Background: There are >50 adenovirus (ADV) serotypes that are divided into 7 species (A-G). The aim of this study was to characterize ADV serotypes and species in hospitalized infants and children in the City of Zagreb and Zagreb County and to describe clinical features and laboratory findings of ADV infections according to the causative ADV serotype.
Methods: During the 3-year period from January 2006 to November 2008, 135 children (<10 years of age) with ADV respiratory infection, based on virus isolation, were treated at 2 hospitals in Zagreb. Demographics, clinical presentations and laboratory findings were evaluated.
Results: Of the 135 ADV isolates, 77 (57.0%) were type 2, followed by 26 (19.3%) of type 1, 15 (11.1%) isolates of type 3, 2 (1.5%) of type 6 and only 1 (0.7%) was type 7. Male-to-female ratio was 3.2:1 (103 boys and 32 girls). The mean age was 22.9 months. The most common symptoms were fever (98%), rhinorrhea (89%) and cough (71%). The mean peak body temperature was 39.8°C. Tonsillitis was present in 79 (59%) and acute otitis media in 37 (28%) patients. Leukocytosis (>15.0×10⁹/L) was noted in 103 (77%) patients. Serum C-reactive protein was >40 mg/L in 74 patients (56%). The erythrocyte sedimentation rate was ≥30 mm/h in 91 (71%) of the 127 patients tested.
Conclusions: In this study, the most common isolated serotype was ADV type 2. Most affected children were younger than 3 years. ADV infections in young children can present with prolonged fever, leukocytosis and significantly elevated C-reactive protein and erythrocyte sedimentation rate, mimicking bacterial infections.