Disease Control

Disease Control

Disease Control Control of communicable diseases, which implies reducing their occurrence, has always been a major public health priority. In the past, control measures were based on incomplete knowledge of the epidemiology of the disease to be controlled and were directed at perceived factors of disease causation. As knowledge of the epidemiology of diseases improved, … Read more Disease Control

Descriptive Studies- Types, Applications, Advantages, Limitations

Descriptive Studies- Types, Applications, Advantages, Limitations

A simple description of the health status of a community, based on routinely available data or on data obtained in special surveys, is often the first step in an epidemiological investigation. Such a study is termed as a descriptive study. A descriptive study – as the name implies – describes the distributions of disease, injury or health in a … Read more Descriptive Studies- Types, Applications, Advantages, Limitations

Error- Types, Sources and Control

Error- Types, Sources and Control

All epidemiological studies are mostly attempting to establish the presence or absence of a causal relationship, and the results are an estimate of the actual effect or degree of association. All studies are subject to error, which can obscure or minimize the truth- the size and nature of a causal relationship. Understanding common errors and … Read more Error- Types, Sources and Control

Types of Bias in Epidemiology

Common Types of Bias

Types of Bias in Epidemiology Any trend in the collection, analysis, interpretation, publication, or review of data that can lead to conclusions that are systematically different from the truth can be termed as bias. Bias is a major consideration in any type of epidemiologic study design. It has been defined as “any systematic error in … Read more Types of Bias in Epidemiology

Field Trials

Field Trials

Field Trials Experimental studies set out to alter, rather than just observe, relevant exposures of interest, and to assess over time their impact on health status or disease outcomes.  The field trial is the one such type of interventional study designed to evaluate prevention strategies. They are studies carried out “on the ground” or “on the … Read more Field Trials

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 more Predictive 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 more Mode 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 more Epidemiologic 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 more Sensitivity 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 more Randomized Controlled Trial (RCTs)