A sheep-pox virus strain has been adapted and multiplied in primary lamb kidney cell cultures. The main characteristics of the strain have been verified in vitro after clones were isolated, and the results confirmed its identity. The safety and the potency of the strain have been investigated in sheep.
The inoculation of the strain to sheep was followed by a post-vaccinal reaction materialised by a nodule at the site of inoculation and an increase of temperature by about 1°C. No reactions adversely affecting pregnancy have been noted. Immunisation was demonstrated by an increase in the level of neutralising serous antibodies and protection against the pathogenic virus. The immunity tended to decrease during the second year after primovaccination and a yearly booster vaccination appeared to be necessary. Primovaccination of lambs over 2 months of age produced a better immunity, especially when the lambs were born from vaccinated ewes.
This strain forms the active principle of a freeze-dried vaccine containing no adjuvant of the immunity. 相似文献
Human infection by Malassez and Vignal's bacillus (Yersinia pseudotuberculosis) can take many clinical aspects, the most frequent of which is mesenteric adenitis with pseudo-appendicular syndrome, but occasionally also appearing as a tumor of the right lower abdominal quadrant.
In a subsequent stage this mesenteric adenitis is often accompanied by erythema nodosum. There also exist some septicemia-like forms, which have become more and more frequent of late, always appearing on a particular terrain (predisposed persons).
These various forms all correspond to contamination via the digestive route. Other, more exceptional modes of contamination may result in much rarer forms, such as ocular or pulmonary forms.
Diagnosis is based on: (a) demonstrating the presence of Yersinia pseudotuberculosis, (b) serodiagnosis, (c) a positive intradermal reaction, (d) the characteristic aspect of lymph node lesions.
Pseudotuberculosis is extremely frequent in animals. Many species, most of them rodents or birds, can serve as healthy carriers. This is how cats, through their access to this natural “reservoir”, get contaminated and thus act as a “conveyor belt” in transmitting the disease to man. 相似文献
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
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
From each of two lentogenic Newcastle disease virus (NDV) strains of the type LaSota and Hitchner B1 a virulent subpopulation could be obtained. The two subpopulations were—in comparison to the two parent viruses—more resistant to the lipid solvent chloroform and more stable against thermal degradation. Also, the glycoproteins haemagglutinin and F (fusion) were more stable against thermal inactivation. Electron microscopic observations revealed in terms of size and morphology all of the characteristics of NDV. Both subpopulations possessed, however, the same elution kinetics as their respective parent strains. The intracerebral and intravenous pathogenicity indices as well as the mean death times of the two subpopulations allow to classify these viruses as virulent Newcastle disease viruses. 相似文献