Rapid Detection Of Influenza Virus Research Articles

Loop-Mediated Isothermal Amplification and Lateral Flow Immunochromatography Technology for Rapid Diagnosis of Influenza A/B.

Influenza viruses cause highly contagious respiratory diseases that cause millions of deaths worldwide. Rapid detection of influenza viruses is essential for accurate diagnosis and the initiation of appropriate treatment. We developed a loop-mediated isothermal amplification and lateral flow assay (LAMP-LFA) capable of simultaneously detecting influenza A and influenza B. Primer sets for influenza A and influenza B were designed to target conserved regions of segment 7 and the nucleoprotein gene, respectively. Optimized through various primer set ratios, the assay operated at 62 °C for 30 min. For a total of 243 (85 influenza A positive, 58 influenza B positive and 100 negative) nasopharyngeal swab samples, the performance of the influenza A/B multiplex LAMP-LFA was compared with that of the commercial AllplexTM Respiratory Panel 1 assay (Seegene, Seoul, Korea). The influenza A/B multiplex LAMP-LFA demonstrated a specificity of 98% for the non-infected clinical samples, along with sensitivities of 94.1% for the influenza A clinical samples and 96.6% for the influenza B clinical samples, respectively. The influenza A/B multiplex LAMP-LFA showed high sensitivity and specificity, indicating that it is reliable for use in a low-resource environment.

Microsphere-Enabled Micropillar Array for Whispering Gallery Mode Virus Detection.

Rapid detection of pathogens and analytes at the point of care offers an opportunity for prompt patient management and public health control. This paper reports an open microfluidic platform coupled with active whispering gallery mode (WGM) microsphere resonators for the rapid detection of influenza viruses. The WGM microsphere resonators, precoated with influenza A polyclonal antibodies, are mechanically trapped in the open micropillar array, where the evaporation-driven flow continuously transports a small volume (∼μL) of sample to the resonators without auxiliaries. Selective chemical modification of the pillar array changes surface wettability and flow pattern, which enhances the detection sensitivity of the WGM resonator-based virus sensor. The optofluidic sensing platform is able to specifically detect influenza A viruses within 15 min using a few microliters of sample and displays a linear response to different virus concentrations.

Accurate detection of influenza A virus by use of a novel cross-priming isothermal amplification-based point-of-care assay.

Influenza virus is known to cause respiratory tract infections of varying severity in individuals of all ages. The EasyNAT Rapid Flu assay is a newly developed in vitro diagnostic test that employs cross-priming isothermal amplification (CPA) to detect and differentiate influenza A and B viruses in human nasopharyngeal (NP) swabs. The aim of this study is to determine the performance characteristics of the EasyNAT Rapid Flu assay for rapid detection of influenza virus. The limit of detection (LOD) and cross-reactivity of the EasyNAT Rapid Flu assay were assessed. The clinical performance of the assay was evaluated using NP swab samples that were tested with real-time reverse-transcription polymerase chain reaction (RT-PCR) and Xpert Xpress Flu/RSV assay. The LOD for the detection of influenza A and B using the EasyNAT Rapid Flu assay was found to be 500 copies/mL. Furthermore, the assay exhibited no cross-reactivity with other common respiratory viruses tested. For the 114 NP swab samples tested for influenza A using both the EasyNAT Rapid Flu assay and real-time RT-PCR, the two assays demonstrated a high level of agreement (κ = 0.963, P < 0.001), with a positive percentage agreement (PPA) of 97.7% and a negative percentage agreement (NPA) of 98.6%. Similarly, for the 43 NP swab samples tested for influenza A and B using both the EasyNAT Rapid Flu assay and Xpert Xpress Flu/RSV assay, the two assays showed a high level of agreement (κ = 0.933, P < 0.001), with the overall rate of agreement (ORA) of 97.7% for influenza A and 100% for influenza B. The EasyNAT Rapid Flu assay demonstrates excellent performance in the detection of influenza A, highlighted by its strong agreement with RT-PCR-based assays.IMPORTANCEThe newly developed EasyNAT Rapid Flu assay is an innovative cross-priming isothermal amplification-based method designed for detecting influenza A and B viruses at point-of-care settings. This study aims to thoroughly assess the analytical and clinical performance of the assay, offering valuable insights into its potential advantages and limitations. The findings of this research hold significant implications for clinical practice.

