Using a field quantitative real-time PCR test to rapidly identify highly viremic Rift Valley fever cases

M. Kariuki Njenga, Janusz Paweska, Rose Wanjala, Carol Y. Rao, Matthew Weiner, Victor Omballa, Elizabeth T. Luman, David Mutonga, Shanaaz Sharif, Marcus Panning, Christian DroSten, Daniel R. Feikin, Robert F. Breiman

Research output: Contribution to journalArticle

Abstract

Approximately 8% of Rift Valley fever (RVF) cases develop severe disease, leading to hemorrhage, hepatitis, and/or encephalitis and resulting in up to 50% of deaths. A major obstacle in the management of RVF and other viral hemorrhagic fever cases in outbreaks that occur in rural settings is the inability to rapidly identify such cases, with poor prognosis early enough to allow for more-aggressive therapies. During an RVF outbreak in Kenya in 2006 to 2007, we evaluated whether quantitative real-time reverse transcription-PCR (qRT-PCR) could be used in the field to rapidly identify viremic RVF cases with risk of death. In 52 of 430 RVF cases analyzed by qRT-PCR and virus culture, 18 died (case fatality rate [CFR] = 34.6%). Levels of viremia in fatal cases were significantly higher than those in nonfatal cases (mean of 10 5.2 versus 10 2.9 per ml; P <; 0.005). A negative correlation between the levels of infectious virus particles and the qRT-PCR crossover threshold (C T) values allowed the use of qRT-PCR to assess prognosis. The CFR was 50.0% among cases with C T values of <27.0 (corresponding to 2.1 X 10 4 viral RNA particles/ml of serum) and 4.5% among cases with C T values of ≥27.0. This cutoff yielded 93.8% sensitivity and a 95.5% negative predictive value; the specificity and positive predictive value were 58% and 50%, respectively. This study shows a correlation between high viremia and fatality and indicates that qRT-PCR testing can identify nearly all fatal RVF cases.

Original languageEnglish (US)
Pages (from-to)1166-1171
Number of pages6
JournalJournal of clinical microbiology
Volume47
Issue number4
DOIs
StatePublished - Apr 1 2009
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology (medical)

Fingerprint Dive into the research topics of 'Using a field quantitative real-time PCR test to rapidly identify highly viremic Rift Valley fever cases'. Together they form a unique fingerprint.

  • Cite this

    Njenga, M. K., Paweska, J., Wanjala, R., Rao, C. Y., Weiner, M., Omballa, V., Luman, E. T., Mutonga, D., Sharif, S., Panning, M., DroSten, C., Feikin, D. R., & Breiman, R. F. (2009). Using a field quantitative real-time PCR test to rapidly identify highly viremic Rift Valley fever cases. Journal of clinical microbiology, 47(4), 1166-1171. https://doi.org/10.1128/JCM.01905-08