The study of the causes of disease. The cause/origin of disease.
This is the occurrence of a disease in a community or region of a group of illnesses, which is clearly more than the normal occurrence or expectancy of a disease. Defining a disease as epidemic depends on the disease itself and it’s known occurrence. Ten cases of small pox is an epidemic. Ten cases of influenza is not.
This is a disease or an infectious agent within a geographical area that is expected to be around to some degree. An example of this is the plague. This is a disease that is endemic unless an outbreak occurs then it can become an epidemic.
This is a disease that exists throughout a wide area, such as the cities, countries or the world.
Isolated incidence of a disease.
= New cases of a disease in a population during a specified time period/ Persons at risk of developing the disease during that time period X 1000
#?/Persons in the population at the time X 1000
= Deaths from all causes occurring in a population during a given time. Period (year) / Average number of people in the population during that period (at midyear) X 1000
= Cases of a disease existing at a particular time, or cases occurring in a defined period of time/ 100,000
Modes of Transmission/Exposure
Fecal/oral, droplet contamination, exudates of mucous membranes, bloodborne, vectorborne, dermal exposure, contaminated food/water, direct contact, contaminated fomites, secondary infection.
The period between infection and the appearance of signs/symptoms of disease
Duration of Symptoms
Length of time symptoms last
A person or animal that harbors a specific infectious agent in the absence of discernible clinical disease and serves as a potential source of infection. The carrier state may exist in an individual with an infection that is inapparent throughout its course (commonly known as healthy or asymptomatic carrier) or during the incubation period, convalescence, and postconvalescence of an individual with a clinically recognizable disease (commonly known as incubatory carrier or convalescent carrier). Under either circumstance, the carrier state may be of short or long duration (temporary or transient carrier, or chronic carrier).3*
Asymptomatic carrier shows no symptoms/signs of illness. Can transfer disease to others.
The time needed to return to health after illness
Period of Communicability
The time period at which the disease can be transfer to others.
Hosts in which the parasite is in a larval or asexual state. AKA secondary host
exposure to and inhalation of respiratory aerosols containing infectious agents
pathogens are passed from fecal particles of one host to the oral cavity of second host