Influenza and Pneumonia

What are influenza and pneumonia?

Influenza (flu) is a highly contagious viral infection that is one of the most severe illnesses of the winter season. The reason influenza is more prevalent in the winter is not known; however, data suggest the virus survives and is transmitted better in cold temperatures. Influenza is spread easily from person to person, usually when an infected person coughs or sneezes.

A person can have flu more than once because the virus that causes the disease may belong to different strains of one of three different influenza virus families, A, B or C. Type A viruses tend to have a greater effect on adults, while Type B viruses are a greater problem in children.

Symptoms of influenza include fever, headache, cough, chills, sore throat, nasal congestion, muscle aches, loss of appetite and a general achy and lousy feeling.

Influenza can be complicated by pneumonia, which is a serious infection or inflammation of the lungs. The air sacs fill with pus and other liquid, blocking oxygen from reaching the bloodstream. If there is too little oxygen in the blood, the body's cells cannot work properly, which can lead to death.

Pneumonia can have over 30 different causes which include various chemicals, bacteria, viruses, mycoplasmasI and other infectious agents such as pneumocystis (fungi). Certain diseases, such as tuberculosis, also can cause pneumonia. Pneumonia also can be caused by the inhalation of food, liquid, gases or dust. The most common cause of community-acquired (compared to hospital-acquired) pneumonia is the pneumococcus bacterium; infection by this bacterium is known as pneumococcal disease. The pneumococcal bacterium also causes meningitis, bacteremia, otitis media and sinusitis.

Symptoms of pneumonia include fever, wheezing, cough, chills, rapid breathing, chest pains, loss of appetite and malaise, or a general feeling of weakness or ill health.