The performance of Luminex ARIES® Flu A/B & RSV and Cepheid Xpert® Flu/RSV XC for the detection of influenza A,influenza B,and respiratory syncytial virus in prospective patient samples

BackgroundThe demand for rapid, accurate viral testing has increased the number of assays available for the detection of viral pathogens. One of the newest FDA cleared platforms is the Luminex ARIES^® Flu A/B & RSV, which is a fully automated, real-time PCR-based assay used for detection of influenza A, influenza B, and respiratory syncytial virus (RSV).ObjectivesWe sought to compare the performance of Luminex ARIES^® Flu A/B & RSV assay to the Cepheid Xpert^® Flu/RSV XC assay for rapid Flu and RSV testing.Study designA series of consecutive nasopharyngeal specimens received in the clinical microbiology laboratory during peak influenza season at a major academic center in Chicago, IL, were prospectively tested, using both the ARIES^® Flu A/B & RSV and Xpert^® Flu/RSV XC assays, side by side. Discrepant results were tested on the BioFire FilmArray^® Respiratory Panel for resolution.ResultsA total of 143 consecutive nasopharyngeal specimens, obtained from patients ranging from six months to ninety-three years in age were received between January 1st, 2017 and March 21st, 2017. There was 96.6% agreement between the two assays for detection influenza A, 100% agreement for detection influenza B and RSV, and 98.9% agreement for negative results. The Xpert^® Flu/RSV XC performed with an average turn-around time of approximately 60 min, compared to the ARIES^® Flu A/B & RSV of approximately 120 min. Both assays were equally easy to perform, with a similar amount of hands-on technologist time for each platform.ConclusionsOverall, these results indicate that both tests are comparable in terms of result agreement and technical ease-of-use. The Xpert^® Flu/RSV XC assay did produce results with less turn-around-time, approximately 60 min quicker than the ARIES^® Flu A/B & RSV.     

Genetic characterization of H5N1 avian influenza viruses isolated in southern China during the 2003–04 avian influenza outbreaks

Summary. The recent H5N1 avian influenza outbreaks in Asia spread over more than 8 countries. It has caused enormous economic loss and grand challenges for the public health. During these breakouts we isolated three strains of H5N1 Avian Influenza Virus (AIV) from chickens and one from duck in different farms of Southern China. We completely sequenced these four AIVs. Molecular characterization demonstrated that these strains retain the reported H5N1 AIV sequence properties relevant to virus virulence and host adaptation. Phylogeny results demonstrated that three of these isolates (except A/Chicken/Guangdong/174/04) were closely linked to other H5N1 AIVs isolated from the recent H5N1 outbreaks in Asia. Six of 8 segments (except PA and M) of A/Chicken/Guangdong/174/04 also shares a close linkage to other H5N1 AIVs isolated from the recent H5N1 outbreaks. However, the PA gene of A/Chicken/Guangdong/174/04 and another H5N1 strain forms a distinct subgroup along with an H6N1 AIV, and the M gene of A/Chicken/Guangdong/174/04 shows a close linkage to some H5N1 AIVs from aquatic species in China. Our findings suggest that a new genotype of AIV (in addition to previous reported ones) was present during the 2003–04 Asian bird flu outbreaks and that continuing virus surveillance of AIVs be conducted to monitor the evolutionary paths of the A/Chicken/Guangdong/174/04-like AIVs.     

Head-to-head comparison of the diagnostic accuracies of BD Veritor™ System RSV and Quidel® Sofia® RSV FIA systems for respiratory syncytial virus (RSV) diagnosis

