ORCID Profile
0000-0003-3027-4662
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Université Laval
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Publisher: American Society for Microbiology
Date: 03-2011
DOI: 10.1128/CVI.00449-10
Abstract: Serology improves influenza diagnosis by capturing cases missed by reverse transcriptase PCR (RT-PCR). We prospectively evaluated microneutralization and hemagglutination inhibition assays for 2009 influenza A (H1N1) virus diagnosis among 24 RT-PCR-confirmed cases and 98 household contacts. 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).
Publisher: University of Toronto Press Inc. (UTPress)
Date: 09-2022
Abstract: BACKGROUND: COVID-19 is usually a time-limited disease. However, prolonged infections and reinfections can occur among immunocompromised patients. It can be difficult to distinguish a prolonged infection from a new one, especially when reinfection occurs early. METHODS: We report the case of a 57-year-old man infected with SARS-CoV-2 while undergoing chemotherapy for follicular lymphoma. He experienced prolonged symptomatic infection for 3 months despite a 5-day course of remdesivir and eventually deteriorated and died. RESULTS: Viral genome sequencing showed that his final deterioration was most likely due to reinfection. Serologic studies confirmed that the patient did not seroconvert. CONCLUSIONS: This case report highlights that reinfection can occur rapidly (62–67 d) among immunocompromised patients after a prolonged disease. We provide substantial proof of prolonged infection through repeated nucleic acid lification tests and positive viral culture at day 56 of the disease course, and we put forward evidence of reinfection with viral genome sequencing.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2018
Publisher: American Society for Microbiology
Date: 02-2009
DOI: 10.1128/AAC.01276-08
Abstract: The new oral neuraminidase (NA) inhibitor A-322278 was evaluated in mice infected with influenza A/H1N1 wild-type virus or the oseltamivir-resistant (H274Y mutant) virus. 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.
Publisher: Massachusetts Medical Society
Date: 03-12-2009
DOI: 10.1056/NEJMC0910060
Publisher: Springer Science and Business Media LLC
Date: 12-11-2019
DOI: 10.1038/S41598-019-51877-4
Abstract: The mouse is the most widely used animal model for influenza virus research. However, the susceptibility of mice to seasonal influenza virus depends on the strain of mouse and on the strain of the influenza virus. Seasonal A/H3N2 influenza viruses do not replicate well in mice and therefore they need to be adapted to this animal model. In this study, we generated a mouse-adapted A/H3N2 virus (A/Switzerland/9715293/2013 [MA-H3N2]) by serial passaging in mouse lungs that exhibited greater virulence compared to the wild-type virus (P0-H3N2). Seven mutations were found in the genome of MA-H3N2: PA(K615E), NP(G384R), NA(G320E) and HA(N122D, N144E, N246K, and A304T). Using reverse genetics, two synergistically acting genes were found as determinants of the pathogenicity in mice. First, the HA substitutions were shown to enhanced viral replication in vitro and, second, the PA-K615E substitution increased polymerase activity, although did not alter virus replication in vitro or in mice. Notably, single mutations had only limited effects on virulence in vitro . In conclusion, a co-contribution of HA and PA mutations resulted in a lethal mouse model of seasonal A/H3N2 virus. Such adapted virus is an excellent tool for evaluation of novel drugs or vaccines and for study of influenza pathogenesis.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2005
DOI: 10.1097/01.INF.0000183743.68569.C7
Abstract: A new human coronavirus (HCoV), HCoV-NL, was recently reported for Dutch patients with acute respiratory tract infections (ARTI). Little information is available on the incidence, clinical manifestations and epidemiologic features of HCoV-NL infections. We performed a prospective study of symptomatic (case subjects with ARTI) and asymptomatic (control subjects undergoing elective surgery) children, <or=3 years of age, hospitalized in Canada during 2 winter seasons (2001-2003), to look at the prevalence of respiratory viruses. Reverse transcription-PCR assays were used to retrospectively detect HCoV-NL and to correlate its presence with clinical symptoms. HCoV-NL was detected in nasopharyngeal aspirates from 3.0% of young children (12 of 396 children) hospitalized for treatment of ARTI (case subjects), compared with 1.7% of asymptomatic control subjects (3 of 177 children) (P = 0.6). Nine (75.0%) of the symptomatic children had mixed viral infections. The mean age and mean duration of hospitalization of case subjects were 10.1 months and 4.9 days, respectively. Final diagnoses consisted of bronchiolitis or bronchitis (9 of 12 cases), pneumonitis (1 of 12 cases) and upper respiratory tract infections (2 of 12 cases), although 2 of 3 subjects with single HCoV-NL infections had upper respiratory tract infections only. Sequence analysis of the 1a and spike genes revealed that multiple HCoV-NL strains circulated in the same geographical area in each of the 2 winter seasons. Variability was more pronounced for the spike gene, with 2 clusters of strains. HCoV-NL was not a major respiratory pathogen in Canada during our study, as shown by its low detection rate in hospitalized children with ARTI, coupled with the high frequency of additional pathogens and its occasional detection in healthy children.
