Laetitia Ninove

Prospective and retrospective evaluation of the Cepheid Xpert® Flu/RSV XC assay for rapid detection of influenza A, influenza B, and respiratory syncytial virus

Abstract A total of 281 clinical specimens (nasal swabs and nasopharyngeal aspirates) were tested with the Xpert® Flu/RSV XC. The results were compared to those obtained with the real-time retro transcriptase-polymerase chain reaction assays routinely used in our laboratory. The Xpert® Flu/RSV XC showed sensitivity/specificity of 97.8%/100% and 97.9%/100% for flu and respiratory syncytial virus, respectively.

The viral etiology of an influenza-like illness during the 2009 pandemic.

Many viruses are known to cause influenza‐like illness (ILI); however, in nearly 50% of patients, the etiologic agent remains unknown. The distribution of viruses in patients with ILI was investigated during the 2009 A/H1N1 influenza pandemic (A/H1N1p). From June 2009 to January 2010, 660 patients with suspected influenza were questioned and examined, and nasal swabs were collected. All patient samples were tested for influenza virus, and 286 negative nasal swabs were tested further for 18 other respiratory viruses using real‐time RT‐PCR. Two waves of ILI were observed in the epidemic curve (weeks 35–42 and 42–49). At least eight viruses co‐circulated during this period: human rhinovirus (HRV) (58), parainfluenza 1–4 viruses (PIV) (9), human Coronavirus (hCoV) OC43 (9), enterovirus (5), adenovirus (AdV) (4), and human metapneumovirus (hMPV) (2); however, 204 samples remained negative for all viruses tested. ILI symptoms, according to the Centers for Disease Control and Prevention criteria for ILI definition, were reported in 75% of cases. These patients had positive swabs for A/H1N1p, HRV, hCoV‐OC43, PIV, AdV, and hMPV without significant difference with non‐ILI patients. This study found that many respiratory viruses circulated during this period and that the A/H1N1p did not impact on the kinetics of other respiratory viruses. The proportion of non‐documented cases remains high. ILI could not distinguish A/H1N1p infection from that due to other respiratory viruses. However, in multivariate anlaysis, cough, chills, hyperemia, and dyspnea were associated significantly with influenza virus versus other respiratory viruses. J. Med. Virol. 84: 1071–1079, 2012.

Impact of diagnostic procedures on patient management and hospitalization cost during the 2000 and 2005 enterovirus epidemics in Marseilles, France

Enteroviruses are frequent aetiological agents of central nervous system infections in humans. In 2000 and 2005, two large outbreaks of Echovirus 30 (a member of species human enterovirus B) were observed in the University Hospitals of Marseilles (France). Between the two epidemics, the diagnostic protocols for enterovirus infection were modified, moving from viral cultures and classic RT-PCR in 2000 to real-time RT-PCR in 2005. We compared some viral and epidemiological characteristics of the 2000 and 2005 outbreaks with special attention to diagnostic procedures and to the subsequent clinical management of patients. Despite similar virological and epidemiological characteristics during both outbreaks, our results show that real-time RT-PCR techniques used in 2005 noticeably shortened the period of time necessary to deliver diagnostic results and suggest that this was associated with a decrease in the duration of hospitalization for positive cases. In conclusion, this study suggests that the improvement of enterovirus diagnosis had a major financial impact on the management of the 2005 epidemic in Marseilles and may constitute an interesting example of how new diagnostic methods in microbiology can be self-financed through improvement in patient management.

Evaluation of the Xpert Flu test and comparison with in‐house real‐time RT‐PCR assays for detection of influenza virus from 2008 to 2011 in Marseille, France

Rapid documentation of respiratory specimens can have an impact on the management of patients and their relatives in terms of preventive and curative measures. We compared the results of the Xpert(®) Flu assay (Cepheid) with three real-time RT-PCR assays using 127 nasopharyngeal samples, of which 75 were positive for influenza A (with 52 identified as A/H1N1-2009) and 52 were positive for influenza B. The Xpert(®) Flu assay presented a quasi-absence of non-interpretable tests, and showed sensitivity and specificity of 100% and 100% for Flu A, 98.4% and 100% for A/H1N1-2009, and 80.7% and 100% for Flu B.

Widespread circulation of a new echovirus 30 variant causing aseptic meningitis and non-specific viral illness, South-East France, 2013

BACKGROUND Human enteroviruses (HEVs) are major cause of aseptic meningitis. A new outbreak of E-30 occurred between April and September 2013 in Marseille, South-East France. OBJECTIVES Better understand what happen locally when an E-30 outbreak occurs. STUDY DESIGN Laboratory data (identification and characterization of circulating E-30 strains by partial/complete genome sequencing) were analyzed together with clinical data from emergency ward of the public hospital of Marseille. RESULTS Compared with data from previous years, we observed an excess of HEV infections between April and September 2013. A total of 202 patients were tested positive of which 79% (160/202) had a cerebrospinal fluid tested positive. Because we performed genotyping using clinical specimens, we obtained representative molecular data related to patients tested positive and found a majority (105/119) of echoviruses 30 (E-30). Phylogenetic analysis revealed that E-30 circulating in Europe since 2000 belong to a unique lineage and showed at the intra-genogroup level the temporal circulation of E-30. Molecular data also indicated that majority of E-30 detected (92%) were almost identical. Compared with data from previous years, this outbreak was finally associated with an excess of patients admitted to an emergency ward for meningitis but also for non-specific viral illness. CONCLUSIONS Our data provide new insights into microevolution of E-30: almost all E-30 emerged from local circulation of one parental virus. Moreover, our findings showed that HEV outbreaks cause an excess of emergency ward consultations but probably also an excess of consultations to general practitioners who receive majority of the non-specific viral illness.

