Autumn exacerbations of pediatric asthma in Japan is strongly associated with rhinovirus (RV) infection

Abstract

Rationale Since more than 40% of admission cases due to childhood asthma exacerbations in our department occurs from September to November, we examined the association between viral infection and asthma exacerbations in our department. Methods In the past two years (2001-2002), two different kinds of studies were performed from October to November. In 2001, total 50 inpatients (mean age: 3.2 y) due to asthma exacerbations were examined about viral infections by using culture method. Based on the data obtained 2001 study, we then focused on RS virus and RV in 2002 study. Total 71 inpatients (mean age: 3.9y) due to asthma exacerbations were recruited to the study. Paired serum and diagnosis kit were used against proof of RS virus infection, and RT-PCR was used against detection of RV infection. Results Four cases of RS infections and three cases of RV infections were detected by culture method in 2001 study. In 2002 study, RV infections were identified in 57 cases out of 71 patients (80%). RS infections were identified in 6 cases out of 71 subjects. Overlapped infection of RS virus and RV were seen in 2 cases. Conclusions These studies indicate strong association between RV infection and pediatric asthma exacerbations in autumn in Japanese children. It is of interest to clarify the mechanisms of these links.