Rapid detection of human pathogenic orthobunyaviruses.
ABSTRACT Modern detection and identification tools can help to provide answers to urgent questions about the incidence, prevalence, and epidemiology of currently emerging diseases. We developed highly sensitive one-step TaqMan reverse transcription-PCR assays with sensitivities ranging from 10(4) to 10(1) molecules for 11 human pathogens of the orthobunyaviruses. We compared the performances of these assays on three currently available cyclers (ABI-PRISM 7700, LightCycler, and SmartCycler). The assay for Oropouche virus (OROV) was tested using sera collected from days 1 to 5 after onset of OROV disease and was found to be greatly superior to an established nested PCR system. A mean copy number of 1.31 x 10(7) OROV RNA/ml of serum was detected. Diagnostic RNA detection can be used as early as day 1 after onset of OROV disease. The use of a mobile SmartCycler and a hands-on time of less than 3 h could help to intensify outbreak surveillance and control, especially in field studies.
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ABSTRACT: Of more than 500 arboviruses recognized worldwide, 5 were first isolated in Canada and 58 were first isolated in the United States. Six of these viruses are human pathogens: western equine encephalitis (WEE) and eastern equine encephalitis (EEE) viruses (family Togaviridae, genus Alphavirus), St. Louis encephalitis (SLE) and Powassan (POW) viruses (Flaviviridae, Flavivirus), LaCrosse (LAC) virus (Bunyaviridae, Bunyavirus), and Colorado tick fever (CTF) virus (Reoviridae, Coltivirus). Their scientific histories, geographic distributions, virology, epidemiology, vectors, vertebrate hosts, transmission, pathogenesis, clinical and differential diagnoses, control, treatment, and laboratory diagnosis are reviewed. In addition, mention is made of the Venezuelan equine encephalitis (VEE) complex viruses (family Togaviridae, genus Alphavirus), which periodically cause human and equine disease in North America. WEE, EEE, and SLE viruses are transmitted by mosquitoes between birds; POW and CTF viruses, between wild mammals by ticks; LAC virus, between small mammals by mosquitoes; and VEE viruses, between small or large mammals by mosquitoes. Human infections are tangential to the natural cycle. Such infections range from rare to focal but are relatively frequent where they occur. Epidemics of WEE, EEE, VEE, and SLE viruses have been recorded at periodic intervals, but prevalence of infections with LAC and CTF viruses typically are constant, related to the degree of exposure to infected vectors. Infections with POW virus appear to be rare. Adequate diagnostic tools are available, but treatment is mainly supportive, and greater efforts at educating the public and the medical community are suggested if infections are to be prevented.Clinical Microbiology Reviews 02/1994; 7(1):89-116. · 16.13 Impact Factor