What is paraflu?

Answer 1

Human Parainfluenza virus (hPIV) is a single-stranded RNA influenza virus of the influenza virus types called paramyxoviridae. It is a very common cause of upper respiratory infections and other respiratory tract diseases in infants and young children.

It gets passed from person to person through direct contact with an infected person or their respiratory droplets in the air or on surfaces from coughs or sneezes, just like any cold or flu virus. It is a much smaller virion (virus particle) than most common seasonal influenza viruses, measuring 150 - 200 nanometers in size compared to around 300 nanometers for some of the other common influenza viruses, and, therefore, is able to stay airborne on respiratory droplets from coughs or sneezes for up to an hour. Most influenza viruses fall out of the air on the droplets soon after the sneeze or cough within a 6 foot diameter of the source. The virus can stay active on surfaces for a few hours.

The incubation period from exposure to symptoms ranges from 2 to 7 days.

Adults can have repeated infections throughout life with symptoms of an upper respiratory illness or infection (e.g., pneumonia, bronchitis, etc.) especially in the elderly or immunocompromised.

The total number of cases per year is unknown, since often the symptoms mimic a common cold with runny nose and cough, and, therefore, the virus is not officially reported or identified by medical professionals in a large percentage of the cases. The estimates of the prevalence of paraflu viral infections are very high as evidenced by studies showing that 75 - 100% of children age 5 and older have antibodies for this type of flu which were developed by exposure to this very common infectious pathogen (some lucky infants also received antibodies originally in their mothers' milk from her exposure).

Paraflu is easily prevented with normal flu prevention habits, such as avoiding crowds, staying a safe distance (approximately 6 foot distance) from others during the peak season (which for most of the serotypes of hPIV is in the fall). Always avoid touching your nose, mouth or eyes before washing your hands properly to help prevent all the various infectious pathogens present on your hands from being introduced to your system. Your hands always carry germs picked up in the environment. Parents and others should wash their hands before handling neonates, especially during flu seasons. Paraflu is easily inactivated by soap and water, so frequent and proper hand washing is very important (see related questions below for the proper method).

There is no vaccine to prevent it, but, as mentioned above, breast fed infants can receive the important antibodies for two of the very common serotypes of hPIV (Types 1 & 2) from their mothers in breast milk (increasing the importance of breast feeding newborns when at all possible, even if for only short periods and in small amounts). Vaccine development is being pursued, but not yet accomplished.

The hPIV can cause serious complications at times. In infants, some of the common complications are croup, bronchiolitis, secondary bacterial infections and pneumonia, and some may lead to airway obstructions. Avoiding early infant outside day care when possible can also help by delaying exposure to other infected children until the babies are older with more mature immune systems to be able to fight the infection better.

There are four serotypes and 2 subtypes of the virus, and they have different patterns of outbreaks in different seasons. They are Types 1, 2, 3, and 4 and the subtypes are called Types 4a and 4b. hPIV-1 outbreaks are most prevalent every other year (in the US it is the odd years), with smaller numbers of infections in the opposite years. Outbreaks of hPIV-2 can also be biennial, or they can be annual. It (hPIV-2) manifests most often as croup in the fall. In reverse, the hPIV-3 influenza is most common in the spring and early summer. The pattern of infection by hPIV-4 and its subtypes is unknown so far, but the CDC is actively studying reported cases to learn more.

See the related questions below for more information.