BackgroundRespiratory syncytial virus (RSV) is one of the most common causes of severe lower respiratory tract disease among infants and young children. BD Veritor™ System RSV (BD) and Quidel^® Sofia^® RSV FIA (QD) are the new generation lateral flow digital immunoassay (DIA) tests with an instrumented read for the qualitative detection of RSV viral antigens.ObjectiveTo compare the diagnostic accuracies of BD and QD for RSV detection using fresh nasopharyngeal aspirates and nasopharyngeal swab specimens collected in universal transport media during 2013–2014 respiratory season.Study designThe two DIA tests were performed simultaneously on randomly selected specimens on a weekly basis during the RSV season until 200 fresh remnant specimens were enrolled. Real-time RT-PCR assay results were used to compare and evaluate the performance of both RSV DIA assays.ResultsAmong 200 specimens tested, RSV real-time RT-PCR assay detected RSV in 104 samples, while QD detected 84 samples and BD detected 74 samples as positive. The overall sensitivity for detection of RSV in comparison to PCR was 71.15% (61.3–79.4) for BD and 80.77% (71.6–87.6) for QD system (P = 0.36). The specificity was 100% (95.2–100) for both systems. The work flow analysis revealed that the overall specimen processing time was significantly lower for BD as compared with the QD assay.ConclusionsIn comparison with the real-time PCR, the QD system showed a higher sensitivity than that of the BD system, but the difference did not reach statistical significance (P = 0.36). Both BD and QD systems were found comparable in terms of specificity.     

The avian influenza epidemic in Italy, 1999—2000: A review

During 1999, northern Italy has been affected by an epidemic of low pathogenicity avian influenza (LPAI) caused by a virus of the H7N1 subtype. Due to the characteristics of the poultry industry in the area and to the absence of specific legislative tools to eradicate infection, the virus continued to circulate for several months until a highly pathogenic virus of the same subtype emerged. The highly pathogenic virus had caused death, at the time of writing, of over 13 million birds in 3 months. The consequences of the highly pathogenic avian influenza (HPAI) epidemic appear to be devastating for the poultry industry and the social community. Several conditions generated the current situation, including the high density of susceptible animals and the structure of the poultry industry in the infected area. In addition, the circulation of LPAI virus for a number of months inevitably delayed the prompt identification of HPAI and complicated the interpretation of diagnostic results. A reconsideration of current European legislation and a reorganization of the poultry industry are suggested to prevent the occurrence of similar situations in countries of the European Union.     

Review: Molecular evolution and the feasibility of an avian influenza virus becoming a pandemic strain––a conceptual shift

During recent years, a conceptual shift took place with respect to the genetic dynamics of influenza A viruses. In difference of the widely accepted approach that avian viral strains have the capacity to infect man only after undergoing genetic reassortment within pigs, it is now contended that direct transfection of man by intact avian-harbored viral genotypes is an actual, recurrent move, which may bring bout the generation of a new pandemic strain. This cardinal conceptual shift has been propelled by the appearance in 1997 of the zoonotic avian influenza H5N1 virus––a virulent, not yet contagious strain for humans––and ostensibly followed a genuine, unprecedented path within the evolutionary paradigm of Influenza A virus. This paper suggests that direct avian-human genetic interface is a pristine fundamental within the natural history of this protean pathogen, points at earlier as well as corroborative findings leading to such postulation, and regards the course of the H5N1 virus (and alike), as a readily detectable and traceable one, presently, rather then a novel development It further examines the general feasibility of various components of that interface at large, such that give rise––whether gradually or abruptly––to pandemic genotypes, in terms of infectivity, pathogenicity and contagiousness. Within that context, the anticipated involvement of certain human-adapted antigenic subtypes is referred to, extrapolatively. Connectedly, the significance of natural ice as plausible regenerator of influenza A viruses, and its possible contribution to the emergence and reemergence of pandemic strains are accentuated.     