Xpert Flu for point-of-care diagnosis of human influenza in industrialized countries.

Respiratory infections, particularly those caused by influenza viruses, represent the third-most important cause of death in the world due to infectious diseases. Nevertheless, despite the enormous publicity attracted by epidemics due to these viruses, laboratory diagnosis, documentation and recording of respiratory diseases is still unsatisfactory. Available diagnostic tests capable of providing results rapidly are either limited and insufficiently sensitive or highly sensitive and specific but insufficiently rapid. Considerable investment and research efforts have been made towards the development of new diagnostics for influenza A and B viruses and the Xpert® Flu assay (Cepheid®, CA, USA) has emerged as one of the most promising. In this article, we review current knowledge of the Xpert Flu test, discuss its potential value as a point-of-care test and outline the potential leads for future development.

Increased incidence of acute parvovirus B19 infections in Marseille, France, in 2012 compared with the 2002–2011 period

Human parvovirus B19 occurs worldwide and causes mild or asymptomatic disease in the form of cyclic local epidemics usually occurring in late winter and early summer. In 2012, a dramatic increase in cases was observed in the Public hospitals system of Marseille, with a total of 53 cases reported. Here, we describe the characteristics of this outbreak and compare it with the local epidemiology of B19V infections observed during the 2002-2011 period.

Molecular detection of human rhinoviruses in respiratory samples: a comparison of Taqman probe-, SYBR green I- and BOXTO-based real-time PCR assays

BackgroundHuman Rhinoviruses (HRV) are major causative agents of acute respiratory tract infections in all age group and important contributing factors of childhood morbidity and mortality. Clinical presentation is poorly specific and the great antigenic and genetic variability of HRVs renders the biological diagnosis complex. Here, we have evaluated several molecular diagnostic protocols, including Taqman probe-based and intercalating agent-based RT-PCR assays.Methods5,627 respiratory samples sent to the laboratory of Virology of the University Hospitals of Marseille, France, from March 2011 to February 2012, were tested using a real-time RT-PCR assay in the 5’NCR of the rhinoviral genome that associated a Taqman probe and the detection of DNA-BOXTO-dye complexes. A sample of 500 BOXTO-positive samples were further tested using the same probe assay (without BOXTO), and a SYBR Green assay (using the same amplification primers). The specific amplification of HRV sequences was assessed by NGS amplicon sequencing.ResultsThe Taqman probe RT-PCR assay identified 696/5,627 samples (12,4%) as HRV-positive. BOXTO-positive samples included all probe-positive samples and 1,913 additional samples, of which only 24.3% were confirmed by sequencing. The SYBR Green assay was more specific (16/550 samples were probe-negative/SYBR Green-positive, all confirmed by 5′NCR sequencing), but 3/500 samples were probe-positive/SYBR Green-negative.ConclusionsOur results highlight the difficulty in detecting HRVs in clinical samples using a single molecular detection system. Amongst the 3 systems tested, the best compromise was obtained with the SYBR Green assay, which, by comparison with our probe-based assay provided an improved sensitivity without altering the detection specificity. Interestingly, a majority of probe-negative/BOXTO- or SYBR Green-positive samples were not associated with mutations in the sequence targeted by the probe. Sequence-based modifications of the secondary structure of the HRV 5′NCR may be associated with a limited access to the probe hybridisation region. Further investigations may identify a test combining a probe based- and an intercalating agent-based detection, which will significantly improve the diagnosis of HRV infections.

Capture-recapture method for estimating annual incidence of imported dengue, France, 2007-2010.

Imported dengue cases pose the public health risk for local circulation in European areas, especially southeast France, where the Aedes mosquito is established. Using a capture–recapture method with Chao’s estimator, we estimated the annual incidence of dengue fever and the completeness of existing mandatory notification and laboratory network surveillance systems. During 2007–2010, >8,300 cases with laboratory evidence of recent dengue infection were diagnosed. Of these cases, 4,500 occurred in 2010, coinciding with intense epidemics in the French West Indies. Over this 4-year period, 327 cases occurred in southeast France during the vector activity period. Of these, 234 cases occurred in 2010, most of them potentially viremic. Completeness of the mandatory notification and laboratory network systems were ≈10% and 40%, respectively, but higher in southeast areas during May–November (32% and 69%, respectively). Dengue surveillance systems in France provide complementary information that is essential to the implementation of control measures.

Zika virus epidemiology in Bolivia: A seroprevalence study in volunteer blood donors

Background Zika virus (ZIKV), was widely reported in Latin America and has been associated with neuropathologies, as microcephaly, but only few seroprevalence studies have been published to date. Our objective was to determine the seroprevalence amongst Bolivian blood donors and estimate the future potential circulation of the virus. Methodology A ZIKV seroprevalence study was conducted between December 2016 and April 2017 in 814 asymptomatic Bolivian volunteer blood donors residing in various eco-environments corresponding to contrasting entomological activities. It was based on detection of IgG to ZIKV using NS1 ELISA screening, followed by a seroneutralisation test in case of positive or equivocal ELISA result. Conclusions/Significance Analysis revealed that ZIKV circulation occurred in tropical areas (Beni: 39%; Santa Cruz de la Sierra: 21.5%) but not in highlands (~0% in Cochabamba, La Paz, Tarija). It was modulated by Aedes aegypti activity and the virus spread was not limited by previous immunity to dengue. Cases were geo-localised in a wide range of urban areas in Santa Cruz and Trinidad. No differences in seroprevalence related to gender or age-groups could be identified. It is concluded that ZIKV has been intensely circulating in the Beni region and has still a significant potential for propagating in the area of Santa Cruz.