Multi-year study of human metapneumovirus infection at a large US Midwestern Medical Referral Center

Abstract

Background: Because of its recent identification, few multi-year epidemiologic studies of hMPV infection have been reported.

Objective: We sought to retrospectively describe hMPV infections among patients evaluated by a large US Midwestern referral laboratory.

Study design: Clinical specimens were submitted to a large US Midwest referral hospital from 1 October 2001 to 18 May 2004. RT-PCR was used to retrospectively screen the clinical specimens for human metapneumovirus. Demographic and clinical data were retrieved.

Results: 34 (2.6%) of 1294 specimens were hMPV positive. Among these, 21 (62%) were culture positive and available for genetic typing. A previously considered rare genotype of hMPV, B1, was the most common single genotype identified, comprising 9 (43%) of the 21 isolates. Multivariate logistic regression modeling identified patients aged 0.4-9 years (OR=8.9; 95% CI=2.0-38.5) and those under intensive care (OR=3.2; 95% CI=1.1-8.7) as more likely to have hMPV infection than their peers.

Conclusion: In this large referral hospital viral assays more often had evidence of hMPV when they were collected from children receiving intensive care.

Fig. 1

Distribution of human metapneumovirus RT-PCR+ specimens from patients with ages 0–9 years old.

Fig. 2

Neighbor joining tree computed from alignment of partial nucleotide sequences of the hMPV G protein gene using the MEGA 2 program (University of Pittsburgh, Pittsburgh, PA). Sequences obtained from hMPV isolates in this study (GenBank accession numbers are listed in Table 2) are compared to prototypic Canadian viruses: HMPV-13-00 (genotype A1), Can97-83 (genotype A2), HMPV-33-01 (genotype B1), and CAN98-75 (genotype B2), GenBank accession numbers AY485232, AY485253, AY485242, and AY485245, respectively.