Rapid Molecular Point of Care Testing for Detection of Influenza A, B Viruses and Respiratory Syncytial Virus Versus Multiplex PCR

Introduction: Rapid detection of influenza viruses and respiratory syncytial virus (RSV) can be achieved by having rapid molecular point of care tests (POCTs). This expedites the diagnosis attributed by having similar clinical presentations leading to facilitation of precision medicine and reduction of antimicrobial resistance. The growing number of POCTs foster the need to ensure that these POCTs have satisfactory and reliable performance. With that the aim of this study is to evaluate the performance of rapid molecular POCT regarded as ‘X’ for the detection of Influenza viruses and RSV in comparison to multiplex PCR. Methods: A laboratory-based study was conducted from January to December 2020 which involved analysis of 116 nasopharyngeal swabs, tested using POCT X and multiplex PCR as a method of reference. The performance analysis incorporated the sensitivity, specificity, positive and negative predicted values determination. The cycle threshold values were reviewed for discordant results. Results: The POCT X demonstrated sensitivity of 88.57% with 100% specificity for Influenza A virus, and 85.71% of sensitivity with 100% specificity for influenza B virus detection. Meanwhile it revealed 100% sensitivity and specificity for RSV detection. There were ten specimens demonstrating discordant results whereby viruses were not detected by POCT X, however detected by multiplex PCR. The POCT X was not able to detect eight (12.9%) and two (16.7%) influenza A and B viruses respectively. Conclusion: The overall performance of POCT X was corresponded to multiplex PCR. This best served as a steadfast ancillary test for influenza and RSV infection.

An automated nucleic acid detection platform using digital microfluidics with an optimized Cas12a system.

Outbreaks of both influenza virus and the novel coronavirus SARS-CoV-2 are serious threats to human health and life. It is very important to establish a rapid, accurate test with large-scale detection potential to prevent the further spread of the epidemic. An optimized RPA-Cas12a-based platform combined with digital microfluidics (DMF), the RCD platform, was established to achieve the automated, rapid detection of influenza viruses and SARS-CoV-2. The probe in the RPA-Cas12a system was optimized to produce maximal fluorescence to increase the amplification signal. The reaction droplets in the platform were all at the microliter level and the detection could be accomplished within 30 min due to the effective mixing of droplets by digital microfluidic technology. The whole process from amplification to recognition is completed in the chip, which reduces the risk of aerosol contamination. One chip can contain multiple detection reaction areas, offering the potential for customized detection. The RCD platform demonstrated a high level of sensitivity, specificity (no false positives or negatives), speed (≤30 min), automation and multiplexing. We also used the RCD platform to detect nucleic acids from influenza patients and COVID-19 patients. The results were consistent with the findings of qPCR. The RCD platform is a one-step, rapid, highly sensitive and specific method with the advantages of digital microfluidic technology, which circumvents the shortcomings of manual operation. The development of the RCD platform provides potential for the isothermal automatic detection of nucleic acids during epidemics. Electronic Supplementary MaterialSupplementary material is available in the online version of this article at 10.1007/s11426-021-1169-1.

Comparison of the Coris Influ A + B K-SeT® and BD Veritor Flu A + B® for rapid detection of influenza viruses in respiratory samples from 3 consecutive flu seasons in Belgium

Comparison of the Coris Influ A + B K-SeT® and BD Veritor Flu A + B® for rapid detection of influenza viruses in respiratory samples from 3 consecutive flu seasons in Belgium

Electrochemical detection of influenza virus H9N2 based on both immunomagnetic extraction and gold catalysis using an immobilization-free screen printed carbon microelectrode

