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1.
Hay infected with Mycoplasma mycoides sub-species mycoides (M mycoides) was fed to six animals on three occasions. Five animals developed complement-fixing antibody in their sera and gave a positive reaction to the comparative intradermal allergic test. No animal died from contagious bovine pleuropneumonia (CBPP) but when they were killed, three had unequivocal lesions of the disease. M mycoides was isolated from the animals with these lesions but not from the others. CBPP was transmitted to two animals put in contact with those animals showing disease, and M mycoides was recovered from lesions in both animals. It is suggested that when unexplained outbreaks of CBPP occur, the possibility of indirect transmission should be considered.  相似文献   

2.
The pneumonic lungs of 42 cattle from 26 feedlots were examined for the presence of mycoplasma, pathogenic bacteria and viruses. Four animals representative of two lots failed to yield mycoplasma. One of these yielded the virus of infectious bovine rhinotracheitis and Pasteurella hemolytica, the other yielded only P. P. multocida. Nine animals in eight lots yielded Mycoplasma sp.: five of these were M. bovirhinis, two were M. arginini and two were untypable. All of these animals yielded one or more of P. hemolytica, P. multiocida, infectious bovine rhinotracheitis virus or bovine virus diarrhea virus. Twenty-five of 29 animals in 16 lots yieled M. agalactiae subsp. bovis from lung tissues. The same organism was recovered from the arthritic joints of 12 of these animals. Eight of the 25 animals yielded no other pathogen and all of these had not received any treatment. Nine of the 25 M. agalactiae subsp. bovis positive animals also yielded one or more of P. hemolytica, P. multocida, Corynebacterium pyogenes or infectious bovine rhinotracheitis virus. Bacteriological and virological studies were not completed for the remaining eight of the 25 positive animals. In five lots of cattle which had not received medication for pneumonia and for arthritis only M. agalactiae subsp. bovis was recovered. Twenty-five grossly normal lungs obtained from normal cattle at the time of slaughter were cultured and all were negative. The possible role of M. agalactiae subsp. bovis in pneumonia and arthritis was discussed.  相似文献   

3.
The bacteriologic, immunologic, and clinical responses of 3- to 4-month old Holstein-Friesian calves to experimental exposure with Moraxella bovis type 10900 has been investigated. After u.v. radiation and intraconjunctival exposure with 1.9 × 107 microorganisms, each eye of 16 calves exhibited signs of blepharospasm, photophobia, and increased lacrimation. Bacteria were recovered from exposed eyes for 2–7 consecutive weeks before maximal clinical response occurred. The severity of the cases varied from eyes that exhibited mild signs to severe clinical cases with profuse lacrimation, conjunctival swelling, corneal opacity, and ulceration. By 70 days after exposure, M. bovis could not be recovered from any conjunctival swabs, and clinical signs were not observed. Four non-exposed control animals did not develop clinical signs nor was M. bovis recovered from conjunctival swabs.Lacrimal secretions collected at the time of and 1 week after maximal clinical response had significantly elevated levels of total protein as compared to those collected 3, 2, and 1 week before, and 2 and 3 weeks after maximal clinical response. A passive hemagglutination test, using tanned formalized sheep erythrocytes sensitized with M. bovis sonicate antigen, detected antibody in lacrimal secretions from 22 of 32 eyes. The appearance of specific antibody in lacrimal secretions correlated with the amelioration of clinical signs and the decline in numbers of M. bovis microorganisms recovered from conjunctival swabs.  相似文献   

4.
Infectious bovine keratoconjunctivitis: contact transmission   总被引：1，自引：0，他引：1  
The transmission of Moraxella bovis was studied in calves in the absence of the face fly (Musca autumnalis) or environmental conditions that might insult the eye. Thirty calves were placed in 10 groups of 1 experimentally infected calf and 2 contact calves each. Over 40 days, only 1 eye in 1 contact calf developed clinical infectious bovine keratoconjunctivitis. The organism was recovered in only 8 of 20 contact calves, whereas infection and disease occurred in all experimentally infected calves. Transmission of M bovis occurring in the absence of some other intervening factor was probably of minimal importance. Seemingly, herd preventive treatment would be most effective when flies and environmental factors are at a minimum.  相似文献   

