Lecture 10; Pathogenicity

Question 1

What are the different types of infectious diseases?

Answer 1

1. Opportunistic pathogens
   
   1. Only cause disease in compromised host
2. True Pathogen
   
   1. Cause disease in anyone

Question 2

What are these sub-types of diseases:

• Newly identified
• Previously controlled diseases (no longer)
• Spread from animal to human

Answer 2

• Emerging diseases
• Re-emergin diseases
• Zoonotic disease

Question 3

• What are sporadic diseases?
• What are endemics?

Answer 3

• Isolated infections in particular population
• Routinely detected in a particular population

Question 4

• What are epidemics (diseases)?
• What are pandemics?

Answer 4

• Widespread disease in a particular place
• An epidemic that spreads to other countries

Question 5

What is the difference between signs and symptoms?

Answer 5

1. Sign= measurable indicator of disease (fever, rash…)
2. Symptom= non-measurable indicator that is sensed by patient (pain, faigue…)

Question 6

What is the difference between active and latent infections?

Answer 6

1. active= host is showing symptoms (symptomatic)
2. Latent= host has no symptoms (asymptomatic)

• virus is inactive

Question 7

What is the difference between acute and chronic infections?

Answer 7

1. acute= rapid onset and progression
2. chronic= slow onset and progression

Question 8

What is the difference between a reservoir and source of infections?

Answer 8

1. Reservoir= Where pathogen is normally found
2. source= transmits the infection from reservoir to new host

Question 9

What are exogenous sources?

give examples

Answer 9

Infection from outside body

• environment
• animals
• other humans

Question 10

What are endogenous sources?

give examples

Answer 10

Infection from person’s own body

• Misplaced microbe (from surgery)
• Disrupted microbe (antibiotic)

Question 11

What are the 2 types of ways disease can spread?

Answer 11

1) Direct contact transmission

contact between source and host

2) Indirect contact transmission

no contact between source and host

Question 12

What are examples of:

1. direct contact transmission
2. indirect contact transmission

Answer 12

1. Person to person, vertical (mother to infant), environment
2. Airborne, contamination, vector (insects)

Question 13

What are the five stages of disease in order?

Answer 13

1. Incubation period
2. Prodromal phase
3. Acute phase
4. Period of decline
5. Convalescent place

Question 14

Give the names for these stages of disease:

• Time between infection and earliest symptoms
• Early symptoms start

Answer 14

• Incubation period
• Prodromal phase

Question 15

Give the names of these stages of disease:

• Peak of disease
• Replication is under control; symptoms resolve

Answer 15

• Acute phase
• Period of decline

Question 16

What is this stage of disease;

Patient recovers; sometimes the disease remains latent

Answer 16

Convalescent period

Question 17

What are the two types of different infections of the acute phase?

Answer 17

1. Clinical infection
   
   1. Full symptoms
2. Sub-clinical infection
   
   1. Infected, do not show symptoms

Question 18

What can occur if the patient stops taking medication during the period of decline?

Answer 18

Relapse (possible resistance to drug)

Question 19

What are the three different ways the convalescent stage can end?

Answer 19

1. Elimination of pathogen
2. Harbor pathogen forever (chronic; cycle between symptoms and no symptoms)
3. Asymptomatic carrier (infected, never show symptoms)

Question 20

What is epidemiology?

• What are its two goals?

Answer 20

Focus of disease in populations

1. Describe new/existing disease in population
2. Intervene to protect/improve population health

Question 21

What are the three points of the triangle of epidemiology?

Answer 21

1. Public education
2. Quarantine
3. Vector control (insects)

Question 22

What are these levels of surveillance and who monitors them?

1. reportable diseases
2. Notifiable diseases

Answer 22

1. State/local list of diseases
2. CDC monitored diseases