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