Background: Adenovirus (HAdV) was identified in blood and stool specimens from 6 children on a pediatric bone marrow transplant (BMT) unit within 2 weeks. Two further adenovirus positive patients were identified in other areas of the childrens' hospital. The study aimed to determine the clinical course of different HAdV subtypes and to investigate whether the cluster was caused by nosocomial transmission or by endogenous reactivation.
Methods: Descriptive epidemiologic investigation was performed reviewing patients′ charts. Molecular typing of identified adenovirus-DNA was performed by partial sequencing of the hexon gene.
Results: In 6 of 8 patients, HAdV-F41 was detected in feces. All but 1 patient presented with vomiting or diarrhea and all were treated with cidofovir. In 4 patients transmissions of HAdV-F41 within the hematological department were probable whereas 2 children on the BMT ward reactivated HAdV-C1 and -C2, respectively. HAdV-F41 was shed in feces for up to 64 days after onset of clinical symptoms. HAdV-F41 DNA in blood reached a maximum of 2 × 105 copies/mL. One patient harbored two HAdV types simultaneously, HAdV-F41 in feces and HAdV-C2 in blood samples. HAdV-C2 reached high virus concentrations in blood (4 × 109 copies/mL) and led to the only fatal case. Although the HAdV-F41 outbreak involving 6 children led to gastroenteritis and may also have been associated with mild hepatitis, coincidental, endogeneous reactivations of other HAdV types (C1 and C2) led to a more severe course.
Conclusions: HAdV typing is essential both for the prognosis and for distinguishing between transmission or endogenous reactivation. Applying HAdV-specific infection control measures is crucial to prevent transmission.