Single-tube and nested reverse transcriptase-polymerase chain reaction fordetection of Rift Valley fever virus in human and animal sera

Rift Valley fever (RVF) is an anthropozoonosis caused by a Phlebovirus (Bun yaviridae family) that has re-emerged recently in East and West Africa in 1 997-1998. This emphasizes the need for early and rapid detection of the vir us and an efficient surveillance system. To this goal, a single tube or a n ested reverse transcriptase-polymerase chain reaction (RT-PCR) method focus ing on the NSs coding region of the S segment was developed and used to det ect the RVF virus (RVFV) genome, resulting respectively in the synthesis of 810 and 662 bp DNA amplimers. The assay was specific for RVFV and did not amplify any other phleboviruses known to circulate in sub-Saharan Africa. W hen serial dilutions of RVFV were artificially mixed with human normal seru m, the minimal detection limits were 50 and 0.5 plaque forming units respec tively using the simple and the nested RT-PCR. The RT-PCR method was effici ent for the detection of RVFV RNA in the blood from experimentally RVFV-inf ected mice and lamb and the nested RT-PCR was found more sensitive than the virus isolation method. Additionally, this detection method was applied su ccessfully for the diagnosis of human cases during the 1998 Mauritanian out break. (C) 2001 Elsevier Science B.V. All rights reserved.