A disease is an abnormal state that negatively impacts the structure or functioning of a part or all of the organisms, and which is not caused by any direct external injury to the organism. Most diseases are known to be associated with certain recognizable signs and symptoms, which may indicate their presence. A wide range of diseases exists, with some being fatal and others being very mild. While all diseases are preventable through appropriate preventative measures, sometimes, these measures cannot prevent certain types of diseases from causing death. In such cases, a disease is diagnosed, and then an effective treatment provided.
The prevention of death caused by infectious diseases can be done through vaccination, while the reduction of death caused by common cold and flu can be ensured by maintaining healthy lifestyles. The term “disease” is generally used as a single word to describe any disorder or abnormality that impairs the normal functioning of a particular system. The immune system is one such system, whose role it is to provide immunity to all body cells against external pathogens, such as bacteria and viruses. An effective immune system helps in preventing most cases of infectious diseases. The immune system is largely influenced by genetic background, but it also undergoes environmental stresses, such as stress, trauma and certain diets.
Germs spread rapidly and become infectious when they find a suitable host to multiply in. Common examples of germs are bacteria and viruses, which cause infection. Infectious diseases are grouped into three main categories: acute, chronic and non-acute. Acute infectious diseases are those that produce short-term symptoms (usually fever) and require hospitalization for recovery. Non-acute diseases are those that produce no known symptoms (they may develop slowly over a long period of time).
The causes of death associated with all infectious diseases are different; they vary from one disease to another, and from one community to another. In acute uncomplicated common cold, pneumonia and sore throat are the most common reasons for death. Acute bronchitis and acute diarrhea are common reasons for pneumonia and strep throat respectively. The most common viral infections, chicken pox, herpes and shingles, account for approximately ten percent of the deaths caused by diseases in the United States.
A majority of deaths from non-communicable diseases are associated with common cold viruses, and they account for nearly ten percent of the total deaths from all illnesses. The most commonly known cause of death from common cold is a sore throat infection. Sore throats, or pharyngitis, usually affect young children and adults. Children can be infected with herpes simplex virus, which is the most commonly known cause of cold sores.
Many forms of contagious diseases have a close association with the environment. For example, many deaths from botulism are due to contaminated food or water. Water contaminated with fungi is one of the causes of infant death syndrome. SARS, the rash associated with a variety of streptococcus bacteria, also occurs in hospitals and other public environments due to contaminated food. In recent years, vaccines against several forms of infectious diseases have been made available for the general public.