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1.
Feline Infectious Peritonitis (F.I.P.) was diagnosed in the kittens of two successive litters born to a female presumed also infected.At the same time, the two fathers and the other subjects of the cattery remained asymptomatic of F.I.P.The clinical observations, supported by electrophoretic data, suggest the possibility of a direct transmission of the disease by the mother to her offspring, either by the transplacentary pathway (epigenetic transmission) or via the milk. 相似文献
2.
From the reasons that canine coronavirus (CCV) grows more efficiently than feline coronavirus in a cell culture and they are mutually related in their antigenicities, an enzyme-linked immunosorbent assay (ELISA) using CCV-infected feline kidney (CRFK) cells as substrate antigens was developed for detection of anti-coronavirus antibodies in cats. It was indispensable for generating coronavirus-specific ELISA antibody activities that the sample was applied to the mock-infected, normal CRFK cells in parallel with the CCV-infected cells and then the optical density values given by the mock-infected cell antigen were subtracted from those given by the virus-infected cell antigen. On the basis of ELISA antibody titers obtained in sera from the cats experimentally infected with CCV and from the spontaneous feline infectious peritonitis (FIP) cases, the ELISA described in the present study was found to be applicable as a simple and easy serologic test which was able to detect anti-coronavirus antibodies as efficiently as the indirect immunofluorescence assay with homologous FIP virus. 相似文献
3.
After mutagenic treatment of the LaSota strain, cold-adapted mutants were selected by serial passages in eggs at 26°C.One of these mutants, RIT 4030, was attenuated for S.P.F. day-old chickens vaccinated by aerosol. In vitro studies were performed to define the properties which differentiate this mutant from the parental LaSota strain. 1. 1. The strain RIT 4030 bears a ts mutation which reduces its multiplication at 41°C. 2. 2. The strain RIT 4030 has modified infectivity properties in CEF and behaves like a “host-range” mutant. The correlation between these mutations and the reduced pathogenicity of this strain for chickens is discussed. 相似文献
4.
The i.v. or i.p. injection of delipidated whole cells of an aerobic Corynebacterium, designated as C. catarrahalis, resulted in the production of a low titre of interferon in mice. Two fractions, a particulate fraction, designated as CBA p40, and a soluble fraction, designated as CBA LS, could be isolated from the delipidated whole cells and were found to lead to the formation of more or less high interferon levels according to the route of administration. Furthermore, the CBA p40 fraction, when injected i.p., elicited the production of a maximum titre of interferon at the 24th hour (viral-like interferon). 相似文献
5.
Standardised procedure for obtaining reproducible haemagglutination-inhibition results for FPV antibody which correlate with serum-neutralization titres was described. Optimal conditions were found to be Alsevers anticoagulant, PBS/0.05% BSA (pH 6.8) as buffer, especially washed round bottom microplates, determination of maximally sensitive porcine erythrocytes, use of reproducible erythrocyte concentrations, inactivation of serum samples at 56 degrees C for 30 min and serum treatment with koalin pH 9.0. The concentration of erythrocyte used for estimation of haemagglutination units in H1 test should not differ from that used as indicator in the test. Predilution of serum beyond 1:4 associated with false results. Reproducible method for removing natural agglutinins in serum by adsorption with erythrocytes was described. 相似文献
6.
Current knowledge of the nature of the antigens and of the host immune responses in vaccinal immunity to Marek's disease is reviewed. It is suggested that a two-step mechanism of resistance operates. The first step involves humoral and cell-mediated responses directed against viral antigens; the second step occurs after challenge with Marek's disease virus and consists of cellmediated responses directed against tumour cells. 相似文献
7.
The clinical and parasitologic features of toxoplasmosis, serologic diagnosis, treatment, transmission and prevention are discussed. 相似文献
8.
Aerosol administrations of RIT 4030 and other available vaccine strains have been carried out in SPF and in conventional chickens. The results indicate that the RIT 4030 and Ulster 2C strains are significantly less reactogenic than the LaSota and the Hitchner B1 strains.The RIT 4030 strain produces an immune response even when administered to chickens with maternal antibodies and induces a better protection to challenge than the Ulster 2C strain.The replication of the RIT 4030 strain in the respiratory tract will be discussed with respect to its attenuation and transmissibility. 相似文献
9.
Chicks and chickens maintained under commercial conditions were vaccinated against Newcastle Disease via drinking water. Prior and after different times of vaccination blood samples were drawn from different numbers of birds and checked for HI antibodies. The modes of distribution of the antibody titers within the random sample were assayed. The following results were obtained: 1. 1. On the basis of the distribution of the serum titers can be concluded whether the antibody level within a flock is increasing or decreasing. - ◦ —A right steep asymmetry can be observed up to 20 days post vaccination.
- ◦ —In the phase of maximal antibody levels an almost symmetric distribution of the titers is present.
