Influenza and other emerging respiratory viruses

Exploring the Protective Effect of Food Drugs against Viral Diseases: Interaction of Functional Food Ingredients and SARS-CoV-2, Influenza Virus, and HSV

A complex network of processes inside the human immune system provides resistance against a wide range of pathologies. These defenses form an innate and adaptive immunity, in which certain immune components work together to counteract infections. In addition to inherited variables, the susceptibility to diseases may be influenced by factors such as lifestyle choices and aging, as well as environmental determinants. It has been shown that certain dietary chemical components regulate signal transduction and cell morphologies which, in turn, have consequences on pathophysiology. The consumption of some functional foods may increase immune cell activity, defending us against a number of diseases, including those caused by viruses. Here, we investigate a range of functional foods, often marketed as immune system boosters, in an attempt to find indications of their potential protective role against diseases caused by viruses, such as the influenza viruses (A and B), herpes simplex virus (HSV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in some cases mediated by gut microbiota. We also discuss the molecular mechanisms that govern the protective effects of some functional foods and their molecular constituents. The main message of this review is that discovering foods that are able to strengthen the immune system can be a winning weapon against viral diseases. In addition, understanding how the dietary components function can aid in the development of novel strategies for maintaining human bodily health and keeping our immune systems strong.

Mask decontamination methods (model N95) for respiratory protection: a rapid review

BACKGROUND

N95 respiratory protection masks are used by healthcare professionals to prevent contamination from infectious microorganisms transmitted by droplets or aerosols.

METHODS

We conducted a rapid review of the literature analyzing the effectiveness of decontamination methods for mask reuse. The database searches were carried out up to September 2020. The systematic review was conducted in a way which simplified the stages of a complete systematic review, due to the worldwide necessity for reliable fast evidences on this matter.

RESULTS

A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. A total of 19 laboratory studies used hydrogen peroxide, 21 studies used ultraviolet germicidal irradiation, 4 studies used ethylene oxide, 11 studies used dry heat, 9 studies used moist heat, 5 studies used ethanol, two studies used isopropanol solution, 11 studies used microwave oven, 10 studies used sodium hypochlorite, 7 studies used autoclave, 3 studies used an electric rice cooker, 1 study used cleaning wipes, 1 study used bar soap, 1 study used water, 1 study used multi-purpose high-level disinfection cabinet, and another 1 study used chlorine dioxide. Five methods that are promising are as follows: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.

CONCLUSIONS

We have presented the best available evidence on mask decontamination; nevertheless, its applicability is limited due to few studies on the topic and the lack of studies on real environments.

Development and Effects of Influenza Antiviral Drugs

Influenza virus is a highly contagious zoonotic respiratory disease that causes seasonal outbreaks each year and unpredictable pandemics occasionally with high morbidity and mortality rates, posing a great threat to public health worldwide. Besides the limited effect of vaccines, the problem is exacerbated by the lack of drugs with strong antiviral activity against all flu strains. Currently, there are two classes of antiviral drugs available that are chemosynthetic and approved against influenza A virus for prophylactic and therapeutic treatment, but the appearance of drug-resistant virus strains is a serious issue that strikes at the core of influenza control. There is therefore an urgent need to develop new antiviral drugs. Many reports have shown that the development of novel bioactive plant extracts and microbial extracts has significant advantages in influenza treatment. This paper comprehensively reviews the development and effects of chemosynthetic drugs, plant extracts, and microbial extracts with influenza antiviral activity, hoping to provide some references for novel antiviral drug design and promising alternative candidates for further anti-influenza drug development.

Quartz crystal microbalance-based biosensors as rapid diagnostic devices for infectious diseases

Infectious diseases are the ever-present threats to public health and the global economy. Accurate and timely diagnosis is crucial to impede the progression of a disease and break the chain of transmission. Conventional diagnostic techniques are typically time-consuming and costly, making them inefficient for early diagnosis of infections and inconvenient for use at the point of care. Developments of sensitive, rapid, and affordable diagnostic methods are necessary to improve the clinical management of infectious diseases. Quartz crystal microbalance (QCM) systems have emerged as a robust biosensing platform due to their label-free mechanism, which allows the detection and quantification of a wide range of biomolecules. The high sensitivity and short detection time offered by QCM-based biosensors are attractive for the early detection of infections and the routine monitoring of disease progression. Herein, the strategies employed in QCM-based biosensors for the detection of infectious diseases are extensively reviewed, with a focus on prevalent diseases for which improved diagnostic techniques are in high demand. The challenges to the clinical application of QCM-based biosensors are highlighted, along with an outline of the future scope of research in QCM-based diagnostics.

