We study the clinical, management and outcome differences between respiratory syncytial virus (RSV) positive and negative bronchiolitis. A retrospective review of the medical records of children ≤ 2 years of age with acute bronchiolitis between January 1995 and December 2006 was done. There were 2,384 patients hospitalized for acute bronchiolitis, and 1,495 (62.7%) were RSV infections. Overall, hospitalization rate was 55/1,000 admissions. Mortality occurred in 0.08% of cases. Bronchiolitis due to RSV was more frequent from November to March (97%). RSV bronchiolitis had longer hospital stays (6 vs. 5 days, P<0.0001), higher risk of intensive care unit (ICU) admission (OR 2.7; 95%CI 1.87-3.9) and more oxygen use (OR 2.2; 95%CI 1.8-2.6). Infants < 2 months had longer median hospital stay (6 vs. 5 days, P <0.0001) and higher risk of ICU admission (OR 3.4; 95%CI 2.5-4.6). Prematures of < 32 gestational weeks, congenital heart disease, and atelectasis/condensation were the main risk factors for ICU admission in both RSV and non-RSV bronchiolitis. The introduction of palivizumab in prematures diminished hospitalization for RSV bronchiolitis, oxygen need, length of hospital stay and mechanical ventilation. In conclusion, this study supports that RSV bronchiolitis seems to be a more severe disease than that caused by other viruses.

Local climatic factors might explain seasonal patterns of rotavirus infections, but few models have been proposed to determine the effects of weather conditions on rotavirus activity. Here, we study the association of meteorologic factors with rotavirus activity, as determined by the number of children hospitalized for rotavirus gastroenteritis on the Mediterranean island of Mallorca (Spain). We conducted a retrospective review of the medical records of children aged 0-5 years admitted for rotavirus gastroenteritis between January 2000 and December 2010. The number of rotavirus hospitalizations was correlated to temperature, humidity, rainfall, atmospheric pressure, water vapor pressure, wind speed, and solar radiation using regression and time-series techniques. A total of 311 patients were hospitalized for rotavirus gastroenteritis in the 11-year study period, with a seasonal pattern from December to June, and a peak incidence in February. After multiple regressions, weekly rotavirus activity could be explained in 82 % of cases (p< 0.001) with a one-week lag meteorologic model. Rotavirus activity was negatively associated to temperature and positively associated to atmospheric pressure, solar radiation, and wind speed. Temperature and solar radiation were the factors that contributed most to the model, with a peak rotavirus activity at 9 °C and 800 10KJ/m(2), respectively. In conclusion, hospitalization for rotavirus was strongly associated with mean temperature, but an association of rotavirus activity with solar radiation, atmospheric pressure, and wind speed was also demonstrated. This model predicted more than 80 % of rotavirus hospitalizations.

Atopy, rhinitis and its exacerbations can be confounders in the interpretation of FeNO levels in asthmatic children.

The annual patterns of RSV hospitalizations were strongly associated with the meteorologic conditions. The mean temperature and atmospheric pressure were the main factors that correlated with increases and declines in RSV activity.