The influenza virus is a highly contagious virus that results in a high fever as well as serious complications such as pneumonia in elderly patients, children and immunocompromised individuals. According to MedlinePlus, a publication of the National Institutes of Health, about 5 to 20 percent of the American population get the flu each year. The influenza virus often affects the respiratory tracts and the gastrointestinal tracts, and also causes a fever, fatigue and headache.
Fever
The influenza virus is an upper respiratory infection typically spread by direct contact with an infected person or by respiratory droplets in the air. The incubation period for the influenza virus is about one to four days followed by the sudden onset of a high fever. According to MayoClinic.com, an influenza viral infection is characterized by a fever over 101 degrees F in adults and a fever often as high as 103 to 105 degree F in children.
Body Aches
During the one- to four-day incubation period with the influenza virus, the immune system mounts a counterattack against the virus, releasing innate immune cells, inflammatory chemicals and eventually antibodies. As the immune cells mount an attack against the invading viral cells, the human body becomes a battleground and the individual begins to feel generalized pain or body aches in the muscles and joints. According to the American Academy of Family Physicians, an influenza viral infection is accompanied by chills, sweating, aches and pains throughout the entire body. Muscle aches are especially prominent in the legs, back and arms.
Respiratory Symptoms
According to the University of Maryland Medical Center, the influenza virus is a highly contagious respiratory tract infection that causes a non-productive cough, a sore throat and in some cases pneumonia. The influenza virus also causes chest congestion, a severe cough, a runny nose and sneezing.