Publisher: MDPI AG
Date: 29-06-2019
DOI: 10.3390/PH12030101
Abstract: In 1947, Zika virus (ZIKV), a mosquito-borne flavivirus was identified in Uganda and subsequently spread to Asia and the Pacific regions. In 2015, it was introduced in Brazil causing an important social and sanitary alarm due to its increased virulence and rapid dissemination. Importantly, ZIKV infections have been associated with severe neurological complications such as Guillain–Barré syndrome and microcephaly in fetuses and newborns. Although enormous efforts were made by investigators in the development of effective countermeasures against ZIKV, there is still no approved specific antiviral drug for the treatment of ZIKV infections. Herein, we review several anti ZIKV candidates including drugs targeting both the virus (structural proteins and enzymes) and cellular elements.
Publisher: American Society for Microbiology
Date: 15-06-2010
DOI: 10.1128/JVI.02658-09
Abstract: Exploration of the genetic ersity of WU polyomavirus (WUV) has been limited in terms of the specimen numbers and particularly the sizes of the genomic fragments analyzed. Using whole-genome sequencing of 48 WUV strains collected in four continents over a 5-year period and 16 publicly available whole-genome sequences, we identified three main WUV clades and five subtypes, provisionally termed Ia, Ib, Ic, II, IIIa, and IIIb. Overall nucleotide variation was low (0 to 1.2%). The discriminatory power of the previous VP2 fragment typing method was found to be limited, and a new, larger genotyping region within the VP2/1 interface was proposed.
Publisher: Elsevier BV
Date: 02-2011
DOI: 10.1016/J.VACCINE.2010.12.023
Abstract: We evaluated the efficacy and tolerability of a single dose of the split virion AS03-adjuvanted pandemic H1N1 influenza vaccine (A/California/7/2009) in 84 HIV-1 infected in iduals. Antibody titers were determined by hemagglutination inhibition assay and by microneutralization. Vaccine was well tolerated. At 21 days post vaccination, 56 (67%) patients had seroconverted. There was no correlation between baseline CD4 cell count (p=0.539) or HIV viral load (p=0.381) and immune response. Other vaccine strategies should be evaluated in this HIV population, to improve response rates.
Publisher: American Society for Microbiology
Date: 02-2012
DOI: 10.1128/CVI.05441-11
Abstract: Influenza A/H3N2 viruses have caused the most severe epidemics since 1968 despite current immunization programs with inactivated vaccines. We undertook a side-by-side preclinical evaluation of different adjuvants (Alum, AS03, and Protollin) and routes of administration (intramuscular [i.m.] and intranasal [i.n.]) for assessing their effect on the immunogenicity and cross-reactivity of inactivated split vaccines (A/H3N2/New York/55/2004). Humoral and T cell-mediated immune responses against the homologous virus and a heterologous drifted strain (A/H3N2/Wisconsin/67/2005) were measured in BALB/c mice at 2, 6, and 19 weeks postboost. The AS03- and Alum-adjuvanted i.m. vaccines induced at least an 8-fold increase over the nonadjuvanted vaccine in functional antibody titers against both the homotypic and heterotypic strains and low IgG2a and high IgG1 levels, suggesting a mixed Th1/Th2 response with a Th2 trend. The Protollin-adjuvanted i.n. vaccine induced the lowest IgG1/IgG2a ratio, which is indicative of a mixed Th1/Th2-type profile with a Th1 trend. This adjuvanted vaccine was the only vaccine to stimulate a mucosal IgA response. Whatever the timing after the boost, both hemagglutination inhibition (HAI) and microneutralization (MN) titers were higher with the AS03-adjuvanted i.m. vaccine than with the protollin-adjuvanted i.n. vaccine. Finally, the Alum-adjuvanted i.m. vaccine and the lower-dose Protollin-adjuvanted i.n. vaccine elicited significantly higher CD4 + Th1 and Th2 responses and more gamma interferon (IFN-γ)-producing CD8 + T cells than the nonadjuvanted vaccine. 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.
