Search Results (154)

Background: Zoonotic influenza viruses pose a significant and evolving public health threat. In response to the recent rise in H5N1 cross-species transmission, the World Health Organization (WHO) R&D Blueprint for Epidemics consultations have prioritized strengthening surveillance, candidate vaccines, diagnostics, and pandemic preparedness. Serological surveillance plays a pivotal role by providing insights into the prevalence and transmission dynamics of influenza viruses. Objective: This scoping review aimed to map the global research landscape on serological surveillance of zoonotic influenza in animals and exposed humans between 2017, the date of the last WHO public health research agenda for influenza review, and 2024, as well as to identify methodological advancements. Methods: Following PRISMA-ScR guidelines, we searched PubMed for English-language peer-reviewed articles published between January 2017 and March 2024. Studies were included if they reported serological surveillance in wild or domestic animals or occupationally exposed human populations, or novel methodologies and their technical limitations and implementation challenges. Results: Out of 7490 screened records, 90 studies from 33 countries, covering 25 animal species, were included. Seroprevalence studies were in domestic poultry and swine. Surveillance in companion animals, wild mammals, and at the human–animal interface was limited. Emerging serological methods included multiplex and nanobody-based assays, though implementation barriers remain. Conclusions: The review is limited by its restriction to one database and English-language articles, lack of quality appraisal, and significant heterogeneity among the included studies. Serological surveillance is a critical but underutilized tool in zoonotic influenza monitoring. Greater integration of serological surveillance into One Health frameworks, especially in high-risk regions and populations, is needed to support early detection and pandemic preparedness. Full article

Background/Objectives: Since the World Health Organization (WHO) recommended HIV self-testing as an alternative to traditional facility-based testing in 2016, it has been increasingly adopted worldwide. This study aimed to evaluate the performance of the ConfiSign HIV Self-Test (GenBody Inc., Republic of Korea), a newly developed blood-based immunochromatographic assay for the qualitative detection of total antibodies (IgG and IgM) against HIV-1/HIV-2. Methods: The evaluation included four components: (1) retrospective analysis of 1400 archived serum samples (400 HIV-positive and 1000 HIV-negative samples), (2) prospective self-testing by 335 participants (112 HIV-positive participants and 223 individuals with an unknown HIV status, including healthy volunteers), (3) assessment using seroconversion panels and diverse HIV subtypes, and (4) analytical specificity testing for cross-reactivity and interference. The Elecsys HIV combi PT and Alinity I HIV Ag/Ab Combo assays were used as reference assays. Results: In retrospective testing, the ConfiSign HIV Self-Test achieved a positive percent agreement (PPA) of 100%, a negative percent agreement (NPA) of 99.2%, and a Cohen’s kappa value of 0.986, showing excellent agreement with the reference assays. In the prospective study, the test showed 100% sensitivity and specificity, with a low invalid result rate of 1.8%. All HIV-positive samples, including those with low signal-to-cutoff (S/Co) values in the Alinity I assay, were correctly identified. The test also reliably detected early seroconversion samples and accurately identified a broad range of HIV-1 subtypes (A, B, C, D, F, G, CRF01_AE, CRF02_AG, and group O) as well as HIV-2. No cross-reactivity or interference was observed with samples that were positive for hepatitis viruses, cytomegalovirus, Epstein–Barr virus, varicella zoster virus, influenza, HTLV-1, HTLV-2, or malaria. Conclusions: The ConfiSign HIV Self-Test demonstrated excellent sensitivity, specificity, and robustness across diverse clinical samples, supporting its reliability and practicality as a self-testing option for HIV-1/2 antibody detection. Full article

The Highly Pathogenic Avian Influenza Virus (HPAIV) H5 clade 2.3.4.4b has caused severe outbreaks in domestic and wild birds worldwide since its emergence in 2014, and especially since 2020, with outbreaks in Europe and North America. The introduction of the virus into South America was reported for the first time in Colombia in October 2022, followed by outbreaks in other South American countries affecting poultry, wild birds, mammals, and humans. In this study, a phylogenetic and mutation analysis of the hemagglutinin (HA) gene of HPAIV H5N1 2.3.4.4b viruses isolated in South America was performed to analyze its evolution and its transmission and zoonotic potential. The analysis shows an increase in the viral effective population size between April and June 2022, which was followed by multiple outbreaks of HPAIV H5N1 clade 2.3.4.4b in South America. Moreover, the virus variants evolved from a recent common ancestor estimated to have existed in June 2017. The mean rate of evolution of the HA gene was 6.95 × 10⁻³ substitutions per site per year, and the sequence analysis of HA identified a mutation (D171N) located at antibody binding sites and viral oligomerization interfaces, with implications for immune response evasion and new host species infection. Additionally, viral strains from South America share the substitutions L104M, T156A, P181S, and V210A, compared to the vaccine strain A/chicken/Ghana/AVL763/2021. Understanding the dynamics of viral evolution and transmission is essential for effective prevention strategies to mitigate future outbreaks. Full article

