Predictive Value

Predictive Value

Predictive Value There are arguably two kinds of tests used for assessing people’s health: diagnostic tests and screening tests. screening tests typically have advantages over diagnostic tests such as placing fewer demands on the healthcare system and being more accessible as well as less invasive, less dangerous, less expensive, less time-consuming, and less physically and … Read morePredictive Value

Mode of Transmission of Diseases

Mode of Transmission of Diseases

Mode of Transmission of Diseases The traditional epidemiologic triad model holds that infectious diseases result from the interaction of agent, host, and environment. More specifically, transmission occurs when the agent leaves its reservoir or host through a portal of exit, is conveyed by some mode of transmission, and enters through an appropriate portal of entry to infect a susceptible host.  An infectious … Read moreMode of Transmission of Diseases

Epidemiologic Triad- Agent, Host, Environment

Epidemiologic Triad- Agent, Host, Environment

Epidemiologic Triad- Agent, Host, Environment The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or “germs” can lead to disease. However, the germ theory of disease has many limitations. For example, it is well-known, that not everyone exposed to tuberculosis develops tuberculosis. The same exposure, however, in an undernourished or otherwise susceptible … Read moreEpidemiologic Triad- Agent, Host, Environment

Sensitivity and Specificity

Sensitivity and Specificity

Sensitivity and Specificity When developing diagnostic tests or evaluating results, it is important to understand how reliable those tests and therefore the results obtained are. By using samples of known disease status, values such as sensitivity and specificity can be calculated that allow its evaluation. Therefore, when evaluating diagnostic tests, it is important to calculate … Read moreSensitivity and Specificity

Randomized Controlled Trial (RCTs)

Randomized Controlled Trial (RCTs)

Randomized Controlled Trial (RCTs) A randomized controlled trial (or randomized control trial; RCT) is a type of scientific (often medical) experiment that aims to reduce certain sources of bias when testing the effectiveness of new treatments. It is a trial in which subjects are randomly assigned to one of two groups: one (the experimental group) receiving the intervention … Read moreRandomized Controlled Trial (RCTs)

Scope of Epidemiology

Scope of Epidemiology

Scope of Epidemiology Epidemiology is defined as “the study of the distribution and determinants of health-related states or events in specified populations, and application of this study to control of health problems.” Epidemiological studies include observation, surveillance, hypothesis‐testing analytic research methods, and experiments. For many years epidemiology was considered to be restricted to the infectious … Read moreScope of Epidemiology

Epidemiological Markers

Phenotypic and Genetic Markers

Epidemiological Markers Epidemiological markers are biological markers that are used to characterize microorganisms or discriminate between genomes based on the genetic variation among microbial isolates. Uses of Epidemiological Markers Epidemiological markers are mostly used for strain typing. It is used to: Classify isolates of microorganisms Catalogue genetic variation Define relatedness or lack of it between … Read moreEpidemiological Markers

Source and Reservoir of Infection

Source and Reservoir of Infection

Source and Reservoir of Infection The starting point for the occurrence of a communicable disease is the existence of a reservoir or source of infection. The source of infection is defined as “the person, animal, object or substance from which an infectious agent passes or is disseminated to the host (immediate source).” The reservoir is … Read moreSource and Reservoir of Infection

Epidemic- Causes, Types, and Response

Epidemic- Causes, Types, and Response

Epidemic- Causes, Types, and Response An epidemic is the rapid spread of infectious disease to a large number of people in a given population within a short period of time. According to modern concepts, an epidemic is defined as the occurrence in a community or region of cases of an illness or other health-related events … Read moreEpidemic- Causes, Types, and Response

Endemic Diseases

Endemic Diseases

Endemic Diseases Communicable diseases are termed endemic when they have a relatively stable pattern of occurrence in a given geographical area or population group at the relatively high prevalence and incidence. It refers to the constant presence of a disease or infectious agent within a given geographic area or population group, without importation from outside. … Read moreEndemic Diseases