Human Metapneumovirus

What is human metapneumovirus?

Human metapneumovirus (hMPV) is a recently identified member of a family of viruses that also includes respiratory syncytial virus and parainfluenza virus. Although identified in 2001 by investigators from the Netherlands, data suggest this is a common virus that has been responsible for respiratory illnesses for at least 50 years worldwide. Human metapneumovirus can cause upper and lower respiratory tract infections in patients of all ages but respiratory illnesses most often occur in young children or older adults.

How is human metapneumovirus transmitted?

Spread of the virus is most likely to occur by direct or close contact with the respiratory secretions of infected persons or by contact with objects and surfaces contaminated by their secretions.

What are the symptoms of human metapneumovirus?

Most persons with hMPV infection have mild symptoms including cough, runny nose or nasal congestion, sore throat and fever. More severe illness, with wheezing, difficulty breathing, hoarseness, cough, pneumonia, and in adults, aggravation of asthma, also has been reported. In children younger than 1 year of age, the elderly and persons who have weak immune systems, hMPV can cause more serious respiratory illness.

When is human metapneumovirus most common?

It is most common in late winter and early spring in the United States, however, one summer outbreak of hMPV respiratory illnesses in residents and staff of a long-term care facility in the United States has been reported.

What is the incubation period for human metapneumovirus?

It is believed most persons who develop illness will do so three to five days after being exposed to this virus.

Is there immunity to human metapneumovirus?

Limited data suggests that reinfection with hMPV can occur. It is believed most children become infected early in life and adult infections represent persons becoming infected with hMPV again. Repeated infection appears to result in milder illness although serious disease is a risk for patients who are immunocompromised.

How is human metapneumovirus diagnosed?

Human metapneumovirus testing is not readily available. At this time, research laboratories and a limited number of commercial laboratories perform testing for this virus.

Can human metapneumovirus be treated?

Supportive treatment for patients varies with the severity of the illness but generally treatment consists of fever reducers, antihistamines, breathing treatments and other means of providing comfort to the patient until the illness resolves.

How can human metapneumovirus be prevented?

Control measures used for other respiratory illnesses should be emphasized: covering the mouth and nose with a tissue when coughing or sneezing, or, coughing or sneezing into the upper sleeve rather than the hands, prompt disposal of used tissues and proper handwashing.

Can any other species become infected?

Non-human primates can become infected with human metapneumovirus; humans are their likely source of infection.

April 2009