- ◦ —In later times (more than three weeks p. vacc.) the distribution shows a left steep asymmetry (Poisson distribution).
2. 2. A poisson distribution is also observable during the elimination of maternal antibodies of chicks until complete elimination. 3. 3. The mode of distribution of the HI titers in sera of day-old chicks correlates with the mode of distribution of the dams. Therefore, conclusions are possible from the status of the chicks to the dams and reverse. 4. 4. Factors which interfere with the mode of distribution are: - ◦ —Two or more peaks after vaccination of chickens. This indicates an uneven immune response within the flock.
- ◦ —Distributions with several peaks may also occur if flocks are composed of day-old chicks from parent flocks with different levels of antibody titers.
RésuméDes poulets et des poussins maintenus dans un élevage conventionnel furent vaccinés contre la maladie de Newcastle par un vaccin administré dans l'eau de boisson. Avant et à différents temps après vaccination, des échantillons de sang furent prélevés sur un certain nombre de poussins et les anticorps inhibants de l'hémagglutination furent recherchés. Les modes de la distribution des titres en anticorps pour les échantillons pris au hasard furent recherchés. Les résultats suivants furent obtenus: 1. 1. Sur la base de la distribution des titres sériques, on peut conclure si le taux en anticorps à l'intérieur d'une population a augmenté ou diminué. - ◦ —Une courbe asymétrique avec un pic déplacé vers la droite peut être observée 20 jours après la vaccination.
- ◦ —La phase correspondant au taux maximal en anticorps présente une distribution presque normale.
- ◦ —Plus tard, (au-delà de 3 semaines après la vaccination), la distribution apparaît asymétrique avec un déplacement vers la gauche (distribution de Poisson).
2. 2. Une distribution de Poisson peut aussi être observée au moment de l'élimination des anticorps d'origine maternelle chez des poussins jusqu'à complète élimination. 3. 3. Le mode de distribution des titres en anticorps inhibant l'hémagglutination dans des sérums de poussins d'un jour correspond au mode de distribution observé chez les mères. Des conclusions peuvent donc être faites à partir de l'état immunologique des poussins vis-à-vis des mères et viceversa. 4. 4. Les facteurs qui peuvent intervenir dans le mode de distribution sont: - ◦ —Deux pics ou plus après la vaccination des poussins. Ceci indique qu'il existe une réponse immunitaire inégale dans la population.
- ◦ —Des distributions avec plusieurs pics peuvent être également observées si les populations sont composées de poussins de un jour provenant de populations parentales ayant des taux différents de titres en anticorps.
Keywords: Newcastle disease; vaccination NDV Mots-clé: Maladie de Newcastle; vaccination Newcastle 相似文献
10.
Hemolytic assays were used to compare alternate and classical C pathway activities in sera obtained from clinically normal newborn dairy calves and their mothers at the time of delivery. Mean alternate and classical CH50 concentrations in sera from newborn calves were both significantly lower than in their dams (P less than 0.001). The titer of alternate C pathway activity, expressed as CH50 units/ml, in sera from 17 calves was 12.9 +/- 5.5, whereas for the cows it was 25.8 +/- 6.2. The ratio of cow: calf serum alternate CH50 titers averaged 2.25 +/- 0.80 and ranged from 0.88 to 4.14. Classical CH50 titers were 78.0 +/- 42.7 units/ml in calf sera and 246.0 +/- 44.5 in cow sera. The ratio of cow: calf serum classical CH50 titers averaged 3.71 +/- 1.49 and ranged from 1.19 to 6.87. The wide range of values, noted for both the alternate and classical C pathways, within maternal and neonatal groups was assumed to reflect the biologic variability of complement levels in bovine serum. The possible relationships between deficient levels of alternate and classical CH50 activity in newborn calves and their susceptibility to infections is discussed. 相似文献
11.
HVT-7, the standard vaccine against MD, was prepared from HVT strain FC126 grown in fibroblast cultures from SPF embryos. Ampoules of freeze dried material were prepared from a cell free suspension of virus in a solution of SPGA. The vaccine is stored at −20°C.The primary purpose of the standard vaccine was to control the variation encountered in the assay of virus content of HVT vaccines. The virus content of the standard vaccine was determined under a range of assay conditions, and the method in current use was shown to be satisfactory.A mean value for the virus content of the standard vaccine was determined using a constant assay method, by titrating 27 ampoules over a period of time. A further series of assays performed after one year's storage showed there to be no significant loss of titre.When several ampoules were titrated at the same time, some vial to vial variation was detected, but this was less than normal assay to assay variation.During routine determinations of the virus content of commercial HVT vaccines, an assay of the standard vaccine was carried out simultaneously to determine whether the assay conditions were acceptable. Assays where the value for the virus content of standard vaccine fell outside the expected range were considered invalid.The stability of the standard vaccine after reconstitution in SPGA was considered satisfactory: when reconstituted in phosphate-buffered saline, the rate of decrease in virus content was significantly greater. The vaccine could therefore be used as a control preparation in stability tests.Preliminary investigations showed that the behaviour of the standard vaccine in vivo was similar to that of satisfactory commercial vaccines, so that the preparation may also be of value in tests of vaccines for their ability to produce viraemia and confer protection. 相似文献
12.