Publisher: MDPI AG
Date: 08-10-2020
DOI: 10.3390/V12101139
Abstract: Two antiviral classes, the neuraminidase inhibitors (NAIs) and polymerase inhibitors (baloxavir marboxil and favipiravir) can be used to prevent and treat influenza infections during seasonal epidemics and pandemics. However, prolonged treatment may lead to the emergence of drug resistance. Therapeutic combinations constitute an alternative to prevent resistance and reduce antiviral doses. Therefore, we evaluated in vitro combinations of baloxavir acid (BXA) and other approved drugs against influenza A(H1N1)pdm09 and A(H3N2) subtypes. The determination of an effective concentration inhibiting virus cytopathic effects by 50% (EC50) for each drug and combination indexes (CIs) were based on cell viability. CompuSyn software was used to determine synergism, additivity or antagonism between drugs. Combinations of BXA and NAIs or favipiravir had synergistic effects on cell viability against the two influenza A subtypes. Those effects were confirmed using a physiological and predictive ex vivo reconstructed human airway epithelium model. On the other hand, the combination of BXA and ribavirin showed mixed results. Overall, BXA stands as a good candidate for combination with several existing drugs, notably oseltamivir and favipiravir, to improve in vitro antiviral activity. These results should be considered for further animal and clinical evaluations.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 07-2005
Abstract: The molecular epidemiology and genetic ersity of the human metapneumovirus (hMPV) were characterized for a 3-year period (2000-2002) from viruses that were identified in South Africa. Two major genetic groups (A and B) and 2 subgroups (1 and 2) of hMPV were identified, as well as 2-6 possible genotypes within the subgroups. A shift in the predominant group was documented in successive seasons. Whereas the F gene was relatively conserved between subgroups, a high degree of variation was observed in the extracellular domain of the G gene of the virus. The G protein identities between groups A and B were 45.1%-53.1% at the nucleotide level and 22.4%-27.6% at the amino acid level. These results provide evidence for the ersity of both surface glycoproteins of hMPV in Africa, which may be a prerequisite to understanding protective immunity against hMPV.
Publisher: Microbiology Society
Date: 06-2017
DOI: 10.1099/JGV.0.000800
Abstract: Influenza A(H1N1)pdm09 virus continues to circulate worldwide without evidence of significant antigenic drift between 2009 and 2016. By using escape mutants, we previously identified six haemagglutinin (HA) changes (T80R, G143E, G158E, N159D, K166E and A198E) that were located within antigenic sites. Combinations of these mutations were introduced into the A(H1N1)pdm09 HA plasmid by mutagenesis. Reassortant 6 : 2 viruses containing both the HA and NA genes of the A(H1N1)pdm09 and the six internal gene segments of A/PR/8/34 were rescued by reverse genetics. In vitro, HA inhibition and microneutralization assays showed that the HA hexa-mutant reassortant virus (RG1) escaped A(H1N1)pdm09 hyper-immune ferret antiserum recognition. C57Black/6 mice that received the vaccine formulated with A/California/07/09 were challenged with 2×104 p.f.u. of either the 6 : 2 wild-type (WT) or RG1 viruses. Reductions in body weight loss, mortality rate and lung viral titre were observed in immunized animals challenged with the 6 : 2 WT virus compared to non-immunized mice. However, immunization did not protect mice challenged with RG1 virus. To further characterize the mutations causing this antigenic change, 11 additional RG viruses whose HA gene contained single or combinations of mutations were evaluated in vitro. Although the RG1 virus was still the least reactive against hyper-immune serum by HAI testing, mutations G158E and N159D within the Sa antigenic site appeared to play the major role in the altered antigenicity of the A(H1N1)pdm09 virus. These results show that the Sa antigenic site contains the most prominent epitopes susceptible to cause an antigenic drift, escaping actual vaccine protection.
Publisher: SAGE Publications
Date: 10-2017
DOI: 10.3851/IMP3180
Abstract: Zika virus, a previously neglected mosquito-borne virus, is prompting worldwide concern because of its connection with congenital defects, Guillain-Barré syndrome, meningoencephalitis and myelitis in infected in iduals. However, no specific antiviral therapy is available at present. In this study, we investigated the in vitro susceptibility of geographically and temporally distinct Zika viruses against the RNA polymerase inhibitors, favipiravir (T-705) and ribavirin. The in vitro activity of each drug and a 1:1 mixture combination was assessed against five geographically and temporally distinct Zika strains by plaque reduction assay (PRA), the gold standard phenotypic method. We showed that both drugs exhibit in vitro inhibitory activity against five different Zika strains isolated in different years and continents, with mean 50% inhibitory concentration (IC 50 ) values of 35 ±14 and 35 ±20 μM, respectively, by PRA. We did not observe a synergistic effect when both drugs were combined at the equimolar concentration (IC 50 =33 ±11 μM). These results indicate that T-705 has the potential to be used in patients with complicated diseases and/or those in iduals presenting with significant comorbidities.