5.
Natural infection of red deer with bovine tuberculosis   总被引：2，自引：2，他引：0  
Six bovine tuberculosis-free red deer hinds were introduced in October 1993 to a 1.8 ha enclosure, within a larger field study site known to contain tuberculous possums, and kept there for 9 months. A Mycobacterium bovis-infected possum was found in the vicinity of the deer enclosure 3 weeks after the introduction. Subsequently, a further eleven infected possums were found in the area. The deer were monitored by repeated composite antibody detection ELISA and lymphocyte transformation assays for tuberculosis, interpreted in parallel, by skin testing and by routine culturing of samples collected from potential excretion sites. Lymphocyte transformation assay evidence of M. bovis infection in four hinds was first observed 4 months after introduction. One other hind became bovine tuberculin lymphocyte transformation assay positive in the 5th month. Positive or equivocal bovine reactivity remained evident at most test episodes. A comparative cervical skin test performed in July 1994, shortly before slaughter, was positive in these five hinds. Mycobacterium bovis was recovered off swabs from the oropharyngeal tonsils of two hinds during routine sampling. Detailed necropsy of the six deer revealed a single typical tuberculous lesion in only one, but culturing of various tissue specimens ascertained that the five blood test and comparative cervical skin test-positive animals were all infected. Mycobacterium bovis was cultured from the oropharyngeal tonsils of four and medial retropharyngeal lymph nodes of two of the deer with no typical gross lesions. Six additional tuberculosis-free hinds were introduced to the enclosure in April 1994 and kept there for 12 months. Four of these animals showed a positive lymphocyte transformation assay response to M. bovis after 9 weeks, but no significant reactivity thereafter. Concurrent observational studies suggest that five of the first six deer probably became infected through close inspection and investigation of the tuberculous possums, although the possibility of deer-to-deer transmission cannot be totally excluded. The likely deer-possum contact, and thus exposure to M. bovis, was related to the curiosity and social ranking of the hinds. The second group appear to have had transient exposure to M. bovis, possibly caused by direct contact with the infected hinds introduced earlier. This group never showed any curiosity toward, or interaction with, possums during the periods of observation.  相似文献   

6.
To assess the rabbit as a model for the study of paratuberculosis infection, two groups of newborn rabbits were orally inoculated at one to two days of age with Mycobacterium paratuberculosis (ATCC 19698 or field strain 22206) and compared to uninoculated controls. Nine of thirteen rabbits (69%) inoculated with ATCC 19698, and all three rabbits inoculated with 22206, experienced episodes of intermittent diarrhea starting four months after inoculation. Multifocal granulomas containing acid-fast organisms were observed in the sacculus rotundus and vermiform appendix of the cecum in three of nine rabbits (all with diarrhea) that had been inoculated with ATCC 19698. Although M. paratuberculosis was not recovered from inoculated rabbits when fecal cultures were incubated three months in vitro, a slow-growing mycobactin-dependent form of Mycobacterium was recovered from feces and ileal tissue after incubation for 11-15 months. Reduced feed intake, body weight loss and reduced abdominal fat at necropsy, were not observed. Epithelial transport function across the distal ileum in vitro was not altered nine months subsequent to inoculation. Diarrhea and the histological lesions indicate that the rabbit may be a useful model for the study of paratuberculosis infection.  相似文献   

7.
Experiments were undertaken in six Holstein-Friesian cattle to determine whether secretory IgA (SIgA) could be transported from serum into exocrine body fluids. Preliminary data indicated that when IgG1, IgG2, IgM and SIgA were administered i.v., only SIgA and IgG1 appeared in bile 90 min later at concentrations equal to or exceeding those in serum at the same time. Two hours post-injection, 70% of the SIgA recovered in bile was intact however only 30% co-precipitable with anti-secretory component (SC) while >90% of the administered IgA was precipitated by this method. All recovered IgG1 was of low molecular weight. More detailed studies indicated that the IgA recovered in bile 7 h post-injection or in milk 3 h post-injection, was predominately lower molecular weight than intact SIgA. Most of this low molecular weight radioactivity was TCA precipitable and ca 50% was dialyzable; these data indicate that TCA-precipitability is an inadequate criterion for determining whether intact SIgA is transported. The radioactivity recovered in parotid saliva was almost entirely non-TCA precipitable and dialyzable. Almost all SIgA recovered in bovine serum remained intact and had a of 15.7 h. When transport into milk and bile was calculated from total, recovered radioactivity (i.e. 29% and 2.7, respectively), data compared favorably with those conducted in sheep in which dimeric IgA (without SC) was administered i.v. When we calculated transport on the basis of recovered intact IgA, only 1.47 and 0.54% of the injected dose had been transported into milk and bile, respectively, 24 h later. Most IgA in ruminant bile may be of serum origin although the same appears to be unlikely for the IgA in milk.  相似文献   

