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