Metapneumovirus, "New" Cause of Flu

Medical Author: Frederick Hecht, M.D., F.A.A.P., F.A.C.M.G.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.

In medicine, "new" things are sometimes discovered that turn out not to be so new. It is like seeing a body in the heavens for the first time although that heavenly body was not born yesterday.

So it is with the human metapneumovirus which goes by the abbreviation hMPV. It is a "new" cause of the flu. But it is not new in the sense that it just arose. Rather, it isnew in the sense that it was only recently recognized. In fact, this subtle distinction about "new" was what led me tocreate an entryfor human metapneumovirus in MedTerms, MedicineNet's Medical Dictionary. The entry reads as follows:

Human metapneumovirus: A novel virus that is a ubiquitous and important agent of respiratory disease. The human metapneumovirus (hMPV) was discovered in 2001 in young children in The Netherlands with acute respiratory illnesses ranging from mild upper respiratory infections to severe bronchiolitis and pneumonia. It has since been found to cause severe acute respiratory infections all over the world in young children, the elderly, and people with weak defense systems (the immunocompromised). It accounts for 1 to 3% of all flu-like illnesses. (The influenza viruses, which belong to the orthomyxovirus family, cause most casesofflu and flu-like illnesses.)

Although hMPV is a distinct and different virus from respiratory syncytial virus (RSV), it shares many features with RSV. For example, it tends to strike in the winter months in temperate climates. And, as already indicated, the young, the elderly, and the immunocompromised are most vulnerable. The signs and symptoms of infection with hMPV also appear indistinguishable from those caused by RSV. Cough, sore throat, runny nose, and high fever are most common. Wheezing,difficulty breathing (dyspnea ), pneumonia, bronchitis, bronchiolitis, conjunctivitis, and inflammation of the middle ear(otitis media) each occur in 10% or more of patients.