Human Parainfluenza Viruses (HPIVs)
What are human parainfluenza viruses?
Human parainfluenza viruses (HPIVs) are a group of viruses that cause different types
of respiratory infections. They are more common in children and babies, but can occur
in people of any age, especially those with weak immune systems. Most HPIVs usually
cause infections of the upper airway, such as a common cold, ear infections, or sore
throat. Other infections caused by HPIVs include infections of the lower respiratory
tract, such as croup (an infection of the airway below the larynx, or "voice box,"
that is characterized by a barky cough and harsh, noisy breathing), pneumonia, or
bronchiolitis (an inflammation of the lower airways):
Croup outbreaks usually occur during the fall season and tend to be worse every other
Lower respiratory tract infections occur during the spring and summer and often continue
into the fall.
Children between the ages of 3 months and 5 years are most likely to develop croup.
Children under the age of 2 are more likely to develop lower respiratory tract infections,
such as pneumonia or bronchiolitis.
Reinfections can occur after the first infection, but are usually less severe.
How are HPIVs transmitted?
HPIVs can be spread by either direct contact with respiratory secretions from an infected
person or by coming in contact with infectious material and then touching your eyes,
nose, or mouth. Most children develop an infection with HPIV before they are 5 years
old. They may then experience occasional re-infection when they are older, but these
are usually less severe. However, a person with a weak immune system may get life
What are the symptoms of HPIVs?
The following are the most common symptoms of HPIV infections:
Redness or swelling of the eyes
Barky (seal-like) cough
Noisy, harsh breathing
Hoarse voice when speaking or crying
Rattling felt over the chest or back when breathing
How are HPIVs diagnosed?
In addition to a complete medical history, physical exam of your child, and knowledge
of regional outbreaks, other diagnostic tests for HPIV may include:
Nasal swab of respiratory secretions
Chest X-ray (a test that produces images of internal tissues, bones, and organs)
What is the treatment for HPIVs?
Once a child is infected, treatment is aimed at making your child more comfortable.
Because a virus causes the infection, antibiotics are not useful. HPIVs usually cause
mild symptoms of a common cold, but are also a common cause of croup. Croup symptoms
can be very scary for parents. Supportive treatment for croup may include:
Taking your child into cool, night air. A steamy bathroom with the shower running
may also help to ease your child's breathing.
Encouraging your child to drink plenty of fluids.
Treating a fever with acetaminophen or ibuprofen (as instructed by your child's doctor).
Keeping your child as quiet and calm as possible to help decrease the breathing effort.
How can HPIVs be prevented?
Strict hand-washing is important to prevent the spread of HPIV to other infants and
children. If your child is in the hospital, healthcare workers may wear special isolation
apparel, such as masks, gowns, and gloves when they enter your child's room. Efforts
are underway to develop a vaccine, but currently there are no immunizations for the