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The concept of waves in epidemics has implications especially for communicable diseases. A working definition for the term "epidemic wave" is based on two key features: 1) it comprises periods of upward or downward trends, and 2) these increases or decreases must be substantial and sustained over a period of time, in order to distinguish them ...
An epidemic (from Greek ἐπί epi "upon or above" and δῆμος demos "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infections , an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic.
Widespread non-communicable diseases such as cardiovascular disease and cancer are not included. An epidemic is the rapid spread of disease to a large number of people in a given population within a short period of time; in meningococcal infections , an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered ...
The number of cases varies according to the disease-causing agent, and the size and type of previous and existing exposure to the agent. Outbreaks include many epidemics, which term is normally only for infectious diseases, as well as diseases with an environmental origin, such as a water or foodborne disease. They may affect a region in a ...
A representation by Robert Seymour of the cholera epidemic depicts the spread of the disease in the form of poisonous air.. The miasma theory was the predominant theory of disease transmission before the germ theory took hold towards the end of the 19th century; it is no longer accepted as a correct explanation for disease by the scientific community.
In epidemiology, a virgin soil epidemic is an epidemic in which populations that previously were in isolation from a pathogen are immunologically unprepared upon contact with the novel pathogen. [1] Virgin soil epidemics have occurred with European settlement , particularly when European explorers and colonists took diseases to lands they ...
Different bat species. While bats are essential members of many ecosystems, [24] they are also frequently implicated as frequent sources of emerging virus infections. [25] Their immune systems have evolved in such a way as to suppress any inflammatory response to viral infections, thereby allowing them to become tolerant hosts for evolving viruses, and consequently provide major reservoirs of ...
The French doctor Charles Anglada (1809–1878) wrote a book in 1869 on extinct and new diseases. [16] He did not distinguish infectious diseases from others (he uses the terms reactive and affective diseases, to mean diseases with an external or internal cause, more or less meaning diseases with or without an observable external cause).