G Boivin

..A good correlation was generally found between replication kinetics of DNA pol mutants and their neurovirulence potential in mice whereas such correlation was not straightforward for TK mutants...

..Thus, active viral replication as determined by a high CMV DNA load in PBL is reflected by expression of the late CMV transcript in the same cells and by the presence of CMV DNA in plasma...

..Despite its major effects related to bronchiolitis, pneumonia and its potential role in recurrent wheezing episodes, there is still no commercial treatment or vaccine available against this paramyxovirus...

..Moreover, hMPV, compared to other paramyxoviruses and to the human immunodeficiency virus, seems to be more susceptible to HRA- than HRB-derived peptides...

..We sought to describe the epidemiological, virological, and histopathological findings associated with a large outbreak of hMPV infection in a long-term care facility...

..On the other hand, TLR9 antagonists can be helpful to control the inflammatory response that could be detrimental after infection...

..In conclusion, amino acid changes at residue I223 may alter the NAI susceptibilities of pH1N1 variants without compromising fitness. Consequently, I223R and I223V mutations, alone or with H275Y, need to be thoroughly monitored...

..Our data indicate that the adjuvanted vaccines tested in this study can elicit stronger, more persistent, and broader immune responses against A/H3N2 strains than nonadjuvanted inactivated influenza vaccines...

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..Thus, emergence of CMV UL54 mutations in the absence of UL97 mutations is a rare but possible event that is not necessarily associated with detrimental clinical outcome in solid organ transplant recipients...

..These findings suggest that HMPV can be associated with severe lower-respiratory-tract infections in very young children, the elderly, and immunocompromised patients...

..Palivizumab is a humanized monoclonal antibody that prevents severe human respiratory syncytial virus (HRSV) infections...

..HMPV is an important cause of illness in young children with a similar, although less severe, clinical presentation to that of HRSV...

..The observed minimal overlap in VNTR patterns between the 2 communities was consistent with sequential, small outbreaks from local sources...

..3% vs. 20.7%). These virological results support the clinical benefit provided by early therapeutic intervention of influenza illness...

..Development of influenza drug resistance is an important problem in immunocompromised children that could result in treatment failure and viral transmission to others...

..Little information is available on the incidence, clinical manifestations and epidemiologic features of HCoV-NL infections...

..Although group A strains predominated, accounting for 69% of all strains, as many B as A strains were found in persons >3 years of age...

..This article presents the current evidence for these and other guidelines for the diagnosis of herpesvirus infections of the CNS...

..Additionally, no CMV resistance mutations were observed in non-lung transplant patients receiving valganciclovir...

..Few studies have performed sequential evaluation of the herpes simplex virus (HSV) load using quantitative PCR during episodes of herpes labialis...

..6%-74.8%, 73.4%-73.6%, and 97.0%-97.1% when compared to HPeV-1, -2, and -3 prototype strains, respectively. Although different, our isolates were closely related; amino acid identity was 99.6%-100% for the last 3 proteins...

..Valganciclovir was associated with negligible risk of resistance and thus constitutes a useful alternative to ganciclovir prophylaxis for CMV in high-risk SOT recipients...

..We evaluated the effect of pretreatment with Toll-like receptor (TLR) agonists in a mouse model of herpes simplex virus type 1 (HSV-1) encephalitis...

..The rate of cytomegalovirus (CMV) mutations conferring ganciclovir resistance was assessed in a trial comparing intravenous ganciclovir and oral valganciclovir for treatment of CMV disease in solid organ transplant (SOT) recipients...

..The use of intravenous ganciclovir or foscarnet therapy to treat cytomegalovirus disease did not affect the HHV-8 DNA load in seven patients for whom serial samples were analyzed...

..03 after adjusting for the initial virus titer and the time between onset of symptoms and treatment). Resistance to zanamivir was not detected in virus isolates by either phenotypic or genotypic assays...

..A positive result by this test seems particularly important since this implies, in most instances, the presence or the imminence of CMV disease, although a negative test result does not rule out disease...

..8%, 39.3%, 77.6%, and 55.0%, respectively...

