Determination of the onset of the herd-immunity induced by the E2 sub-unit vaccine against classical swine fever virus

• Published in: Vaccine 2000-01, Vol.18 (14), p.1374-1381
• Main Authors: Bouma, A., De Smit, A.J., De Jong, M.C.M., De Kluijver, E.P., Moormann, R.J.M.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; CERDO; Classical Swine Fever - immunology; Classical Swine Fever - prevention & control; Classical Swine Fever - transmission; Classical Swine Fever - virology; Classical swine fever virus; Classical Swine Fever Virus - immunology; Fundamental and applied biological sciences. Psychology; Hog cholera virus; IMMUNE RESPONSE; IMMUNISATION; IMMUNIZATION; Immunization Schedule; INMUNIZACION; Microbiology; PESTE PORCINA; PESTE PORCINE CLASSIQUE; PORCIN; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; Subunit vaccine; SWINE; SWINE FEVER; SWINE FEVER VIRUS; VACCIN; VACCINATION; VACCINES; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; VACUNA; VACUNACION; Viral Envelope Proteins - immunology; Viral Vaccines - immunology; Viral Vaccines - therapeutic use; Virology; VIROSE; VIROSES; VIROSIS
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/S0264-410X(99)00398-9

For a recently developed E2 subunit vaccine against classical swine fever (CSF), the reduction in transmission, at different moments after vaccination, was assessed by animal experiments and statistical calculations. Two experiments were performed to estimate the reproduction ratio R. Experiment 1 consisted of three groups and experiment 2 of two groups each of 10 pigs. In four of these groups, all pigs were vaccinated intramuscularly with the vaccine. The pigs in the fifth group remained unvaccinated (control group). After treatment, half of each group was intranasally inoculated with the virulent CSFV strain Brescia. In the vaccine groups, the following vaccination–challenge intervals were applied: 14, 14, 10, and 7 days, respectively. The occurrence of (contact-) infection was determined using the E rns ELISA. In the 7-days interval group and in the control group, virus transmission to all contact pigs occurred, indicating R>1. Neither in the two 2-week interval groups nor in the 10-day interval group did contact-infections occur. Hence, the estimated R is less than one, which indicates that an epidemic would fade out. Therefore, the E2 subunit vaccine may be an efficacious tool in a control program during an outbreak of CSF as from 10 days after vaccination.