Influenza is a viral infectious disease considered as a source of many health problems and enormous socioeconomic disruptions. Conventional methods are inadequate for in-field detection of the virus and generally suffer from being laborious and time-consuming. Thus, studies aiming to develop effective alternatives to conventional methods are urgently needed. In this work, we developed an approach for the isolation and detection of influenza A virus subtype H9N2. For this aim, two specific influenza receptors were used. The first, anti-matrix protein 2 (M2) antibody, was attached to iron magnetic nanoparticles (MNPs) and used for the isolation of the virus from allantoic fluid. The second biomolecule, Fetuin A, was attached to an electrochemical detectable label, gold nanoparticles (AuNPs), and used to detect the virus tacking advantage from fetuin-hemagglutinin interaction. The MNP-Influenza virus-AuNP formed complex was isolated and treated by an acid solution then the collected gold nanoparticles were deposited onto a screen printed carbon electrode. AuNPs catalyzes the hydrogen ions reduction in acidic medium while applying an appropriate potential, and the generated current signal was proportional to the virus titer. This approach allows the rapid detection of influenza virus A/H9N2 at a less than 16 HAU titer.

Assesing sensitivity and specificity of rapid diagnostic test : the importance and challenges of Influenza surveillance in Indonesia

Background: The rapid detection of influenza viruses from clinical samples is important for establishing public health and clinical decisions, including infection prevention and control measures. The SD Bioline rapid influenza test (Standard Diagnostics, Inc., Suwon, Korea) is a point-of-care (POC) diagnostic test which based on influenza-specific monoclonal antibodies. The purpose of this study is to assess the performance of this assay against the reference diagnostic standards of RT-PCR for Influenza diagnosis in Surveillance activity.Methods: 4,262 nasal and throat swab specimens were collected from influenza-like illness (ILI) patients from sentinel hospital and health-care sites across 10 provinces in Indonesia. Specimens were tested with the SD Bioline rapid influenza test in sentinels and rRT-PCR test was conducted in referral laboratory in Jakarta. Data analysis was performed by comparing the results of rapid test conducted in the POC settting and the results of rRT-PCR test.Results: Testing of throat and nasal swabs from children and adults indicated the specificity of The SD Bioline rapid influenza test to be 97% for influenza A and B, respectively, in 4262 specimens. However, the overall sensitivity of the SD Bioline rapid influenza test for these samples was low at 25%.Conclusions: Overall, the results indicated that the SD Bioline rapid influenza test has a high specificity but low sensitivity for detection influenza from throat and nasal swabs therefore it will be a challenge of laboratory testing on site.Keywords: Influenza, rapid diagnostic test, surveillance

Performance of the Alere i influenza A&B assay and mariPOC test for the rapid detection of influenza A and B viruses

BackgroundTimely detection of influenza viruses is required to facilitate infection control measures and appropriate patient management. The Alere™ i Influenza A&B assay for detection of viral RNA and multianalyte mariPOC® test for detection of viral antigens enable rapid detection of influenza viruses with little hands-on time. ObjectivesTo evaluate the performance of the Alere i Influenza A&B assay and the mariPOC test in comparison to the Xpert® Flu A/B assay and laboratory-developed real-time reverse transcription-polymerase chain reaction. Study designA total of 140 and 108 nasopharyngeal specimens were analysed for evaluation of the Alere i and mariPOC, respectively. ResultsThe sensitivity and specificity of the Alere i Influenza A&B assay for detection of influenza A virus was 80.0% and 98.1%, and for influenza B virus 45.2% and 98.2%, respectively. For the mariPOC test, a sensitivity and specificity of 53.1% and 98.7%, respectively, for detection of influenza A virus was achieved. ConclusionsThe mariPOC test proved insensitive for detection of influenza A virus and therefore unsuitable for individual patient diagnosis without confirmatory testing. In contrast, the Alere i Influenza A&B assay was reasonably sensitive and specific for detection of influenza A and B virus, although decreased detection of specimens with low viral load was observed particularly for detection of influenza B virus. Taken together with its rapidity and ease of use, the Alere i influenza A&B assay is a welcome alternative to immunochromatographic rapid influenza detection tests and may provide timely results that enable appropriate patient care and management of patient flow during high-prevalence seasons.