Publisher: Oxford University Press (OUP)
Date: 10-09-2012
Publisher: American Chemical Society (ACS)
Date: 06-12-2016
DOI: 10.1021/JACS.6B10399
Abstract: Zika virus (ZIKV) is an emerging mosquito-borne virus recently linked to intrauterine growth restriction including abnormal fetal brain development. The recent outbreak of ZIKV reached pandemic level resulting in an alarming public health emergency. At present, there is limited understanding of the infectious mechanism and no approved therapy. Nonstructural protein 5 is essential for capping and replication of viral RNA and comprises a methyltransferase (MTase) and RNA dependent RNA polymerase domain. Here we used molecular modeling to obtain the structure of ZIKV MTase and molecular docking to identify the additional hydrophobic region uniquely conserved in flavivirus MTase that can be used as a druggable site. Subsequently, a virtual screening with a library of 28 341 compounds identified 10 best hits showing decisive contacts with the MTase. In vitro efficacy analysis of these compounds against ZIKV, by plaque reduction assay, has confirmed four of the top scored ligands (Life Chemicals ID: F3043-0013, F0922-0796, F1609-0442, and F1750-0048) having EC50 (50% effective concentration) values of 4.8 ± 2.3, 12.5 ± 7.4, 17.5 ± 8.4, and 17.6 ± 3.1 μM respectively, identifying lead compounds for anti-ZIKV drug development.
Publisher: Oxford University Press (OUP)
Date: 15-12-2003
DOI: 10.1086/379771
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 08-2012
Publisher: Elsevier BV
Date: 05-2007
DOI: 10.1016/J.ANTIVIRAL.2006.10.012
Abstract: There is a limited information with regard to the neuraminidase (NA) mutations conferring resistance to peramivir and zanamivir in the influenza N1 background. In this study, an influenza A/WSN/33 (H1N1) recombinant virus was passaged under peramivir or zanamivir pressure. The peramivir-selected variant had a H274Y mutation in the neuraminidase (NA) gene conferring resistance to peramivir and oseltamivir but susceptibility to zanamivir. 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.
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.VACCINE.2008.04.052
Abstract: With the emergence of highly virulent influenza viruses and the consequent risk of pandemics, new approaches to designing universal influenza vaccines are urgently needed. In this report, we demonstrate the potential of using a papaya mosaic virus (PapMV) platform carrying the universal M2e influenza epitope (PapMV-CP-M2e) as a candidate flu vaccine. We show that PapMV-CP-M2e virus-like particles (VLPs) can induce production in mice of anti-M2e antibodies that can recognize influenza-infected cells. PapMV-CP-M2e discs made of 20 coat protein (CP) subunits were shown to be poorly immunogenic compared to PapMV-CP-M2e VLPs composed of several hundred CP subunits. We also show that addition of either alum or PapMV-CP VLPs as adjuvant dramatically increased the immunogenicity of PapMV-CP-M2e-containing vaccine, and led to 100% protection against a challenge of 4LD(50) with the WSN/33 strain. These results show, for the first time, the potential of a recombinant plant virus protein to serve as both peptide delivery system and adjuvant in the crucial field of influenza vaccine development.
Publisher: Oxford University Press (OUP)
Date: 15-01-2009
DOI: 10.1086/595736
Abstract: Neuraminidase (NA) mutations responsible for influenza resistance to oseltamivir vary according to the NA subtype in influenza A/H3N2 viruses, NA-gene mutations occur predominantly at codons E119 and R292. In an oseltamivir-resistant influenza A/H3N2 virus isolated from an immunocompromised child after 107 days of cumulative treatment, the NA gene contained 3 aa substitutions (N146K, S219T, and A272V) and a 4-aa deletion (Del245-248) reversion mutation experiments using recombinant NA proteins determined that the deletion was the sole change responsible for resistance to oseltamivir. This study highlights the ersity of mechanisms of resistance to oseltamivir in clinical settings, reinforcing the need for novel anti-influenza strategies.
Publisher: Oxford University Press (OUP)
Date: 16-08-2020
Abstract: Baloxavir is a cap-dependent inhibitor of the polymerase acid (PA) protein of influenza viruses. While appearing virologically superior to oseltamivir, baloxavir exhibits a low barrier of resistance. We sought to assess the impact of the common baloxavir-resistant I38T PA substitution on in vitro properties and virulence. Influenza A/Quebec/144147/2009 (H1N1)pdm09 and A/Switzerland/9715293/2013 (H3N2) recombinant viruses and their I38T PA mutants were compared in single and competitive infection experiments in ST6GalI-MDCK cells and C57/BL6 mice. Virus titers in cell culture supernatants and lung homogenates were determined by virus yield assays. Ratios of wild-type (WT) and I38T mutant were assessed by digital RT-PCR. I38T substitution did not alter the replication kinetics of A(H1N1)pdm09 and A(H3N2) viruses. In competition experiments, a 50%:50% mixture evolved to 70%:30% (WT/mutant) for A(H1N1) and 88%:12% for A(H3N2) viruses after a single cell passage. The I38T substitution remained stable after 4 passages in vitro. In mice, the WT and its I38T mutant induced similar weight loss with comparable lung titers in both viral subtypes. The mutant virus tended to predominate over the WT in mouse competition experiments. The fitness of baloxavir-resistant I38T PA mutants appears relatively unaltered in seasonal subtypes warranting surveillance for its dissemination.
