Respiratory viral infections are the most important triggers of asthma exacerbations. Rhinovirus (RV), the common cold virus, is clearly the most prevalent pathogen constantly circulating in the community. This virus also stands out from other viral factors due to its large diversity (about 170 genotypes), very effective replication, a tendency to create Th2-biased inflammatory environment and association with specific risk genes in people predisposed to asthma development (CDHR3). Decreased interferon responses, disrupted airway epithelial barrier, environmental exposures (including biased airway microbiome), and nutritional deficiencies (low in vitamin D and fish oil) increase risk to RV and other virus infections. It is intensively debated whether viral illnesses actually cause asthma. Respiratory syncytial virus (RSV) is the leading causative agent of bronchiolitis, whereas RV starts to dominate after 1 year of age. Breathing difficulty induced by either of these viruses is associated with later asthma, but the risk is higher for those who suffer from severe RV-induced wheezing. The asthma development associated with these viruses has unique mechanisms, but in general, RV is a risk factor for later atopic asthma, whereas RSV is more likely associated with later non-atopic asthma. Treatments that inhibit inflammation (corticosteroids, omalizumab) effectively decrease RV-induced wheezing and asthma exacerbations. The anti-RSV monoclonal antibody, palivizumab, decreases the risk of severe RSV illness and subsequent recurrent wheeze. A better understanding of personal and environmental risk factors and inflammatory mechanisms leading to asthma is crucial in developing new strategies for the prevention and treatment of asthma.

中文翻译：

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病毒在哮喘中的作用。

呼吸道病毒感染是哮喘急性发作的最重要诱因。鼻病毒（RV），常见的感冒病毒，显然是社区中不断传播的最流行的病原体。该病毒还具有多种多样（约170个基因型），非常有效的复制，易于产生Th2偏向的炎性环境以及与易患哮喘的人群中特定风险基因相关的倾向，因此在其他病毒因素中也脱颖而出（CDHR3）。干扰素反应降低，气道上皮屏障破坏，环境暴露（包括气道微生物组偏向）和营养缺乏（维生素D和鱼油含量低）增加了RV和其他病毒感染的风险。关于病毒性疾病是否确实引起哮喘，人们进行了激烈的辩论。呼吸道合胞病毒（RSV）是毛细支气管炎的主要病原体，而RV在1岁以后开始占主导地位。这两种病毒引起的呼吸困难与后来的哮喘有关，但是对于那些患有严重的RV引起的喘息的人来说，风险更高。与这些病毒相关的哮喘发展具有独特的机制，但是通常，RV是后来的特应性哮喘的危险因素，而RSV更可能与后来的非特应性哮喘有关。抑制炎症的治疗（皮质类固醇，奥马珠单抗）可有效减少RV引起的喘息和哮喘发作。抗RSV单克隆抗体palivizumab降低了严重RSV疾病和随后复发性喘息的风险。更好地了解导致哮喘的个人和环境危险因素以及炎症机制，对于制定预防和治疗哮喘的新策略至关重要。