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 person may result in clinical disease. Similarly, not everyone exposed to beta-hemolytic streptococci develops acute rheumatic fever. There are other factors relating to the host and environment which are equally … Read more

Sensitivity and Specificity- Definition, Formula, Calculation, Relationship

Sensitivity and Specificity- Definition, Formula, Calculation, Relationship

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 the sensitivity and specificity for that test to determine its effectiveness. Image Source: Wikipedia Sensitivity The term sensitivity was introduced by Yerushalmy in the 1940s as a statistical … Read more

Epidemic vs Pandemic with Definition and Examples

The occurrence of COVID-19 has resurrected terminologies that are rarely used practically. The theoretical understanding of epidemiological terms i.e Epidemic, Endemic, and pandemic have been in a class of Biology or Microbiology where you are taught what these terms represent when it comes to a disease spread. However, lately, the globe has been made to understand and differentiate what an epidemic and pandemic means, through COVID-19. Definitions An endemic refers to disease occurrence within a population and it remains consistently … Read more

Pandemic- definition, features, causes, effects, examples

Pandemic Definition The word pandemic comes from the Greek pandemos meaning “pertaining to all people.” The Greek word pan means “all” and the Greek word demos means “people.” An epidemic usually affecting a large proportion of the population, occurring over a wide geographic area such as a section of a nation, the entire nation, a continent or the world is called a pandemic. It is the worldwide spread of a new disease. Throughout history, there have been a number of pandemics, such as smallpox, tuberculosis, influenza, … Read more

Randomized Controlled Trial (RCTs)- Definition, Features, Principle, Steps

Randomized Controlled Trial (RCTs)- Features, Principle, Steps, Bias

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 that is being tested, and the other (the comparison group or control) receiving an alternative (conventional) treatment. The two groups are then followed up to see if there are … Read more

Phases of Clinical Trials for Drugs and Vaccine Development

Phases of Clinical Trials for Drugs and Vaccine Development

In clinical research, clinical trials are a type of research experiment done on people aiming at finding a solution to a disease. These trials include studies of diagnostic tests, treatments, and monitoring and evaluation of human health outcomes. The interventions of clinical trials include: Drugs Vaccines Biological products Surgical and radiation procedures Medical devices Preventive treatment (vaccines) Behavioral treatment. Clinical trials normally begin in laboratories experimenting on animals and some human cell experiments. When the first experiment is successful using … Read more

Area, Scope, and Fields of Epidemiology

Area, Scope, and Fields 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 diseases, epidemics, and endemics which were the major health problem in the past. With changing pattern of population morbidity and mortality, the scope of epidemiology has been enlarging. The scope … Read more

Epidemiological Markers- Phenotypic and Genetic 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 microbial species or genera It can be applied in infection control to: Confirm an outbreak in an institution Identify an outbreak in what appears to be sporadic … Read more

Positive and Negative Predictive Value- Definition and Significance

Positive and Negative Predictive Value- Definition and Significance

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 psychologically discomforting for clients. Screening tests are also, however, well-known for being imperfect and they are sometimes ambiguous. It is, therefore, important to determine the extent to … Read more

Disease Control- Methods, Early Detection, and Treatment

Disease Control- Methods, Early Detection, and Treatment

Introduction 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, and with the development of scientifically sound intervention techniques, it has been possible to direct specific control measures at factors related to the occurrence of particular … Read more