Publisher: American Society for Microbiology
Date: 19-07-2022
DOI: 10.1128/AAC.00198-22
Abstract: In vitro selection of remdesivir-resistant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revealed the emergence of a V166L substitution, located outside of the polymerase active site of the Nsp12 protein, after 9 passages of a single lineage. V166L remained the only Nsp12 substitution after 17 passages (10 μM remdesivir), conferring a 2.3-fold increase in 50% effective concentration (EC 50 ).
Publisher: MDPI AG
Date: 11-12-2020
DOI: 10.3390/MICROORGANISMS8121968
Abstract: The prolonged treatment of immunosuppressed (IS) in iduals with anti-influenza monotherapies may lead to the emergence of drug-resistant variants. Herein, we evaluated oseltamivir and polymerase inhibitors combinations against influenza A/H3N2 infections in an IS mouse model. Mice were IS with cyclophosphamide and infected with 3 × 103 PFU of a mouse-adapted A/Switzerland/9715293/2013 (H3N2) virus. Forty-eight hours post-infection, the animals started oseltamivir, favipiravir or baloxavir marboxil (BXM) as single or combined therapies for 10 days. Weight losses, survival rates and lung viral titers (LVTs) were determined. The neuraminidase (NA) and polymerase genes from lung viral s les were sequenced. All untreated animals died. Oseltamivir and favipiravir monotherapies only delayed mortality (the mean day to death (MDD) of 21.4 and 24 compared to 11.4 days for those untreated) while a synergistic improvement in survival (80%) and LVT reduction was observed in the oseltamivir/favipiravir group compared to the oseltamivir group. BXM alone or in double/triple combination provided a complete protection and significantly reduced LVTs. Oseltamivir and BXM monotherapies induced the E119V (NA) and I38T (PA) substitutions, respectively, while no resistance mutation was detected with combinations. We found that the multiple dose regimen of BXM alone provided superior benefits compared to oseltamivir and favipiravir monotherapies. Moreover, we suggest the potential for drug combinations to reduce the incidence of resistance.
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.NANO.2018.08.010
Abstract: Influenza virus infections are a significant public threat and the best approach to prevent them is through vaccination. Because of the perpetual changes of circulating influenza strains, the efficacy of influenza vaccines rarely exceeds 50%. To improve the protection efficacy, we have designed a novel vaccine formulation that shows a broad range of protection. The formulation is made of the matrix protein 2 (M2e) and the nucleoprotein (NP) antigens. The multimerization of NP into nanoparticles improved significantly the immune response to NP. The combination of the NP nanoparticles with the PapMV-M2e nanoparticles enhances significantly the immune response directed to NP revealing the adjuvant property of the PapMV platform. The vaccine formulation combining these two types of nanoparticles protects mice from infectious challenges by two different influenza strains (H1N1 and H3N2) and is a promising influenza A vaccine capable to elicit a broad protection.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 06-2004
Abstract: We analyzed 64 human metapneumovirus strains from eight countries. Phylogenetic analysis identified two groups (A and B, amino acid identity 93%-96%) and four subgroups. 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.
Publisher: Microbiology Society
Date: 02-2018
DOI: 10.1099/JGV.0.000992
Abstract: Toll-like receptors and RNA helicases are involved in the control of RNA virus infection through production of type I interferons (IFNs). To delineate the relative contributions of these signalling pathways in the innate immune response and the control of Zika virus (ZIKV) pathogenesis, the impact of a deficiency in TRIF and/or IPS-1 adaptor proteins was investigated in mice. Mice were infected intravenously with ZIKV and monitored for clinical signs for 14 days. Groups of mice were sacrificed on days 1, 3 and 7 post-infection (p.i.) and viral RNA was measured by digital droplet PCR in serum, spleen, brain and eyes. Some mice were sacrificed at 12 h p.i. for determination of the levels of IFN-α/-β (ELISA), cytokines/chemokines (Luminex) and total hosphorylated IRF3 and IRF7 (Western blotting). All groups of mice infected with ZIKV exhibited no clinical signs of infection. However, IPS-1
Publisher: Public Library of Science (PLoS)
Date: 22-07-2010
Publisher: SAGE Publications
Date: 07-2011
DOI: 10.3851/IMP1794
Abstract: The H275Y neuraminidase mutation conferring oseltamivir resistance has been reported in several pandemic A/H1N1 (pH1N1) isolates. We sought to evaluate transmission of this mutant virus through the direct contact and the airborne (aerosol and droplet) routes in the ferret model. Groups of four ferrets were infected with either wild-type (WT) or oseltamivir-resistant pH1N1 (H275Y) strains. At 24 h following viral infection, a receptive ferret was introduced in the same cage as the infected animal to assess direct contact transmission. For the airborne transmission, naive ferrets were placed in a modified separate cage adjacent to that of their respective index ferret. The H275Y mutant virus was as efficiently transmitted as the WT strain by direct contact, as 100% (4/4) of contact ferrets in both groups seroconverted and shed virus. Mean peak viral titres were similar in both groups (4x10 4 and 2.63x10 4 plaque-forming units/ml after WT or H275Y mutant virus transmission, respectively). Peak viral shedding occurred on day 2 post-contact for the WT group and on day 4 post-contact for the H275Y mutant group. By contrast, airborne transmission of the mutant strain was less efficient, as only 25% (1/4) of contact ferrets seroconverted and shed virus, whereas 100% (4/4) of the WT ferrets did. Peak of viral replication was delayed compared to direct contact transmission and occurred on day 4 post-contact. Transmission of the H275Y pH1N1 mutant strain by the airborne route is somewhat compromised, which may limit its widespread dissemination.