The Central Role of Non-Structural Protein 1 (NS1) in Influenza Biology and Infection

Influenza (flu) is a contagious viral disease, which targets the human respiratory tract and spreads throughout the world each year. Every year, influenza infects around 10% of the world population and between 290,000 and 650,000 people die from it according to the World Health Organization (WHO). Influenza viruses belong to the Orthomyxoviridae family and have a negative sense eight-segment single-stranded RNA genome that encodes 11 different proteins. The only control over influenza seasonal epidemic outbreaks around the world are vaccines, annually updated according to viral strains in circulation, but, because of high rates of mutation and recurrent genetic assortment, new viral strains of influenza are constantly emerging, increasing the likelihood of pandemics. Vaccination effectiveness is limited, calling for new preventive and therapeutic approaches and a better understanding of the virus-host interactions. In particular, grasping the role of influenza non-structural protein 1 (NS1) and related known interactions in the host cell is pivotal to better understand the mechanisms of virus infection and replication, and thus propose more effective antiviral approaches. In this review, we assess the structure of NS1, its dynamics, and multiple functions and interactions, to highlight the central role of this protein in viral biology and its potential use as an effective therapeutic target to tackle seasonal and pandemic influenza.

O impacto da vacinação contra influenza na morbimortalidade dos idosos nas regiões do Brasil entre 2010 e 2019

Resumo: Devido à importância da vacinação anual contra a gripe em idosos, objetivou-se analisar o impacto da vacinação contra gripe na morbimortalidade por influenza nos idosos no período de 2010 a 2019 nas regiões do Brasil. Trata-se de um estudo epidemiológico ecológico, com dados do Sistema de Informações do Programa Nacional de Imunizações, do Sistema de Informações Hospitalares e do Sistema de Informação sobre Mortalidade, disponíveis por intermédio do Ministério da Saúde. Os dados foram referentes ao Brasil e regiões, e contemplaram as taxas de cobertura vacinal contra gripe em idosos e de morbidade e mortalidade por causas relacionadas à influenza e pneumonia em idosos. Modelos de regressão linear simples foram utilizados para estudar a relação entre as taxas de morbidade e mortalidade e a cobertura vacinal. Houve um aumento da cobertura vacinal no período, e a meta de 80% de cobertura foi atingida em todas as regiões a partir de 2011. Identificou-se uma relação diretamente proporcional entre as variáveis estudadas, sendo que o aumento da cobertura vacinal resultou no aumento da morbimortalidade pelas causas avaliadas. Esses dados podem estar relacionados com a literatura, que mostra que o efeito da vacina é modesto em idosos. Porém, foi visto que o cálculo das taxas não leva em consideração o envelhecimento da população, utilizando dados com estimativas censitárias desatualizadas, e que os dados de internação e óbito podem incluir outros vírus e bactérias circulantes que não a influenza. A manutenção da cobertura vacinal elevada pode prevenir que o impacto da gripe seja ainda maior na morbimortalidade em idosos.

Human Coronavirus 229E Remains Infectious on Common Touch Surface Materials

The evolution of new and reemerging historic virulent strains of respiratory viruses from animal reservoirs is a significant threat to human health. Inefficient human-to-human transmission of zoonotic strains may initially limit the spread of transmission, but an infection may be contracted by touching contaminated surfaces. Enveloped viruses are often susceptible to environmental stresses, but the human coronaviruses responsible for severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) have recently caused increasing concern of contact transmission during outbreaks. We report here that pathogenic human coronavirus 229E remained infectious in a human lung cell culture model following at least 5 days of persistence on a range of common nonbiocidal surface materials, including polytetrafluoroethylene (Teflon; PTFE), polyvinyl chloride (PVC), ceramic tiles, glass, silicone rubber, and stainless steel. We have shown previously that noroviruses are destroyed on copper alloy surfaces. In this new study, human coronavirus 229E was rapidly inactivated on a range of copper alloys (within a few minutes for simulated fingertip contamination) and Cu/Zn brasses were very effective at lower copper concentration. Exposure to copper destroyed the viral genomes and irreversibly affected virus morphology, including disintegration of envelope and dispersal of surface spikes. Cu(I) and Cu(II) moieties were responsible for the inactivation, which was enhanced by reactive oxygen species generation on alloy surfaces, resulting in even faster inactivation than was seen with nonenveloped viruses on copper. Consequently, copper alloy surfaces could be employed in communal areas and at any mass gatherings to help reduce transmission of respiratory viruses from contaminated surfaces and protect the public health.

