Influenza :
Influenza is a contagious respiratory infection that is caused by the influenza virus. Influenza is of different types. Influenza A and B are the most common ones that have severe symptoms and are seasonal, as most people get affected by them in winter. Swine flu and bird flu are both subtypes of influenza A. Influenza C is not seasonal and doesn't present more severe symptoms than other types. The presenting complaints of people with influenza are headache, body ache, sore throat, fever, chills, runny nose, cough, diarrhea or vomiting in kids and tiredness. Influenza virus spreads directly or through indirect contact with an affected person. To prevent this disease, you should wash your hands regularly with soap and water. One should cover one's nose and mouth while sneezing or coughing and and wear a mask if sick. Sharing food or eating utensils should not be encouraged.