Diagnosis of Ebola haemorrhagic fever by RT-PCR in an epidemic setting

This study reports the first field evaluation of a new diagnostic technique for Ebola virus disease with sensitivity and specificity. Ebola virus caus es rare but fulminating outbreaks in Equatorial Africa. Rapid differentiati on from other infections is critical for timely implementation of public he alth measures. Patients usually die before developing antibodies, necessita ting rapid virus detection. A reverse transcriptase-polymerase chain reacti on (RT-PCR) assay was developed, implemented and evaluated at Centre Intern ational de Recherches Medicales de Franceville (CIRMF) in Gabon, to detect Ebola viral RNA in peripheral blood mononuclear cells (PBMC). Twenty-six la boratory-confirmed patients during and 5 after the acute phase of Ebola hae morrhagic fever, 15 healthy controls and 20 febrile patients not infected w ith Ebola virus were studied. RT-PCR results were compared with ELISA antig en capture, and Ebola specific IgM and IgG antibody detection. Ebola virus RNA was amplified from 26/26 specimens from the acute phase, 3/5 during rec overy, 0/20 febrile patients and 1/15 negative controls. Sensitivity of RT- PCR in identifying acute infection and early convalescence compared with an tigen or IgM detection was 100% and 91% respectively, and specificity compa red with antigen detection and IgM assay combined was 97%. Antigen capture detected only 83% of those identified by PCR, and IgM only 67%. Ebola virus RNA was detected in all 13 fatalities, only 5 of whom had IgM and none IgG . RT-PCR detected Ebola RNA in PBMC one to th ree weeks after disappearance of symptoms when antigen was undetectable. RT-PCR was the most sensitive m ethod and able to detect virus from early acute disease throughout early re covery. J. Med. Virol. 60:463-467, 2000. (C) 2000 Wiley-Liss, Inc.