtained from cattle raised in an anaplasmosis-free area, 98 yielded negative results, and sera obtained from 35 cattle (97 sera) infected with B bigemina and from 18 cattle infected with Theileria orientalis yielded negative results. By use of this test, 99 of 100 sera obtained from cattle with B bovis infection were negative for A marginale. Anaplasma marginale antibodies were detected in 18 cattle that had been pastured in a Boophilus microplus-free area for 2 years after natural infection. After 3 years, 16 of these cattle were still seropositive for A marginale. Sixteen cattle pastured in a Bo microplus-infested area had detectable antibody against A marginale 27 months after initial infection with A marginale. Sensitivity and specificity of the test were assessed as 98.8% for each.  相似文献   

10.
Cattle persistently infected with bovine viral diarrhea (BVD) virus have decreased neutrophil and lymphocyte functions. We reevaluated these functions and further characterized the inhibition of persistent BVD virus infection in neutrophils, using sensitive kinetic assays. In addition, the influence of in vitro incubation of neutrophils with recombinant bovine interferon gamma (rBoIFN gamma) and in vitro incubation of lymphocytes with recombinant bovine interleukin-2 was evaluated. Significant (P less than 0.05) decrease in random migration under agarose, Staphylococcus aureus ingestion, cytochrome-C reduction, iodination, antibody-independent cell-mediated cytotoxicity, oxidant production, and cytoplasmic calcium flux were observed in neutrophils from cattle persistently infected with BVD virus, compared with noninfected control cattle. Incubation of neutrophils from noninfected controls with rBoIFN gamma significantly (P less than 0.05) decreased random migration under agarose, cytochrome-C reduction, and cytoplasmic calcium flux. Neutrophils from cattle persistently infected with BVD virus also had decreased random migration under agarose after incubation with rBoIFN gamma; in addition, antibody-independent cell-mediated cytotoxicity, elastase release, and cytoplasmic calcium flux were significantly enhanced. The rBoIFN gamma induced significantly (P less than 0.05) different effects on chemotaxis, cytochrome-C reduction, iodination, and cytoplasmic calcium flux of neutrophils from infected and control cattle. The rBoIFN gamma was more effective at improving the function of neutrophils from cattle persistently infected with BVD virus, compared with neutrophils from controls. Lymphocytes from infected cattle had decreased blastogenesis in response to phytohemagglutinin, concanavalin A, and pokeweed mitogen.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
Most researchers in South Africa found that although BT virus could be isolated from apparently healthy cattle and from inoculated cattle the virus did not produce overt clinical disease in cattle. However, when epizootics were reported outside Africa, clinical signs were observed in cattle in Israel, Palestine, Syria, Portugal, and Spain. Most natural BT infections in cattle in the United States do not result in overt clinical signs. However, in certain infected herds, approximately 5% of the cattle show from mild to severe disease. Except for severe cases, spontaneous recovery is usual. The clinical diagnosis of BT in cattle is difficult and requires laboratory assistance. Culicoides variipennis can serve as a vector of BT virus from cattle to cattle, cattle to sheep, sheep to cattle, and sheep to sheep. In utero transmission occurs in cattle and can result in abortion, hydraencephaly, congenital deformity, and birth of viraemic calves which may or may not develop BT antibody. Calves inoculated in utero or those born to infected dams may have a persistent viraemia with or without BT antibody. tone such animal has been held in insect-secure quarters and has continued to harbour virus for 3 years. Bluetongue virus was isolated from the semen of experimentally infected bulls. Calves inoculated with BT virus and also given an immuno-suppressant developed marked clinical disease in 8 to 12 days. Bluetongue virus is very closely associated with the erythrocytes of infected cattle, sheep, and goats. Cattle are considered important and relatively long-term virus reservoirs. In attempts to determine the maximum period of viraemia in cattle it is necessary to inoculate washed erythrocytes, rather than whole blood, and to use susceptible sheep as the assay system rather than embryonated chicken eggs.  相似文献   