Twenty steers, positive to the single intradermal comparative tuberculin test (SICTT), were selected fromherds with a recent history of Mycobacterium bovis infection. Ten steers, negative to SICTT, were selected from herds with no history of M. bovis infection and served as in-contact animals. The animals were divided into 10 groups, each consisting of two SICTT-positive (reactor) animals and one in-contact animal. Each group was housed in an individual loose-box for a period of 1 year. Five of the groups were fed a restricted diet for part of the experiment. All cattle were slaughtered at the end of the study period and examined at post mortem. Transmission of infection to an in-contact animal occurred in four of the 10 groups. One of the four in-contact animals, which became infected, had a retropharyngeal lymph node tubercle and M. bovis was isolated from lymph nodes without visible lesions from the other three. Two of the infected in-contact animals without visible lesions did not show any detectable cell-mediated immune response. There was no evidence that dietary, restriction had any effect on transmission of disease. 相似文献
14.
Clinical and histopathological aspects were studied in two splenectomized foals, naturally or experimentally infected with B. equi. The animals presented pyrexia, pale and icteric mucous membranes, hemoglobinuria, and microcytic hypochromic anemia, which coincided with the peak in parasitemia. Histopathological lesions were observed in the liver, kidneys, lungs and heart, and were suggestive of a serious hemolytic crisis provoked by the high level of parasitemia, causing hypoxy in the tissues. 相似文献
15.
Feline splenocytes were fused to the murine myeloma lines NSO or Ag8. Autologous serum and taurine were used as media supplements for the cat × mouse heterohybridomas. The best results were obtained by the use of NSO as fusion line with taurine-supported media. 相似文献
16.
Synthetic N-acetyl muramyl-l-alanyl-d-isoglutamine, syn. muramyl-dipeptide (MDP) was found to be immunostimulatory in several experimental animal species. In order to determine the influence of MDP on the chicken immune response, different doses (0.05–0.2 mg) of this compound were administered to 6-week old chickens, and cellular as well as humoral immune functions were tested. Neither the immune response against sheep red blood cells or Newcastle disease virus (strain Hitchner B 1), nor the ability to reject skin grafts, or to react in the delayed hypersensitivity (tuberculin) test, were affected significantly under the experimental conditions employed. This study reveals little evidence for parallels between the ability of the chicken immune system and the immune system of other animal species examined so far, to develop enhanced immune reactions under the influence of MDP. 相似文献
17.
Resistance of mice to Listeria monocytogenes was shown to be enhanced by pretreatment with either intact or delipidated whole cells of a new species of aerobic corynebacteria, designated as Corynebacterium catarrhalis, as well as with fractions isolated therefrom. Both whole cells and a particulate fraction (CBAp40) proved to be effective when given intravenously, whereas a water-soluble fraction (CBA-LS) was not. In contrast, CBA-LS, as well as CBAp40 and whole cells were found to be effective when given subcutaneously as far as they had previously been adsorbed onto a gel of either calcium phosphate or aluminum hydroxide. Furthermore, pretreatment of mice with either of the mineral gels in the absence of the products failed to confer protection on them to the challenge with L. monocytogenes. It is suggested that C. catarrhalis or products derived therefrom could be used as agents for enhancing resistance to infections of immuno-compromised individuals. 相似文献
18.
A number of cat colonies in The Netherlands, in which upper respiratory tract disease (U.R.D.) was endemic, were examined for the presence of feline herpes virus (H) and feline calici virus (C) infections. In total 108 cats were examined. In 59% of the cases feline calici virus was isolated and feline herpes virus in 39% of the cases. Mixed infections were found in 26% of the cats. The virus isolates were all neutralised by anti-sera against attenuated strains of feline herpes virus and feline calici virus which are incorporated in a newly developed combined C-H vaccine against U.R.D. in cats. Intranasal application of this vaccine induced a distinct increase in resistance against experimental challenge with virulent C and H, as soon as 24 hours after vaccination. 相似文献
20.
Serum neutralization tests conducted by microtiter procedure on 2970 serum samples from calves, heifers and adult cows from representative regions of Italy indicate that rotaviruses, and the infection which they cause, existed in Italy long before the virus was isolated. At the present time the infection is distributed fairly uniformly throughout the cattle population with both sexes and all age groups being equally susceptible. 相似文献
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