Influenza, commonly known as flu, is a well-known disease, often appearing during or after the rainy season. Supplements and vitamins are among the treatments for the disease. Influenza is a contagious respiratory diseases caused by the influenza virus.
The influenza virus is an RNA virus classified as Orthomyxoviridae. It is spread through the air or direct contact such as using saliva as the intermediary. Two types of influenza are known to infect humans: virus A and virus B.
There are various types of influenza based on the outspread and time: seasonal influenza, pandemic influenza, and zoonotic/variant influenza.
Seasonal Influenza
The disease’s circulation infects humans every year, usually seasonal in every winter. It spreads through the air (when a person infected coughs or sneezes) or direct contact such as through saliva. Its symptoms vary, from mild symptoms to severe ones that lead to death in several cases.
This type of influenza is the most commonly found. There are three categories: viruses A, B, and C. The type A virus has subtypes based on the variation and combination of two proteins on the virus’s surface: hemagglutinin (H) and neuraminidase (N). One of the best known type A influenza subtypes is H1N1, previously known as a type of pandemic influenza but having become a seasonal influenza recently, such as during the 2009 outbreak.
Pandemic Influenza
This type of influenza is a mutation or a new type of the disease ready to infect the host. A pandemic takes place when the influenza virus previously could not spread between humans with no immunity to the disease. This virus can spread widely outside the seasonal influenza circulation. Most people have no immunity to the disease, which often causes an outbreak. Currently there is no known factor behind pandemic influenza. For example, the 1918-1919 Spanish flu caused the deaths of 20-40 million people around the world, and 2009 saw a H1N1 outbreak.
Zoonotic / Variant Influenza
This type of influenza can both infect humans and spread among animals, such as the H5N1, H1N1, H3N2, and H9N2 viruses. The symptoms range from pneumonia to severe complications that ultimately lead to death. Upon infecting human, zoonotic influenza is labelled as a variant. For example, after H3N2 spread among pigs, the virus was labelled V by researches upon infecting humans in the US in 2011.
Text by Rezky Zakiri
Stock photos from Google Search Images
Source(s):
- WHO - Influenza virus infections in humans (2013). http://www.who.int/influenza/GIP_InfluenzaVirusInfectionsHumans_Jul13.pdf.
- Flu Shots, Antibiotics, & Your Immune System (2009). http://www.drabelson.com/PDF/Flu.pdf.
- Influenza (2009). http://www.csfph.iastate.edu/pdfs/influenza.pdf.