Cellular basis for the spread of infectious diseases

Question 1

What are the five stages of an infectious disease?

Answer 1

• Incubation period (no signs or symptoms)
• Prodromal period (vague, general symptoms)
• Illness (most severe signs and symptoms)
• Decline (declining signs and symptoms)
• Convalescence (no signs or symptoms)

Question 2

What is the most infectious stage of a disease?

Answer 2

The illness stage

Question 3

Why do the length of time between each stage vary?

Answer 3

Because of the specific pathogen you are infected with

Question 4

What is the rhinovirus?

Answer 4

• Causes the common cold
• ssRNA non encapsulated
• On the outside of the virus are proteins, that specifically bind to respiratory epithelia
• Grows in the nasal cavities as they are 32 degrees

Question 5

What are the five components of disease transmission?

Answer 5

• Person at risk (young/elderly, immunocompromised)
• Causative agent: pathogenic organism (virus/ bacteria/ parasite)
• Reservoir/source (human/ animal/ fomite - inanimate object/ food/ water)
• Means of exit: way out of body (excretions/ secretions/ droplets)
• Mode of transmission: method of spread (contact/ airborne/ vector e.g. insect)
• Portal of entry: way into the body (Respiratory/ GI/ GU/ mucous/ skin)

Question 6

How do we break the chain of infection via the person at risk?

Answer 6

Identifying at risk and targeting them for special care, vaccination and education

Question 7

How do we break the chain of infection via causative agent?

Answer 7

Rapid detection and treatment

Question 8

How do we break the chain of infection via reservoir/ source?

Answer 8

Good hygiene/ sterilisation/ disinfection

Question 9

How do we break the chain of infection via means of exit?

Answer 9

Waste removal / disinfection

e.g. cover mouth and nose while coughing and sneezing

Question 10

How do we break the chain of infection via Mode of transmission?

Answer 10

Airflow control / bed spacing

Question 11

How do we break the chain of infection via portal of entry?

Answer 11

Aseptic technique

Catheter / wound care

Question 12

What is the main cause of the symptoms of the common cold?

Answer 12

The overreaction of the immune system

Question 13

What is Mortality?

Answer 13

The incidence of death in a population

Question 14

What is morbidity?

Answer 14

Refers to the incidence of disease, including fatal and nonfatal diseases

Question 15

What is the incidence of a disease?

Answer 15

The number of new cases of the disease in a given period of time

Question 16

What is the prevalence of a disease?

Answer 16

Total number of new and exciting cases in a population in a given time

Question 17

What is an Endemic?

Answer 17

The amount of a particular disease that is usually present in a community is referred to as the baseline or endemic level of the disease (of a particular geographic area)

Question 18

What is a Sporadic?

Answer 18

A disease that occurs infrequently and irregularly

Question 19

What is a Epidemic?

Answer 19

An increase, often sudden, in the number of cases of a disease above what is normally expected in the population in that area

Question 20

What is a Pandemic?

Answer 20

An epidemic that has spread over several countries or continents, usually affecting a large number of people