Polymicrobial community-acquired pneumonia requiring mechanical ventilation: A case series

Polymicrobial pneumonia may cause by combinations of respiratory viruses and bacteria in a host. Colonization by Streptococcus pneumoniae was associated with increased risk of Intensive Care Unit admission or death in the setting of influenza infection whereas the colonization by methicillin resistant Staphylococcus aureus coinfection was associated with severe disease and death in adults and children. The principal association of pathogens in community-acquired pneumonia (CAP) is bacteria and viral coinfection and accounts approximately on 39% of microbiological diagnosed cases of CAP. The emergency of influenza virus H1N1 in 2009 caused the first pandemic in more than 40 years. Several studies found bacterial coinfection in a quarter and one-half of influenza infections, the pathogens more frequent isolates were S. pneumoniae and S. aureus mixed pneumonia in all patient groups. The high rate of viral bacterial infection in CAP, should suggest the consideration of new treatments, also during influenza season, the rapid detection of influenza virus (A or B) may allow physician the effective use of neuraminidase inhibitors within 36-48 h of symptoms onset, reducing the complication of secondary bacterial infection. On the other hand, prevention of mixed infection by influenza and pneumococcal vaccine should be addressed. The differential clinical diagnosis between a viral and a bacterial CAP is not easy: No clinical signs or radiological findings help the clinician to suspicious the diagnosis. In this case series, we report five different cases of severe polymicrobial CAP: All of them required mechanical ventilation: Invasive the first two and noninvasive ventilation the last three cases.

Evaluation of the Simplexa Flu A/B and RSV test for the rapid detection of influenza viruses

Recently, various molecular systems have been introduced for the detection of influenza viruses. Among these, the Simplexa Flu A/B and respiratory syncytial virus (RSV) test can provide results in approximately 2 hr. Nasopharyngeal swabs from 241 patients (influenza A, n = 81; influenza B, n = 80; influenza A and influenza B mixed, n = 1; influenza A and RSV A mixed, n = 2; and influenza and RSV negative, n = 77) were analyzed using the Simplexa Flu A/B and RSV test, a conventional reverse-transcription polymerase chain reaction (RT-PCR) assay, and a real-time RT-PCR assay. Compared to conventional RT-PCR, the Simplexa test had respective sensitivities and specificities of 100% and 100% for influenza A and 100% and 99.4% for influenza B with extracted RNA samples, and 91.7% and 99.4% for influenza A, and 97.5% and 98.1% for influenza B with unprocessed patient specimens. All RSV A specimens were successfully detected by the Simplexa test using both extracted RNA samples and unprocessed patient specimens. The real-time RT-PCR assay had respective sensitivities and specificities of 96.4% and 99.4% for influenza A, and 98.8% and 99.4% for influenza B. The Simplexa test was effective at detecting influenza viruses from extracted RNA samples as well as from unprocessed patient specimens. The assay was not only simple and rapid for influenza detection, but the performance was also comparable to that of other conventional molecular methods.

Evaluation of a Rapid Detection Influenza Virus A Antigens Kit Using Paired Serum Antibody Test

PurposeTo evaluate the feasibility for gold immunochromatographic assay (GICA) in rapid detection of influenza virus A infection.Materials and MethodsSeventy-three patients were enrolled. All patients contributed nasopharyngeal secretions and paired serum samples. Nasopharyngeal secretions was used for colloidal gold immunochromatographic rapid assay for influenza A virus immediately after the collection of specimen. Paired serum samples were used for the hemagglutination inhibition assay at the Centers for Disease Control and Prevention influenza network laboratory in Beijing.ResultsCompare GICA test to hemagglutination inhibition (HI) assay, the Kappa value was 0.402 and the p value in the paired χ2 test was higher than 0.05. Therefore, the difference was not statistically significant. The sensitivity of GICA was 50.0% and the specificity was 90.2%, and the negative predictive value was 90.2%.ConclusionThe sensitivity for Influenza A antigen detection by using GICA is relatively low, the specificity is relatively satisfactory.