8.
Infectious bovine keratoconjunctivitis is a common and highly contagious ocular disease affecting cattle worldwide. The tremendous economic losses attributable to this disease warrant continued investigation into methods of prevention. Multiple virulence factors have been linked to the primary aetiologic agent, Moraxella bovis. Efforts to develop an efficacious vaccine have primarily focused upon the use of surface pili or cytolysin to stimulate host immunity; however, M. bovis possesses other virulence determinants that include proteases, fibrinolysins, phospholipases and other cell surface components such as outer membrane proteins. These potentially conserved antigens provide additional possibilities for vaccine development. Examination of appropriate antigen presentation is necessary to attain an adequate immune response. Further, the potential for antigenic diversity as well as epitope conversion requires continuous epidemiological surveillance of isolates recovered from outbreaks. Current work targeting conserved immunogens provides hope for efficacious vaccines that when used in tandem with proper management may control, if not prevent, infectious bovine keratoconjunctivitis.  相似文献   

9.
The response of isolated tracheal and bronchial strips to isoproterenol in vitro was studied in eleven male Jersey calves. Clinical, microbiological and pathological evaluations of the calves were carried out. In calves exposed once or twice to infectious bovine rhinotracheitis virus, the relaxation threshold of the trachealis muscle to isoproterenol was significantly (p less than 0.05) impaired (threshold 5.0 X 10(-7) M, single exposure and 1.0 X 10(-7) M, double exposure), when compared with uninfected controls (threshold 1.0 X 10(-8) M). Single infection significantly impaired tracheal relaxation to isoproterenol doses from 1.0 X 10(-7) to 5.0 X 10(-4) M, and double infection significantly impaired tissue responses at drug doses from 1.0 X 10(-7) to 1 X 10(-4) M. Bronchial relaxation threshold was not significantly inhibited (p less than 0.05) in singly infected or doubly infected animals (threshold 5.0 X 10(-8) M and 1.0 X 10(-8) M, respectively), when compared with uninfected controls (threshold 1.0 X 10(-9) M). Single infection significantly impaired bronchial relaxation at isoproterenol doses from 1.0 X 10(-7) M to 5.0 X 10(-6) M while double infection significantly impaired relaxation only at 5.0 X 10(-7) M. The disruption of normal homeostatic bronchodilatory mechanisms may predispose animals infected with infectious bovine rhinotracheitis virus to secondary bacterial infections due to excessive airway constriction and subsequent compromise of lung defenses.  相似文献   

10.
Studies on the pathogenesis of epizootic bovine abortion   总被引：2，自引：0，他引：2  
Ornithodoros coriaceus Koch ticks were fed on 37 pregnant cows. The fetuses were obtained from the cows at 23 to 126 days after maternal tick exposure. Characteristic lesions of epizootic bovine abortion were observed only in those fetuses recovered 100 days more or after maternal tick exposure. Fetuses collected between 50 and 100 days showed mild-to-moderate lymphoid and mononuclear cell hyperplasia. Reaction in fetuses studied less than 50 days after maternal tick exposure were mild. Lesions could not be seen in 2 of the youngest fetuses. Increases in serum immunoglobulin concentrations were present only in those fetuses examined 80 days or more after their dams had been exposed to ticks. The specificity of the immunoglobulins could not be determined. Sera from 12 fetuses tested failed to fix complement in tests for group-specific chlamydial antibodies. A wide variety of microbiological cultivation attempts were made to recover the causative agent of epizootic bovine abortion from these fetuses; however, no agent was recovered regularly, and chlamydial organisms were not recovered from any. The significance of 2 recovered agents, apparently viral, is still to be determined. Fetal tissues, both frozen and fresh, collected from fetuses of dams exposed to a feeding of ticks were capable of reproducing the disease after inoculation into pregnant cows or directly into fetuses.  相似文献   

11.
Four isolates of bovine adenovirus type 4 were recovered from Oregon cattle. One isolate was recovered from a 1-week-old calf with pneumoenteritis, and 1 isolate from an 8-month-old bull with fever and respiratory disease. Two isolates were recovered as latent viruses in testicular cell cultures. All 4 isolates of the virus were shown to have certain physical, chemical, biologic, and antigenic characteristics similar to previously described strains of bovine adenovirus type 4. Of 246 adult beef and dairy cattle in Oregon, 51% had serum-viral neutralizing antibodies to the type 4 virus at the 1:8 dilution level.  相似文献   

12.
Bovine viral diarrhea virus (BVDV) has been segregated into two genotypes, type 1 and type 2. To determine the efficacy of the commercially available bovine viral diarrhea type 1 vaccine used in Japan against BVDV type 2, calves were infected with BVDV type 2 strain 890 4 weeks after administration of the vaccine. The vaccinated calves did not develop any clinical signs and hematological changes such as observed in unvaccinated calves after the challenge. Furthermore, the challenge virus was not recovered from the vaccinated calves throughout the duration of the experiment, whereas it was recovered from all unvaccinated calves. The bovine viral diarrhea vaccine used in Japan is efficacious against infection with BVDV type 2 strain 890.  相似文献   

