scholarly journals Respiratory Viral Infections in Infants: Causes, Clinical Symptoms, Virology, and Immunology

2010 ◽  
Vol 23 (1) ◽  
pp. 74-98 ◽  
Author(s):  
John S. Tregoning ◽  
Jürgen Schwarze

SUMMARY In global terms, respiratory viral infection is a major cause of morbidity and mortality. Infancy, in particular, is a time of increased disease susceptibility and severity. Early-life viral infection causes acute illness and can be associated with the development of wheezing and asthma in later life. The most commonly detected viruses are respiratory syncytial virus (RSV), rhinovirus (RV), and influenza virus. In this review we explore the complete picture from epidemiology and virology to clinical impact and immunology. Three striking aspects emerge. The first is the degree of similarity: although the infecting viruses are all different, the clinical outcome, viral evasion strategies, immune response, and long-term sequelae share many common features. The second is the interplay between the infant immune system and viral infection: the immaturity of the infant immune system alters the outcome of viral infection, but at the same time, viral infection shapes the development of the infant immune system and its future responses. Finally, both the virus and the immune response contribute to damage to the lungs and subsequent disease, and therefore, any prevention or treatment needs to address both of these factors.

2020 ◽  
Vol 4 (1) ◽  
pp. 020-027
Author(s):  
Nikhra Vinod

The global virome: The viruses have a global distribution, phylogenetic diversity and host specificity. They are obligate intracellular parasites with single- or double-stranded DNA or RNA genomes, and afflict bacteria, plants, animals and human population. The viral infection begins when surface proteins bind to receptor proteins on the host cell surface, followed by internalisation, replication and lysis. Further, trans-species interactions of viruses with bacteria, small eukaryotes and host are associated with various zoonotic viral diseases and disease progression. Virome interface and transmission: The cross-species transmission from their natural reservoir, usually mammalian or avian, hosts to infect human-being is a rare probability, but occurs leading to the zoonotic human viral infection. The factors like increased human settlements and encroachments, expanded travel and trade networks, altered wildlife and livestock practices, modernised and mass-farming practices, compromised ecosystems and habitat destruction, and global climate change have impact on the interactions between virome and its hosts and other species and act as drivers of trans-species viral spill-over and human transmission. Zoonotic viral diseases and epidemics: The zoonotic viruses have caused various deadly pandemics in human history. They can be further characterized as either newly emerging or re-emerging infectious diseases, caused by pathogens that historically have infected the same host species, but continue to appear in new locations or in drug-resistant forms, or reappear after apparent control or elimination. The prevalence of zoonoses underlines importance of the animal–human–ecosystem interface in disease transmission. The present COVID-19 infection has certain distinct features which suppress the host immune response and promote the disease potential. Treatment for epidemics like covid-19: It appears that certain nutraceuticals may provide relief in clinical symptoms to patients infected with encapsulated RNA viruses such as influenza and coronavirus. These nutraceuticals appear to reduce the inflammation in the lungs and help to boost type 1 interferon response to these viral infections. The human intestinal microbiota acting in tandem with the host’s defence and immune system, is vital for homeostasis and preservation of health. The integrity and balanced activity of the gut microbes is responsible for the protection from disease states including viral infections. Certain probiotics may help in improving the sensitivity and effectivity of immune system against viral infections. Currently, antiviral therapy is available only for a limited number of zoonotic viral infections. Because viruses are intracellular parasites, antiviral drugs are not able to deactivate or destroy the virus but can reduce the viral load by inhibiting replication and facilitating the host’s innate immune mechanisms to neutralize the virus. Conclusion: Lessons from recent viral epidemics - Considering that certain nutraceuticals have demonstrated antiviral effects in both clinical and animal studies, further studies are required to establish their therapeutic efficacy. The components of nutraceuticals such as luteolin, apigenin, quercetin and chlorogenic acid may be useful for developing a combo-therapy. The use of probiotics to enhance immunity and immune response against viral infections is a novel possibility. The available antiviral therapy is inefficient in deactivating or destroying the infecting viruses, may help in reducing the viral load by inhibiting replication. The novel efficient antiviral agents are being explored.


Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 505 ◽  
Author(s):  
Carrie-Anne Malinczak ◽  
Nicholas W. Lukacs ◽  
Wendy Fonseca

Respiratory syncytial virus (RSV) is often the first clinically relevant pathogen encountered in life, with nearly all children infected by two years of age. Many studies have also linked early-life severe respiratory viral infection with more pathogenic immune responses later in life that lead to pulmonary diseases like childhood asthma. This phenomenon is thought to occur through long-term immune system alterations following early-life respiratory viral infection and may include local responses such as unresolved inflammation and/or direct structural or developmental modifications within the lung. Furthermore, systemic responses that could impact the bone marrow progenitors may be a significant cause of long-term alterations, through inflammatory mediators and shifts in metabolic profiles. Among these alterations may be changes in transcriptional and epigenetic programs that drive persistent modifications throughout life, leaving the immune system poised toward pathogenic responses upon secondary insult. This review will focus on early-life severe RSV infection and long-term alterations. Understanding these mechanisms will not only lead to better treatment options to limit initial RSV infection severity but also protect against the development of childhood asthma linked to severe respiratory viral infections.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ma. Del Rocío Baños-Lara ◽  
Boyang Piao ◽  
Antonieta Guerrero-Plata

Mucins (MUC) constitute an important component of the inflammatory and innate immune response. However, the expression of these molecules by respiratory viral infections is still largely unknown. Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are two close-related paramyxoviruses that can cause severe low respiratory tract disease in infants and young children worldwide. Currently, there is not vaccine available for neither virus. In this work, we explored the differential expression of MUC by RSV and hMPV in human epithelial cells. Our data indicate that the MUC expression by RSV and hMPV differs significantly, as we observed a stronger induction of MUC8, MUC15, MUC20, MUC21, and MUC22 by RSV infection while the expression of MUC1, MUC2, and MUC5B was dominated by the infection with hMPV. These results may contribute to the different immune response induced by these two respiratory viruses.


Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3198 ◽  
Author(s):  
Francesco Pecora ◽  
Federica Persico ◽  
Alberto Argentiero ◽  
Cosimo Neglia ◽  
Susanna Esposito

Viral infections are a leading cause of morbidity and mortality worldwide, and the importance of public health practices including handwashing and vaccinations in reducing their spread is well established. Furthermore, it is well known that proper nutrition can help support optimal immune function, reducing the impact of infections. Several vitamins and trace elements play an important role in supporting the cells of the immune system, thus increasing the resistance to infections. Other nutrients, such as omega-3 fatty acids, help sustain optimal function of the immune system. The main aim of this manuscript is to discuss of the potential role of micronutrients supplementation in supporting immunity, particularly against respiratory virus infections. Literature analysis showed that in vitro and observational studies, and clinical trials, highlight the important role of vitamins A, C, and D, omega-3 fatty acids, and zinc in modulating the immune response. Supplementation with vitamins, omega 3 fatty acids and zinc appears to be a safe and low-cost way to support optimal function of the immune system, with the potential to reduce the risk and consequences of infection, including viral respiratory infections. Supplementation should be in addition to a healthy diet and fall within recommended upper safety limits set by scientific expert bodies. Therefore, implementing an optimal nutrition, with micronutrients and omega-3 fatty acids supplementation, might be a cost-effective, underestimated strategy to help reduce the burden of infectious diseases worldwide, including coronavirus disease 2019 (COVID-19).


2021 ◽  
Vol 2 ◽  
Author(s):  
Roopali Rajput ◽  
Jitender Sharma

The risk of viral infection during pregnancy is well-documented; however, the intervention modalities that in practice enable maternal-fetal protection are restricted by limited understanding. This becomes all the more challenging during pandemics. During many different epidemic and pandemic viral outbreaks, worse outcomes (fetal abnormalities, mortality, preterm labor, etc.) seem to affect pregnant women than what has been evident when compared to non-pregnant women. The condition of pregnancy, which is widely understood as “immunosuppressed,” needs to be re-understood in terms of the way the immune system works during such a state. The immune system gets transformed to accommodate and facilitate fetal growth. The interference of such supportive conversion by viral infection and the risk of co-infection lead to adverse fetal outcomes. Hence, it is crucial to understand the risk and impact of potent viral infections likely to be encountered during pregnancy. In the present article, we review the effects imposed by previously established and recently emerging/re-emerging viral infections on maternal and fetal health. Such understanding is important in devising strategies for better preparedness and knowing the treatment options available to mitigate the relevant adverse outcomes.


2021 ◽  
Vol 15 ◽  
Author(s):  
Karen Bohmwald ◽  
Catalina A. Andrade ◽  
Nicolás M. S. Gálvez ◽  
Valentina P. Mora ◽  
José T. Muñoz ◽  
...  