Publisher: American Society for Microbiology
Date: 11-2014
DOI: 10.1128/AAC.02956-14
Abstract: The evolution of oseltamivir resistance mutations during selection through serial passages in animals is still poorly described. Herein, we assessed the evolution of neuraminidase (NA) and hemagglutinin (HA) genes of influenza A/WSN/33 (H1N1) and A/Victoria/3/75 (H3N2) viruses recovered from the lungs of experimentally infected BALB/c mice receiving suboptimal doses (0.05 and 1 mg/kg of body weight/day) of oseltamivir over two generations. The traditional phenotypic and genotypic methods as well as deep-sequencing analysis were used to characterize the potential selection of mutations and population dynamics of oseltamivir-resistant variants. No oseltamivir-resistant NA or HA changes were detected in the recovered A/WSN/33 viruses. However, we observed a positive selection of the I222T NA substitution in the recovered A/Victoria/3/75 viruses, with a frequency increasing over time and with an oseltamivir concentration from 4% in the initial pretherapy inoculum up to 28% after two lung passages. Although the presence of mixed I222T viral populations in mouse lungs only led to a minimal increase in oseltamivir 50% enzyme-inhibitory concentrations (IC 50 s) (by a mean of 5.7-fold) compared to that of the baseline virus, the expressed recombinant A/Victoria/3/75 I222T NA protein displayed a 16-fold increase in the oseltamivir IC 50 level compared to that of the recombinant wild type (WT). In conclusion, the combination of serial in vivo passages under neuraminidase inhibitor (NAI) pressure and temporal deep-sequencing analysis enabled, for the first time, the identification and selection of the oseltamivir-resistant I222T NA mutation in an influenza H3N2 virus. Additional in vivo selection experiments with other antivirals and drug combinations might provide important information on the evolution of antiviral resistance in influenza viruses.
Publisher: Oxford University Press (OUP)
Date: 15-12-2006
DOI: 10.1086/508777
Abstract: Development of influenza drug resistance is an important problem in immunocompromised children that could result in treatment failure and viral transmission to others. A total of 17 influenza A/H3N2 isolates were recovered over a period of 1 year from an immunocompromised child who was initially treated with oseltamivir and then with amantadine and zanamivir for viral pneumonitis. Drug susceptibility phenotypes to oseltamivir, zanamivir, and peramivir were evaluated by neuraminidase (NA) inhibition assays, and sequence analysis of key viral genes (i.e., M2, NA, and hemagglutinin [HA]) was performed. The impact of NA mutations identified in oseltamivir-resistant isolates was analyzed using recombinant NA proteins. An influenza A variant with NA mutations E59G, E119V, and I222V was first detected after 38 days of oseltamivir treatment. In an NA inhibition assay, this variant was 274 times more resistant to oseltamivir than the original isolate but was susceptible to zanamivir. The I222V substitution enhanced the level of oseltamivir resistance that was primarily conferred by the E119V mutation in recombinant NA proteins. Remarkably, the E119V mutation persisted for 8 months after cessation of oseltamivir. Amantadine therapy led to rapid emergence of the M2 mutation S31N, which is known to confer amantadine resistance. The patient shed the virus intermittently while receiving nebulized zanamivir therapy despite the absence of a resistance phenotype, which could be the result of nonoptimal drug delivery and impaired host immunity. This study highlights the potential for emergence and persistence of multidrug-resistant influenza isolates in immunocompromised subjects even after cessation of treatment, reinforcing the need for development of new anti-influenza compounds.
