Background: Human adenovirus (HAdV), especially species C (HAdV-C), can be detected incidentally by polymerase chain reaction in nasopharyngeal (NP) samples, making it difficult to interpret clinical significance of a positive result. We classified patients into groups based on HAdV culture positivity from respiratory specimens and the presence of an identified co-pathogen. We hypothesized that HAdV-C would be over-represented and viral burden would be lower in patients most likely to have incidental detection (ie, with a negative viral culture and documented co-pathogen).
Methods: Immunocompetent children with HAdV + nasopharyngeal specimens were classified into 4 groups: group I (HAdV culture (+) and no co-infection), group II (culture (+) and co-infection), group III (culture (−) and no co-infection) and group IV (culture (−) and co-infection). Viral burden (cycle threshold) and species were compared among groups.
Results: Of 483 nasopharyngeal specimens, HAdV was isolated in culture in 252 (52%); co-infection was found in 265 (55%) patients. Group I (most consistent with acute disease) had significantly lower cycle thresholds (median 23.9; interquarile range 22.2–28.1) compared with group IV (most consistent with incidental detection; median 37.3; interquarile range 35.3–38.9; P < 0.0001). HAdV-C accounted for 41% samples of group I and 83% of group IV (P < 0.0001). We identified a subset of 22 patients with bacterial or fungal co-pathogens, 18 of whom had no growth on viral culture (group IV) with a median cycle threshold of 37.4 (interquarile range 33.9–39.2).
Conclusions: Species identification and viral burden may assist in interpretation of a positive HAdV result. Low viral burden with HAdV-C may be consistent with incidental detection.
From the *Division of Pediatric Infectious Diseases and †Department of Pathology and Laboratory Medicine, Nationwide Children’s Hospital, Columbus, Ohio; ‡Infectious Disease Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico; and §The Ohio State University, Columbus, Ohio.
Accepted for publication August 11, 2015.
The authors have no funding or conflicts of interest to disclose.
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Address for correspondence Preeti Jaggi, MD, Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205. E-mail: Preeti.email@example.com