Detection of the pandemic H1N1/2009 influenza A virus by a highly sensitive quantitative real-time reverse-transcription polymerase chain reaction assay

Influenza viruses and SARS-CoV-2 diagnosis via sensitive testing methods in clinical application

The identification of influenza viruses and SARS-CoV-2 has garnered increasing attention due of their longstanding global menace to human life and health. The point-of-care test is a potential approach for identifying influenza viruses and SARS-CoV-2 in clinical settings, leading to timely discovery, documentation, and treatment. The primary difficulties encountered with conventional detection techniques for influenza viruses and SARS-CoV-2 are the limited or inadequate ability to identify the presence of the viruses, the lack of speed, precision, accuracy, sensitivity, and specificity, often resulting in a failure to promptly notify disease control authorities. Recently, point-of-care test methods, along with nucleic acid amplification, optics, electrochemistry, lateral/vertical flow, and minimization, have been demonstrated the characteristics of reliability, sensitivity, specificity, stability, and portability. A point-of-care test offers promising findings in the early detection of influenza viruses and SARS-CoV-2 in both scientific research and practical use. In this review, we will go over the principles, advantages, limitations, and real-world applications of point-of-care diagnostics. The significance of constraints of detection, throughput, sensitivity, and specificity in the analysis of clinical samples in settings with restricted resources is underscored. This discussion concludes with their prospects and challenges.

In Memory of the Virologist Jianguo Wu, 1957-2022

It is with deep sorrow that we mourn the passing of the virologist Professor Jianguo Wu [...].

Inhibition of H1N1 influenza virus by selenium nanoparticles loaded with zanamivir through p38 and JNK signaling pathways

Zanamivir is an effective drug for influenza virus infection, but strong molecular polarity and aqueous solubility limit its clinical application.

A diagnostic one-step real-time reverse transcription polymerase chain reaction method for accurate detection of influenza virus type A

INTRODUCTION

Influenza A is known as a public health concern worldwide. In this study, a novel one-step real-time reverse transcription polymerase chain reaction (rtRT-PCR) assay was designed and optimized for the detection of influenza A viruses.

MATERIAL AND METHODS

The primers and probe were designed based on the analysis of 90 matrix nucleotide sequence data of influenza type A subtypes from the GenBank database of the National Center for Biotechnology Information (NCBI). The influenza virus A/Tehran/5652/2010 (H1N1 pdm09) was used as a reference. The rtRT-PCR assay was optimized, compared with that of the World Health Organization (WHO), and its analytical sensitivity, specificity and reproducibility were evaluated. In total, 64 nasopharyngeal swabs from patients with influenza-like illness (ILI) and 41 samples without ILI symptoms were tested for the virus, using conventional cell culture, direct immunofluorescence antibody (DFA) methods, and one-step rtRT-PCR with the designed primer set and probe and the WHO's.

RESULTS

The optimized assay results were similar to the WHO's. The optimized assay results were similar to WHO's, with non-significant differences for 10-10³ copies of viral RNA/reaction (p > 0.05). It detected 10 copies of viral RNA/reaction with high reproducibility and no cross reactivity with other respiratory viruses. A specific cytopathic effect was observed in 6/64 (9.37%) of the ILI group using conventional culture and DFA staining methods; however, it was not seen in non-ILI. Also, the results of our assay and the WHO's were similar to those of viral isolation and DFA staining.

CONCLUSIONS

Given the high specificity, sensitivity and reproducibility of this novel assay, it can serve as a reliable diagnostic tool for the detection of influenza A viruses in clinical specimens and lab experiments.

Oral Delivery of a Novel Attenuated Salmonella Vaccine Expressing Influenza A Virus Proteins Protects Mice against H5N1 and H1N1 Viral Infection

Attenuated strains of invasive enteric bacteria, such as Salmonella, represent promising gene delivery agents for nucleic acid-based vaccines as they can be administrated orally. In this study, we constructed a novel attenuated strain of Salmonella for the delivery and expression of the hemagglutinin (HA) and neuraminidase (NA) of a highly pathogenic H5N1 influenza virus. We showed that the constructed Salmonella strain exhibited efficient gene transfer activity for HA and NA expression and little cytotoxicity and pathogenicity in mice. Using BALB/c mice as the model, we evaluated the immune responses and protection induced by the constructed Salmonella-based vaccine. Our study showed that the Salmonella-based vaccine induced significant production of anti-HA serum IgG and mucosal IgA, and of anti-HA interferon-γ producing T cells in orally vaccinated mice. Furthermore, mice orally vaccinated with the Salmonella vaccine expressing viral HA and NA proteins were completely protected from lethal challenge of highly pathogenic H5N1 as well as H1N1 influenza viruses while none of the animals treated with the Salmonella vaccine carrying the empty expression vector with no viral antigen expression was protected. These results suggest that the Salmonella-based vaccine elicits strong antigen-specific humoral and cellular immune responses and provides effective immune protection against multiple strains of influenza viruses. Furthermore, our study demonstrates the feasibility of developing novel attenuated Salmonella strains as new oral vaccine vectors against influenza viruses.

Swine flu is back again: a review

Flu viruses have mainly affected humans, birds and pigs worldwide. During the past 10 years these viruses are in limelight at a global level due to pandemic threats of Avian/Bird Flu and Swine Flu and their public health impacts, with added pandemic of swine flu virus recently. The current ongoing episodes of bird flu and swine flu are beyond the control, when and where or which country they start with nobody can predict. The continuous evolution and emergence of new strains indicate that the flu viruses are becoming more and more dangerous and this situation has posed a challenge to researchers to discover effective vaccines and therapeutics. Moreover, the role of pig as 'mixing bowl' for the virus to get reassorted has added to the complicated epidemiological scenario. The swine flu H1N1 reassorted subtype caused the first global pandemic in last 40 years, resulting in substantial illness, hospitalizations of millions of peoples and thousands of deaths throughout the world. A pace is there within these novel and emerging flu viruses and the scientific community, where the scientific community has to win the race so as to save the mankind. In this review, a brief overview on swine flu is presented highlighting the characteristics of the causative virus, the disease and its public health consequences, advances made in its diagnosis, vaccine and control, precautionary measures to be adapted in the wake of an outbreak.