Cell-based phenotypic screening of a privileged in-house library composed of pyridobenzothiazolone (PBTZ) analogues was conducted against representative viruses responsible for common respiratory tract infections in humans, i.e., respiratory syncytial virus (RSV), human coronavirus type OC43 (HCoV-OC43), and influenza virus type A (IFV-A). We identified a compound with broad-spectrum inhibitory activity against multiple strains of RSV, HCoV, and IFV, with EC₅₀ values in the low micromolar range and cell-independent activity. Its antiviral activity and cytocompatibility were confirmed in a fully differentiated 3D model of the bronchial epithelium mimicking the in vivo setting. The hit compound enters cells and localizes homogeneously in the cytosol, inhibiting replicative phases in a virus-specific manner. Overall, the selected PBTZ represents a good starting point for further preclinical development as a broad-spectrum antiviral agent that could address the continuous threat of new emerging pathogens and the rising issue of antiviral resistance. Full article

This study explored the distribution and genetic characteristics of respiratory pathogens in outpatients with acute respiratory infections (ARIs) in Yangon, Myanmar, during the 2023 rainy season. Among 267 patients who tested negative for influenza, RSV, and SARS-CoV-2 using rapid diagnostic tests, 84.6% were positive for at least one pathogen according to a multiplex polymerase chain reaction (PCR) assay, the BioFire^® FilmArray^® Respiratory Panel 2.1. The most common viruses detected were rhinovirus/enterovirus (RV/EV) at 37.8%, respiratory syncytial virus (RSV) at 22.4%, and human metapneumovirus (hMPV) at 10.0%. These pathogens co-circulated mainly from July to September, with RV/EV consistently predominant. Symptom comparison among RV/EV-, RSV-, and hMPV-infected patients showed similar clinical features, though fever was more common in hMPV cases. Among RV/EV-positive patients, 59.3% had single infections, while 40.7% experienced co-infections, especially with RSV and adenovirus. Genotyping identified 28 types from five species, primarily RV-A and RV-C, which were genetically diverse. One EV-D68 case was also found, emphasizing its potential risk. This study underscores the genetic diversity and clinical impact of RV/EV and stresses the importance of ongoing molecular surveillance in Myanmar’s post-COVID-19 context to inform effective public health responses. Full article

The CRISPR–Cas system has transformed molecular biology by providing precise tools for genome editing and pathogen detection. Originating from bacterial adaptive immunity, CRISPR technology identifies and cleaves genetic material from pathogens, thereby preventing infections. CRISPR–Cas9, the most widely utilized variant, creates double-stranded breaks in the target DNA, enabling genetic disruptions or edits. This approach has shown significant potential in antiviral therapies, addressing chronic infections, such as HIV, SARS-CoV-2, and hepatitis viruses. In HIV, CRISPR–Cas9 edits the essential viral genes and disrupts latent reservoirs, while CCR5 gene modifications render the T cells resistant to viral entry. Similarly, SARS-CoV-2 is targeted using CRISPR–Cas13d to inhibit the conserved viral genes, significantly reducing viral loads. Hepatitis B and C treatments leverage CRISPR technologies to target conserved genomic regions, limiting replication and expression. Emerging innovations, such as the PAC-MAN approach for influenza and base-editing systems to reduce off-target effects, further highlight the therapeutic versatility of CRISPR. Additionally, advances in Cas12a and Cas13 have driven the development of diagnostic platforms like DETECTR and SHERLOCK, which provide rapid and cost-effective viral detection. Innovative tools like AIOD-CRISPR enable accessible point-of-care diagnostics for early viral detection. Experimental approaches, such as targeting latent HSV-1 reservoirs, highlight the transformative potential of CRISPR in combating persistent infections. Full article

