Global distribution of disease. ~ Medicine

Global distribution of disease.

When the distribution of disease worldwide is studied. the most striking feature to emerge is the difference between develop and developing countries.(Pic 01) show the number of death and the percentage of death due to different causes in developed (industrialized) countries and developing (third world) countries. Infectious and parasitic disease represent a relatively high proportion of disease in developing countries, whereas circulatory and degenerative disease are, relatively speaking, the most important in developed countries. The infectious disease measles, for example, is still an important killer disease in many developing countries (Pic01) although it is declining rapidly as a result of vaccination programs. Measles is amore series disease than most people think. It can cause pneumonia, blindness, deafness and inflammation of the brain which in turn may cause brain damage. It use to be an important killer in developed countries (Pic02),4188 people died of measles in England and wales in 1930, but only 26 in 1980.

Why have these change come about and why are there such striking difference between developed and developing countries? The temptation is to suggest that medical intervention is responsible, but that death rates from measles were declining rapidly in England and wales long before medical intervention. Vaccination against measles was not introduced in Britain unit 1968. The same is true of some other infectious disease which have been killers in the past, such as whooping cough and tuberculosis. The truth is that, in fighting disease, social and economic factor are just as important medical intervention.

Some important infectious disease are transmitted by faecal contamination of water and food. Example are cholera, diarrhea, typhoid and dysentery. These declined rapidly in England and wales after the public health act, 1875 which introduced public hygiene measures for the proper disposal and treatment of sewage, and the purification of water. When considering infectious disease in general, improvements in living standards have been just as important. These increase resistance to disease. particularly important are good nutrition and housing. Tuberculosis, a respiratory infection, began to decline as living standards improved since it is typically spread when people live in close contact, such as several people living in one room, and also when people are malnourished. measles is a particularly important disease in developing countries because it tends to affect very young children, often under the age of one year before they have been vaccinated, and when the body is less able to fight infection. If the body is weakened by maturation, or by other infectious disease much more dangerous. Most measles death are caused by secondary infections.

To summaries, infectious disease have been brought under control in the UK and other developed countries by improvements in hygiene, housing and nutrition as well as by direct medical intervention. The latter includes improvements in prevention, such as vaccination, and in treatment, such as the use of antibiotics(considered in more detail later). Overall social, economic and medical factor are all important and all interact in a complex way.

As vaccination programmers are extended to developing countries, so the incidence of infectious disease is declining in them. Measles is one of six major diseases targetted by the World Health Organization (WHO) for prevention by means of vaccination in its Expanded programme on immunization. The five others are tetanus, pertussis (whooping cough) and polio, tuberculosis and diphtheria.

As infectious disease has been virtually eliminate as a major killer in develop countries, so other diseases have taken their place (Pic 1,2).Notable among the circulatory disease and strokes. The emergence of circulatory disease and cancer as leading cause of death in developed countries is partly related to change in lifestyle. These disease are regarded as modern epidemic and will probably be brought under much greater control as societies develop strategies to tackle them. It can be argued that they are self-inflicted. Some major disease of developed countries however are not related to lifestyle. They are due to an increasing length of life(longevity). As we age, so the body begins to degenerate. A whole range of degenerative disease exists. Cancer for example, become more common as we age.

Pic2 compares cause of death in England and wales for 1851 and 1990. Such data give an indication of the change that can be expected as countries tackle infectious disease.