13.
The objective of this study is to examine the expression of Mannheimia haemolytica genes over time during the early stage of infection. In addition, gene expression at different sites of infection in the bovine host was examined. A time-course experiment was designed to collect pharyngeal swabs and lung washings from the same animals over two time points. Six calves were experimentally challenged with M. haemolytica A1; pharyngeal swabs were collected from all animals 5h post infection. Three calves were euthanized at 6h; pharyngeal swabs were collected from the remaining 3 calves at 12h and the calves were euthanized. Lung washings were recovered from all animals at necropsy. Total RNA was prepared from the pharyngeal swabs and lung washings and primers for eight well characterized virulence-associated genes were used in qRT-PCR to examine mRNA levels. The expression of key virulence genes such as lktA, gcp and tbpB was higher in vivo compared to in vitro with the highest changes observed from 6 to 12h. The expression of lktA and gapA increased while expression of fbpA, gs60, nmaA and tbpB was found to decreased over time in the 6h period. Gene expression profiles in the lungs versus the pharynx also differed, with most genes (fbpA, tbpB, nmaA, gs60, lktA and narP) showing higher expressing in lung washings. This is the first study to follow gene expression by M. haemolytica in the same animal over time during an infection.  相似文献   

14.
This experiment was performed to clarify relationships between conditions of bovine ovaries and developmental capacity of the follicular oocytes recovered from them and to compare two methods of oocyte collection, aspiration and mincing. Follicular oocytes with surrounding intact, unexpanded cumulus recovered by follicular aspiration or by mincing of tissue from 24 pairs of ovaries were matured and fertilized in vitro. The number of follicular oocytes recovered from pairs of ovaries averaged 32.1 +/- 3.2, but the number recovered varied greatly among the 24 pairs of ovaries (range, 7 to 71). The overall rate of development to the blastocyst stage was 18% (137/771), and the average number of blastocysts produced from a pair of ovaries was 5.7 +/- 1.1 (range, 0 to 17). No relationships were found between the presence of corpora lutea or large follicles and the proportion of oocytes capable of reaching the blastocyst stage in vitro. However, a positive correlation was observed between the number of oocytes obtained from each pair of ovaries and subsequent in vitro development; the correlation was especially high for oocytes obtained by aspiration. These data suggest that the developmental capacity of bovine follicular oocytes after in vitro maturation and fertilization is correlated to the number of antral follicles aspirated from the pair of ovaries.  相似文献   

15.
Holstein/Friesian embryos, progeny of citrullinaemia heterozygotes, were transferred to recipient cows. The citrullinaemia genotype of the fetus/calf was established, at birth, by estimation of citrulline concentration in plasma or by analyses of argininosuccinate synthetase exon 5 sequences in dna from blood leucocytes. Between 115 and 125 days of gestation amniotic fluid was collected transabdominally from nine recipient cows. The mean citrulline concentration in amniotic fluid from fetuses unaffected with citrullinaemia was 28 μM, SD 9 and range 15 to 38 μM. Citrulline concentration was 107 and 130 μM in amniotic fluid from two fetuses homozygous for the citrullinaemia mutation. Only the normal bovine citrullinaemia sequence was detected in cells cultured from amniotic fluid taken from two homozygous normal and two heterozygous fetuses. Both normal and mutant sequences were found in cells cultured from amniotic fluid collected from three of five heterozygous fetuses. Only the mutant sequence was found in cells cultured from the two citrullinaemia affected fetuses. mhc class II DRB3 haplotyping revealed that in four instances cultured cells were from the surrogate mother, not the fetus, these included samples from two heterozygotes in which only the normal sequence was detected in amniotic fluid.  相似文献   

16.
A strain of bovine herpesvirus-4 isolated from cows with mammary pustular dermatitis was used for experimental inoculation of cattle. This strain is serologically indistinguishable from the group prototype Movar 33/63 and from strain DN-599. Seronegative cattle were inoculated IV or by simultaneous intranasal, IV, intramammary (via teat channel), and intradermal inoculations. All inoculated cattle seroconverted. Clinical signs of disease or lesions were not evident, except for a dermal lesion corresponding with one intradermal inoculation site. Virus was recovered from the dermal lesion and was excreted in the milk for 17 days. Virus was recovered from esophagopharyngeal fluid at 9 and 13 days after inoculation. At different times of euthanasia (2 to 14 months after inoculation), virus was recovered from cocultures with bovine lung cells and/or explant cultures of lymph nodes, spleen, tonsils, and, in one case, kidney. In 2 animals, the virus was recovered repeatedly during 1 year from peripheral blood leukocytes by cocultivation with bovine lung cells. The number of infectious leukocytes, as determined by infectious center assay, ranged from less than 1 to 6 infectious cells/10(7) leukocytes.  相似文献   