Publisher: Elsevier BV
Date: 02-2008
DOI: 10.1016/J.ANTIVIRAL.2007.08.008
Abstract: Clinical use of the neuraminidase inhibitor (NAI) oseltamivir has been associated with the emergence of viral resistance resulting from subtype-specific neuraminidase (NA) mutations. In this study, we evaluated the impact of the most frequent oseltamivir-resistant NA mutations including E119V, H274Y, R292K and N294S on the susceptibility profile to a novel NAI (A-315675) using recombinant NA proteins of N1 and N2 subtypes and also selected oseltamivir-resistant influenza H1N1 and H3N2 viruses. In the N1 subtype, recombinant NA proteins containing mutations H274Y and N294S previously associated with resistance to oseltamivir (754- and 197-fold increases in IC(50) values, respectively, compared to WT) remained susceptible to A-315675 (2.5- and 2-fold increases in IC(50) values(,) respectively). In the N2 subtype, NA proteins harboring mutations E119V and R292K conferring high levels of resistance to oseltamivir (1016- and >10,000-fold increases in IC(50) values, respectively) had IC(50) values that increased by only 1.5- and 13-fold, respectively, against A-315675. Similar susceptibility patterns to A-315675 were obtained when testing recombinant H1N1 mutant viruses (H274Y and N294S) and clinical H3N2 mutants (E119V). The V116A and I117V mutations, previously associated with oseltamivir resistance in H5N1 viruses, were susceptible to oseltamivir when tested in the H1N1 background suggesting a strain-specific impact of these mutations. 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.
Publisher: MDPI AG
Date: 03-11-2018
DOI: 10.3390/V10110610
Abstract: Immunosuppressed in iduals can shed influenza virus for prolonged periods of time, leading to the frequent emergence of antiviral resistance. We evaluated the benefits of oseltamivir and favipiravir combination therapy compared to single antiviral agents and monitored the emergence of drug-resistant variants in a pharmacologically immunosuppressed mouse model infected with the A(H1N1) pandemic influenza virus. C57BL/6 mice were immunosuppressed with cyclophosphamide and infected with a lethal dose of pandemic influenza A(H1N1) virus. Forty-eight hours post-infection, mice were treated with oseltamivir (20 mg/kg), favipiravir (20 or 50 mg/kg) or both agents BID for 5 or 10 days. Body weight losses, survival rates, lung viral titers, cytokine levels and emergence of resistant viruses were evaluated. Treatment of immunosuppressed mice with high (50 mg/kg) but not low (20 mg/kg) doses of favipiravir in combination with oseltamivir (20 mg/kg) significantly delayed mortality and reduced lung viral titers compared to treatment with a single drug regimen with oseltamivir but did not prevent the emergence of oseltamivir-resistant H275Y neuraminidase variants. Combination therapy with oseltamivir and favipiravir should be considered for evaluation in clinical trials.
Publisher: American Society for Microbiology
Date: 05-2015
Abstract: Resistance following antiviral therapy is commonly observed in human influenza viruses. Although this evolutionary process is initiated within in idual hosts, little is known about the pattern, dynamics, and drivers of antiviral resistance at this scale, including the role played by reassortment. In addition, the short duration of human influenza virus infections limits the available time window in which to examine intrahost evolution. Using single-molecule sequencing, we mapped, in detail, the mutational spectrum of an H3N2 influenza A virus population s led from an immunocompromised patient who shed virus over a 21-month period. In this unique natural experiment, we were able to document the complex dynamics underlying the evolution of antiviral resistance. In idual resistance mutations appeared weeks before they became dominant, evolved independently on cocirculating lineages, led to a genome-wide reduction in genetic ersity through a selective sweep, and were placed into new combinations by reassortment. Notably, despite frequent reassortment, phylogenetic analysis also provided evidence for specific patterns of segment linkage, with a strong association between the hemagglutinin (HA)- and matrix (M)-encoding segments that matches that previously observed at the epidemiological scale. In sum, we were able to reveal, for the first time, the complex interaction between multiple evolutionary processes as they occur within an in idual host. IMPORTANCE Understanding the evolutionary forces that shape the genetic ersity of influenza virus is crucial for predicting the emergence of drug-resistant strains but remains challenging because multiple processes occur concurrently. We characterized the evolution of antiviral resistance in a single persistent influenza virus infection, representing the first case in which reassortment and the complex patterns of drug resistance emergence and evolution have been determined within an in idual host. Deep-sequence data from multiple time points revealed that the evolution of antiviral resistance reflects a combination of frequent mutation, natural selection, and a complex pattern of segment linkage and reassortment. In sum, these data show how immunocompromised hosts may help reveal the drivers of strain emergence.