Avian influenza A viruses (AIV) significantly impact both animal and human health. Reliable diagnostics are crucial for controlling AIV, including the highly pathogenic strains like H5Nx. In this study, we developed and validated the on-site Alveo Sense Poultry Avian Influenza Tests to rapidly detect the AIV M-gene and subtypes H5, H7, and H9 in unprocessed samples using reverse-transcription loop-mediated isothermal amplification (RT-LAMP) and impedance-based measurements. The Alveo Sense tests, using single-use microfluidic cartridges, deliver results within 45 min. Each cartridge includes assays for the AIV M gene and specific H5 and H7 or H9 subtypes, with internal process controls. The laboratory validation involved specificity, limit of detection (LoD), diagnostic sensitivity, reproducibility, and robustness tests using various AIV strains, other avian pathogens, and field samples. The assays showed 100% specificity for AIV subtypes without cross-reactivity with non-AIV pathogens. The LoD95 for H5, H7, and H9 ranged between RT-PCR Ct values of 29–33 in both cloacal and oropharyngeal samples and were able to detect avian influenza virus in both spiked samples and field samples. Reproducibility and repeatability studies showed perfect agreement across operators and laboratories and remained stable and accurate under different pre-analytical conditions. The Alveo Sense tests offer rapid, accurate, and reliable on-site diagnostics for AIV subtypes H5, H7, and H9 on samples from fresh dead and sick birds, valuable for early flock-level detection and outbreak control. Further field validation will improve the understanding of their diagnostic performance across various avian species. Full article

Influenza is a communicable disease caused by RNA viruses. Strains A (affecting animals, humans), B (affecting humans), C (affecting rarely humans and pigs), and D (affecting cattle) comprise a variety of substrains each. Influenza A strain, affecting both humans and animals, is considered the most infectious, causing pandemics. There is an emerging need for the accurate classification of the different influenza A virus (IAV) subtypes, elucidating their mode of infection, as well as their fast and accurate diagnosis. Notably, in recent years, oligomeric sequences (words) that are present in the pathogen genomes and entirely absent from the host human genome were suggested to provide robust biomarkers for virus classification and rapid detection. To this end, we performed updated phylogenetic analyses of the IAV hemagglutinin genes, focusing on the sub H1N1 and H5N1. More importantly, we applied in silico methods to identify minimum length “words” that exist consistently in the IAV genomes and are entirely absent from the human genome; these sequences identified in our current analysis may represent minimal signatures that can be utilized to distinguish IAV from other influenza viruses, as well as to perform rapid diagnostic tests. Full article

With the concurrent circulations of SARS-CoV-2 omicron and influenza A viruses in the community, there is evidence showing co-infection with both viruses. However, disease severity may vary due to the complex immunity landscape of the patients and the neutralizing antibody waning status. The intrinsic dynamic relationship and pathological significance for such co-infections remain largely unknown. The replication kinetics and innate immune responses from the co-infections of SARS-CoV-2 (Omicron BA.1 and D614G variant) and influenza A viruses (pandemic H1N1, seasonal H3N2 and highly pathogenic avian H5N1) were characterized in human respiratory tissue explants, human airway, and alveolar epithelial cells. SARS-CoV-2 reduced the replication of influenza A viruses, but not vice versa, during co-infections in human bronchial tissues and airway epithelial cells. In lung tissues, the co-infections showed minimal effects on each other, but the viral replications of the two viruses were mutually reduced except for H1N1pdm in the alveolar epithelial cells irrespective of the enhancement of the ACE2 receptor. Notably, the co-infections showed a significant upregulation of the innate immune responses of SARS-CoV-2 in comparison to single infections in both respiratory epithelial cells, suggesting that co-infections of influenza A viruses potentially lead to more severe damage to the host than SARS-CoV-2 single infections. Full article

