368 research outputs found
Quantitative real-time PCR detection of Zika virus and evaluation with field-caught mosquitoes
No full textBACKGROUND Zika virus (ZIKV), a mosquito borne flavivirus is a pathogen affecting humans in Asia and Africa. ZIKV infection diagnosis relies on serology-which is challenging due to cross-reactions with other flaviviruses and/or absence or low titer of IgM and IgG antibodies at early phase of infection- virus isolation, which is labor intensive, time consuming and requires appropriate containment. Therefore, real-time RT-PCR (rRT-PCR) is an appealing option as a rapid, sensitive and specific method for detection of ZIKV in the early stage of infection. So far, only one rRT-PCR assay has been described in the context of the outbreak in Micronesia in 2007. In this study, we described a one step rRT-PCR for ZIKV which can detect a wider genetic diversity of ZIKV isolates from Asia and Africa. RESULTS The NS5 protein coding regions of African ZIKV isolates were sequenced and aligned with representative flaviviruses sequences from GenBank to design primers and probe from conserved regions. The analytical sensitivity of the assay was evaluated to be 32 genome-equivalents and 0.05 plaque forming unit (pfu). The assay was shown to detect 37 ZIKV isolates covering a wide geographic in Africa and Asia over 36 years but none of the 31 other flaviviruses tested showing high analytical specificity. The rRT-PCR could be performed in less than 3 hours. This method was used successfully to detect ZIKV strains from field-caught mosquitoes. CONCLUSION We have developed a rapid, sensitive and specific rRT-PCR for detection of ZIKV. This assay is a useful tool for detection of ZIKV infection in regions where a number of other clinically indistinguishable arboviruses like dengue or chikungunya co-circulate. Further studies are needed to validate this assay in clinical positive samples collected during acute ZIKV infection
One-step RT-PCR for detection of Zika virus
No full textBackground: Zika virus (ZIKV) is an emerging mosquito-borne flavivirus circulating in Asia and Africa. Human infection induces an influenza-like syndrome that is associated with retro-orbital pain, oedema, lymphadenopathy, or diarrhea. Diagnosis of Zika fever requires virus isolation and serology, which are time consuming or cross-reactive. Objective: To develop a one-step RT-PCR assay to detect ZIKV in human serum. Study design: An assay targeting the envelope protein coding region was designed and evaluated for its specificity, detection limit, repeatability, and capacity to detect ZIKV isolates collected over a 40-year period from various African countries and hosts. Results: The assay's detection limit and repeatability were respectively 7.7 pfu/reaction and 100% in serum and L-15 medium; none of 19 other flaviviruses tested were detected. Conclusions: The assay is rapid, sensitive, and specific to detect ZIKV in cell culture or serum, but needs to be validated for diagnosis using clinical samples
Preparation of the new binucleating ligand 2,6-Bis(carboxymethylsulfanylmethyl)-4-methylphenol and its mono-and bi-nuclear complexes.
No full textMono- and bi-nuclear complexes of transition metals have been prepared by the reaction of 2,6-bis(carboxymethyl-
sulfanylmethyl)-4-methylphenol (H3L) with the appropriate metal salt
Zahedan rhabdovirus, a novel virus detected in ticks from Iran
No full textBackground: Rhabdoviridaeinfect a wide range of vertebrates, invertebrates and plants. Their transmission can occur via various arthropod vectors. In recent years, a number of novel rhabdoviruses have been identified from various animal species, but so far only few tick-transmitted rhabdoviruses have been described. Methods: We isolated a novel rhabdovirus, provisionally named Zahedan rhabdovirus (ZARV), fromHyalomma anatolicum anatolicumticks collected in Iran. The full-length genome was determined using 454 next-generation sequencing and the phylogenetic relationship to other rhabdoviruses was analyzed. Inoculation experiments in mammalian Vero cells and mice were conducted and a specific PCR assay was developed. Results: The complete genome of ZARV has a size of 11,230 nucleotides (nt) with the typical genomic organization ofRhabdoviridae. Phylogenetic analysis confirms that ZARV is closely related to Moussa virus (MOUV) from West Africa and Long Island tick rhabdovirus (LITRV) from the U.S., all forming a new monophyletic clade, provisionally designatedZamolirhabdovirus, within theDimarhabdovirussupergroup. The glycoprotein (G) contains 12 conserved cysteins which are specific for animal rhabdoviruses infecting fish and mammals. In addition, ZARV is able to infect mammalian Vero cells and is lethal for mice when inoculated intracerebrally or subcutaneously. The developed PCR assay can be used to specifically detect ZARV. Conclusion: The novel tick-transmitted rhabdovirus ZARV is closely related to MOUV and LITRV. All three viruses seem to form a new monophyletic clade. ZARV might be pathogenic for mammals, since it can infect Vero cells, is lethal for mice and its glycoprotein contains 12 conserved cysteins only found in animal rhabdoviruses. The mammalian host of ZARV remains to be identified
A recombinase polymerase amplification assay for rapid detection of rabies virus
No full textRabies is a generally fatal encephalitis caused by a negative-sense single-stranded RNA lyssavirus transmitted to humans mainly from dog bite. Despite the recommendation by WHO and OIE to use the direct immunofluorescence test as standard method, molecular diagnostic assays like reverse transcription quantitative polymerase chain reaction (RT-qPCR) are increasing as a confirmatory method. However, both technologies are inaccessible in resource-limited settings. Moreover, the available point-of-need molecular assay is of poor detection limit for African strains. Herein, we developed a reverse transcription recombinase polymerase amplification (RT-RPA) assay as potential point-of-need diagnostic tool for rapid detection of various strains of rabies virus including locally isolated African strains. The sensitivity and specificity of the method was evaluated using a molecular RNA standard and different Rabies-related viruses belonging to the Rhabdoviridea family, respectively. The RABV-RPA performances were evaluated on isolates representative of the existing diversity and viral dilutions spiked in non-neural clinical specimen. The results were compared with RT-qPCR as a gold standard. The RABV-RPA detected down to 4 RNA molecules per reaction in 95% of the cases in less than 10 min. The RABV-RPA assay is highly specific as various RABV isolates were identified, but no amplification was observed for other member of the Rhabdoviridea family. The sample background did not affect the performance of the RABV-RPA as down to 11 RNA molecules were identified, which is similar to the RT-qPCR results. Our developed assay is suitable for use in low-resource settings as a promising alternative tool for ante-mortem rabies diagnosis in humans for facilitating timely control decisions
Zum Telos des Philänenexkurses in Sall. Iug. 79
No full textThe tale of the Philaeni brothers in Sall. Iug. 79 not only brings the description of the war to a halt, it also pleases the reader. Moreover, it is used by the author as a reflection point, when it comes to Marius appealing to his audience only six chapters after the digression. Marius’ concept of virtus as well as that of Sallust himself as shown in the prooemium is illustrated by the heroic feat of the two Carthaginians who give their life for their people.Рассказ о братьях Филенах (Sall. Iug. 79) нужен не только ради ретардации в повествовании о войне, но и ради удовольствия читателя. Более того, он подготавливает к восприятию речи Мария, которая расположена на шесть глав ниже. Подвиг двух карфагенян, отдавших жизнь за свой народ, иллюстрирует категорию virtus в понимании Мария, а судя по проэмию – и самого Саллюстия
Evaluation of On-site Treatment and Disposal of Domestic Wastewater in an Unsewered Urban Developing Countries : A Case Study of Dakar-Pikine, Senegal
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