Viral infections of the respiratory tract in patients with cystic fibrosis

The role of viruses and bacteria in the development of respiratory tract infections causing acute deteriorations in lung function in patients with cystic fibrosis (CF) was investigated. Over a period of 30 months, 29 viral respiratory diseases were proven serologically by testing 275 sporadically collected sera from 75 patients with cystic fibrosis. The influenza A virus was the most frequent responsible viral pathogen (11 × ), followed by adenovirus (8 × ), influenza B virus (5 × ), parainfluenza virus type 3 (3 × ), parainfluenza virus type 1 and respiratory syncytial virus (RSV) (each of 1 × ). There was no serological evidence for infections with parainfluenza virus type 2, Mycoplasma pneumoniae or Coxiella burnetii. Deterioration of the clinical condition was found in 78% of the viral infections leading in 70% to hospital admission. Patients with cystic fibrosis and viral respiratory illnesses showed significantly more admissions to the hospital (3·2 ± 2·7) with a longer stay (90·6 ± 99·6 days). Nearly all viral episodes (93%) were accompanied or followed by a significant change of the microbial flora in the sputum especially by colonisation with Pseudomonas aeruginosa, Staphylococcus aureus and Haemophilus influenzae. Seventy-two per cent of the viral infections occurred at home and 28% seemed to be hospital acquired. Our study emphasises the importance of improving antibacterial therapy at home to reduce the number of hospital admissions. Efforts for prophylaxis by vaccination or the use of chemotherapeutic agents should be made for the patients with cystic fibrosis.