SAN FRANCISCO — Human meta-pneumovirus emerged as the second most common virus detected during a 4-year study of young children with alveolar pneumonia who are admitted to the emergency room, Dr. Dana G. Wolf reported at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
This particular finding is important because while an association between human metapneumovirus (hMPV) and bronchiolitis has been documented, “the involvement of hMPV in pneumonia remains unknown,” said Dr. Wolf, head of clinical virology in the department of clinical microbiology and infectious diseases at Hadassah University Hospital, Jerusalem.
She and her associates prospectively obtained nasal wash specimens from 1,296 children aged 5 years or younger who were admitted to the emergency room with alveolar pneumonia and from 136 age-matched controls who were admitted for elective surgery between November 2001 and October 2005.
The researchers used real-time polymerase chain reaction (PCR) to test for the presence of hMPV, and they used direct immunofluorescence or real time PCR to test for respiratory syncytial virus (RSV), adenovirus parainfluenza, and influenza viruses.
Dr. Wolf reported that of the children tested, hMPV was detected in 108 (8.3%) of the children admitted with alveolar pneumonia, compared with only 3 (2.2%) of the controls. hMPV was the second most common viral pathogen after RSV (23.1%), followed by adenovirus (3.4%), parainfluenza (2.9%), and influenza A (2.9%).
Most hMPV infections (88%) occurred between November and May, and hMPV was the second most common virus in each of the 4 years in this particular study.
Specifically, hMPV was detected between November and May in 14.5% of patients in year 1; 5.8% of patients in year 2; 6.2% of patients in year 3, and 12.2% of patients in year 4.
The researchers observed differences in the rates of RSV infection by age. Specifically, 37% of children younger than 1 year of age were infected with RSV, compared with 11% of those aged 1 year and older.
By contrast, the rates of hMPV infection remained the same among both age groups (6.5%).
“The important role of hMPV in community-acquired alveolar pneumonia, usually considered to be of bacterial origin, supports the notion of hMPV-bacterial coinfection as suggested by vaccine probe studies,” Dr. Wolf said at the meeting, sponsored by the American Society for Microbiology.