Evaluation of RT-PCR for Rapid Detection of Vaccine Strains Of Rift Valley Fever Virus

Abstract

A single-tube conventional gel-based reverse transcriptase (RT) polymerase chain reaction (RT-PCR) assay, for rapid detection of Rift Valley fever (RVF) virus (RVFV) was developed. The RT-PCR assay was evaluated for detection of vaccine (Smith burn) strain of the virus in cell culture. Two pairs of primers (RV1 and RV2), selected from the medium (M) RNA segment of RVFV, were used as a target for RT- PCR amplification. The outer pair of primers (RV1 and RV2) resulted in amplification of a primary 848 base pair (bp) PCR product. Application of this RT-PCR-based assay to the South African vaccine strains (Smith burn) resulted in direct detection of RVFV RNAs in Vero cell culture. Sensitivity test has confirmed that this technique could be used to detect 1 picogram from the viral genome in vero cells, this degree of sensitivity could be compared with virus detection through virus isolation. Amplification products were not detected when the RT-PCR-based assay was applied to RNA from other haemorrhagic fevers viruses including Crimean Congo hemorrhagic fever virus (CCHFV), dengue virus; Yellow fever virus, total nucleic acid extracts from uninfected Vero cells. The RT-PCR provides a rapid, sensitive and specific assay for detection of RVFV in cell culture. The assay could be recommended for inclusion during an outbreak of the disease among susceptible populations.