Influenza is the seasonal flu affecting the world every year in outbreaks of about 3 to 5 million cases resulting in 290,000 to 650,000 deaths. It attacks your respiratory system and when infected you will exhibit the following symptoms; high fever, headache, coughing, fatigue, sore throat, runny nose, muscle, and joint aches. It is caused by up to 4 different types of influenza viruses known as Type A, Type B, Type C and Type D that evolve into new strains very rapidly. It is spread through the air in moist particles when an infected person coughs or sneezes.
The influenza is punishing to children and older people because of their weaker immune systems. It is also lethal on people who have underlying health conditions such as asthma, diabetes and cardiac diseases. Influenza virologists study the direction of evolution of the viruses and environmental factors to develop new effective vaccines for influenza every flu season.