A common flu is caused by influenza virus and doctors classify them as influenza type A and type B. Each of this includes several subtypes or strains different from the original virus but retain some of its characteristics. Type A is generally responsible for the annual outbreaks that occur in the late fall and early winter.

The influenza virus do change often. Because of this flu caused by one strain does not give full immunity to other strains. Widespread outbreaks of the flu usually occur about every 10 years. Those who get the flu tend to become sicker when a shift in the flu virus do happens. Minor changes in the virus do happen every year.

The flu virus is spread from one person to another through direct contact, such as shaking hands or through small droplets that is formed while sneezing or coughed.
Any contact with objects such as handkerchiefs which has fluids from an infected person’s nose or throat can also cause the spreading of virus.
 
The flu virus could be spread from one person to another within the 1 day to 5 days after symptoms develop. This may be up to 6 days in the case of children. The influenza could go away on its own in about 7 to 10 days.

During the period of influenza, it is advised to have rest. Drinking plenty of fluids to replace those lost from fever is also recommended. Fluids would ease a scratchy throat and would keep nasal mucus thin. Hot tea with lemon, water, fruit juice, and soup can also be had during the period. Acetaminophen or ibuprofen would prevent headaches and acnes. If you are suffering from dry, hacking cough, it is advised to take a non prescription cough medicine that contains dextromethorphan. Also you should stay away from smoking as it could cause a respiratory infection like a cold or the flu.