A novel high-speed droplet-polymerase chain reaction can detect human influenza virus in less than 30 min

BackgroundThe polymerase chain reaction (PCR) has been widely used for diagnosis of infection. Rapid detection of influenza virus is useful for therapeutic decisions. We attempted to develop a novel assay by real-time droplet-PCR machine for influenza virus. MethodsRNA extracted from nasal swabs or primary swabs pretreated only were used for PCR analyses. We evaluated reaction time, amplification efficiency, sensitivity, and specificity of the novel droplet-PCR. ResultsThe reaction time of the novel droplet-PCR was 28min, whereas that of PCR using the conventional PCR machine was 80min. The standard curve constructed from the amplification plots by the novel droplet-PCR was: y=−3.6x+42.9; that by PCR using the conventional PCR machine was: y=−3.5x+37.8. The sensitivity and specificity of the novel droplet-PCR were 86.7% and 91.7% for the influenza A and 100.0% and 100.0% for the influenza B, respectively. The novel droplet-PCR provided the specific amplification when using primary swabs without RNA extraction. ConclusionsOur novel droplet-PCR markedly reduced the reaction time while showing same reactivity as that by PCR using the conventional PCR machine. Thus, the novel droplet-PCR assay can be used as a rapid assay for detection of influenza virus.

Impact of influenza during the post-pandemic season: epidemiological picture from syndromic and virological surveillance.

Following the observation that 1 or 2 pandemic peak due to the circulation ofAHINlv had occurred in most countries and in most World Health Organization (WHO) Regions, WHO declared on August 10"h, 2010 that the world was moving into the post-pandemic period, whose surveillance presents considerable interest both from epidemiological and clinical point of view. We described the epidemiological picture emerged from syndromic and virological surveillance during the post-pandemic season in Liguria, Italy. An Emergency Department Syndrome surveillance system, based on data collected at "San Martino" and IRCCS "G. Gaslini" Liguria Regional Reference University Hospitals for adults and children is active since July 2007. Monitored syndromes include "Influenza-Like Illness" (ILl) and "Low Respiratory Tract Infections" (LRTI). The Ligurian Regional Reference laboratory for Influenza virological surveillance and diagnosis offers rapid detection of influenza viruses by real-time and block RT-PCR, viral culture and genetic characterization by entire sequence analysis of haemagglutinin- and neuraminidase-coding regions in accordance with the international standards established by the global laboratory network. The integration of syndromic surveillance system and laboratory surveillance for rapid detection and characterization of the disease responsible agent represented a specific and sensitive tool for influenza surveillance. The post-pandemic season was characterized by early onset and by the heaviest impacts for ILI and LRTI among the recent epidemic seasons. In contrast to the picture observed during the pandemic season, the 2010/11 winter was characterized by the intensive circulation of pandemic AH1N1v coupled with sustained activity due to influenza B and Respiratory Syncytial Virus (RSV). Antigenic and molecular characterization of influenza strains confirmed the good matching between circulating and 2010/11 vaccine viruses.

New developments in the diagnosis of avian influenza

Avian influenza has become a serious concern from both veterinary and public health points of view. National and international organisations, veterinary health authorities, research institutions, diagnostic laboratories and field services make enormous efforts worldwide to detect, combat and prevent this important disease. Accordingly, the standard diagnostic protocols are being supported by a wide variety of molecular detection techniques, including improved polymerase chain reaction assays, microarray-based detection and characterisation methods, very rapid sequencing, simple pen-side tests and other on-site approaches. These recently developed 'closer to the field' methods allow rapid detection of influenza viruses and the identification of pathogenicity variants. However, in order to harmonise the diagnosis worldwide, attention has to be paid to the validation and standardisation of these technologies, to avoid erroneous interpretation of assay results, and, consequently, inappropriate epidemiological measures. This review gives an overview of the current and potential future developments related to avian influenza diagnostics.

Evaluation of Three Immunochromatographic Kits for Rapid Detection of Influenza Virus A and B

Background: Clinically, it is difficult to distinguish influenza infection from febrile infections caused by respiratory syncytial virus, adenovirus, rhinovirus, and human metapneumovirus without the use of rapid diagnostic tests. Methods: Nasopharyngeal aspirates (NPAs) were collected from 494 pediatric patients and were tested for the presence of influenza A and B virus antigen using 3 rapid diagnotic kits: ESPLINE Influenza A and B-N, Directigen EZ Flu A and B, and Binax NOW Influenza A and B. Results: Fifty-three specimens positive by viral culture were positive for influenza A by all 3 kits. Of the 270 influenza B virus cellculture-positive specimens, the sensitivities of ESPLINE, EZ, and NOW were 86%, 76%, and 78%, respectively. Conclusion: Under well-controlled conditions, influenza A virus sensitivities for all 3 kits can be 100% with specificities ranging from 98% to 100%.

