الفهرس 
الملخص العربى
Respiratory viruses and disease syndromesOnly 14 pages are availabe for public view
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Abstract
Viral respiratory tract infections are a major cause of wheezing in infants and adult patients with asthma. Their role may have been underestimated in early epidemiological studies because of difficulties with isolation and identification. The introduction of molecular biological techniques has implicated viral infection in the majority of asthma exacerbation.
In almost all studies of asthmatics the predominant viruses are RVs, RSVs , bocavirus , human metapneumovirus and parainfluenza viruses. RV alone is detected in ~50% of virus-induced asthma attacks. Adenoviruses, enteroviruses and coronaviruses are also detected, but less frequently. Influenza is only found during annual epidemics .There is substantial evidence that respiratory viral infections are associated with the development of allergic sensitization, asthma and other allergy-related illnesses. However, both an enhancing and a protective role have been proposed.
The respiratory tract and immune system undergo rapid maturation during the first years of life and postnatal lung development is affected by and affects responses to viral infection. Several factors, including age, type of virus, severity, location and timing of the infection along with the interaction with allergens and/or pollutants, have been implicated in the development of allergic diseases, particularly asthma, in relation to viral infection.
There is still some controversy as to whether a sever bronchiolitis marks out individuals susceptible to develop asthma or some infections may actually initiate asthma and/or atopy. These suggestions are not mutually exclusive: it is possible that a combination of predisposition and infection sequelae may affect the initiation
and/or persistence of asthma and IgE-mediated allergy.