Human metapneumovirus infections cause similar symptoms and clinical severity as respiratory syncytial virus infections

Abstract

Human metapneumovirus (hMPV) is a recently discovered pathogen in respiratory tract infection. The published literature suggests milder illness severity in hMPV compared with respiratory syncytial virus (RSV) infection. In two consecutive seasons, 637 nasopharyngeal aspirates from pediatric patients were tested by hMPV polymerase chain reaction, and risk factors and clinical and laboratory items were analyzed. The hMPV patients were compared with hMPV-negative but RSV-positive patients by matched pair analysis. HMPV was detected in 17.9% of all samples. In total, 88 hMPV-infected patients with complete datasets were considered. More than half of all hMPV patients were older than 12 months, 45.5% had at least one risk factor for a severe course of viral respiratory tract infection, and 27.3% were born prematurely, 15.9% with a birth weight <1,500 g. At least one other virus was also detected in 39 patients (44.3%; RSV in 29.5%). Coinfection did not result in greater severity of illness. On matched pair analysis (hMPV-positive/RSV-negative vs. hMPV-negative/RSV-positive), the epidemiological and clinical features of hMPV infection were similar to those of RSV infection, as in the hMPV group higher proportions of patients with hypoxemia on admission (33% vs. 21%) and of intensive care treatment (20.8% vs. 10.4%) were observed. More hMPV patients showed lobar infiltrates in radiological chest examination. In 60% of all hMPV infections, the attending physicians prescribed antimicrobial chemotherapy. We conclude that in hospitalized children, hMPV infection is as serious as RSV infection and therefore deserves the same attention. Virologic diagnosis from respiratory secretions is mandatory because clinical, laboratory, and radiological signs cannot sufficiently discriminate between viral and bacterial respiratory tract infection in infants and children.

HMPV infections are frequently accompanied by co‐infections

“…Coinfections may be detected more frequently in hospitalized patients simply as a result of a more sophisticated diagnostic approach. 5,6 In our study 3 39 patients (44.3 %) with a coinfection were observed, none of them displayed a more severe clinical course than mono-infected patients. Moreover, other studies described striking coinfection rates of up to 70% of patients, although in smaller cohorts (e.g., Ref.…”

“…This is in contrast to earlier observations (reviewed by Kahn [5] and Schildgen et al [6]), but in high agreement with our study. 3 This controversially discussed observation consequently has to be investigated more in detail, probably by the use of an appropriate animal model system.…”

Apnea como forma de presentación de una infección por metapneumovirus humano

“…La presentación de apneas durante el curso de una infección por MPVh ha sido descrita en 2 a 6% de los casos en algunas series, aumentando a 40% en el caso de prematuros, en quienes se describe el llamado complejo apnea-bradicardia [52][53][54] . La causa de esta forma de presentación aún no está establecida y pareciera ser de tipo obstructivo.…”

Animal models for human Metapneumovirus (HMPV) infections

“…Interestingly, prolonged shedding of the virus in respiratory secretions was also observed in high risk children [25], thus the observation of viral persistence in the HMPV infected mouse might be an important hint on the infection cycle also in humans. In this context, the results of a comparative analysis of the activity and regulation of IFN-α in BALB/c mice infected with HMPV or RSV are of interest [5].…”

“…However, it should be noted that prolonged replication or viral persistence of either HMPV or RSV was not observed in fully immunocompetent humans but in high risk patients [25], and that this phenomenon may occur only in mice. Furthermore, the BALB/c mice infected with HMPV exhibited symptoms that included ruffled fur, huddling behavior and weight loss [4].…”