Epidemiology and Disease Transmission

Flashcards on Epidemiology and Disease Transmission

What is Epidemiology?

The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

What is the fundamental assumption of epidemiology regarding disease occurrence?

Disease and other health events do not occur randomly in a population; they are more likely to occur in some members due to risk factors.

What are the components of the epidemiologic triad?

Agent, Host, and Environment.

In the epidemiologic triad, what is the 'Agent'?

A virus, bacterium, parasite, or other microbe; also includes chemical and physical causes of disease or injury.

Give some examples of host risk factors.

Age, sex, personal choices, genetic composition, presence of disease, and medications.

What are the three categories of environmental factors in the epidemiologic triad?

Physical, biologic, and socioeconomic factors.

In Rothman's causal pies, what does each piece of the pie represent?

Each piece of pie represents an individual factor that contributes to causing a disease.

In Rothman's causal pies, what is a 'sufficient cause'?

A complete pie, representing a causal pathway where disease occurs.

In Rothman's causal pies, what is a 'necessary cause'?

A component that appears in every pie or pathway.

What are the components of the chain of infection?

Reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.

What is a reservoir?

The habitat in which an agent normally lives, grows, and multiplies.

What is a carrier?

A human reservoir who does not manifest the disease.

Give some examples of portals of exit.

Respiratory tract, urine, faeces, skin, cuts or needles.

What are the two main modes of disease transmission?

Direct and Indirect

What are the two types of direct modes of transmission?

Direct contact and droplet spread.

What are the three types of indirect modes of transmission?

Airborne, vehicles, and vectors.

What are vehicles in the context of indirect disease transmission?

Inanimate objects that can carry infectious agents.

Give some examples of vectors in disease transmission.

Flies, mosquitos and water fleas.

What factors affect the susceptibility of a host?

Genetic or constitutional factors, specific immunity, and nonspecific factors.

Give some examples of measures to control disease at the reservoir, mode of transmission and susceptible host stages.

Treatment of reservoir, isolation of infected patient and counselling on behavioural change.