What is the relationship between host agent and environment?
The triad consists of an external agent, a susceptible host, and an environment that brings the host and agent together. In this model, disease results from the interaction between the agent and the susceptible host in an environment that supports transmission of the agent from a source to that host.
What is the wheel model of causation?
The Wheel – In this model, the host, with its genetic make-up as its core, is presented as the hub of the wheel, surrounded with the environment, which is separated into biological, social and physical components.
What is web of causation?
Introduction. Medicineamigo (2007) defines web of causation as a medical term used to represent a complex group of subjects and relationships that can contribute to occurrence and spread of a disease.
What is disease causation?
The standard model of infectious disease causation under the epidemiological triad theory states that an external agent can cause diseases on a susceptible host when there is a conducive environment. Within the epidemiological triad the agent is known as a ‘necessary’ factor.
What is the difference between host and agent?
The agent infects the host, which is the organism that carries the disease. A host doesn’t necessarily get sick; hosts can act as carriers for an agent without displaying any outward symptoms of the disease. Hosts get sick or carry an agent because some part of their physiology is hospitable or attractive to the agent.
What is the meaning of host factor?
Host factor is a medical term referring to the traits of an individual person or animal that affect susceptibility to disease, especially in comparison to other individuals.
What is the iceberg phenomenon?
The iceberg phenomenon describe a situation in which a large percentage of a problem is subclinical, unreported, or otherwise hidden from view. Thus, only the “tip of the iceberg” is apparent to the epidemiologist.
What is multifactorial causation?
Multifactorial causation: Pettenkofer proposed. that disease is a result of many factors as opposed. to germ theory where the idea of a single cause was. used.
What is Prepathogenesis phase?
This refers to the period preliminary to the onset of disease in man. The disease agent has not yet entered man, but the factors which favor its interaction with the human host are already existing in the environment.
What are the different types of host?
Types of hosts
- accidental host. a host that shelters an organism which does not usually parasitize that host.
- incidental host (a.k.a. dead-end host) a host that shelters an organism but is unable to transmit the organism to a different host.
- primary host (a.k.a. definitive/final host) …
- reservoir host.
What are the different modes of transmission?
Modes of transmission
- Direct. Direct contact. Droplet spread.
- Indirect. Airborne. Vehicleborne. Vectorborne (mechanical or biologic)
What are the two kinds of transmission?
There are two types of contact transmission: direct and indirect. Direct contact transmission occurs when there is physical contact between an infected person and a susceptible person. Indirect contact transmission occurs when there is no direct human-to-human contact.
What is epidemiological triad?
A traditional model of infectious disease causation, known as the Epidemiologic Triad is depicted in Figure 2. The triad consists of an external agent, a host, and an environment in which host and agent are brought together, causing the disease to occur in the host.
Which example would be considered a host factor?
Host factors include those that are largely fixed (such as demographics, ancestry, and genetics) and those that are influenced by early life exposure to other risk factors.
What is host in epidemiological triad?
The Host—“Who” Hosts are organisms, usually humans or animals, which have been exposed to and harbor a disease. The host can be the organism that gets sick, as well as any animal carrier (including insects and worms) that may or may not get sick.
What are the three components of the triad?
The CIA triad refers to an information security model made up of the three main components: confidentiality, integrity and availability. Each component represents a fundamental objective of information security.
What are the 3 main elements of descriptive epidemiology?
Descriptive epidemiology searches for patterns by examining characteristics of person, place, & time . These characteristics are carefully considered when a disease outbreak occurs, because they provide important clues regarding the source of the outbreak.
What are the 4 important elements of epidemiology?
Key terms in this definition reflect some of the important principles of epidemiology.
- Study. Epidemiology is a scientific discipline with sound methods of scientific inquiry at its foundation. …
- Distribution. …
- Determinants. …
- Health-related states or events. …
- Specified populations. …
- Application. …
What is another word for epidemiology?
epizootiological, endemic, contagious, epizootic.
What are the 3 types of epidemiological studies?
Three major types of epidemiologic studies are cohort, case-control, and cross-sectional studies (study designs are discussed in more detail in IOM, 2000). A cohort, or longitudinal, study follows a defined group over time.