Reports regarding brain inflammation, known as encephalitis, have shown an increasing frequency during the past years. Encephalitis is a relevant concern to public health due to its high morbidity and mortality. Infectious or autoimmune diseases are the most common cause of encephalitis. The clinical symptoms of this pathology can vary depending on the brain zone affected, with mild ones such as fever, headache, confusion, and stiff neck, or severe ones, such as seizures, weakness, hallucinations, and coma, among others. Encephalitis can affect individuals of all ages, but it is frequently observed in pediatric and elderly populations, and the most common causes are viral infections. Several viral agents have been described to induce encephalitis, such as arboviruses, rhabdoviruses, enteroviruses, herpesviruses, retroviruses, orthomyxoviruses, orthopneumovirus, and coronaviruses, among others. Once a neurotropic virus reaches the brain parenchyma, the resident cells such as neurons, astrocytes, and microglia, can be infected, promoting the secretion of pro-inflammatory molecules and the subsequent immune cell infiltration that leads to brain damage. After resolving the viral infection, the local immune response can remain active, contributing to long-term neuropsychiatric disorders, neurocognitive impairment, and degenerative diseases. In this article, we will discuss how viruses can reach the brain, the impact of viral encephalitis on brain function, and we will focus especially on the neurocognitive sequelae reported even after viral clearance.


Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 147 ◽  
Author(s):  
Retamal-Díaz ◽  
Covián ◽  
Pacheco ◽  
Castiglione-Matamala ◽  
Bueno ◽  
...  

Worldwide, human respiratory syncytial virus (RSV) is the most common etiological agent for acute lower respiratory tract infections (ALRI). RSV-ALRI is the major cause of hospital admissions in young children, and it can cause in-hospital deaths in children younger than six months old. Therefore, RSV remains one of the pathogens deemed most important for the generation of a vaccine. On the other hand, the effectiveness of a vaccine depends on the development of immunological memory against the pathogenic agent of interest. This memory is achieved by long-lived memory T cells, based on the establishment of an effective immune response to viral infections when subsequent exposures to the pathogen take place. Memory T cells can be classified into three subsets according to their expression of lymphoid homing receptors: central memory cells (TCM), effector memory cells (TEM) and resident memory T cells (TRM). The latter subset consists of cells that are permanently found in non-lymphoid tissues and are capable of recognizing antigens and mounting an effective immune response at those sites. TRM cells activate both innate and adaptive immune responses, thus establishing a robust and rapid response characterized by the production of large amounts of effector molecules. TRM cells can also recognize antigenically unrelated pathogens and trigger an innate-like alarm with the recruitment of other immune cells. It is noteworthy that this rapid and effective immune response induced by TRM cells make these cells an interesting aim in the design of vaccination strategies in order to establish TRM cell populations to prevent respiratory infectious diseases. Here, we discuss the biogenesis of TRM cells, their contribution to the resolution of respiratory viral infections and the induction of TRM cells, which should be considered for the rational design of new vaccines against RSV.


2018 ◽  
Vol 27 (147) ◽  
pp. 170133 ◽  
Author(s):  
Peter Le Souëf

Over the past year, studies into virus-induced wheeze in children have shifted towards investigations that examine the mechanisms by which respiratory viruses cause wheeze and an increase in studies examining the effects of novel interventions to reduce wheezing exacerbations. Studies on rhinovirus species (RV)-C infection have found that this is associated with a decrease in expression of CDHR3, the cellular receptor specific for this virus, and a decrease in interferon-β expression, both of which are likely to favour RV-C infection. Recent clinical trials in children have found a decrease in wheezing exacerbations with both anti-respiratory syncytial virus antibody and anti-immunoglobulin E antibody therapy, and a clinical trial of prednisolone in children with their first RV-induced wheeze showed that only those with an RV viral count >7000 copies·mL−1responded. Further studies on the effects of bacterial lysates on immune system function continue to support the potential of this approach to reduce virus-induced wheezing exacerbations in children. These studies and many previous investigations into immunomodulation using bacterial lysates have led to the funding and commencement of a large study in which long-term administration of a bacterial lysate in young children will be assessed for its ability to prevent asthma.


2018 ◽  
Vol 2 (S1) ◽  
pp. 32-32
Author(s):  
Darrell Dinwiddie ◽  
Ashlee K. Bradley ◽  
Jesse L. Denson ◽  
Joshua L. Kennedy ◽  
Walter N. Dehority ◽  
...  

