Influenza (the flu or grippe) is a debilitating generalised viral infection caused by one of the more than 80 known strains of the influenza virus. Influenza was originally a disease of pigs and ducks, that passed to humans only after these animals were domesticated seven thousand years ago. It was once thought to be due to “influences in the atmosphere”, thus giving its name. The various flu virus strains are named after the places where they were first isolated. It spreads by microscopic droplets in a cough or sneeze from one person to another.
Muscular aches and pains, overwhelming tiredness, fever, headache, cough, runny nose, stuffed sinuses, painful throat and nausea are the main symptoms. It can be a very serious disease, but deaths are now rare except in the elderly and debilitated.
The diagnosis of influenza, and the specific form present, can be confirmed by a blood test that detects a specific immunoglobulin antibody. The test is not routinely performed as it does not change the treatment and often serves no useful clinical purpose.