Leo Lm Poon

..However, the low viral load in the respiratory tract makes early diagnosis of SARS a diagnostic challenge, although improvements in the sensitivity of molecular diagnostic methods continue to be made...

..Thus, the findings of this study suggest that bats may play an integral role in the ecology and evolution of coronaviruses...

..This effect was not observed in cells treated with RNAPII kinase inhibitors. In addition, the loss of RNAPII(a) in infected cells was due to the shift of nonphosphorylated RNAPII (RNAPII(a)) to hyperphosphorylated RNAPII (RNAPII(o))...

..The observations suggested that, with the cooperation between the homologous 5' and 3'segment-specific sequences, the introduced mutations could specifically enhance the replication of NA and NS vRNA...

..Since respiratory epithelial cells are the primary target cell for replication of influenza viruses, it is pertinent to investigate the cytokine induction profile of H5N1 viruses in these cells...

..A better understanding of viral evolution and host adaptive responses might help control this disease...

..We compared the abilities of conventional and real-time reverse transcription-PCR (RT-PCR) assays to detect SARS CoV in clinical specimens...

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..The aim of the present work was to develop a simple, inexpensive molecular test for Plasmodium falciparum...

..In particular, 63% (12 of 19) of fecal samples from Miniopterus pusillus were positive for the virus. These findings suggest that this virus might be commonly circulating in M. pusillus in Hong Kong...

..The simpler operation of LAMP might be a possible solution for on-site diagnosis...

..Molecular assays currently available for detection of SARS-coronavirus (SARS-CoV) have low sensitivity during the early stage of the illness...

..These possible reassortment events might alter virulence and/or transmissibility of the new reassortants. Investigations to detect such possible reassortants should be included as a part of pandemic influenza surveillance plans...

..Our results were correlated 100% with results deduced from routine clinical diagnostic tests. In addition, we also developed a LAMP assay specific for human beta-actin cDNA as a quality control test...

..There are few data in the literature on viral sequence variation between host generations/successive transmission events. Relatively little is known about the sequence heterogeneity of the influenza viruses transmitted within families...

..Together, these results confirm that HK-39 is a novel and distinct member of the Coronaviridae family, with unknown origin. The completion of the genomic sequence of the virus will assist in tracing its origin...

..These findings highlight that co-infections of some coronaviruses might be common events in nature. The biological basis for the host restriction of bat coronaviruses, however, is yet to be determined...

..The acquisition by the viruses of characteristics that enhance virulence in humans and waterfowl and their potential for wider distribution by infected migrating birds are causes for renewed pandemic concern...

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..The detection of SCoV-like viruses in small, live wild mammals in a retail market indicates a route of interspecies transmission, although the natural reservoir is not known...

..This study demonstrates the importance of systematic virological surveillance in market animals for understanding the evolution and emergence of viruses with infectious potential...

..An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients...

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..However, several reports have shown that conventional and real-time PCR assays were very specific for SARS CoV but lack sensitivity depending on the assay, specimen, and time course of disease...

..These results provide further evidence of the pivotal role of the live poultry market system of southern China in generating increased genetic diversity in influenza viruses in this region...

..These findings are likely to provide new insights into the ecology and evolution of astroviruses and reinforce the role of bats as a reservoir of viruses with potential to pose a zoonotic threat to human health...

..The internal gene constellation is also different from H5N1/97, but these variants have the potential for further reassortment events that may allow the interspecies transmission of the virus...

..Testing more than one respiratory specimen will maximize the sensitivity of PCR assays for SARS CoV...

..There is a need for awareness of cross-reactive antibody responses between coronaviruses when interpreting IF serology...

..Here, we review some of the recent developments in this area...

..Our study provides insight into the ongoing evolution of H5N1 influenza viruses that are transmitting in diverse avian species and at the interface between avian and human hosts...

..Continued reassortment of H1N1/2009 with swine influenza viruses could produce variants with transmissibility and altered virulence for humans. Global systematic surveillance of influenza viruses in swine is warranted...

..The biological basis for the severity of human H5N1 disease has remained unclear. We tested the hypothesis that virus-induced cytokine dysregulation has a role...

..These results also indicated that the M2 ion-channel protein is critical, but not essential, for virus replication in cell culture. This approach may provide a new way of producing attenuated influenza A virus...

..A novel swine origin influenza virus (S-OIV) (H1N1) is spreading worldwide and threatens to become pandemic...

..We now demonstrate that ex vivo cultures of human nasopharyngeal, adenoid and tonsillar tissues can be infected with H5N1 viruses in spite of an apparent lack of these receptors...

..The type I IFN receptor signaling pathway in host cells is mainly involved in the inhibition of SCoV infection and replication. Type I IFNs could be used as potential agents for anti-SARS treatment...

..The nucleic acids recovered by all three methods gave comparable sensitivities in PCR tests, and the three methods gave comparable viral loads. There was no evidence of residual PCR inhibitors and no evidence of PCR cross-contamination...

..A mutation in the spike gene (residue 24079) appeared to be unique to adaptation in FRhK4 cells. It is important to be aware of cell culture associated mutations when interpreting data on molecular evolution of SARS coronavirus...

..Furthermore, together with previously described viral enzymes, they will be important targets for the design of antiviral strategies aimed at controlling the further spread of SARS-CoV...

..The viral genome contains eight RNA viral segments and the functions of viral proteins encoded by this genome are described. In addition, the RNA transcription and replication of this virus are reviewed...

..These results demonstrate that plant-derived siRNAs can inhibit viral propagation through RNA interference and could potentially be applied in control of viral-borne diseases...

..The reaction products were specific and could be used for direct DNA sequencing. These assays might be useful tools to study the sequences of these genes...

..The poor induction of IFN-beta, a key component of innate immunity, and the ability of the virus to induce chemokines could explain aspects of the pathogenesis of SARS...

..To our knowledge, there have been no comprehensive studies investigating viral infection at the cellular level in humans...

..Combinations of virus-neutralizing, noncompeting mAbs may have these properties...

..13 x 10(6) copies per ml, from a 35-year-old woman with pneumonia. Our data support the existence of a novel group 2 coronavirus associated with pneumonia in humans...

..Mortality data for patients with SARS should be interpreted in light of age, comorbidity and viral load. These considerations will be important in future studies of SARS...

..This is confirmed by analytical ultracentrifugation and dynamic light scattering. We show that nsp9 binds RNA and interacts with nsp8, activities that may be essential for its function(s)...

..We found a large variation in the apparent strength of binding of different homopolynucleotides, with dT24 binding over 10 times more strongly than dA24 as observed by the apparent Km...

..The high-throughput capacity of this procedure and the safety of using SARS pseudoviruses should make possible large-scale analyses of neutralizing antibody responses against SARS-CoV...

..CONCLUSIONS: These results represent the first use of fetal epigenetic markers in noninvasive prenatal analysis. These data may also have implications for the investigation of other types of chimerism...

..Thus, homozygosity for L-SIGN plays a protective role during SARS infection...

..The case definition of SARS should acknowledge the range of lung pathology associated with this disease...

..The assay was tested by using a panel of highly pathogenic H5N1 subtypes isolated over the past 10 years and clinical specimens. The assay produced negative results for all non-H5N1 subtypes...