| Epidemiological evidence suggests that certain viral | | | | respiratory tract infections remains controversial, |
| infections not only trigger asthma-related symptoms | | | | influenza virus (INF), respiratory syncitial virus (RSV) |
| but also contribute to allergic sensitisation and the | | | | and Rhinovirus (RV) have been implicated in causing |
| development of asthma. | | | | allergic sensitisation and the development of asthma.4 |
| Read about the role of viruses in the development of | | | | Traditionally, RSV has been considered as the most |
| allergic sensitisation and asthma…… | | | | frequent cause of respiratory symptoms in preschool |
| Brief Statistics | | | | children, whilst in older children and adults, RV |
| 1. Asthma costs 1-2% of the total health budgets in | | | | accounts for more than 50% of viral-triggered |
| direct costs, with large indirect costs for time lost | | | | exacerbations.2, 3 What is peculiar about RSV is that |
| from work and reduced productivity.1 | | | | unlike many other viral infections, it regularly |
| 2. Survey data demonstrates that 95% of | | | | re-infects children and adults. As with exposure to |
| asthmatics have the dust mite allergen | | | | allergens, the age at first infection may play an |
| (Dermatophagoides pteronyssinus) within their | | | | important role in the subsequent response to |
| mattress, to levels in excess of WHO guidelines.1 | | | | re-infection at a later age; this fact is especially |
| 3. Survey data demonstrates that approximately | | | | important in children of preschool age. Exposure to |
| 17% of homes are contaminated with mould. This is | | | | both allergens and viruses can occur anywhere: at |
| significant as there is strong evidence linking asthma | | | | home, in offices, factories, schools, etc. |
| exacerbations to contamination of the indoor | | | | Current preventative measures for viral allergic |
| environment with moulds.1 | | | | asthma exacerbation |
| 4. Since most people spend 90% of their time | | | | Current preventative measures include, |
| indoors, exposure to major allergens is significant.1 | | | | 1. Vaccination: This is often given in early childhood |
| 5. Up to 35% of the population demonstrate | | | | and some evidence suggests that some vaccines |
| evidence of reactivity to allergens.1 | | | | might influence the development of allergy. However, |
| 6. 5-10% of the population show clinical features of | | | | no clinical trials have been done to assess the immune |
| one or more allergic disorders such as asthma, hay | | | | modulatory effect of vaccination in the primary |
| fever or eczema.1 | | | | prevention of allergy. There is also no feasible |
| 7. The Health Survey for England (2002) reported | | | | vaccination against viruses such as rhinovirus.5 |
| rates of doctor-diagnosed asthma of 20.5% in 0-15 | | | | 2. Antiviral Agents: There is currently no specific |
| year olds and 14.5% for all ages.1 | | | | agent active against the human rhinovirus, which is |
| 8. Repeated surveys have proven that incidence of | | | | the main cause for viral-triggered asthma |
| asthma is steadily on the increase.1 | | | | exacerbations in adults and children. Several potential |
| 9. Epidemiological evidence suggests that certain viral | | | | antiviral compounds are being evaluated, and some |
| infections may not only trigger asthma-related | | | | have reached clinical trial testing.3 |
| symptoms but also contribute to allergic sensitisation | | | | 3. In the absence of the effective strategies to |
| and the development of asthma.2 | | | | control viruses, a reduced exposure to allergens is |
| 10. Clinical and epidemiological observations strongly | | | | also a preventative measure; however, how feasible |
| link viral infection with acute worsening of asthma in | | | | is this? 1 |
| as many as 80% of cases in children and 60% in | | | | 4. Air quality solutions such as air purifiers and air |
| adults.3 | | | | sterilisers, which are becoming increasingly popular. |
| Introduction | | | | Recommended products include, |
| Allergic asthma is a chronic inflammatory lung disease | | | | 1. The 5000 Exec-UV |
| characterised by airway inflammation (resulting in | | | | 2. The Airfree Air Sterilizer |
| airway swelling), mucus hypersecretion and airway | | | | 3. The LightAir Air Ionizer |
| hyperreactivity in response to inhaled allergens, such | | | | Useful link |
| as pollens, dust mite, moulds, fungal spores, etc., | | | | References |
| causing narrowing of the airways.4 Over the last few | | | | 1. Green, R. M. et al. (2002) Synergism betweens |
| decades, there has been a dramatic increase in the | | | | allergens and viruses and risk of hospital admission |
| prevalence of asthma and other allergic diseases in | | | | with asthma: case-control study, British Medical |
| more economically developed and rapidly developing | | | | Journal; 324: 1-5. |
| countries. As a result, they have become major public | | | | 2. Xepapadaki, P. et al. (2007) Viral infections and |
| health problems and an enormous burden on health | | | | allergies, Immunobiology; 212 (6): 453-9. |
| care resources. Severe asthma and systemic allergic | | | | 3. Tan, W. C. (2005) Viruses in Asthma Exacerbation, |
| reactions are potentially life-threatening conditions, | | | | Current Opinion in Pulmonary Medicine; 11(1): 21-26. |
| which adversely affect the quality of life of millions of | | | | 4. van Rajit, L. S. et al (2005) Respiratory viral |
| adults and children.5 | | | | infections and asthma pathogenesis: A critical role for |
| Role of viruses | | | | dendritic cells?, Journal of Clinical Virology; 34: 161-169. |
| There is substantial evidence that respiratory viral | | | | 5. Arshad, S. H., Primary prevention of asthma and |
| infections are associated with the development of | | | | allergy, Current Reviews of Allergy and Clinical |
| allergic sensitisation, asthma and other allergy-related | | | | Immunology; 116: 3-14. |
| illnesses. Several factors including age, type of virus, | | | | Disclaimer |
| severity, location and timing of infection as well as | | | | This article is only for informative purposes. It is not |
| the interactions with allergens and/or pollutants have | | | | intended to be a medical advice and is not a |
| been implicated in the development of allergic | | | | substitute for professional medical advice. Please |
| diseases related to viral infections, particularly | | | | consult your doctor for all your medical concerns. |
| asthma.2 Recent studies have shown that allergens | | | | Kindly follow any information given in this article only |
| and viruses may act together to exacerbate asthma. | | | | after consulting your doctor or qualified medical |
| This indicates that domestic exposure to allergens | | | | professional. The author is not liable for any outcome |
| acts in collaboration with viruses in sensitised patients | | | | or damage resulting from any information obtained |
| (that is allergic individuals), thereby increasing the risk | | | | from this article. |
| of hospital admission.1 Although their exact role in viral | | | | |