Clinical Evaluation of the SD Bioline Influenza Virus Antigen Test for Rapid Detection of Influenza Viruses A and B in Children and Adults during the Influenza Season

The performance of the SD Bioline rapid antigen test kit for influenza virus detection was evaluated with 295 respiratory specimens during the influenza season. The overall sensitivity and specificity of the SD Bioline test were 61.9% and 96.8% for the influenza A virus antigen and 54.5% and 100% for the influenza B virus antigen, respectively. The results were consistent with peak influenza activities.

Comparison of two rapid influenza A/B test kits with reference methods showing high specificity and sensitivity for influenza A infection

The rapid detection of influenza viruses is important for forming preventative strategies, directing initiation of anti-viral therapy, detecting potential avian influenza viruses, and excluding influenza-like pathogens, such as SARS. The ImmunoCard STAT! Flu A and B Plus test (Meridian Bioscience, Cincinnati, OH) is a new point of care (POC) test utilizing influenza-specific monoclonal antibodies for rapid diagnosis. The performance of this assay was compared to the established POC Binax NowFlu A and NowFlu B test, and the reference diagnostic standards of viral culture, indirect immunofluorescence (IFA), and RT-PCR where appropriate. Testing of nasopharyngeal aspirates (NPA) from children, throat swabs, and nasal swabs from adults indicated ImmunoCard STAT! specificity of 98% and 100% for influenza A and B, respectively in 224 specimens. The Binax test showed specificity of 99% and 100%, respectively for influenza A and B. Sensitivity results were identical for both rapid detection kits (80% and 47% for Flu A and B, respectively). Overall results were very similar for both testing devices with the advantage of ImmunoCard STAT! Flu A and B Plus test detecting influenza A and B with sharp and easy to read results.

Comparison of the BD Directigen Flu A+B Kit and the Abbott TestPack RSV with a multiplex RT-PCR ELISA for rapid detection of influenza viruses and respiratory syncytial virus

The Directigen Flu A+B enzyme immunoassay and the Abbott TestPack RSV enzyme immunoassay were each compared with a multiplex RT-PCR ELISA by testing 635 nasopharyngeal aspirates collected from children aged < 16 years who had been hospitalised with acute respiratory tract infection during the epidemic season 2002-2003. In this study, the sensitivity of the Directigen Flu A+B assay was unacceptably low (29.3% and 10.0%, respectively) for the detection of influenza A and B viruses. The sensitivity of the Abbott TestPack RSV assay (77.4%) was acceptable and in agreement with the multiplex RT-PCR ELISA.

Evaluation of Three Immunoassay Kits for Rapid Detection of Influenza Virus A and B

Influenza causes high morbidity and mortality in very young and elderly individuals, which can be controlled with antivirals and/or vaccines. The success of therapeutic measures is predicated on the rapid and precise diagnosis of the infection. We compared three rapid influenza immunoassay (RIIA) kits for the diagnosis of influenza virus A and B using 178 respiratory specimens submitted for routine testing. BD Directigen Flu A+B (Directigen), Directigen EZ Flu A+B (EZ), and NOW Flu A NOW Flu B (NOW; Binax) tests had comparable combined influenza virus A and B specificities, varying from 94 to 98%. In contrast, the sensitivity of EZ was significantly lower (39%) than that of NOW (76%) and marginally lower than that of Directigen (56%). The differences in sensitivity were most evident in patients who were >9 years old (Directigen, 53%; EZ, 32%; and NOW, 69%). Among specimens, bronchoalveolar lavage fluids yielded the most discrepant results, with sensitivities varying from 0 (EZ) to 100% (NOW), followed by nasopharyngeal swabs (sensitivities of 27 to 100%) and nasal washes (50 to 81%). The Directigen kit format allowed for faster completion but more cumbersome performance and more difficult interpretation compared with the other two kits. Overall, NOW provided the most accurate diagnoses and had user-friendly technical characteristics. However, the low overall sensitivity of the RIIAs indicates that these can be used as screening tools only.