The kit is a valuable tool for assisting in the rapid diagnosis, patient management and epidemiology of suspected MERS-CoV cases.
A novel commercial Chikungunya virus real-time reverse transcription-PCR (RT-PCR) kit was evaluated on a comprehensive panel of original patient samples. The assay was 100% sensitive and specific in comparison to a published real-time RT-PCR. Viral loads from both assays were highly correlated. The kit proved to be suitable for routine use in patient care.Since 2005, an epidemic of Chikungunya fever has been ongoing in the Indian Ocean region (2). The disease is caused by Chikungunya virus (CHIKV), an arthropod-borne RNA virus endemic in parts of sub-Saharan Africa and Southeast Asia. Along with the current Indian Ocean epidemic, hundreds of imported cases have been reported worldwide (5, 7). In humans, CHIKV infection is characterized by acute febrile illness, rash, and severe polyarthralgia (3, 11). The clinical picture can mimic that of dengue fever or malaria, which are often coendemic (9). Definite laboratory diagnosis of CHIKV is therefore crucial for case management and prognostic appreciation. The viremic phase in infected patients is short-lived, and sensitive methods are required for accurate diagnosis. Pilot studies have shown that reverse transcription-PCR (RT-PCR) assays are reliable in diagnosing acute infections (7). Concomitantly from a public health perspective, active surveillance is of importance to contain epidemics (10). However, laboratory methods for CHIKV were not widely available before the current epidemic. We have recently demonstrated that the provision of a preformulated RT-PCR assay could significantly improve the performance of laboratories in diagnosing CHIKV infection (6). This preformulated real-time RT-PCR provided desirable features similar to other assays commercially available for more prevalent viruses, including quality-controlled oligonucleotides and RNA standards.Despite the apparent lack of diagnostic tools, the industry did not prioritize for a long time on the development of CHIKV test kits. In this study, we did the first premarket evaluation of a commercial CHIKV real-time RT-PCR kit and compared it with a published CHIKV real-time RT-PCR assay on a comprehensive panel of CHIKV patient plasma samples.The RealStar CHIKV RT-PCR kit (astra Diagnostics, Hamburg, Germany) used a target region in the nonstructural protein (nsP-1) gene similar to that of our previously evaluated in-house assay (7). The published oligonucleotides were updated upon the latest gene bank entries as of 2008. The RealStar kit claimed to provide detection of all three CHIKV genotypes (West African, East/Central African, Asian) upon addition of auxiliary oligonucleotides. Two versions of the assay were available for evaluation. One was specified for LightCycler 1.1, 1.2, 1.5, and 2.0 (Roche) and the other for ABI Prism 7000/7500 (Applied Biosystems), LightCycler 480 (Roche), and RotorGene 600 (Corbett-Research) instruments, respectively. Both versions included noncompetitive internal controls along with four external RNA standards for quantification purposes (the underlying in-house assay had a co...
Molecular detection of Bordetella pertussis DNA is a sensitive and specific method for the rapid diagnosis of pertussis. In this study, a new molecular assay for the detection and differentiation of Bordetella spp. based on automated DNA extraction and real-time PCR was evaluated. The analytical sensitivity of the new assay was determined by Probit analysis of serial dilutions of both cloned PCR products IS481 and IS1001 and cell suspensions of B. pertussis, B. parapertussis, and B. bronchiseptica. The specificity was analyzed by testing a number of pathogens producing respiratory infections. Moreover, a total of 92 clinical samples were investigated. The results were compared to those obtained by an in-house assay based on manual DNA extraction, followed by real-time PCR and detection of IS481. The analytical sensitivity of the new assay for the detection of IS481 and IS1001 was determined to be 2.2 and 1.2 genome equivalents/l, respectively. The analytical sensitivity for the detection of B. pertussis, B. parapertussis, and B. bronchiseptica was determined to be 1.6, 1.0, and 2.7 genome equivalents/l, respectively. When clinical specimens were tested with the new assay, 46 of 92 were found to be positive for Bordetella DNA. With the in-house assay, 45 samples tested positive. The new molecular assay proved to be suitable for the rapid diagnosis of pertussis in the routine diagnostic laboratory.Bordetella pertussis is the agent responsible for producing pertussis, also called whooping cough. B. parapertussis, B. bronchiseptica, and B. holmesii may also cause a pertussis-like respiratory disease but with a milder clinical course (7). Pertussis occurs worldwide, with an increased incidence among young unvaccinated infants. Neonates and elderly patients may show an atypical course of disease (2, 4). A rapid and reliable diagnostic method is thus essential for appropriate treatment and prophylaxis. Culture has been considered the gold standard for detection of B. pertussis but often lacks sensitivity, and a minimum of 4 days may be required to obtain results (1).Today, PCR has been shown to be a sensitive and specific method for the rapid diagnosis of pertussis (3,6,11). In the Bordetella genome, there are repetitive insertion sequences present in a high copy number that may be useful for the amplification of different bacterial strains. Insertion sequences include IS481 in B. pertussis, B. holmesii, and, occasionally B. bronchiseptica, and IS1001 in B. parapertussis and, occasionally, B. bronchiseptica and B. holmesii. These sequences have been reported as target sequences in several PCR protocols (5,10,13,15).In the present study, the new artus Bordetella LC PCR Kit (QIAGEN Hamburg GmbH, Germany), which includes a multiplex PCR system consisting of four independent PCRs for qualitative detection and differentiation of B. pertussis, B. parapertussis, B. bronchiseptica, and the heterologous internal control (IC), was evaluated. After we tested these methods for analytical sensitivity and specificity, clinical speci...
We investigate the pricing of cliquet options in a jump-diffusion model. The considered option is of monthly sum cap style while the underlying stock price model is driven by a drifted Lévy process entailing a Brownian diffusion component as well as compound Poisson jumps. We also derive representations for the density and distribution function of the emerging Lévy process. In this setting, we infer semi-analytic expressions for the cliquet option price by two different approaches. The first one involves the probability distribution function of the driving Lévy process whereas the second draws upon Fourier transform techniques. With view on sensitivity analysis and hedging purposes, we eventually deduce representations for several Greeks while putting emphasis on the Vega.
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