DETECTION OF RIFT-VALLEY FEVER VIRUS IN MOSQUITOS BY RT-PCR

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay to de tect Rift Valley fever (RVF) virus RNA in experimentally infected mosq uitoes was developed. The specificity of the assay was evaluated with th ree other phleboviruses; sandfly fever Sicilian (Sabin), sandfly fe ver Naples (Sabin) and Punta Toro (MSP 3) viruses. The relative sensit ivity of the assay, determined by using RVF virus RNA extracted from s erial dilutions of virus culture, was approximately 50 plaque forming units. This sensitivity level was 100-fold higher when a nested PCR pr ocedure was used. When the RT-PCR assay was used with coded samples of intrathoracically-infected and uninfected mosquito, the assay detecte d the virus in ail infected mosquitoes. With this assay, it was possib le to detect RVF virus RNA in a single infected mosquito in the backgr ound of 10, 25 or 50 uninfected mosquitoes. (C) 1997 Academic Press Li mited.