Molecular epidemiology and clinical presentation of human adenovirus infections in Kansas City children

Abstract

Background A significant increase in adenovirus detection among patients at the Children's Mercy Hospital, Kansas City was observed between June 2007 and January 2008. Objective To molecularly characterize the human adenoviruses and describe their association with clinical illness in children. Study design One hundred adenovirus-positive specimens from 79 children were typed by hexon gene sequence typing method. Restriction enzyme analysis (REA) was performed on isolates of HAdV-3, -7 and -14 to identify genomic variants. Medical records were reviewed to understand the clinical illnesses associated with adenovirus serotypes and genome types. Results The most prevalent HAdV serotypes were HAdV-3 (37%), HAdV-7 (25%), HAdV-1 (16%), HAdV-2 (8%). HAdV infection was common in children ≤3 years of age (71%) versus children >3 years (29%). Majority of the HAdV-infected children were hospitalized (78%); 22/79 (28%) stayed >3 days and 8/79 (10%) required intensive care unit stay. Hospitalization rates for HAdV-3 (36%) and HAdV-7 (25%) were comparable. REA data indicated that HAdV-3a2 was the predominant HAdV-3 genome type. Two novel genomic variants of HAdV-3 exhibiting unique BglII or BstEII profiles were identified in isolates from patients with bronchiolitis. All HAdV-7 and -14 isolates were identified as corresponding to genome types 7d2 and 14p1, respectively. Conclusions In Kansas City, we noticed an increase in the incidence of HAdV-7 (25%; n = 24/98) infections compared to the previous two years (6%; n = 6/107). Two new genomic variants of HAdV-3 appear to have emerged in our area and seem to be associated with lower respiratory tract infections in children.