12.
Results of a double agar gel immunodiffusion (Ouchterlony) test that contained a polysaccharide (poly-B) antigen of Brucella melitensis strain B115 were compared with those of 5 other serotests. To determine the sensitivity and specificity of the immunodiffusion, standard tube, 2-mercaptoethanol, Rivanol, card, and complement fixation tests, sera obtained from 1,328 vaccinated, infected, and seronegative cattle, 56 of which had been examined bacteriologically, were used to evaluate the humoral response to Brucella sp. The poly-B antigen confirmed infection in 87.5% of the 56 cattle from which Brucella abortus biotype 1 had been isolated, and in 96.6% (205/212) of a group of cattle suspected to be infected on the basis of results of conventional serotests. Likewise, sera from 4 groups of vaccinated cattle did not react with poly-B antigen, whereas they did react in conventional tests. The poly-B antigen was more specific in detecting infected cattle even in a group of vaccinated adults. A useful strategy to identify infected cattle might be screening, using a combination of the Rivanol and card tests together with the agar-gel immunodiffusion test containing poly-B antigen.  相似文献   

13.
A simple ELISA is described for quantifying expression of bovine leukaemia virus (BLV) antigens in short-term cultures of peripheral blood lymphocytes (PBL) isolated from infected cattle. The PBL-ELISA demonstrated that antigen expression levels in infected cattle could vary by more than 50-fold. Inoculation of sheep with dilutions of lymphocytes from two BLV-infected cattle, differentiated in the PBL-ELISA by 50 to 100-fold, suggested that antigen expression levels were correlated with infectivity. Haematological data indicated that increased antigen expression in PBL cultures was associated with an increased number of circulating B-lymphocytes, irrespective of whether or not an animal had lymphocytosis. This supported the hypothesis that BLV-infected cattle that are PBL-ELISA positive are more infectious and may present a greater risk of transmitting the disease. The applicability of the PBL-ELISA to a field situation was assessed with 98 BLV-infected cattle from three commercial dairy herds with infection prevalences of 11%, 23% and 47%. Similar percentages (49%, 50% and 52%) of PBL-ELISA positive cattle were identified among those infected cattle available for testing in the three herds. An additional 22 infected cattle from an experimental herd were tested to assess the stability of antigen expression levels over an 8 month period. Fewer (27%) of these cattle were identified as PBL-ELISA positive and antigen expression levels were generally lower than those observed in the commercial herds. Antigen expression levels in the experimental herd remained stable over the period of the study. The potential of the PBL-ELISA to assist in BLV eradication programs by identifying those seropositive cattle with the greatest potential to transmit infection is discussed.  相似文献   

14.
This study investigated the immunoglobulin isotype responses of sheep and cattle chronically infected with Fasciola hepatica and Fasciola gigantica to adult F. hepatica excretory/secretory products (Fh-ES) or F. gigantica excretory/secretory products (Fg-ES), respectively. An antibody enzyme-linked immunosorbent assay (Ab-ELISA) was used to determine serum antibody (total Ig, IgG(1), IgM, IgG(2) and IgA) responses. At necropsy, the mean number of flukes recovered was lower in cattle than in sheep. All F. hepatica and F. gigantica infected sheep and cattle showed an increased total Ig levels from 3 to 4 weeks post-infection (wpi). Among isotypes IgG(1) was most dominant while IgM was the earliest (2 wpi) to be detected in both sheep and cattle infected with both F. hepatica and F. gigantica animals. IgG(2) response was early (2 wpi) in sheep infected by F. hepatica but there was no response in sheep infected with F. gigantica. There was a late and strong IgG(2) response in cattle infected with both flukes. The IgA isotype showed an early and a clear biphasic response in sheep with F. hepatica but was less pronounced in F. gigantica infected sheep. While IgA response to Fh-ES was noticed 5 wpi in F. hepatica infected cattle, it appeared much later (21 wpi) in those infected with F. gigantica. The dominance of IgG(1) isotype in infected sheep and cattle suggest an associated Th2 response. This early response to adult Fasciola spp. ES antigen suggests an early exposure to the antigen presumably through the cross-reacting ES products of juvenile flukes. There is clearly difference in IgG(2) isotype response in cattle (resistant) compared to sheep (susceptible). The late IgG(2) response in cattle may suggest late Th1 involvement in bovine cellular responses to adult Fh-ES/Fg-ES.  相似文献   