(1) Background: The ongoing panzootic of highly pathogenic avian influenza virus (HPAIV) of subtype H5N1, clade 2.3.4.4b, has decimated wild/domestic birds and mammals’ populations worldwide with reports of sporadic cases in humans. (2) Methods: This study aimed to compare the mutational profile of H5N1 avian Influenza virus isolated from a Peruvian natural reserve, with recent data from other related international studies made in human and different species of domestic and wild birds and mammals. Briefly, the near complete protein sequences of the Influenza virus coming from a Calidris alba were analyzed at a multisegmented level, together with 55 samples collected between 2022 and 2024 in different countries. Moreover, the glycosylation patterns were also predicted in silico. (3) Results: A total of 603 amino acid changes were found among H5N1 viruses analyzed, underscoring the detection of critical mutations HA:11I, HA:211I, HA:336T, HA:492D, HA:527I, NA:10T, NA:269L, NA:405T, NP:377N, PA:57R, PA:68S, PA:322V/L, PA:432I, PB2:539V, PB1:207R, PB1:375N, PB1:264D, PB1:429R, PA-X:250Q, PB1-F2:65R, and PB1-F2:42Y, as well as PA:13V, PA-X:13V, PA20T, PA-X:20T, PA:36T PA-X:36T, PA:45S, PA-X:45S, PA:57Q, PA-X:57Q, PA:61I, PA-X:61I, PA:68S, PA-X:68S, PA:70V, PA-X:70V, PA:75Q, PA-X:75Q, PA:85T, PA-X:85T, PA:86I, PA-X:86I, PA:100I, PA-X:100I, PA:142E, PA-X:142E, PA:160E, PA-X:160E, PA:211I, PA-X:211Y, among others, considered of importance under the One Health perspective. Similarly, changes in the N-linked glycosylation sites (NLGs) predicted in both HA and NA proteins were found, highlighting the loss/acquisition or changes in some NLGs, such as 209NNTN, 100 NPTT, 302NSSM (HA) and 70NNTN, 68NISS, and 50NGSV (NA). (4) Conclusions: This study provides our understanding about the evolution of current Influenza A viruses H5N1 HPAIV circulating globally. These findings outline the importance of surveillance updating mutational profiles and glycosylation patterns of these highly evolved viruses. Full article

In February 2024, while conducting surveillance for novel respiratory viruses, we studied four beef cattle farms near Monterrey, Mexico. Nasal swabs were collected from sick and healthy beef cattle along with 3 h aerosol samples. None of the samples had molecular evidence of influenza A viruses. Three (8%) of thirty-six nasal swabs collected from the four farms and four (33.3%) of the twelve bioaerosol specimens had molecular evidence of influenza D virus. Five sick cow nasal swabs and one bioaerosol sample on a single farm had molecular evidence of rodent coronavirus-like (RCoV), an alphacoronavirus. Three (60%) of the five RCoV-positive cattle nasal swabs also had molecular evidence of influenza D. Attempts to isolate the RCoV in Vero-E6, LLC-MK2, MDBK, and L-2 cells were unsuccessful. However, we were able to assemble ~60% of the RCoV genome using next-generation sequencing. The six RCoV-positive samples clustered with RCoV strains identified in China in 2021. During the last 12 months, we have studied an estimated 478 dairy and beef cattle nasal swabs on 11 farms in the US and Mexico, and these RCoV detections are the first we have encountered. While feed contamination cannot be ruled out, given the propensity of CoVs to jump species and that we detected RCoV only in the noses of sick cows on this one farm, we are concerned that these findings could represent an isolated RCoV spillover event. With this report, we are alerting veterinarians and cattle farm owners of our observations that RCoV may be a new cause of bovine respiratory disease. Full article

Background/Object: This study investigates the in vitro antiviral potential of D-limonene (DLM), monolaurin (ML), and cetylpyridinium chloride (CPC) in formulations targeting SARS-CoV-2 and influenza viruses. The aim was to develop oral and nasal formulations with optimized concentrations of these active ingredients to evaluate their efficacy, safety, and stability. Methods: Oral (formulation D) and nasal (formulation E) products were developed using specific concentrations of DLM (0.2–0.3% w/w), ML (0.1–0.2% w/w), and CPC (0.05–0.075% w/w). In vitro virucidal activity assays were conducted to assess the antiviral efficacy of the formulations against SARS-CoV-2 and influenza viruses. Stability testing was also performed under various storage conditions. Results: Formulation D (0.3% w/w DLM, 0.2% w/w ML, 0.05% w/w CPC, and 1.5% w/w Cremophor RH40) demonstrated a 3.875 ± 0.1021 log reduction and 99.99 ± 0.0032% efficacy against SARS-CoV-2 within 120 s. Formulation E (0.2% w/w DLM, 0.05% w/w CPC, and 0.75% w/w Cremophor RH40) showed a 2.9063 ± 0.1197 log reduction and 99.87 ± 0.0369% efficacy against SARS-CoV-2. Both formulations achieved >99.99% efficacy and log reductions exceeding 4.000 against various influenza strains. Stability testing confirmed optimal performance at 4 °C with no microbial contamination. Conclusions: The findings suggest that both formulations exhibit broad-spectrum antiviral activity against SARS-CoV-2 and influenza viruses in vitro. These results support their potential for further clinical evaluations and therapeutic applications, particularly in oral and nasal spray formulations. Full article