..The rate of positivity of the FLU OIA test (41.5%) was significantly lower than that of cell culture (55.2%) or reverse transcription-PCR (55.9%) during a season in which only influenza A virus was detected...

..The rate of emergence of ganciclovir-resistant viruses with use of oral valganciclovir is no greater than that reported with use of intravenous ganciclovir...

..These results confirm animal studies reported elsewhere regarding the genetic stability of influenza M2 mutants and their potential for transmission in humans...

..87 nM) viruses. Oseltamivir carboxylate was more active than zanamivir for influenza A(H3N2) isolates (mean IC(50): 0.73 vs. 2.09 nM) whereas it was less potent against B viruses (mean IC(50): 11.53 vs. 4.15 nM)...

..We conclude that, among the influenza virus-negative preselected cases of this study, rhinoviruses were relatively frequent pathogens associated with important respiratory and systemic symptoms...

..The replication capacity of both mutants, in particular that of the His274Tyr virus, was impaired when compared with the wild-type virus in vitro...

..Alterations in both conserved and nonconserved regions of the TK gene were shown to confer high levels of resistance to ACV...

..Our studies suggest that molecular analysis of the HA1 gene should complement the HI assay for a more accurate analysis of influenza A virus drift...

..Drug-resistant cytomegalovirus (CMV) infections can cause significant morbidity among high-risk transplant recipients...

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..In this study of clinical HSV isolates, DNA pol mutations conferring foscarnet resistance were not associated with decreased acyclovir or cidofovir susceptibility...

..Frequent monitoring of the CMV viral load and/or mutational studies are warranted in highly immunocompromised transplant recipients to prevent the development of CMV disease caused by ganciclovir-resistant strains...

..CONCLUSIONS: Some thymidine kinase HSV mutants associated with drug resistance may retain their pathogenicity at least in the mouse model described in this study...

..Two infected patients (1 child with leukemia and a 78-year-old woman) died of septic shock and severe pneumonia, respectively...

..This animal model will be of a great benefit in the evaluation of novel therapeutic and prophylactic modalities...

..Two clades of HBoV were identified. The pathogenic role of HBoV in RTIs is uncertain because it was frequently detected in symptomatic and asymptomatic children and was commonly found with other viruses in symptomatic children...

..This new system allows a rapid and accurate evaluation of the functional role of various DNA Pol mutations, which should translate into improved management of drug-resistant HSV infections...

..In conclusion, real-time PCR assays aimed at amplifying the N and L genes which are coding for two internal viral proteins appear particularly suitable for hMPV diagnostic...

..61 microM), adefovir (18.00 microM), acyclovir (31.00 microM), and foscarnet (34.15 microM). The potential therapeutic efficacy for HHV-8 (i.e., peak serum drug level/IC(50)) is highest for cidofovir (167) and foscarnet (22)...

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..We performed a surveillance study of outpatients who presented with fever and respiratory symptoms to examine the role of viral pathogens in these patients...

..It suggests that certain drug-resistant NA mutants may still be virulent although additional studies using clinical isolates are needed to confirm our results...

..The zanamivir-selected variant had a massive deletion in the region encoding the NA active center and an A200T hemagglutinin mutation. This variant exhibited reduced susceptibility to zanamivir with a drug-dependent phenotype...

..These findings could help explain the frequent emergence and transmission of amantadine-resistant influenza viruses during antiviral pressure in the clinical setting...

..The aim of this study was to characterize the role of two HCMV DNA polymerase mutations (K805Q and T821I) found in a ganciclovir- and foscarnet-resistant clinical isolate from an AIDS patient...

..Group A and genotype GA2 strains were associated with greater severity of hRSV disease than were group B strains...

..Phylogenetic analysis confirmed the relatedness between Can82853-01 and A308/99 and their divergence from other picornaviruses...

..5 and 98.9% compared to 81.6 and 94.7% for the antigenic test. In conclusion, our multiplex real-time PCR assay combines both rapidity and sensitivity for detecting the most important respiratory viral pathogens in children...

..Our results provide a new model allowing the investigation of the potential benefit of using NA inhibitors in the treatment of HIV-1-infected patients suffering from coinfection with NA-bearing pathogens...