15.
Aim: To discover whether cross infection between red deer (Cervus elaphus) and cattle is possible with either a bovine isolate of the cattle lungworm, Dictyocaulus viviparus, or with a cervine isolate of the lungworm, Dictyocaulus eckerti which is thought to be maintained primarily in deer. Method: Twelve cattle and 12 red deer were reared parasite-free from birth. At 3-4 months of age, half of each species (n=6) were experimentally infected with D. viviparus and the other half with D. eckerti. The course of infection was monitored for 34 days, after which the animals were slaughtered and the lungs removed to assess levels of infection. Results: Faecal larval counts demonstrated that patent Dictyocaulus infections occurred in all groups. At necropsy, adult worms were found in the lungs in all groups except the cattle that were infected with D. eckerti. The largest numbers of adult worms were found in the red deer infected with D. eckerti. Conclusion: It was demonstrated that both cattle and red deer could be infected with either D. viviparus or D. eckerti. However, D. eckerti larvae that originated from deer established more successfully in deer and D. viviparus larvae that originated from cattle established more successfully in cattle.  相似文献   

16.
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   

17.
The aim of this study was to determine the population of ticks in infected cattle and to identify the tick vectors of bovine theileriosis in an endemic area of Iran from 1998 to 1999. A total of 120 suspected cattle suffering from theileriosis were clinically examined and investigated for the presence of Theileria annulata in blood smears and the presence of any tick species on the body of cattle. In this study, 680 ticks were collected from 107 cattle infected with T. annulata. The prevalence of ticks infesting cattle was 92.35% Hyalomma anatolicum excavatum, 5.14% H. marginatum marginatum, 1.17% H. asiaticum asiaticum and 1.32% Rhipicephalus sanguineus. The examination of 510 tick salivary glands revealed that 51% of H. a. excavatum and 1.3% of H. a. asiaticum were infected with sporozoites of T. annulata.  相似文献   

18.
A 'dipstick' immunoassay for bovine cysticercosis, using an antigen isolated from Taenia hydatigena cyst fluid, was evaluated in cattle experimentally infected with Taenia saginata. The assay correctly identified six out of seven infected cattle, including an animal in which only 12 living cysticerci were found. Cattle became seropositive as early as 3 weeks post-infection. A false-negative reaction was found for one very lightly infected animal, from which only four living cysticerci were recovered at necropsy. The assay was also used to detect circulating antibodies in experimentally infected cattle before and after therapeutic treatment with anthelminthics. The results suggest that praziquantel-treated animals gradually revert to being seronegative after the cysticerci are killed.  相似文献   

19.
Brucella abortus strain 19 salt-extractable proteins fractionated by differential ammonium sulfate precipitation were used in a western blotting method to detect bovine immunoglobulin G antibodies to B. abortus. Sera from infected cattle and from cattle vaccinated with strain 19 and subsequently exposed to virulent B. abortus bound to a common group of antigens ranging in molecular weights from 31,000 to 45,000 daltons. Immunoglobulin G antibodies in sera from the latter group in addition also bound to antigens with molecular weights of 66,000 to 71,000 daltons. Some sera from cattle vaccinated when sexually mature reacted similar to those from infected cattle, while immunoglobulin G antibodies in sera from Brucella-free cattle and vaccinated calves did not bind to either group of antigens. In general, fractionation of the proteins by ammonium sulfate precipitation offered no advantage for detecting differences between groups of sera. Ammonium sulfate fraction 0 to 35% reacted with a larger number of sera from a naturally infected group than fraction 0 to 70%. Both fractions reacted equally well with sera from the other groups of cattle, while fractions 35 to 70% and 70 to 100% reacted poorly in this technique. The attractive feature of the blot is that sera from calfhood-vaccinated cattle did not react.  相似文献   

20.
In controlled experiments in an insect-free stable, cattle became infected with Parafilaria bovicola when Musca lusoria, infected with the larvae of this worm, were allowed to feed on a fresh skin incision, and when infective larvae were placed on fresh skin incisions, injected subcutaneously or into the jugular vein, or instilled into the eyes. The sites of blood spots caused by ovipositing P. bovicola females and the sites of carcass lesions were seldom close to the site of infection, an indication that the worms had migrated. The prepatent period of P. bovicola in 4 cattle which developed blood spots ranged from 242--319 days. Neither of the infected cattle that were kept continuously in a shady stable showed blood spots, but 4 out of 7 infected cattle which spent some time in the sun bled. However, carcass lesions on shaded cattle were similar in appearance to those on cattle kept outdoors. Infective larvae were stimulated to escape from the mouth-parts of infected M. lusoria and Musca xanthomelas s.s. when these were fed citrated ox blood warmed to 38--40 degrees C. No escape took place when the flies were fed warmed saline or warmed 15% sucrose solution.  相似文献   

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