Biomedical subjects

P Tsvetkov

Publications and source records attributed to P Tsvetkov.

8 recordsLinked to original sources

PubMed1979

[Trial of a hyperimmune serum against para-influenza 3, bovine adenovirus 1, infectious rhinotracheitis and mucosal disease].

A four-valent serum was obtained by parallel hyperimmunization of cattle with live viral suspensions of parainfluenza-3, bovine adenovirus I, the virus of infectious rhinotracheitis and the mucous disease virus. The serum's neutralizing titres are between 1:1280 and 1:2560. The lasting exploitation of serum producing cattle indicates that no competition exists between the four antigens used in the process of hyperimmunization. Experimental testing of the serum on calves and its application in practical work proved its prophylactic and medicative effect. These results confirm the thesis that the use of passive immunoprophylaxis is needed in respiratory diseases of calves under conditions existing in intensive cattle-breeding.

Adenoviridae↗

PubMed1979

[Isolation of the bovine herpesvirus-3 from sick calves].

Three herpes strains identified as herpes virus-3 were isolated in revolving test-tubes with cell cultures of nasal samples and lung parenchyma from diseased calves at the time of a respiratory enzooty. Large crystalloid aggregates of herpes virus virions were observed in the nucleus and in the cytoplasma by the electron-microscopic investigation performed on infected cell cultures. The experimental infection of calves with the isolated strain produced slight symptoms of respiratory disease in single calves only. The infected calves were susceptible to a following infection with cattle herpes virus-1.

Animals↗

PubMed1979

[Production and study of the immunogenic properties of a bivalent inactivated vaccine against mucosal disease (bovine viral diarrhea and infectious rhinotracheitis)].

Bivalent inactivated vaccine against mucous disease (MD) and infectious rhinotracheitis (IR) in cattle was produced from cell cultural MD and IR virus suspensions. The vaccine was concentrated on aluminium hydroxide, inactivated by ethanol and is without residual virus. Saponine in final 1:1500 dilution is added as supplementary adjuvant. Immunogeneity of the vaccine was tested on 10-month-old calves, which had shown full resistance against experimental infection with virulent strains of both viruses. Testing on calves for harmlessness by use of a five-fold higher vaccine dose indicated complete tolerance of the vaccine. The prophylactic effect of the vaccine applied in practical work to directly threatened with immediate MD and IR infection cows, including pregnant ones, consisted in reduced number of cases of abortion, of inborn malformations, in lower neonatal calf death-rate, etc. No disturbances were observed following two-fold vaccination of the animals, a fact proving its harmlessness. The positive results of the studied vaccine allow its further application in the combined prophylaxis of MD and IR in calf fattening and breeding complexes.

Animals↗

PubMed1978

[Trials to obtain a hyperimmune serum against bovine mucosal disease-virus diarrhea].

Obtained are two types of hyperimmune sera against the virus of the mucous disease--viral diarrhea (MD--VD) by means of subcutaneous and venous hyperimmunization of cattle with a live viral suspension: (a) A polyvariant hyperimmune serum, obtained by the use of four local and reference strains of the MD--VD virus with a neutralization titre against the Nadl strain of 1 : 1280. (b) Monovariant hyperimmune serum, prepared by the use of a reference strain of the MD--VD virus with a neutralization titre against the Nadl strain of 1 : 1280. On testing experimental calves and application in practice, it has not been established that the polyvariant serum possesses a marked protective effect at a dose of 1 cm3/kg.

Animals↗

PubMed1977

[Serological response of rabbits following immunization with M. parainfluenzae-3, adenovirus I and infectious bovine rhinotracheitis virus associated antigens].

The immunization of rabbits separately with virus suspensions of Myxovirus parainfluenzae-3, adenovirus serotype I, and bovine rhinotracheitis virus or with combinations of each two of them and with a combination of all three viruses led to the production of sera having titers of virus-neutralizing antibodies acting against each of the antigens that participated in the combination. Results showed that no inhibition existed of the antigens during immunization as established by the serologic response of the rabbits. The demonstrated specificity of the monovalent sera points to the fact that the latter could be used for the diagnostic purposes.

Adenoviridae↗

PubMed1977

[Immunoprophylaxis of infectious bovine rhinotracheitis].

The live attenuated vaccine against infectious rhinotracheitis (LAV), the live trivaccine against infectious rhinotracheitis (LT), the concentrated etanolsaponin vaccine against infectious rhinotracheitis (CESV) and the ethanol-saponin vaccine against infectious rhinotracheitis (ESV) can all be used as immunoprophylactic means in the control of infectious rhinotracheitis in cattle. The first two live vaccines are applied to calves in infection foci, and the two inactivated vaccines are used with cows. The comparative testing of CESV and ESV in experimental conditions on calves has shown that the first possesses higher immunogenicity--used in a twice lower dose it produces several times higher level of the neutralizing antibodies against the infectious rhinotracheitis virus. The use of LAV and LT in the practice under the conditions of established infections of infectious rhinotracheitis in calves has given good results. The immunization of calves at the immediate menace of this infection has lowered the morbidity rate, and death cases were no longer observed. The use of CESV and ESV with pregnant cows on a prophylactic basis against infectious rhinotracheitis has also given good results manifested in the full suppression of abortions.

Animals↗

PubMed1976

[Study of one enzootic of viral diarrhea in calves].

Described is the course of a virus diarrhea in calves aged from 40 up to 180 days, the morbidity rate reaching 50 per cent and the mortality rate--28 per cent. The morphologic survey established erosions and inflammatory lesions in the mouth, abomasum, rumen, and intestines. Histologically, there was balooning degeneration of the cells involved as well as karyopycnosis. Virus strains were isolated from the spleen of diseased calves. They were identified as the causative agent of the virus diarrhea-mucosal disease complex. It was found through immunodiffusion that a specific viral antigen exists in the involved mucous membranes of the intestinal tract. The live vaccine was found to be promising of the immunoprophylactic means tested.

Animals↗

PubMed1975

Immunization against mucosal disease--bovine viral Diarrhea (MD-BVD) in calves applying lapinized vaccine against swine fever and a modified live virus of MD-BVD.

Calves vaccinated with the modified strain C24V react by creating neutralizing antibodies in high titres and are resistent to infection while non-immunized calves manifest the clinical symptoms of MD-BVD. Calves, vaccinated with the lapinized strain "K" of the SF virus react by creating neutralizing antibodies in low titres against the vius of MD-BVD and manifest no apparent clinical symptoms after challenge with the virulent strain MD-BVD.

Animals↗