Epidemiology : Dynamics Of Disease Transmission

Question 1

What is a communicable disease

Answer 1

-Illness due to specific biological agent or its toxic product capable of direct or indirect transmission from man to man , animal to man , or from
Environment to man

Question 2

What is an infection

Answer 2

• entry and multiplication from an infectious agent in the body of man or animal
• does not always cause disease

Question 3

Gradient / Levels infection

Answer 3

1 colonization
2 sub clinical ie inapparent infection
3 latent infection
4 clinical infection

Question 4

What is latent, sub clinical and clinical infection

Answer 4

• infectious agent present in body but not causing any overt symptoms. Patient is still infected and can pass on to others
• no detectable signs. Patient is asymptotic
• a stage in pathological condition where infectious agent causes anatomical or physiological changes sufficient to be recognized as signs and symptoms

Question 5

What is contamination

Answer 5

-presence of an infectious agent on a body surface clothes beddings toys surgical instruments or substances including water and food or soil

Question 6

What is infestation

Answer 6

-lodgment or development and reproduction of arthropods on body surface or clothes and bed lining

Question 7

Ascariasis

Answer 7

-invasion of gut by parasitic worms

Question 8

What is a contagious disease

Answer 8

-disease transmission through contact

Question 9

What is opportunistic infection

Answer 9

-infection by organism that take opportunity provided by a defect in host defense to enter multiply and cause disease

Question 10

Nosocomial infections

Answer 10

-hospital acquired

• infection originating in patient while in hospital or other health Care facility
• new disorder has to be unrelated to patients primary condition

Question 11

List Host conditions

Answer 11

• biological characteristics
• behavioral
• demographic
• socioeconomic

Question 12

List types of agents

Answer 12

• biological
• chemical
• physical
• nutritional

Question 13

List types of environments leading to disease

Answer 13

• social
• physical
• biological

Question 14

What is virulence of agent

What is case fatality rate for infectious disease

Answer 14

• degree of pathogenicity
• disease evoking power of micro organism and in a given host
• numerically is ratio of # of overt cases TO # of total infections
• shows severity of infection
• ratio of infected and died TO # of total infection

Question 15

What is a host and susceptible host

Answer 15

• a person or animal that affords subsistence or lodgment to an infectious agent under natural conditions
• more likely to succumb to infectious agent so that it can easily achieve parasitism

Question 16

4 stages of parasitism

Answer 16

1 portal entry
2 lodgment or development inside host
3 portal of exit
4 survival in external environment

Question 17

What is source of disease

Answer 17

• starting point for the occurrence of a communicable disease
• can be place, person, animal or object from which infectious agent is disseminated to susceptible hosts

Question 18

What is special host : reservoir

Answer 18

• natural habitat for infectious agents
• any person, place, or animal or combination of these in which infectious agent normally lives , depends primarily on for survival and where it’s reproduces in such a manner it can be transmitted to susceptible host

Question 19

What is incubation and latent period

Answer 19

• time from exposure to appearance of first signs of disease

- time from exposure to shedding ( onset of infectiousness )

Question 20

What is a disease

Answer 20

• a particular abnormal condition that negatively affects the function of part or all of an organism not caused by external injury and is associated with specific signs and symptoms
• caused by external pathogen or internal dysfunction

Question 21

What is a case

Answer 21

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

Question 22

What is a carrier

Answer 22

• infected person or animal that harbors specific agent but without any discernible clinical disease
• serve as source of infection to others

Question 23

3 elements needed to form a carrier

Answer 23

• disease present in body
• absence of recognizable signs
• shedding of disease in discharge

Question 24

What causes formation of carrier

Answer 24

-inadequate treatment or immune response and agent not completely eliminated leading to carrier state

Question 25

Describe animal reservoirs and zoonosis

Answer 25

-zoonosis are infectious transmissible under natural conditions from vertebrae animals to people

Question 26

What is a vector

Answer 26

-an insect or living carrier that transports that transports infectious agents from other infected hosts, from its food , waste or immediate surroundings to non/infected susceptible host

Question 27

Non living reservoirs

Answer 27

-soil and inanimate objects can also serve as reservoirs for infections

Question 28

Type of carriers

Answer 28

1 incubatory
2 healthy
3 convalescent ( recovering )

Question 29

Exit portals via carriers

Answer 29

• urinary
• respiratory
• intestinal

Question 30

Duration of carrier state

Answer 30

• chronic

- temporary

Question 31

Types of cases

Answer 31

1 clinical ( mild / severe-typical / atypical )
2 sub clinical
3 latent

Question 32

Levels of cases and describe

Answer 32

1 index - patient zero. 1st documented patient within a population of a condition or syndrome

2 primary case - infectious disease that spread from human to human and refers to person who 1st brings disease into a group of people

3 secondary case - occurring of disease due to close contacts of a primary case patient 24 hours after onset of illness in primary case