Publisher: Oxford University Press (OUP)
Date: 11-2010
DOI: 10.1086/656582
Abstract: Characterizing household transmission of the 2009 pandemic A/H1N1 influenza virus (pH1N1) is critical for the design of effective public health measures to mitigate spread. Our objectives were to estimate the secondary attack rates (SARs), the proportion of asymptomatic infections, and risk factors for pH1N1 transmission within households on the basis of active clinical follow-up and laboratory-confirmed outcomes. We conducted a prospective observational study during the period May-July 2009 (ie, during the first wave of the pH1N1 pandemic) in Quebec City, Canada. We assessed pH1N1 transmission in 42 households (including 43 primary case patients and 119 contacts). Clinical data were prospectively collected during serial household visits. Secondary case patients were identified by clinical criteria and laboratory diagnostic tests, including serological and molecular methods. We identified 53 laboratory-confirmed secondary case patients with pH1N1 virus infection, for an SAR of 45% (95% confidence interval [CI], 35.6%-53.5%). Thirty-four (81%) of the households had ≥1 confirmed secondary case patient. The mean serial interval between onset of primary and confirmed secondary cases was 3.9 days (median interval, 3 days). Influenza-like illness (fever and cough or sore throat) developed in 29% (95% CI, 20.5%-36.7%) of household contacts. Five (9.4%) of secondary case patients were asymptomatic. Young children (<7 years of age) were at highest risk of developing laboratory-confirmed influenza-like illness. Primary case patients with both diarrhea and vomiting were the most likely to transmit pH1N1. Household transmission of pH1N1 may be substantially greater than previously estimated, especially in association with clinical presentations that include gastrointestinal complaints. Approximately 10% of pH1N1 infections acquired in the household may be asymptomatic.
Publisher: Oxford University Press (OUP)
Date: 03-2010
DOI: 10.1086/650464
Abstract: The viral fitness of neuraminidase inhibitor (NAI)-resistant influenza viruses is believed to be impaired. Unexpectedly, an oseltamivir-resistant A(H1N1) variant containing the H274Y neuraminidase (NA) mutation recently disseminated worldwide, suggesting that the replication and virulence properties of this mutant virus were not compromised. In vitro replicative capacities were determined for old (A/WSN/33, A/Mississipi/3/01, A/New Caledonia/20/99, and A/Solomon Islands/03/06) and recent (A/Brisbane/59/2007-like) influenza A(H1N1) viruses either harboring or not harboring the H274Y NA mutation. Ferrets were infected with the A/Brisbane/59/2007-like wild-type (WT) isolate and its H274Y NA variant. Old A(H1N1) WT viruses grew at higher titers than did the A/Brisbane/59/2007-like viruses in vitro. The H274Y mutation was associated with reduced viral plaque areas in cells infected with A/WSN/33 and A/Mississippi/3/01, whereas the 2 A/Brisbane/59/2007-like isolates showed similar plaque sizes. In ferrets, the pyrexic response induced by the A/Brisbane/59/2007-like H274Y mutant was significantly higher than that induced by the WT isolate. Nasal wash viral titers were significantly greater for the mutant isolate on day 2 after inoculation, whereas the 2 viruses showed similar titers between days 3 and 7 after inoculation. The viral fitness of the recent A/Brisbane/59/2007-like H274Y variant is not impaired, consistent with its global dissemination. These results reinforce the need for new antiviral strategies.
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.ANTIVIRAL.2018.04.009
Abstract: Neuraminidase (NA) mutations conferring resistance to NA inhibitors (NAIs) are expected to occur at framework or catalytic residues of the NA enzyme. Numerous clinical and in vitro reports already described NAI-resistant A(H1N1)pdm09 variants harboring various framework NA substitutions. By contrast, variants with NA catalytic changes remain poorly documented. Herein, we investigated the effect of R152K and R368K NA catalytic mutations on the NA enzyme properties, in vitro replicative capacity and virulence of A(H1N1)pdm09 recombinant viruses. In NA inhibition assays, the R152K and R368K substitutions resulted in reduced inhibition [10- to 100-fold increases in IC
Publisher: Microbiology Society
Date: 07-2011
Abstract: Human metapneumovirus (hMPV) is a paramyxovirus responsible for respiratory tract infections in humans. Our objective was to investigate whether hMPV could predispose to long-term bacterial susceptibility, such as previously observed with influenza viruses. BALB/c mice were infected with hMPV or influenza A and, 14 days following viral infection, challenged with Streptococcus pneumoniae . Only mice previously infected with influenza A demonstrated an 8 % weight loss of their body weight 72 h following S. pneumoniae infection, which correlated with an enhanced lung bacterial replication of log 10 compared with pneumococcus infection alone. This enhanced bacterial replication was not related to altered macrophage or neutrophil recruitment or deficient production of critical cytokines. However, bacterial challenge induced the production of gamma interferon in bronchoalveolar lavages of influenza-infected mice, but not in those of hMPV-infected animals. In conclusion, hMPV does not cause long-term impairment of pneumococcus lung clearance, in contrast to influenza A virus.
No related grants have been discovered for Guy Boivin.