IMPORTANCE

Respiratory viruses are responsible for more deaths globally than any other infectious agent. Animal coronaviruses that "host jump" to humans result in severe infections with high mortality, such as severe acute respiratory syndrome (SARS) and, more recently, Middle East respiratory syndrome (MERS). We show here that a closely related human coronavirus, 229E, which causes upper respiratory tract infection in healthy individuals and serious disease in patients with comorbidities, remained infectious on surface materials common to public and domestic areas for several days. The low infectious dose means that this is a significant infection risk to anyone touching a contaminated surface. However, rapid inactivation, irreversible destruction of viral RNA, and massive structural damage were observed in coronavirus exposed to copper and copper alloy surfaces. Incorporation of copper alloy surfaces in conjunction with effective cleaning regimens and good clinical practice could help to control transmission of respiratory coronaviruses, including MERS and SARS.

Influenza viruses: update on epidemiology, clinical features, treatment and vaccination

PURPOSE OF REVIEW

In the last decade, sporadic and lethal human disease caused by zoonotic avian influenza viruses, and the seasonal activity of human H1N1 2009 pandemic type have driven intense epidemiological and laboratory studies into the virus life cycle. This article highlights major developments from mid-2012 to early 2014.

RECENT FINDINGS

Advances in molecular techniques and efficient rollout of diagnostic tests have enabled the rapid identification of clinical cases and detailed genetic sequencing of viral genomes. Studies have contributed widely to the understanding of how and when influenza viruses circulate, what determines their innate pathogenicity in particular hosts and whether host cofactors influence disease severity. Other imperatives include investigations into how influenza can be better prevented by vaccination, or treated with antiviral drugs.

SUMMARY

Avian influenza viruses present a continuous threat to human populations. There is a need for sustained surveillance and downstream research to evaluate the potential for future pandemics.

Inaccurate ascertainment of morbidity and mortality due to influenza in administrative databases: a population-based record linkage study

BACKGROUND

Historically, counting influenza recorded in administrative health outcome databases has been considered insufficient to estimate influenza attributable morbidity and mortality in populations. We used database record linkage to evaluate whether modern databases have similar limitations.

METHODS

Person-level records were linked across databases of laboratory notified influenza, emergency department (ED) presentations, hospital admissions and death registrations, from the population (∼6.9 million) of New South Wales (NSW), Australia, 2005 to 2008.

RESULTS

There were 2568 virologically diagnosed influenza infections notified. Among those, 25% of 40 who died, 49% of 1451 with a hospital admission and 7% of 1742 with an ED presentation had influenza recorded on the respective database record. Compared with persons aged ≥65 years and residents of regional and remote areas, respectively, children and residents of major cities were more likely to have influenza coded on their admission record. Compared with older persons and admitted patients, respectively, working age persons and non-admitted persons were more likely to have influenza coded on their ED record. On both ED and admission records, persons with influenza type A infection were more likely than those with type B infection to have influenza coded. Among death registrations, hospital admissions and ED presentations with influenza recorded as a cause of illness, 15%, 28% and 1.4%, respectively, also had laboratory notified influenza. Time trends in counts of influenza recorded on the ED, admission and death databases reflected the trend in counts of virologically diagnosed influenza.

CONCLUSIONS

A minority of the death, hospital admission and ED records for persons with a virologically diagnosed influenza infection identified influenza as a cause of illness. Few database records with influenza recorded as a cause had laboratory confirmation. The databases have limited value for estimating incidence of influenza outcomes, but can be used for monitoring variation in incidence over time.