Viral wheezing is virus specific and not just host specific.

Daytime sleepiness and neural cardiac modulation in sleep-related breathing disorders. Viral wheezing is virus specific and not just host specific To the Editors: In a recent issue of the European Respiratory Journal, STRIPPOLI et al. [1] reported their interesting findings on exclusive viral wheezing versus allergic wheezing in a large population-based, prospectively followed cohort including 4,102 children at 1 yr and 1,858 children at 9 yrs of age. The parents reported current wheezing in 36, 20, 16 and 16% of the children at age 1, 4, 6 and 9 yrs, respectively. The study showed considerable age-related, parent-reported changes in the relative importance of triggers for wheezing in children. The proportion of infection decreased constantly from 94.1% (at age 1 yr) to 81.0% (at age 9 yrs) and the proportion of allergic wheeze increased constantly from 7.5% (at age 1 yr) to 62.4% (at age 9 yrs). The proportion of exercise as a trigger for wheezing was rather similar at all ages, being lowest (35.5%) at age 1 yr and highest (48.6%) at age 6 yrs. The association between exercise and allergens as triggers for wheezing was significant at age 1, 4 and 6 yrs, and between exercise and infection at age 1, 6 and 9 yrs. Conversely, allergens and infection were not associated at any age; the association was even negative (OR 0.54; p50.051) at age 6 yrs. Thus, the authors confirmed positive associations between exercise and allergens, and between exercise and infection as triggers for wheezing, but there were no positive associations between allergens and infection at any age. The authors concluded that exclusive viral wheezing and allergen-induced, multiple-trigger wheezing are distinct disease entities presenting in genetically different children [1]. The findings are in agreement with those from post-bronchiolitis studies [2], and with clinical experience as well. If bronchiolitis is defined as wheezing-associated respiratory infection at age ,24 months, post-bronchiolitis wheezing during subsequent viral infections is common. In long-term, prospective post-bronchiolitis studies, 60% of the former bronchiolitis patients have wheezed at age 2–3 yrs and 15–40% have had doctor-diagnosed asthma at school age [2]. However, if bronchiolitis has been caused by respiratory syncytial virus (RSV) [2], or has taken place at age ,6 months when RSV is the predominant causative agent [3], later asthma seems not to be substantially more common than in the non-selected population. Doctor-diagnosed asthma was present at age 6.5 yrs in 12.7% of the 166 …