Detection of measles virus RNA on SYBR green real-time reverse transcription-polymerase chain reaction
Kyoto City Institute of Health and Environment Science, Nakagyo, Kyoto, Japan. Pediatrics International
(Impact Factor: 0.73).
03/2010; 52(4):611-5. DOI: 10.1111/j.1442-200X.2010.03124.x
As the coverage rate of the measles vaccine increases, not all patients present the typical symptoms of measles after exposure to the measles virus (MV). The virus loads in clinical specimens from patients with vaccine-modified non-typical measles are expected to be low compared with those of primary MV infection. A rapid and sensitive laboratory procedure is required for diagnosis of measles.
SYBR Green (TaKaRa) and TaqMan (ABI) real-time reverse transcription-polymerase chain reaction (RT-PCR) assays were developed to detect MV-RNA. For the real-time RT-PCR, primer sets were designed from a region of the MV H gene of the Edmonston strain (genotype A). A TaqMan probe specific for the H gene of genotype D MV was used. The minimum detectable level of MV-RNA in the SYBR Green and TaqMan real-time RT-PCR assays was evaluated using synthetic MV-RNA. The sensitivity of real-time RT-PCR was compared with that of nested RT-PCR and the virus isolation method using throat swabs and peripheral blood samples from patients with measles.
The minimum detectable level of RNA was 10 and 10(2) copies for SYBR Green RT-PCR and TaqMan RT-PCR, respectively. Ten-10(6) copies of standard RNA were linearly detected on SYBR Green RT-PCR. The sensitivity of SYBR Green RT-PCR was equal to that of nested RT-PCR. MV-RNA was detected in virus isolation-negative throat swabs on SYBR Green RT-PCR.
SYBR Green RT-PCR is a highly sensitive, rapid, and useful diagnostic procedure for the detection of MV.
Available from: Antoine Garbarg-chenon
- "MV-RNA can be detected in a large variety of samples, including blood, throat swabs, nasopharyngeal aspirates, urine, and oral fluid, an alternative non-invasive, easy to collect sample, recommended by the WHO for the European measles elimination program [CDC, 2008; Hutse et al., 2010; Rota et al., 2011]. Although numerous molecular techniques for MV- RNA detection have been described [van Binnendijk et al., 2003; Ozoemena et al., 2004; Tischer et al., 2004; El Mubarak et al., 2005; Fujino et al., 2005; Hummel et al., 2006; Hubschen et al., 2008; Akiyoshi et al., 2010; Ito et al., 2010; Rota et al., 2011], few studies have evaluated the combined use of serological and molecular methods for measles diagnosis [van Binnendijk et al., 2003; Tischer et al., 2004; Hyde et al., 2009; Sanz et al., 2010]. Only a small number of studies have evaluated the use of molecular techniques in the context of MV outbreaks [Mosquera et al., 2005] and data concerning MV-RNA detection in oral fluid samples are limited [van Binnendijk et al., 2003; Hutse et al., 2010]. "
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ABSTRACT: During the 2011 measles outbreak in Paris (France), patients with clinical suspicion of measles were tested for virological confirmation of measles virus (MV) infection. To assess the practical value of molecular diagnosis in an epidemic setting, 171 oral fluid samples and 235 serum samples collected from 270 patients were tested prospectively for MV-RNA using a novel one-step real-time RT-PCR assay including an internal control. Serum samples were also tested for MV-specific IgG and IgM antibodies. MV infection was confirmed by detection of MV-RNA and/or MV-IgM for 229 of the 270 patients. The results for the 102 cases with both serum and oral fluid samples available were used to compare the techniques. The detection rate of MV-RNA by RT-PCR was 98% (100/102) for oral fluid and 95% (97/102) for serum samples. The detection rate of MV-IgM was 85% (87/102). Negative MV-IgM results were observed mostly for serum samples collected early after the onset of the rash. A MV-RNA standard of known concentration obtained by in vitro transcription was used to quantify MV-RNA in samples. MV-RNA copy numbers were significantly higher in oral fluid than in serum samples, but did not correlate with time of sampling (within 1 week after the onset of the rash), patient age, or vaccination status. During the early stage of infection, the MV-RNA viral load in serum was lower in patients positive than in those negative for MV-IgG. In conclusion, the one-step real-time RT-PCR assay is a simple and sensitive tool suitable for MV diagnosis within hours. J. Med. Virol. © 2013 Wiley Periodicals, Inc.
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ABSTRACT: Since the confirmation of measles cases represents an important indicator regarding the performance of the measles-elimination program, the aim of this study was to evaluate the effectiveness of the routine procedures followed in Morocco for the laboratory confirmation of measles cases. Suspected cases reported between January 2010 and December 2012 were assessed for the timeliness of the sample collection, occurrence of measles clinical symptoms, and the results of the laboratory diagnoses. For 88% of the 2,708 suspected cases, a clinical specimen was collected within 7d of rash onset, of which 50% were IgM-positive and 2.6% were equivocal. The measles symptoms were reported in 91.4% of the cases; the occurrence of symptoms showed a positive association with the serological results (odds ratio [OR] = 2.9883, 95% confidence interval [CI] 2.2238–4.0157). Of the negative samples, 52% (n = 116) tested positive by real-time polymerase chain reaction (PCR). These results are in favor of using molecular detection to complement serological diagnosis in the context of measles surveillance approach in Morocco. In addition, the introduction of additional laboratory methods for differential diagnosis is required for the final classification of suspected cases with maculopapular rash and fever in the context of the measles elimination program.
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