Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In four composting experiments, survival of avian influenza (AI) and Newcastle disease (ND) viruses was assessed by virus isolation in embryonated chicken eggs (ECEs) and by real-time reverse transcriptase-polymerase chain reaction. Specimens contained in nylon mesh bags consisted of 20-g samples of chicken manure, used litter, or feed that had been inoculated with allantoic fluid containing an AI virus (H6N2, Expt. 1) or an ND vaccine virus (Expt. 2). Other specimens consisted of 20-g samples of infected ECEs that had been homogenized and mixed with corn silage. As a control, allantoic fluid diluted in phosphate-buffered saline was contained in sealed vials. Except for the feed, in which the AI virus was inactivated soon after the specimen was inoculated, on day 0 the specimens buried in compost or placed outside at ambient temperatures contained at least 5.0 log10 of virus and 7.7 log10 of viral RNA. By day 7, temperatures in compost ranged from 50 C to 65 C, and viruses had been killed in all specimens in bags. In comparison, viruses in sealed vials remained viable to day 10. Viral RNA in mesh-bag specimens had been degraded to nondetectable levels by day 10, but it was still detected in sealed vials on day 21. In specimens that were held at ambient temperatures (13 C-28 C), the viruses in mesh-bag specimens were inactivated by day 21, but their RNA was still detected. In comparison, the viruses in sealed vials survived to day 21. In Expts. 3 and 4, viruses were inactivated in carcass specimens and in whole ECEs during composting. In an in vitro experiment, the time required for a 1-log10 reduction of viruses was significantly shorter (P < 0.05) in water extracts from compost than in phosphate buffers at temperatures of 25 C to 45 C. This study provided evidence that microbial activity during composting contributed to the rapid killing of AI and ND viruses and to the degradation of their viral RNA.
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PMID:Survival of avian influenza and Newcastle disease viruses in compost and at ambient temperatures based on virus isolation and real-time reverse transcriptase PCR. 1943

We developed a reverse transcriptase polymerase chain reaction (RT-PCR) method for the detection of duck hepatitis virus type 1 (DHV-1) in the tissues of infected and clinically affected ducks and in chick and duck embryos. We found the assay to be effective in detecting the virus in China, where it is being used in studies on the epidemiology of the disease. We applied this simple and rapid diagnostic method to the detection of DHV isolates grown in chick and duck embryos and in tissues obtained from infected birds. The assay also proved useful for the differentiation of DVH from the duck plague virus (DPV), muscovy parvovirus (MPV), gosling parvovirus (GPV), avian influenza virus (AIV/H5N1), Pasteurella multocida (PA/5:A), Riemerella anatipestifer (RA/serotype 1), and Salmonella enteritidis (SE). The limit of the sensitivity of this method for the detection of DHV-1 RNA was 3 pg/10 microl. As compared to Dot-ELISA and virus isolation, the rate of agreement for the detection of experimentally infected livers was 100%; moreover, the RT-PCR method was also capable of detecting DHV-1 RNA from the livers that had been infected and stored at -20 degrees C for 22 years; in contrast, Dot-ELISA and virus isolation method could only detect DHV-1 from the livers that had been infected and stored at -20 degrees C for 13 and 11 years, respectively. The rate of positivity in 185 clinically suspected diseased livers subjected to detection by RT-PCR, Dot-ELISA, and virus isolation was 89.2%, 69.2%, and 55.7%, respectively. These results indicated that the RT-PCR approach is rapid, sensitive, and reliable for the detection and differentiation of DHV-1 from the other clinical samples and suspected isolates.
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PMID:Development and application of a reverse transcriptase polymerase chain reaction to detect Chinese isolates of duck hepatitis virus type 1. 1870 44