Development and clinical validation of multiplex TaqMan® assays for rapid diagnosis of viral gastroenteritis

There is a need to provide rapid, sensitive, and often high throughput detection of pathogens in diagnostic virology. Viral gastroenteritis is a serious health issue often leading to hospitalization in the young, the immunocompromised and the elderly. The common causes of viral gastroenteritis include rotavirus, norovirus (genogroups I and II), astrovirus, and group F adenoviruses (serotypes 40 and 41). This article describes the work‐up of two internally controlled multiplex, probe‐based PCR assays and reports on the clinical validation over a 3‐year period, March 2007 to February 2010. Multiplex assays were developed using a combination of TaqMan? and minor groove binder (MGB?) hydrolysis probes. The assays were validated using a panel of 137 specimens, previously positive via a nested gel‐based assay. The assays had improved sensitivity for adenovirus, rotavirus, and norovirus (97.3% vs. 86.1%, 100% vs. 87.8%, and 95.1% vs. 79.5%, respectively) and also more specific for targets adenovirus, rotavirus, and norovirus (99% vs. 95.2%, 100% vs. 93.6%, and 97.9% vs. 92.3%, respectively). For the specimens tested, both assays had equal sensitivity and specificity for astrovirus (100%). Overall the probe‐based assays detected 16 more positive specimens than the nested gel‐based assay. Post‐introduction to the routine diagnostic service, a total of 9,846 specimens were processed with multiplex 1 and 2 (7,053 pediatric, 2,793 adult) over the 3‐year study period. This clinically validated, probe‐based multiplex testing algorithm allows highly sensitive and timely diagnosis of the four most prominent causes of viral gastroenteritis. J. Med. Virol. 83:1650–1656, 2011. © 2011 Wiley‐Liss, Inc.     

Evaluation of the SD BIOLINE TB Ag MPT64 Rapid® for the diagnosis of tuberculosis

The purpose of this study was to evaluate the SD Bioline Ag MPT64 Rapid^® for identification of the Mycobacterium tuberculosis complex. The method uses an immunochromatographic assay and needs 100 μl of sample taken from liquid culture or colonies suspended. The sensitivity was determined using 99 strains of M. tuberculosis complex and the specificity using 10 nontuberculous mycobacteria and 85 strains other than mycobacteria genus. The test showed excellent sensitivity (99%) and specificity (100%). This technique displays several advantages and is destined to spread in all laboratories and particularly in endemic areas.     

Genetic characterization of avian influenza viruses isolated in Israel during 2000–2006

Our aim was to establish the phylogenetic and genetic relationships among avian influenza viruses (AIV) recently isolated from poultry in Israel. During this study we analyzed complete nucleotide sequences of two envelope (hemagglutinin and neuraminidase) and six internal genes (polymerase B1, polymerase B2, polymerase A, nucleoprotein, nonstructural, and matrix) of 29 selected H9N2 and six internal genes of five H5N1 viruses isolated in Israel during 2000–2006. Comparative genetic and phylogenetic analyses of these sequences revealed that the local H5N1 viruses are closely related to H5N1 viruses isolated in European, Asian, and Middle Eastern countries in 2005–2006. The H9N2 Israeli isolates, together with viruses isolated in Jordan and Saudi Arabia formed a single group. Our data support the claim that during recent years a new endemic focus of H9N2 has been formed in the Middle East. The introduction of H5N1 and co-circulation of these two subtypes of AIV in this region may augment the risk of potentially pandemic strains emergence.     

Multi-center evaluation of the cobas® Liat® Influenza A/B & RSV assay for rapid point of care diagnosis

Point of Care Testing (POCT) provides the capability for rapid laboratory test results in patient care environments where a traditional clinical laboratory is not available. POCTs have shorter turn-around times (TATs), they may be performed by non-laboratory personnel, and the need for transport time is eliminated. The Food and Drug Administration (FDA) recently granted Clinical Laboratory Improvements Amendment (CLIA) waiver status to the cobas^® Influenza A/B & RSV assay, a rapid, accurate point-of-care test for Influenza and respiratory syncytial virus (RSV) performed on the Liat^® System. The performance characteristics of this test were determined though a multi-site study consisting of different point of care testing environments. Prospectively collected Nasopharyngeal (NP) swabs from 1361 patients seen at 8 primary care clinics and 4 emergency departments (EDs) and 295 retrospectively identified specimens were tested for Influenza A/B and RSV on the cobas^® Liat^® platform. Performance characteristics were determined through comparison to ProFlu+, a laboratory-based PCR test for Influenza A/B and RSV (reference test). Discordant specimens were adjudicated following bi-directional sequencing. The cobas^® Influenza A/B and RSV assay showed sensitivities of 99.6%, 99.3%, and 96.8% for Influenza A, Influenza B, and RSV, respectively as determined from percent positive agreement (PPA) following comparison to the reference test. Sequencing confirmed cobas^® Influenza A/B and RSV results in 49.2% of reference test discordant specimens, while crossing threshold data suggest increased sensitivity compared to the reference test. The cobas^® Influenza A/B and RSV assay was found to be a rapid, sensitive POCT for the detection of these viruses, and provides laboratory-quality PCR-based diagnostic results in point of care settings.     

