Influenza Virus - General Overview          prepared by Agron Plevneshi

Influenza (commonly known as "the flu") is an acute respiratory illness caused by one of the family of influenza viruses. In neonates, persons over the age of 65 years, and those with chronic medical conditions, influenza can lead to pneumonia, hospitalization, and even death.

Since influenza was first described by Hippocrates in 412 BC, 31 influenza pandemics (worldwide epidemics) have been documented. The most devastating of the 20th century influenza pandemics was that known as the Spanish-flu, which killed more than 20 million people between 1918-1920. However, every year, influenza kills between 1,000 and 4,000 Canadians, making influenza the most common infectious cause of mortality.

Influenza viruses are divided into types A, B and C. Type C rarely causes illness. Types A and B circulate in human populations and they constantly change their antigenic coat to evade the human immune system, resulting in the need for a new vaccine every year to protect against the most current circulating virus strains.

Immunization with inactivated flu virus vaccines is the cornerstone of efforts to reduce the impact of influenza. Two types of drugs are can also be used to treat and prevent influenza.