A disease is a disorder with a specific cause and recognizable signs and symptoms; any bodily abnormality or failure to function properly; except that resulting directly from physical injury.
Infection: It refers to the invasion of body by pathogen and their development and multiplication inside the body.
Infestation: It refers to the presence of pathogens on the skin or inside the body.
Contamination: It is used for inanimate objects, which do not respond pathogen in a way that a living organism does. It refers to the presence of disease causing agent in non-living materials.
Contagious: It refers to the disease transmitted only by direct physical contact.
Communicable diseases: It refers to any disease that can be transmitted form an infected individual to a healthy person.
---- All cancers except cancer of cervix are non-communicable.
---- All contagious diseases are communicable but all communicable diseases are not contagious.
Epidemiology: It is the branch of science dealing with occurrence, distribution and control of diseases.
Endemic: An endemic is a disease which occurs in a particular geographical region continuously for a long time in smaller number without importation from outside.
Epidemic: It is a disease or a group of illness of similar nature in a particular geographical region in a larger number that is greater than normal expectation.
Sporadic: It refers to a disease that occurs only occasionally or in a few isolated places.
Pandemic: Pandemic is an epidemic so widely spread that vast numbers of people in different countries are affected.
---- The Black Death, the epidemic plague that ravaged Europe in the fourteenth century and killed over one third of the population, was a classical pandemic.
---- AIDS is currently considered to be a pandemic.
Ecdemic: A disease not occurring normally in the population of a country. It is applied sometimes to unusual diseases brought in from abroad by immigrants or travelers.
Systemic: A disease which affects the body as a whole, rather than individual parts and organs is a systemic disease.
Acute: describing a disease of rapid onset, severe symptoms and brief duration.
Chronic: describing a disease of long duration involving very slow changes. Such disease if often of gradual onset. The term doesn't imply anything about the severity of the disease.
