RESUMO
A new quantitative RT-PCR assay was developed to differentiate Rift Valley fever (RVF) Smithburn vaccine strain from Clone 13 vaccine strain. The new qRT-PCR assay targeting the S segment (NSs and N gene) was tested on synthesized standard RNA and MP-12 strain viruses. The detection limit of the new qRT-PCR assay is 1 copy/µL of NSs and N, and is able to differentiate the Smithburn vaccine strain of RVF from the Clone 13 vaccine strain. No cross-reactivity with other vector-borne viruses was observed, a factor that is especially important in the Republic of Korea (ROK). To examine the performance of the qRT-PCR, intra- and inter-assay variability data were analyzed and showed high reproducibility. These results indicate that the new qRT-PCR can be used as a safe and cost-effective test. Furthermore, this result suggests the possibility of differentiation between infected and vaccinated animals diagnostic test in RVF-free countries including ROK.
Assuntos
Febre do Vale de Rift/prevenção & controle , Vírus da Febre do Vale do Rift/genética , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais , Reprodutibilidade dos Testes , República da Coreia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Febre do Vale de Rift/virologia , Vírus da Febre do Vale do Rift/imunologia , Sensibilidade e EspecificidadeRESUMO
Rift Valley fever (RVF) is an acute mosquito-borne viral zoonotic disease that affects mainly domestic ruminants and humans. RVF virus (RVFV) was first identified in Kenya in 1931 and was reported to be endemic in Africa but has recently spread to the Arabian Peninsula. With increasing climate change and globalization of trade in animals and animal products, there is great concern that the disease will spread worldwide to regions such as Europe, Asia, and the Americas. Although RVFV has not been reported in the Republic of Korea (ROK), the possibility of RVFV introduction is increasing because transmissible mosquito vectors are present and direct flights to Africa were added in 2012. For these reasons, we conducted a surveillance study to detect RVFV in mosquito vectors collected around the airport and harbor from 2012 to 2013. A total of 36,734 mosquitoes were collected and tested by real-time RT-PCR. A total of 1837 mosquito pools were used, and all were confirmed to be negative. This is the first report in the ROK concerning RVFV surveillance in mosquito vectors, and continuous surveillance will be conducted for the early warning of RVFV introduction.