Influenza which is commonly called flu is a respiratory illness which is caused by a virus whereas swine flu is an infection which is caused by one of the several types of swine influenza virus. Influenza is a contagious disease which spreads through cough and sneeze of an infected person. A person is contagious one day before developing the symptoms of the flu and thus this influenza virus can spread even before you know that you are infected. Some of the most common symptoms of influenza include high temperature, headache, aching joints, fatigue, shivers, cold sweats and many others. These symptoms may last for last for about a week or so but the tiredness continues for several weeks. The most common type of swine flu is of H1N1 influenza subtype which infects human being but they can also occur from other types like H1N2, H3N1 and H3N2. Swine flu spread when people get infected with the virus by inhaling the droplets which are coughed or sneezed by an infected person. A person may also get infected by touching something that has swine flu virus on it. The virus of swine flu survives for about 8 hours outside a human body. The initial symptoms of swine flu are similar to those of seasonal flu.