S1 - Infectious Disease Basics

Question 1

Define epidemic.

Answer 1

An epidemic is a period of time with a higher than expected incidence rate but over a broader geographic region.

Question 2

Define endemic.

Answer 2

The term endemic refers to a region where there is a persistent baseline incidence and prevalence rate.

Question 3

Define pandemic.

Answer 3

A pandemic is an epidemic where the disease is being actively transmitted on multiple continents.

Question 4

Define outbreak.

Answer 4

An outbreak is defined as a higher than expected incidence rate tied to a geographic focal point.

Question 5

What are some modes of infectious disease transmission?

Answer 5

Airborne
water-borne
fecal-oral 
vector-borne
fomite
perinatal 
food-borne 
animal bites 
sexual transmission

Question 6

Define incubation period.

Answer 6

The time between being infected with a pathogen and showing symptoms (Actively dividing pathogen)

Question 7

Define latency period.

Answer 7

The time between being infected with a pathogen and showing symptoms (Non-actively dividing pathogen)

Question 8

What is the difference between the latency period and the incubation period?

Answer 8

In an incubation period, the pathogen is actively dividing. In a latency period, it is not.

Question 9

Define infectious dose.

Answer 9

The number of a certain type of pathogenic microb needed in order to cause disease in an infected individual.

Question 10

What is the difference between eradication and elimination?

Answer 10

Eradication refers to the complete removal of a disease from the world (E.g. smallpox).

Elimination refers to the complete removal of a disease from a specific geographic region (E.g. polio).

Question 11

Define pathogen.

Answer 11

A microorganism that can cause disease.

Question 12

Are all infectious diseases widely contagious?

Answer 12

No (Think botulism or tetanus). They are infectious but not widely transmissible from person to person.

Question 13

Describe fomite transmission.

Answer 13

Touching surface, object or person

Question 14

Describe airborne transmission.

Answer 14

Respiratory drops in the air (Due to sneezing, coughing, breathing)

Question 15

Describe vector-borne transmission.

Answer 15

Carried by non-host species to host (Typically insects)

Question 16

Describe fecal-oral transmission.

Answer 16

Ingesting microscopic amounts of contaminated fecal matter

Question 17

What are some other types of modes of transmission?

Answer 17

Water-borne
Perinatal (mother to child) 
Food-borne 
Animal bites (Zoonotic)
Sexual transmission

Question 18

What are anti-helminthic drugs?

Answer 18

Anti-parasitic drugs

Question 19

What are antibiotic drugs?

Answer 19

Drugs that kill bacteria or interfere with bacterial growth

Question 20

What is a non-pharmacological intervention?

Answer 20

Non-drug related treatments.

E.g. hand washing, exercise, isolation of infected individuals

Question 21

What are the characteristics of a bacteria?

Answer 21

Prokaryotic cells that can both be helpful and harmful to humans. They reproduce on their own (Unlike viruses).

Helpful bacteria work as our microbiome and protect us and help us with digestion.

Question 22

What are the characteristics of a virus?

Answer 22

They are not alive. They are protein shells (Capsids made of protomers) that contain genetic material (Single- or double-stranded DNA or RNA) and require a host cell in order to replicate themselves. They hijack the host cell’s enzymes and other machinery.

Viral glycoproteins allow the cell to interact with host cells in order to inject their genetic material or to be completely endocytosed.

More complex viruses sometimes have a lipid coat around their capsid.

Question 23

What are the characteristics of a parasite?

Answer 23

Multicellular (Usually) eukaryotic organisms (Like us). Things like malaria, leishmaniasis, hookworm, guinea worm, etc.