Question

Epidemiological triad refers to
A. Host, disease and environment
B. Host, agent and environment
C. Host, agent and disease
D. Agent, disease and environment

Answer 1

Disease does not occur randomly in a population. It spreads via some members of the population. There is always an interrelation between the cause and effect of a disease. This root cause will help to reach us to the treatment of the infection

Complete answer:
Firstly we need to know the terms in the question-
1. Agent – it is the infection causing microorganism (pathogen).
2. Host – the person who gets affected by the pathogen.
3. Environment – this refers to the factors that help the agent to get an exposure to affect the host.
Epidemiology is the study of spreading and controlling the disease.

What is an epidemiological triad? It’s a triangle which depicts the relation between the agent of the disease causation and the host it has affected. It is a model that has been proposed to know the cause of a disease.
- It helps us to understand the risk of the extent of disease to affect a population. We can get to know the sum of factors responsible for the presence of a disease.
- The diagnosis of a disease is by 5 W’s – what, who, where, when and why.
- The epidemiological triad consists of a susceptible agent, an agent and environment that will be a link between the host and the agent. They all are interrelated to each other.
- The agent will always need some extrinsic factors to spread the infection whereas the intrinsic factors help the agent to target a particular host. Intrinsic factors are:- immunity level of a person, a prior encounter with the disease, age, sex, hygiene practices etc.

So the answer is option B: Host, agent and environment.

Note: Biological agents can be bacteria, virus, fungi etc. They can be virulent.
Excessive heat, cold, radiations etc will help the spread of the infection.