Intro to Infectious Disease

Question 1

What are the top 3 infectious killers around the world?

Answer 1

1. HIV
2. Malaria
3. Tuberculosis

Question 2

What is DALY?

Answer 2

Disability-adjusted life year (DALY) measures the overall disease burden expressed as the number of years lost due to ill health, disability, and early death

Question 3

What is the DALY due to infectious and parasitic diseases around the world?

Answer 3

~445 million

Question 4

What is inoculum vs virulence?

Answer 4

Inoculum: is the amount of bacteria
Virulence: is the ability of an organism to cause infection

Question 5

What are the 5 stages of zoonotic disease transmission? Briefly describe each and give an example

Answer 5

Stage 1: Agent is only found in animals
Stage 2 (Primary Infection): Agent can only be transmitted from animals to humans
Stage 3 (Limited Outbreak): Agent is still mostly passed from animal to human but with limited human to human transmission
Stage 4 (Long Outbreak): Agent still passed from animal to human but also transmitted easily from human to human
Stage 5 (Exclusive Human Agent): Agent is transmitted only from human to human without any animal reservoir

Question 6

What are the 6 modes of transmission of infectious agents?

Answer 6

1. Contact (either direct/body to body or indirect via fomites)
2. Large droplet (>5um; travels up to 3 ft)
3. Small droplet (<5um; airborne)
4. Endogenous (auto-inoculation/device related)
5. Common source
6. Vector borne

Question 7

What 3 diseases are transmitted by small droplets?

Answer 7

1. Measles
2. TB
3. Varicella

Question 8

What 4 diseases are transmitted by large droplets?

Answer 8

1. SARS
2. Influenza
3. Pertussis
4. Mumps

Question 9

Who is the father of hand anti-sepsis and how did they figure out the importance of hands in disease transmission?

Answer 9

Ignaz Semmelweis: discovered that infection (puerperal sepsis) in post-partum women due to strep) was significantly higher for those who’s babies were delivered by medical students than midwives. This is because medical students were performing autopsies and then delivering babies

Question 10

What is the most important technique we can use to prevent the spread of infection?

Answer 10

Hand washing/hygiene

Question 11

What is a common form of infection control which exists mainly in asian countries?

Answer 11

Removing shoes before entering house

Question 12

When is a standard precaution used? What are 4 types of standard precautions?

Answer 12

Used when contact with patient blood or bodily fluid is anticipated
Gloves, Gown, Mask/Eye protection/Face shield, Environmental (routine cleaning/disinfection of environmental surfaces)

Question 13

What are the two main cancer vaccines on the market today?

Answer 13

1. HBV (first cancer vaccine)

2. HPV

Question 14

Approximately what percentage of the population need to be vaccinated for herd immunity to work?

Answer 14

80%

Question 15

What are the 2 highest, 4 intermediate, and 3 lowest factors that are contributing to antimicrobial resistance?

Answer 15

Highest
1. Human antimicrobial misuse/overuse
2. Animal antimicrobial misuse/overuse
Intermediate
1. Healthcare transmission
2. Suboptimal dosing
3. Environmental contamination
4. Suboptimal vaccination
Lowest
1. Suboptimal rapid diagnostics
2. Travel
3. Mass drug administration for human health

Question 16

Use of antibiotics is the single most important factor for what two things?

Answer 16

1. Resistance

2. C. Diff infections (~500K/year)

Question 17

What are the different phases of a pandemic?

Answer 17

Phases 1-3: Predominantly animal infections with few human infections
Phase 4: Sustained human to human transmission
Phase 5-6 (Pandemic): Widespread human infection
Post-Peak: Possibility of recurrent events
Post-Pandemic: Disease activity at seasonal levels

Question 18

What are the two ways that an infection dies out?

Answer 18

1. People die

2. People gain immunity

Question 19

What does the basic reproduction number tell us?

Answer 19

R>1 => spread of infection

R<1 => containment of infection

Question 20

What is the reservoir for MERS?

Answer 20

Camels

Question 21

What are some examples of internationally notifiable infectious diseases?

Answer 21

Plague, cholera, yellow fever, smallpox, wild type poliovirus, SARS, and novel influenza

Question 22

What is isolation?

Answer 22

Restriction of movement/separation of a sick infected person with a contagious disease

Question 23

What is quarantine?

Answer 23

Restriction of movement/separation of a well person(s) presumed exposed to a contagious disease