17.
The pathogenesis of infectious bovine rhinotracheitis (IBR) virus (bovine herpesvirus-1) was studied in porcine fetuses after in utero inoculation. Laparotomies were performed on 8 seronegative pregnant sows at 34 to 86 days of gestation, and all fetuses in 1 uterine horn of each sow were exposed to IBR virus via inoculation into the amniotic sacs. Fetuses in the other horn served as controls. Clinical signs of infection were not observed in the sows, except for 2 sows that aborted at postinoculation days (PID) 11 and 15. Fetuses of the remaining 6 sows were collected at slaughter on PID 15 to 28. Fetuses were examined for gross abnormalities, presence of IBR virus in tissues, and the formation of neutralizing antibodies to IBR virus. Of 33 inoculated fetuses from 6 sows, 10 were mummified, 11 were hemorrhagic and/or edematous, and 12 were alive. Necrotic lesions were observed on the skin and in the liver of dead and live fetuses. Virus was recovered from 29 of 33 inoculated fetuses. Infectious bovine rhinotracheitis virus was isolated from fetal skin, liver, lungs, kidney, spleen, stomach contents, brain, amniotic fluid, and placenta. Virus was isolated from 4 of 11 fetuses recovered from 1 aborting sow. Antibodies to IBR virus were not detected in sera from the sows. However, antibodies were detected in 6 of 15 fetuses inoculated at 63 to 86 days of gestation and collected at slaughter at 86 to 112 days of gestation. The youngest fetus with detectable IBR antibody was estimated to be 74 days of gestation by measuring crown-rump length of the fetus.  相似文献   

18.
To characterize factors affecting the number of bovine oocytes recovered transvaginally, a regression analysis was performed between the responsiveness to multiple-ovulation treatment and the number of oocytes recovered transvaginally. The number of embryos recovered following multiple-ovulation treatment and the number of oocytes recovered transvaginally increased when the number of follicles to be aspirated transvaginally increased (P<0.05. P<0.01). The number of cumulus-oocyte complexes recovered transvaginally also increased when the number of oocytes to be aspirated transvaginally increased (P<0.001). However, the number of viable embryos that recovered following multiple-ovulation treatment had no relation to the number of cumulus-oocyte complexes recovered transvaginally. These results suggested that more oocytes can be recovered from donors that have a high responsiveness to multiple-ovulation treatment.  相似文献   

19.
Cryopreservation of bovine embryos   总被引：1，自引：0，他引：1  
The method of cryopreservation of embryos aged seven days, proposed for embryo transfer with cattle by Niemann (1985), was tested under production conditions on three cattle breeding farms and three experimental animal units. The number of donors was 128, and 467 intact embryos were obtained from them and were cryopreserved in semen straw. Following thawing, 455 were recovered, and 439 (96.5 percent) of these were suitable for transfer. A pregnancy rate of 49.0 percent was recorded from 412 transfers. This rate was differentiated by oestric cycle conditions of heifer recipients, which gave percentages of 46.0 among recipients of seven-day old embryos, 45.7 for eight-day recipients, and 65.8 for six-day recipients. Related to pregnancy results recorded on the same units from transfer of freshly collected seven-day embryos, the efficiency coefficient was 0.69 (550 fresh transfers = 65.4 percent and 222 cryopreserved transfers = 48.2 percent). The method is recommended for general field practice.  相似文献   

20.
An attempt was made to transmit contagious bovine pleuropneumonia (CBPP) from 22 animals recovered from artificial infection to healthy animals. Despite close contact and the imposition of a number of stresses no disease was transmitted. An unsuccessful attempt was made to reactivate old CBPP lesions by corticosteroid treatment, and by splenectomy. Four animals recovered from artificial infection did not become reinfected when put in contact with acute disease. Seven animals were reinoculated with Mycoplasmamycoides sub-species mycoides by endobronchial intubation. No clinical disease resulted. It is concluded that sequestra do not break down easily and that it is difficult to reinfect recovered animals. It is suggested that in field outbreaks of obscure origin, investigation should be thorough before it is concluded that an animal with an old sequestrum was responsible.  相似文献   

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