As a result, over 20 million people died. Influenza epidemics spread fast because it is a virus that is very contagious. Flu symptoms are much worse than a cold. The flu will affect your entire body. There is no cure for viruses, so most flu cases just run their course in about one to two weeks.
Influenza is spread easily by coughing and sneezing.
The incubation period lasts for two to three days. More symptoms appear after that including chills and fever. Suddenly more symptoms, like sensitivity to light, headache, soreness, weakness, backache and fatigue appear. The flu virus infects the respiratory tract and will go from being mild to severe. You may have a dry cough, sore throat, scratchy throat, loss of appetite, nausea, vomiting, diarrhea, and a stuffy or runny nose.