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Parainfluenza

Last updated Dec. 16, 2018

Approved by: Krish Tangella MD, MBA, FCAP

CDC/Dr. Erskine Palmer

This transmission electron micrograph (TEM) depicts parainfluenza virions, and free filamentous nucleocapsid material. Human parainfluenza viruses (HPIVs) commonly cause upper and lower respiratory illnesses in infants and young children. But, anyone can get respiratory illness from HPIV.


What are the other names for this Condition? (Also known as/Synonyms)

  • HPIV Infection
  • Human Parainfluenza Virus Infection

What is Parainfluenza? (Definition/Background Information)

  • Parainfluenza results in infections of the upper and lower respiratory system. It can cause cold-like symptoms, such as runny nose, sneezing, fever, labored breathing, and cough
  • Parainfluenza is caused by a group of viruses belonging to the family referred to as human parainfluenza virus (HPIV)
  • It mainly affects the young, elderly, and those with weak respiratory or immune systems. The viruses can be transmitted either through the air or by touching infected surfaces
  • 4 different human parainfluenza viruses (serotypes) have been identified so far. These include:
    • HPIV1; known to affect children, causing upper respiratory illnesses and croup
    • HPIV2; known to affect children most often, causing cold-like symptoms and croup
    • HPIV3; that is associated with pneumonia and bronchiolitis in children
    • HPIV4; that is subdivided into HPIV-4A and HPIV-4B, is not very common, but can cause respiratory distress
  • A healthcare provider might evaluate the symptoms presented, check for viral particles in a nasal swab, request a chest x-ray, and may employ other diagnostic tools, to diagnose HPIV Infection and assess the extent of the disease in an individual
  • In normal cases, Parainfluenza does not require any treatment, other than taking plenty of rest, drinking lots of fluids, and if needed, availing over-the-counter medication for fever
  • However, if complications, such as croup, pneumonia, or bronchitis, arise, then corticosteroids, nebulizers, and antibiotics may be required to overcome the disease
  • Most individuals infected with HPIV recover in due course of time, unless any complications are observed that necessitates prolonged treatment or hospitalization. The prognosis may be dictated by economic conditions of the affected individuals (particularly with respect to children). However, death due to Parainfluenza is reportedly rare
  • Some simple practices, such as washing hands before touching any part of one’s face, avoiding crowded areas, disinfecting frequently touched surfaces, and staying home when sick, are all steps that can significantly contribute to help curb spread of Parainfluenza

Who gets Parainfluenza? (Age and Sex Distribution)

  • Parainfluenza can affect individuals of any age and belonging to any racial or ethnic group
  • But, it mainly affects very young children and the elderly adults
  • Both males and females can be affected

What are the Risk Factors for Parainfluenza? (Predisposing Factors)

Some risk factors for Parainfluenza include:

  • Age: Infants, young children, and older adults are at a greater risk for Parainfluenza
  • Weakened immune system: Either due to diseases, such as HIV/AIDS, or as a result of being on immunity-suppressing drugs, or having had other illnesses
  • Season: The infections tend to be more common during the fall and spring
  • Living/working in close proximity with infected individuals (such as hospital workers, people working in daycare centers)
  • Poverty, poor socioeconomic status;
  • Malnutrition
  • Vitamin A deficiency
  • Young children, who have not been breastfed

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Parainfluenza? (Etiology)

Parainfluenza is caused by the human parainfluenza virus (HPIV). There are 4 types of viruses that can cause the infection, and they include HPIV-1, HPIV-2, HPIV-3, and HPIV-4.

  • It is usually spread by having close contact with an infected individual
  • It can also occur after touching an infected surface, and then touching the mouth or nose
  • HPIV can live outside of the human body for about an hour in the air, and for about 10 hours on a surface; thus, it easily spreads in crowded spaces 

What are the Signs and Symptoms of Parainfluenza?

Parainfluenza is an infection affecting the upper and lower respiratory tract. It can result in a variety of signs and symptoms such as:

  • Fever
  • Runny nose
  • Cough
  • Difficulty breathing, wheezing
  • Red eye
  • Vomiting, diarrhea
  • Decreased appetite

How is Parainfluenza Diagnosed?

A healthcare professional might use the following tests to diagnose the Human Parainfluenza Virus Infection:

  • Complete physical examination and medical history evaluation (including previous history of lung infections, pre-existing conditions)
  • Evaluation of one’s signs and symptoms
  • Nasal swab
  • Chest x-ray (in case of complications)

Note: Generally, HPIV Infection does not require any specific diagnosis, unless it affects individuals with autoimmune diseases.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Parainfluenza?

Some possible complications of Parainfluenza Virus Infection could include:

  • Croup: It is a type of bronchitis in which affected children have symptoms of labored breathing and a “barking” cough
  • Pneumonia; inflammation of air sacs in the lungs
  • Bronchitis
  • Bronchiolitis
  • Airway remodeling has been reported in some individuals, which can probably contribute to certain chronic illnesses

How is Parainfluenza Treated?

Parainfluenza is caused by a virus, and therefore, there is no way to truly treat the condition. Most individuals with HPIV Infection get better on their own, after a certain period of time. It is recommended that the affected individuals:

  • Take adequate rest
  • Drink lots of fluids
  • Take ibuprofen or acetaminophen to treat the fever 

If complications, such as breathing difficulties, are observed then, corticosteroids and nebulizers may be recommended. Secondary bacterial infections might need treatment with antibiotics.

Note: Viral infections do not respond to antibiotics. Using antibiotics unnecessarily can lead to the evolution of antibiotic-resistant bacteria in one’s body.

How can Parainfluenza be Prevented?

To date, there are no vaccines available for the prevention of Parainfluenza infections. However, the following simple measures can ensure prevention of the infection:

  • Washing hands frequently with soap and water
  • Avoiding crowded areas during seasons where there are outbreaks of HPIV
  • Avoiding close proximity with Parainfluenza infected individuals

To prevent spread of the disease further, individuals who are infected with HPIV are advised to:

  • Stay indoors
  • Avoid crowded spaces and closed areas
  • Cover their noses and mouths when sneezing or coughing

Cleaning frequently touched surfaces, such as railings, elevator buttons, computers, telephones, and doorknobs, can also help reduce the spread of HPIV.

What is the Prognosis of Parainfluenza? (Outcomes/Resolutions)

  • In most cases, the prognosis for Parainfluenza affecting older children and healthy adults is good, since the condition resolves on its own with no complications
  • However, when very young children, the elderly or immune-compromised individuals are affected, there could be certain serious complications requiring hospitalization; the recovery times may be extended
  • In rare cases, HPIV infections can be fatal 

Additional and Relevant Useful Information for Parainfluenza:

  • Most people are exposed to Parainfluenza before they reach the age of five
  • Young children are usually protected from Parainfluenza during the first 6 months of their life

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: March 18, 2016
Last updated: Dec. 16, 2018