Communicable disease refers to diseases that can pass from one person to another. Non-communicable diseases occur in one person and cannot be passed on to another person. Communicable diseases are also known as infectious diseases, and non-communicable diseases are referred to as chronic. Communicable and non-communicable disease usually require different treatments.
The separation of illness into communicable and non-communicable disease is useful for developing prevention and control strategies. The distinction does not mean that one group is intrinsically more dangerous than the other, although the World Heath Organization (WHO) estimates that 60 percent of deaths worldwide are caused by non-communicable diseases. Communicable diseases are more prevalent in underdeveloped countries than developed countries.
According to the WHO, there are four types of non-communicable diseases. These are cardiovascular disease, cancers, non-infectious diseases of the respiratory system, and diabetes. The major causes of these diseases are lifestyle related. Lack of exercise, smoking, unhealthy diet, and abuse of alcohol are all important causes.
One important difference between communicable and non-communicable disease is that non-communicable diseases tend to be chronic, which means they last a long time and progress slowly. Communicable diseases are more likely to be acute, which means the disease develops quickly. Both types of disease may require medication, but non-communicable diseases may be better treated with lifestyle changes.
Communicable diseases are caused by infectious organisms, like bacteria, fungi, and yeast. Viruses and parasites can also be spread from person to person or from animal to person. A communicable disease can spread directly from person to person, such as in the case of a cold or flu virus.
It can also spread indirectly from a person to another person. Malaria is an example of an indirect transmission. To illustrate, an infected mosquito feeds and subsequently infects one person. Then, another mosquito can feed from that person, picking up the parasite and infecting the next person it feeds from.
Each region of the world has its own particular communicable disease profile as infectious organisms may require certain environmental conditions to thrive. For example, malaria is common in Sub-Saharan Africa, tuberculosis is a problem in Asia, and the hepatitis C virus affects millions of Americans. Some infectious diseases, such as polio, are preventable by mass vaccination.
The line between communicable and non-communicable disease is sometimes blurred. Certain chronic diseases are actually caused by an infectious organism when previously they were thought to be unrelated to infection. Cervical cancer is one such case; it is caused by the human papilloma virus. Also, Epstein-Barr virus can cause various types of lymphoma cancers. Research is ongoing into other chronic diseases to see if they are caused by communicable diseases.