Infectious Disease Epidemiology

Question 1

“any deviation from or interruption of the normal structure or function of any part, organ, or system (or combination thereof) of the body that is manifested by a characteristic set of symptoms and signs . . .”.

Answer 1

disease

Question 2

“a state of optimal physical, mental, and social well-being, and not merely the absence of disease and infirmity.”

Answer 2

Health

Question 3

an illness due to a specific infectious (biological) agent or its toxic products capable of being directly or indirectly transmitted

Answer 3

communicable (infectious) disease

Question 4

transmitted through contact.

Answer 4

contagious disease

Question 5

t/f All contagious diseases are communicable

Answer 5

true

Question 6

Not all communicable diseases are contagious

Answer 6

dengue

Question 7

Some diseases are both communicable and contagious

Answer 7

measles

Question 8

the person, animal, object or substance from which an infectious agent passes or is disseminated to the host (immediate source).

Answer 8

Source of infection

Question 9

any person, animal, arthropod, plant, soil, or substance, or a combination of these, in which an infectious agent normally lives and multiplies, on which it depends primarily for survival, and where it reproduces itself in such a manner that it can be transmitted to a susceptible host. It is the natural habitat of the infectious agent.”

Answer 9

Reservoir

Question 10

infection that is transmissible under natural conditions from vertebrate animals to man

Answer 10

Zoonosis

rabies, plague, bovine tuberculosis…..

Question 11

a person in the population or study group identified as having the particular disease, health disorder, or condition under investigation

Answer 11

case

Question 12

Person who brings the disease/infection into a population

Answer 12

Primary Case

Question 13

Persons who are infected by primary case

Answer 13

Secondary case

Question 14

First case discovered during an outbreak

Answer 14

Index case

Question 15

infected person or animal that harbors a specific infectious agent in the absence of discernible (visible) clinical disease and serves as a potential source of infection to others.

Answer 15

CArrier

Question 16

Three elements have to occur to form a carrier state

Answer 16

The presence in the body of the disease agent.
The absence of recognizable symptoms and signs of disease.
The shedding of disease agent in the discharge or excretions.

Question 17

An insect or any living carrier that transports an infectious agent from an infected individual or its wastes to a susceptible individual or its food or immediate surroundings.

Answer 17

VECTOR of INFECTION

Question 18

An infectious agent seeks a susceptible host aiming “successful parasitism

Answer 18

Susceptible host

Question 19

Four stages are required for successful parasitism:

Answer 19

Portal of entry
Site of election inside the body
Portal of exit
Survival in external environment

Question 20

Features unique to infectious diseases:

Answer 20

1. A case may also be a source.
2. People may be immune.
3. A case may be a source without being recognized.
4. There is often a need for urgency.
5. Preventive measures often have good scientific basis.

Question 21

Outcomes of exposure

Answer 21

1. No infection
2. Clinical infection resulting in death, immunity, carrier or non-immunity
3. Sub-clinical infection resulting in immunity, carrier or non-immunity
4. Carrier

Question 22

entry and development or multiplication of an infectious agent in the body of man or animals.

Answer 22

INFECTION

Question 23

time from exposure to development of disease. In other words, the time interval between invasion by an infectious agent and the appearance of the first sign or symptom of the disease in question.

Answer 23

Incubation period

Question 24

the period between exposure and the onset of infectiousness (this may be shorter or longer than the incubation period).

Answer 24

Latent Period

Question 25

Length of time a person can transmit the disease (sheds the infectious agent)

Answer 25

Infectious period

Question 26

This is infection by organisms that take the opportunity provided by a defect in host defense (e.g. immunity) to infect the host and thus cause disease.

Answer 26

Opportunistic infection

Question 27

The presence of an infectious agent on a body surface, on or in clothes, beddings, toys, surgical instruments or dressings, or other articles or substances including water and food

Answer 27

contamination

Question 28

It is the lodgment, development and reproduction of arthropods on the surface of the body or in the clothing, e.g. lice, itch mite. This term could be also used to describe the invasion of the gut by parasitic worms, e.g. ascariasis.

Answer 28

Infestation

Question 29

is an infection originating in a patient while in a hospital or another health care facility

Answer 29

Nosocomial (hospital acquired) infection

Question 30

The way the disease progresses in the absence of medical or public health intervention

Answer 30

Natural History of Disease

Question 31

BIOLOGIC SPECTRUM OF DISEASE

Answer 31

ICEBERG PHENOMENON

Question 32

Studying only symptomatic individuals may produce misleading

Answer 32

ICEBERG PHENOMENON

Question 33

a host characteristic that can limit the ability of an infectious agent to produce infection

Answer 33

Immunity

Question 34

resistance of a group of people to an attack by a disease to which a large proportion of the members of the group are immune.

Answer 34

Herd immunity

Question 35

The unusual occurrence in a community of disease, specific health related behavior, or other health related events clearly in excess of expected occurrence”

Answer 35

Epidemic

Question 36

It refers to the constant presence of a disease or infectious agent within a given geographic area or population group. It is the usual or expected frequency of disease within a population.

Answer 36

Endemic