Type A influenza virus causes avian influenza also known as the flu. It is a contagious disease and the main way that  influenza viruses are spread is from person to person in  respiratory droplets of coughs and sneezes. (This is called "droplet spread."). The flu is different from a cold. The symptoms can vary from a mild disease with little or no mortality to a highly fatal, rapidly spreading epidemic (highly pathogenic avian influenza) depending on the infecting virus strain, host factors, and environmental stressors. Some of the symptoms include:

     Fever.

    Headache.

    Tiredness (can be extreme).

   Dry cough.

   Sore throat.
 
   Nasal congestion.

   Body aches.

Most people who get influenza will recover in one to two weeks, but some people will develop life-threatening complications (such as pneumonia) as a result of the flu. Anyone can get the flu (even healthy people), and serious problems from influenza can happen at any age. People age 65 years and older, people of any age with chronic medical conditions, and very young children are more likely to get complications from influenza. Pneumonia, bronchitis, and sinus and ear infections are three examples of complications from flu.