Protection of cattle against rinderpest by vaccination with wild type but not attenuated strains of peste des petits ruminants virus

Although Rinderpest virus (RPV) has been eradicated in the wild, efforts are still continuing to restrict the extent to which live virus is distributed in facilities around the world, and to prepare for any reappearance of the disease, whether through deliberate or accidental release. In an effort to find an alternative vaccine which could be used in place of the traditional live attenuated RPV strains, we have determined whether cattle can be protected from rinderpest by inoculating with vaccine strains of the related morbillivirus, Peste des petits ruminants virus (PPRV). Cattle were vaccinated with wild type PPRV or either of two established PPRV vaccine strains, Nigeria/75/1 or Sungri/96. All animals developed antibody and T cell immune responses to the inoculated PPRV. However, only the animals given wild type PPRV were protected from RPV challenge. Animals given PPRV/Sungri/96 were only partially protected, and animals given PPRV/Nigeria/75/1 showed no protection against RPV challenge. While sera from animals vaccinated with the vaccine strain of RPV showed cross-neutralising ability against PPRV, none of the sera from animals vaccinated with any strain of PPRV were able to neutralise RPV, although sera from animals inoculated with wild type PPRV were able to neutralise RPV-pseudotyped Vesicular stomatitis virus.Importance: Rinderpest virus has been eradicated, only the second virus to be so. Significant efforts are still required to ensure preparedness for a possible escape of RPV from a laboratory or its deliberate release. Since RPV vaccine protects sheep and goats from PPRV, it is important to determine if the reverse was true, as this would provide a non-RPV vaccine for dealing with suspect RPV outbreaks. This is probably the last in vivo study with live RPV that will be approved.