The objectives of this study were to determine the survival of avian influenza virus (AIV) subtype H5N1 under various physical and chemical treatments, including disinfectants, temperature and pH. The highly pathogenic AIVs subtype H5N1 were isolated from internal organs of suspected chickens and were characterized by the inoculation into chicken embryonated eggs (CEEs), hemagglutination (HA) test, hemagglutination inhibition (HI) test, reverse transcriptase polymerase chain reaction (RT-PCR) and nucleotide sequencing of hemagglutinin (H) and neuraminidase (N) genes. Three H5N1 isolates, at the concentration of 10(9) 50% embryo lethal dose (ELD(50))/ml, were used for the determination of the survival of the virus under different chemical and physical treatments. The chemical treatments were performed by incubating the viruses with various types of disinfectants including glutaraldehyde (Glu), hydrogen peroxide, quaternary ammonium compounds (QAC), Glu+QAC, iodine, chlorine, formalin and phenol, at 25 and 37 degrees C, for 0, 5, 7, and 14 days. The physical treatments included incubation of the viruses at 55, 60, 65, 70 and 75 degrees C for 10, 15, 30, 45 and 60 min or pH 3, 5, 7, 9 and 12. The results revealed that AIV H5N1 reference viruses, 2004.1, CUK-2/04 and 2004.2, showed low or no resistance against Glu+QAC, chlorine and phenol at both tested temperatures. Incubations at 70 degrees C for 60 min or at least 75 degrees C for at least 45 min could effectively inactivate all of the isolates, whereas all ranges of pH could not inactivate any of them. In this study, CUK-2/04 was more resistant to the disinfectants, temperatures, and pH compared to the other isolates.
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PMID:The inactivation of avian influenza virus subtype H5N1 isolated from chickens in Thailand by chemical and physical treatments. 1963 71

A pandemic caused by a novel influenza A virus (H1N1) poses a serious public health threat. In this study, a real-time reverse transcriptase PCR (RT-PCR) assay based on the hemagglutinin gene was developed that discriminates the novel H1N1 from swine influenza virus, seasonal H1N1/H3N2 virus and the highly pathogenic H5N1 avian influenza virus. The sensitivity of this assay was 0.2 50% tissue culture infective dose of virus and 200 copies of in vitro-transcribed target RNA. Three hundred and forty-eight clinical specimens from suspected H1N1 patients were tested using this assay, and forty-two (12.07%) were found to be positive. Tests using the real-time PCR assay recommended by WHO and virus isolation gave identical results. This sensitive and specific real-time RT-PCR assay will contribute to the early diagnosis and control of the emerging H1N1 influenza pandemic.
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PMID:Development of a real-time RT-PCR assay for a novel influenza A (H1N1) virus. 1981 30

In the spring of 2009, a novel (H1N1) influenza A virus began to spread among humans worldwide. Although the 2009 H1N1 is related genetically to swine influenza viruses, human infection has not been connected to pig exposure. Because the virus is now circulating widely in the human population, swine herds are at increased risk of becoming infected. In order to investigate potential outbreaks of the 2009 pandemic virus in pigs, a quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) for the detection of the (H1N1) 2009 RNA in clinical specimens was developed. To evaluate the applicability of the test as a diagnostic tool in the screening of field specimens from swine, 64 field isolates of North American swine, 5 equine and 48 avian influenza viruses collected during diagnostic investigations were analyzed retrospectively as well as samples collected during an experimental in vivo infection with two novel H1N1 isolates, A/California/04/2009 (H1N1)v virus and A/Mexico/4108/2009 (H1N1)v. The sensitivity of the qRT-PCR was shown to be higher with respect to standard techniques such as virus isolation and the reproducibility was satisfactory. The present unique and highly sensitive assay is able to detect as little as 1 x 10(1) copies of RNA per microl of template and it represents a rapid and useful approach for the screening and quantitation of (H1N1) 2009 RNA in porcine specimens.
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PMID:One-step real-time RT-PCR for pandemic influenza A virus (H1N1) 2009 matrix gene detection in swine samples. 2000 4

Since the spread of H5N1 highly pathogenic avian influenza virus in 2005, many surveillance programmes have been initiated in poultry and wild birds worldwide. This study describes for the first time the detection of different subtypes of avian influenza viruses (AIV) in wild birds in the West Mediterranean area (Catalonia, North-Eastern Spain). During a 3-year period (from mid-2006 to mid-2009), 1374 birds from 16 different families were examined, and a total of 62 AIV were detected by means of a real-time reverse transcriptase PCR assay. AIV were more frequently detected in Anatidae, Phoenicopteridae, Rallidae and Laridae families. Of the 62 positive samples, 28 AIV could be isolated in embryonated eggs. All isolates were subtyped by haemagglutinin and neuraminidase inhibition techniques and 10 different haemagglutinins (HA) and 7 neuraminidases (NA) were found in 13 different subtype combinations. The most common combinations were H4N6 (22.2%) and H1N1 (18.5%). The HA and NA gene sequences of different AIV subtypes were compared and aligned with those available AIV strains from genome databases. Our studies on AIV phylogenetic analysis revealed that all AIV genes sequenced from wild birds in North-Eastern Spain clustered within Eurasian avian clades, including the sequences of H8, N4 and N5 genes analyzed for the first time in Europe. The results contribute to the understanding of AIV in the Mediterranean area and in Europe.
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PMID:Influenza A virus subtypes in wild birds in North-Eastern Spain (Catalonia). 2004 39