Induction of TNF-α in human macrophages by avian and human influenza viruses

The highly pathogenic avian influenza virus H5N1 is known to induce high level of tumor necrosis factor α (TNF-α) from primary macrophages. However, it is still unclear whether current H5N1 strains also induce high TNF-α production, as most of the data were derived from extinct clade 0 H5N1 strain. Here, we show that current clade 1 and 2 H5N1 strains induce variable levels of TNF-α that are not necessarily higher than those induced by seasonal influenza viruses. The result suggests that hyper-induction of TNF-α in human macrophages is not always associated with a highly pathogenic phenotype. We further tested the contribution of the NS gene segment from H5N1 isolates to TNF-α induction by using reverse genetics. While NS conferred some variation in TNF-α induction when incorporated into an H1N1 virus genetic background, it did not affect TNF-α induction in an H5N1 virus genetic background, suggesting that other viral genes are involved.     

Characterization of a reassortant H11N9 subtype avian influenza virus isolated from bean goose along the East Asian–Australian flyway

During the surveillance of avian influenza viruses in the Dongxi Lake wetland of Hubei in 2015–2016, an H11N9 avian influenza virus was isolated from a bean goose (Anser fabalis). Phylogenetic analysis showed that the HA gene of this isolate belongs to the North American lineage; however, the NA and the internal genes of the isolate were generated from the Eurasian lineage. This strain had reduced pathogenicity in mice and was capable of replication in the mouse lung without prior adaptation. This is the first report detecting H11N9 subtype influenza virus from migratory birds in central China. These findings highlight the transmission of avian influenza virus along the East Asian–Australian flyway and the need for continuing surveillance in central China.     

The use of whey protein concentrate in management of chronic hepatitis C virus – a pilot study

Introduction

Whey protein contains biologically active ingredients that can prevent and attenuate disease besides being nutritive. The aim of the study was to clarify the effects of oral administration of whey protein on viral load and host defence mechanisms, in particular, phagocytic function of neutrophils, selected immunomodulatory cytokines and serum inflammatory markers, in compensated chronic hepatitis C virus (HCV) patients.

Material and methods

Twenty-seven HCV patients (20 males and 7 females) recruited from the hepatology clinic of the Theodor Bilharz Research Institute (TBRI) were given whey protein concentrate (WPC) twice daily for two months. In addition, 15 age and sex matched healthy participants were included in the study, as a control group. Neutrophil phagocytic activity, serum intercellular adhesion molecule (sICAM), interleukin-2 (IL-2), nitric oxide (NO), as well as HCV-RNA levels and routine investigations were determined for patients, before and after WPC supplementation and once for the control group.

Results

There was a significant decrease in viral load and markers of active inflammation, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), while serum albumin, total leucocyte counts and absolute neutrophil counts showed significant elevation accompanied by improvement of neutrophil phagocytic activity after WPC supplementation compared to pre-treated levels. The oral WPC supplementation was well tolerated without any serious adverse events.

Conclusions

Oral supplementation of WPC has promising results as a new therapeutic strategy against HCV and its sequelae by decreasing the viral load and active inflammation as well as improving the synthetic capacity of the liver and the phagocytic function of neutrophils, in these patients.