In late 2021, Eurasian-lineage highly pathogenic avian influenza (HPAI) A(H5N1) viruses from HA clade 2.3.4.4b were first detected in the United States. These viruses have caused severe morbidity and mortality in poultry and have been detected in numerous wild and domestic animals, including cows and humans. Notably, infected cows transmitted the virus to cats, causing extreme pathogenicity and death. While human-to-human spread of the virus has not been recorded, efficient transmission of the bovine-origin virus has also led to extreme pathogenicity and death in ferret models. Recently, markers in PB2 (E627K) and HA (E186D, Q222H), indicating mammalian adaptation mutations, were detected in an H5N1-infected patient manifesting critical illness in Canada. These, combined with instances of interspecies spread of the virus, have raised global public health concerns. This could highlight the potential for the virus to successfully adapt to mammals, posing a serious risk of a global outbreak. A One Health approach is, thereby, necessary to monitor and control the outbreak. This review aims to analyze the epidemiology, transmission, and ecological impacts of HPAI A(H5N1) clade 2.3.4.4b in the U.S., identify knowledge gaps, and inform strategies for effective outbreak management and mitigation. Full article

Influenza poses a serious threat to both individual and public health. This study aimed to investigate the virological and epidemiological characteristics of influenza infections and to explore the genetic diversity of the circulating influenza viruses. In total, 1886 nasopharyngeal specimens from patients with acute respiratory illnesses were tested against 13 respiratory viruses using a multiplex real-time PCR. Whole-genome sequencing, phylogenetic, and amino acid analyses of representative influenza strains were performed. At least one respiratory virus was detected in 869 (46.1%) patients; 87 (4.6%) were co-infected with two or three viruses. Influenza A(H1N1)pdm09 was the most prevalent virus (16.1%), followed by rhinoviruses (8.1%) and RSV (6.7%). Hemagglutinin (HA) genes of the 74 influenza A(H1N1)pdm09 viruses were categorized in subclades C.1.8, C.1.9, and C.1 within clade 5a.2a and D1, D.2, and D.3 within clade 5a.2a.1. The A(H3N2) viruses analyzed belonged to clade 2a.3a.1, subclades J.2 and J.1. The sequenced B/Victoria lineage viruses fell into clade V1A.3a.2, subclades C.5.6 and C.5.7. Amino acid substitutions in most viral proteins were identified compared with the vaccine strains, including in the HA antigenic sites. This study demonstrated the dominant distribution of the influenza A(H1N1)pdm09 virus among the respiratory viruses studied and the genetic diversity of the circulating influenza viruses. Full article

Respiratory viral infections present significant global health challenges, causing substantial morbidity and mortality, particularly among highly susceptible components of the population. The emergence of pandemics and epidemics, such as those caused by influenza viruses and coronaviruses, emphasizes the urgent need for effective antiviral therapeutics. In this review, we explore the potential of broad-spectrum antiviral agents targeting respiratory RNA viruses, including influenza viruses, coronaviruses, respiratory syncytial virus, human metapneumovirus, human parainfluenza viruses, and rhinoviruses. Various broad-spectrum direct-acting and host-targeting antivirals are discussed, including monoclonal antibodies targeting conserved regions of viral surface proteins, molecules interfering with host cell receptors or viral replication machinery, viral protease inhibitors, siRNA therapies, ribonuclease, and 3D8 scFv. Advancements in host-targeting approaches to reduce resistance and RNA-based therapeutics offer significant potential for combating respiratory viral threats. Despite challenges, broad-spectrum antiviral agents represent a crucial strategy, particularly when specific viral pathogens are unidentified or rapid intervention is essential, such as during pandemics or outbreaks. Full article