Respiratory tract viral infections in inner-city asthmatic adults

Background: Respiratory tract viral infections (RTVIs) have been identified frequently in association with asthma exacerbations in children, but few s tudies have shown similar rates of viral infections in adults with asthma. Further studies using newer diagnostic techniques to evaluate the frequency of RTVIs in adults with acute exacerbations of asthma need to be performed . Methods: Twenty-nine asthmatic adults were recruited from the pulmonary cli nic of an urban county hospital and were followed up in a longitudinal coho rt study for signs and symptoms of asthma and RTVI. One hundred twenty-two asthmatic adults presenting to the emergency department (ED) of the same ho spital with acute symptoms of asthma underwent evaluation for RTVI in a cro ss-sectional prevalence study. In both studies, respiratory secretions and paired serum samples were collected from subjects with acute wheezing episo des and evaluated using virus culture, serologic testing, and reverse trans cription-polymerase chain reaction (RT-PCR). Results: In the longitudinal cohort study, 138 respiratory illnesses, of wh ich 87 were asthma exacerbations, were evaluated; 41% of all illnesses and 44% of asthma exacerbations were associated with an RTVI. In the ED study, 148 asthma exacerbations were evaluated; 55% were associated with an RTVI. An RTVI was identified in 21 (50%) of 42 of the subjects hospitalized in th e ED study. Picornaviruses (rhinoviruses), coronaviruses, and influenza vir uses were the most commonly identified causes of RTVI. Forty-six (60%) of t he 77 picornavirus infections and 22 (71%) of the 31 coronavirus infections were identified only using RT-PCR. Conclusions: Asthmatic exacerbations in adults are frequently associated wi th an RTVI. Identification of such infections often requires newer diagnost ic methods, such as virus-specific RT-PCR. The high frequency of RTVIs iden tified in association with asthmatic exacerbations in adults from the inner city suggests that strategies for the prevention of RTVI should be targete d toward this population.