Wild birds have been implicated in the spread of highly pathogenic avian influenza (HPAIV) of the H5N1 subtype, prompting surveillance along migratory flyways. Sampling of wild birds is often conducted in remote regions, but results are often delayed because of limited local analytical capabilities, difficulties with sample transportation and permitting, or problems keeping samples cold in the field. In response to these challenges, the performance of a portable real-time, reverse transcriptase-polymerase chain reaction (rRT-PCR) unit (RAPID((R)), Idaho Technologies, Salt Lake City, UT) that employed lyophilized reagents (Influenza A Target 1 Taqman; ASAY-ASY-0109, Idaho Technologies) was compared to virus isolation combined with real-time RT-PCR conducted in a laboratory. This study included both field- and experimental-based sampling. Field samples were collected from migratory shorebirds captured in northern California, while experimental samples were prepared by spiking fecal material with an H6N2 AIV isolate. Results indicated that the portable rRT-PCR unit had equivalent specificity to virus isolation with no false positives, but sensitivity was compromised at low viral titers. Use of portable rRT-PCR with lyophilized reagents may expedite surveillance results, paving the way to a better understanding of wild bird involvement in HPAIV H5N1 transmission.
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PMID:Field detection of avian influenza virus in wild birds: evaluation of a portable rRT-PCR system and freeze-dried reagents. 2020 50

In this study, a total of 402 samples (173 cloacal swab samples, 169 tracheal swab samples and 60 organ pools including the lung, spleen, liver, trachea and brain) obtained from 27 different wild avian species from Kizilirmak delta and the adjacent wetlands in northern Turkey were surveyed for the presence of RNA from Avian influenza virus (AIV) and West Nile virus (WNV) by Taqman-based real-time reverse transcriptase-polymerase chain reaction assay. No WNV genomic RNA was detected in any sample. In contrast, AIV RNA was found in two of 402 samples (0.49%).
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PMID:Molecular detection of avian influenza virus but not West Nile virus in wild birds in northern Turkey. 2029 88

A total of 1 330 oropharyngeal swabs collected from wild and domestic birds in Lebanon were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) for type A avian influenza virus (AIV) during the migratory season between the autumn of 2005 and winter of 2006. Twenty-five species of birds were included in the study. There are 14 species of migratory wild birds, 4 species of resident wild birds, 3 species of pet birds and 4 species of farm birds. The number and percentage of positive type A avian influenza viruses in collected oropharyngeal swabs was 190 positive out of 1 330 samples tested (14.3%). The 190 oropharyngeal samples positive for AIV were further tested by specific RT-PCR for H5 and H7 subtypes. The 190 AIV-positive samples were all negative for H5, while 13 of the 190 (6.8%) were positive for H7. The H7-positive samples were confined to sparrows (resident wild bird species) and to backyard chicken in the south province, located 10-20 km from the Israeli-Lebanese border.
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PMID:Reverse transcriptase-polymerase chain reaction-based surveillance of type A influenza viruses in wild and domestic birds of the Lebanon. 2041 99

Molecular-based techniques for detecting influenza viruses have become an integral component of human and animal surveillance programs in the last two decades. The recent pandemic of the swine-origin influenza A virus (H1N1) and the continuing circulation of highly pathogenic avian influenza A virus (H5N1) further stress the need for rapid and accurate identification and subtyping of influenza viruses for surveillance, outbreak management, diagnosis and treatment. There has been remarkable progress on the detection and molecular characterization of influenza virus infections in clinical, mammalian, domestic poultry and wild bird samples in recent years. The application of these techniques, including reverse transcriptase-PCR, real-time PCR, microarrays and other nucleic acid sequencing-based amplifications, have greatly enhanced the capability for surveillance and characterization of influenza viruses.
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PMID:Methods for molecular surveillance of influenza. 2045 81


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