Ashry Gad Mohamed Prof. of Epidemiology Terms in Epidemiology Ashry Gad Mohamed Prof. of Epidemiology

What is Epidemiology? Study of distribution and determinants of health- related events and application of this study to control health problems.

Epidemic: The occurrence of more cases of disease than expected In a given area or among a specific group of people over a particular time.

Endemic: Constant presence of a disease or infectious agent within a given geographical area or population group

Pandemic: An epidemic occurring over a very wide area (several countries or contents) and usually affecting a large proportion of the population

well being and not merely the absence of disease or infirmity Health: A state of complete physical, mental, social and environmental well being and not merely the absence of disease or infirmity

entry and development or multiplication of an Infection: The entry and development or multiplication of an infectious agents in the body of person or animal

Contagious Agent or disease that is capable of being transmitted from one person to anther by contact or close proximity.

under normal conditions from Zoonosis An infectious disease that is transmissible under normal conditions from animal to human.

Communicable disease An illness due to a specific infectious agent or its toxic products that arises through transmission of that agent from reservoir to susceptible host.

Period of Communicability The time during which an infectious agent may be transmitted directly or indirectly from infected person to anther person or animal.

Nosocomial infection An infection occurring in a patient in healthcare facility in whom it was not present or incubating at the time of admission.

Reservoir The habitat in which infectious agent normally lives, grows and multiplies. It may be human, animal or environment.

Carrier A person or animal without apparent disease Who harbors a specific infectious agent and is capable of transmitting the agent to others.

of symptoms or signs of infectious disease. Incubation period The period from infection to the Onset of symptoms or signs of infectious disease.

Prepatent period The period in people between time of exposure to parasite and the time when the parasite can be detected in blood or stool.

Host: A person or other living organism That can be infected by an infectious agent under normal condition.

Chemoprophylaxis The administration of chemicals, including antibiotics, to prevent the development of an infection or the progression of an infection to active disease or to eliminate the carriage of a specific infectious agent to prevent its transmission to disease.

including antibiotics, to Chemotherapy The administration of chemicals, including antibiotics, to treat diseases.

Morbidity Any departure, subjective or objective from state of physiological or psychological well being.

of disease or other health-related event or condition. Risk factor: Factor Associated with an increased occurrence of disease or other health-related event or condition.

Pathogenicity: The proportion of persons infected after exposure to a causative agent, who then develops clinical disease.

Virulence Degree of pathogenicity of a microorganism as indicated by the severity of the disease produced and its ability to invade the tissues of a host; the competence of any infectious agent to produce pathologic effects.

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