<p><strong>BACKGROUND: </strong>Human adenoviruses (HAdV) are known opportunistic pathogens in hematopoietic stem cell transplant (SCT) recipients. The detection of HAdV infection in children after SCT has been implicated as a determinant of poor outcome but specific associations between HAdV species or individual HAdV types and disease are poorly understood.</p>

<p><strong>OBJECTIVES: </strong>Characterization of a HAdV-D strain isolated from multiple clinical specimens of an 11-year-old female recipient of a matched unrelated donor peripheral SCT for T-cell lymphoma and case report.</p>

<p><strong>STUDY DESIGN: </strong>Archived HAdV PCR-positive plasma, urine, and stool specimens were processed for virus isolation and detailed molecular typing. Complete genomic sequencing was carried out on 2 isolates.</p>

<p><strong>RESULTS: </strong>The patient tested positive for HAdV DNA by real-time PCR of a stool specimen at 44 days after initiation of a SCT conditioning regimen. In the subsequent 3 months, HAdV was detected in plasma, urine and stool specimens in association with symptoms of gastroenteritis and hemorrhagic cystitis. A novel HAdV-D with a HAdV20-like hexon gene was isolated from both urine and stool specimens. All isolates yielded identical restriction profiles with endonucleases BamHI, BglII, BstEII, HindIII, PstI and SmaI. Analysis of 2 complete genomic sequences further identified the virus as a novel intertypic recombinant HAdV-D (P20/H20/F42) closely related to HAdV42.</p>

<p><strong>CONCLUSIONS: </strong>This case highlights the identification of a previously unknown HAdV-D from an immunocompromised host. In this patient, the course of adenovirus infection is compatible with reactivation of a latent virus or a primary opportunistic infection. Adenoviremia in this patient resolved without definitive adenovirus-directed antiviral therapy.</p>