..6-fold compared to pre-foscarnet or wild-type isolates) suggesting that adefovir-resistant HSV could be selected in vivo by foscarnet therapy...

..A-322278 decreased mortality rates and lung virus titers significantly more than oseltamivir in mice infected with the NA H274Y mutant when therapy was started 4 h before or even 48 h after infection...

..Hydroxyurea, a ribonucleotide reductase inhibitor, can increase the activity of nucleoside/nucleotide analogues against drug-resistant viruses...

..This study highlights the diversity of mechanisms of resistance to oseltamivir in clinical settings, reinforcing the need for novel anti-influenza strategies...

..We report the case of a young, immunocompromised child who had severe lower respiratory tract infections during two consecutive winter seasons caused by genetically distinct HMPV strains...

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..These results suggest that the pathogenesis of the two HHV8-associated diseases (i.e., KS and MCD) might be different, as only the latter was associated with important viremia in our patients...

..Self-isolation only until fever abates appears insufficient to limit transmission. Self-isolation for a week may be more effective, although some case-patients still would shed infectious virus...

..1%) of 145 adult patients who presented to the emergency department for pneumonia or acute exacerbation of chronic obstructive pulmonary disease during 2 winter/spring seasons in Quebec, Canada...

..Furthermore, the H274Y mutant strain was transmitted to ferrets. In conclusion, viral fitness of the H274Y pH1N1 isolate is not substantially altered and has the potential to induce severe disease and to disseminate...

..The two methods yielded concordant results for 94.1% of specimens. These tests allowed a thorough etiological assessment of respiratory viruses infecting children in hospital settings and would assist public health interventions...

..Our study shows the importance of the HA1 229 residue in virus binding to MDCK cells and confirms the unreliability of cell-based assays in predicting the in vivo susceptibility of HA variants to NAIs...

..Prior infection with either hMPV or influenza A virus predisposes mice to severe pneumococcus infection...

..Ribavirin significantly decreased both hMPV replication in lungs (by 5 log10) and global pulmonary inflammation on day 5 postinfection, whereas glucocorticoids reduced only alveolar and interstitial inflammation, compared to controls...

..All recombinant viruses containing these unknown mutations were found to be susceptible to ganciclovir...

..No commercial treatments are yet available for hMPV, although ribavirin has shown activity both in vitro and in animal models. Live attenuated vaccines produced by reverse genetics have also shown good efficacy in animals...

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..Human metapneumovirus (hMPV) is associated with acute respiratory tract infections (ARTI) in patients from all age groups...

..These results confirm the potent inhibitory effect of A-315675 against oseltamivir-resistant influenza viruses of the N1 and N2 subtypes and support the clinical development of its bioavailable prodrug A-322278...

..Our data demonstrate the risks associated with immunization using inactivated hMPV in this animal model and that this aberrant response should be considered in the development of hMPV vaccines...

..This transfer is deviant in mice lacking E(2), which allows pathogens to hide from immune surveillance and exacerbates neuronal damages during viral encephalitis...

..These results constitute a first step towards facilitating our understanding of drug resistance mechanisms for CMV and the interpretation of novel viral mutations...

..radicum into North America, probably via the north-eastern coast (New York area) from north-western Europe. The implications of this study in assisting selection of natural enemies of this important agricultural pest are discussed...

..The expression of the HSV TK gene in Leishmania provides an easy, reliable, and sensitive assay for evaluating HSV susceptibility to nucleoside analogues and for assessing the role of specific viral TK mutations...

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..Based on plaque size, yield assays, and NA activity, the impaired viral fitness of the E119V mutant was partially restored by the I222V NA mutation...

..There is a need to develop new antiherpetic compounds with different mechanisms of action...

..Compared to hemagglutination inhibition, microneutralization demonstrated a higher level of concordance with RT-PCR (kappa = 0.69 versus kappa = 0.60) and greater sensitivity (83% versus 71%; P = 0.016)...

..cholerae can revert to the pathogenic, transmissible state. We concluded that V. cholerae O1 is a resident of Argentinean waters, as has been shown to be the case in other geographic regions of the world...