Infant Deaths Associated with Human Parechovirus Infection in Wisconsin

Background: From December 1987 through August 2004, lung tissue, nasopharyngeal swabs, and colon swab specimens obtained during 1263 autopsies of infants and young children were examined to assess the role of viruses in deaths of children aged <2 years.

Methods: Multiple cell cultures were used to isolate viruses. With 4 exceptions, virus isolates were identified by neutralization, immunofluorescence assay, or enzyme immunoassay. RNA extracted from these 4 isolates and associated autopsy specimens was tested using parechovirus-specific real-time polymerase chain reaction (RT-PCR) and sequencing assays.

Results: Specimens from 426 (34%) autopsies were positive for at least 1 virus; enteroviruses and adenoviruses were the most commonly identified. Human parechoviruses (HPeVs) were identified antigenically in isolates from 18 decedents (all HPeV type 1) and by RT-PCR in isolates and multiple autopsy specimens from 4 decedents with untypeable virus isolates. Sequencing of the VP1 region identified these 4 HPeVs as HPeV type 3 (n = 3) and HPeV type 6 (n = 1). Despite the detection of HPeV, the deaths of decedents 3 and 4 were determined to have been from noninfectious causes.

Conclusions: These are the first confirmed HPeV type 3 and HPeV type 6 detections in the United States. This is also the initial report of fatal cases with associated HPeV type 3 infection. These results support prior findings associating HPeVs with serious disease in young children. Clinical testing for HPeVs and routine HPeV surveillance by public health laboratories will help determine the burden of disease caused by HPeVs.