ABSTRACT
Four goats were inoculated with an inactivated peste des petits ruminants virus (PPRV) vaccine. Three unvaccinated goats were kept as controls. After 36 days, the four goats were revaccinated. The immune response was monitored by virus neutralization test showing that two doses of the vaccine were able to stimulate strong immune response in all the vaccinated animals. The vaccinated goat and the controls were challenged with virulent PPRV intranasally. After PPRV challenge, the three control goats showed fever, viremia and virus excretion through mucosal surfaces, whereas the vaccinated goats were fully protected against PPRV infection and replication.
Subject(s)
Goat Diseases/virology , Peste-des-petits-ruminants virus/immunology , Viral Vaccines , Animals , Antibodies, Viral/blood , Goats , Vaccines, InactivatedABSTRACT
A duplex real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed for a simple and rapid diagnosis of Peste des petits ruminants (PPR). qRT-PCR primers and TaqMan probe were designed on a conserved region of nucleocapsid protein (Np) of PPR virus (PPRV) genome. An in vitro transcript of the target region was constructed and tested to determine analytical sensitivity. Commercial heterologous Armored RNA(®) was used as an internal positive control (IPC) for either RNA isolation or RT-PCR steps. The detection limit of the newly designed duplex real-time RT-PCR (qRT-PCR PPR_Np) was approximately 20 copies/µl with a 95% probability. No amplification signals were recorded when the qRT-PCR PPR_Np was applied to viruses closely related or clinically similar to PPRV- or to PPR-negative blood samples. A preliminary evaluation of the diagnostic performance was carried out by testing a group of 43 clinical specimens collected from distinct geographic areas of Africa and Middle East. qRT-PCR PPR_Np showed higher sensitivity than the conventional gel-based RT-PCR assays, which have been used as reference standards. Internal positive control made it possible to identify the occurrence of 5 false-negative results caused by the amplification failure, thus improving the accuracy of PPRV detection.
Subject(s)
Peste-des-Petits-Ruminants/diagnosis , Peste-des-petits-ruminants virus/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , Africa , Animals , DNA Primers/genetics , Goats , Middle East , Nucleocapsid Proteins , Nucleoproteins , Peste-des-Petits-Ruminants/genetics , Peste-des-Petits-Ruminants/virology , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Sensitivity and Specificity , Sheep , Viral ProteinsABSTRACT
Although susceptibility to scrapie is largely controlled by the PRNP gene, we have searched for additional genomic regions that affect scrapie incubation time in sheep, using two half-sib families with a susceptible PRNP genotype and naturally infected by scrapie. Quantitative trait loci were detected on OAR6 and OAR18.
Subject(s)
Genetic Predisposition to Disease/genetics , Immunity, Innate/genetics , Quantitative Trait Loci/genetics , Scrapie/genetics , Animals , Likelihood Functions , Sheep , Survival Analysis , Time FactorsABSTRACT
The bovine spongiform encephalopathy (BSE) crisis clearly demonstrated the need to keep animal transmissible spongiform encephalopathies (TSE) under control in order to protect animal and human health. Scrapie is the most widespread TSE of livestock in the world. For this reason, health authorities in different countries have elaborated plans that aim towards scrapie eradication. The unusual nature of the scrapie agent and the fragmented status of scientific knowledge about it, along with the limitations of currently available diagnostic tools, make it unlikely that the objective of eradication will be achieved in the near future. Scientific research is focused on acquiring the knowledge that will improve the efficiency of these efforts.