OBJECTIVES/SPECIFIC AIMS: We sought to investigate the role of the host microbiome during severe, acute respiratory infection (ARI) to understand the drivers of both acute clinical pathogenesis. METHODS/STUDY POPULATION: Nasopharyngeal swabs comprised of mixed cell populations at the active site of infection were collected from 192 hospitalized pediatric patients with ARI. We combined comprehensive respiratory virus detection and virus genome sequencing with 16S rRNA gene sequencing to evaluate the microbial content of the airway during ARI. This data was coupled with 11 clinical parameters, which were compiled to create a clinical severity score. The microbiome profiles were assessed to determine if clinical severity of infection, and/or specific virus was associated with increased clinical severity. RESULTS/ANTICIPATED RESULTS: We identified 8 major microbiome profiles classified by dominant bacterial genus, Moraxella, Corynebacterium, Staphylococcus, Haemophilus, Streptococcus, Alloiococcus, Schlegelella, and Diverse. Increased clinical severity was significantly associated with microbiome profiles dominated by Haemophilus, Streptococcus, and Schlegelella, whereas Corynebacterium and Alloiococcus were more prevalent in children with less severe disease. Independent of the microbial community, more than 60% of patients with the highest clinical severity were infected with either respiratory syncytial virus or rhinovirus. DISCUSSION/SIGNIFICANCE OF IMPACT: Our results indicate that individually and in combination, both virus and microbial composition may drive clinical severity during acute respiratory viral infections. It is still unclear how the complex interplay between virus, bacterial community, and the host response influence long-term respiratory impacts, such as the development of asthma. Nonetheless, during ARIs therapeutic interventions such as antibiotics and probiotics may be warranted in a subset of patients that are identified to have both a virus and microbiome profile that is associated with increased pathogenesis to limit both acute and long-term phenotypes.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. LBA-2-LBA-2
Author(s):  
Aurelien Marabelle ◽  
Holbrook E Kohrt ◽  
Joshua Brody ◽  
James Anthony Torchia ◽  
Gang Zhou ◽  
...  

Abstract LBA-2 Background: CD4+CD25+FOXP3+ regulatory T-cells (Tregs) protect cancers from the immune system. They express important functional molecules such as CTLA-4 and Ox40 on their surface. Anti-CTLA4 monoclonal antibody (mAb) is the first drug to improve survival of refractory metastatic melanoma. Its recent approval by the FDA/EMEA inaugurates a paradigm shift in cancer therapy where the immune system is targeted rather than the tumor itself. Scientific question: Does local immunomodulation of tumor specific Tregs trigger a systemic anti-tumor immune response and cure disseminated lymphoma? Results: The Tregs that infiltrate the tumor site preferentially express CTLA4 and OX40 compared to their counterparts in the blood and other lymphoid organs, both in mice and in humans. Upon injection of low doses of anti-CTLA4 and anti-OX40 together with CpG, a TLR-9 agonist, directly into the tumor, tumor-specific Tregs are depleted from the tumor-infiltrate. This immunomodulatory combination therapy triggers an anti-tumor immune response able to cure mice with established disseminated disease. The triple combination is uniquely required as neither CpG alone nor mAbs without CpG are effective. The local Treg immunomodulation with anti-CTLA4+anti-OX40+CpG in a single sub-cutaneous tumor eradicates disease in mice with established CNS lymphoma, even with leptomeningeal and spinal cord metastases, whereas chemotherapies or mAb therapy directed against the tumor cells have little effect in the CNS site. Moreover, these cured mice have a long term intra-cranial anti-tumor immunity since they are protected against late intra-cranial re-challenge. Significance: Immunomodulatory antibodies are currently under clinical development for cancer treatment, and their major side effect is the triggering of auto-immune diseases. We show here that injecting very little doses of these antibodies in combination with CpG at one tumor site is sufficient to trigger a systemic anti-tumor response able to eradicate distant sites, including in the CNS which is usually considered a sanctuary site for conventional systemic therapies. Impact: We recently have published positive results of intra-tumoral CpG in patients with follicular Lymphoma (Brody,Levy, et al. JCO, 2010). Anti-CTLA4 has just been FDA approved in patients with metastatic melanoma, and anti-Ox40 antibodies are currently being tested in phase I/II clinical trials. Therefore, the combination described here can be tested in patients with injectable sites of lymphoma, even if they have CNS disease. Disclosures: No relevant conflicts of interest to declare.


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