Comparative efficacy of two next-generation Rift Valley fever vaccines.
Vaccine
; 32(39): 4901-8, 2014 Sep 03.
Article
en En
| MEDLINE
| ID: mdl-25050973
ABSTRACT
Rift Valley fever virus (RVFV) is a re-emerging zoonotic bunyavirus of the genus Phlebovirus. A natural isolate containing a large attenuating deletion in the small (S) genome segment previously yielded a highly effective vaccine virus, named Clone 13. The deletion in the S segment abrogates expression of the NSs protein, which is the major virulence factor of the virus. To develop a vaccine of even higher safety, a virus named R566 was created by natural laboratory reassortment. The R566 virus combines the S segment of the Clone 13 virus with additional attenuating mutations on the other two genome segments M and L, derived from the previously created MP-12 vaccine virus. To achieve the same objective, a nonspreading RVFV (NSR-Gn) was created by reverse-genetics, which not only lacks the NSs gene but also the complete M genome segment. We have now compared the vaccine efficacies of these two next-generation vaccines and included the Clone 13 vaccine as a control for optimal efficacy. Groups of eight lambs were vaccinated once and challenged three weeks later. All mock-vaccinated lambs developed high fever and viremia and three lambs did not survive the infection. As expected, lambs vaccinated with Clone 13 were protected from viremia and clinical signs. Two lambs vaccinated with R566 developed mild fever after challenge infection, which was associated with low levels of viral RNA in the blood, whereas vaccination with the NSR-Gn vaccine completely prevented viremia and clinical signs.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fiebre del Valle del Rift
/
Enfermedades de las Ovejas
/
Vacunas Virales
Límite:
Animals
Idioma:
En
Revista:
Vaccine
Año:
2014
Tipo del documento:
Article