Chapter 9: Principles Of Infectious Disease And Epidemiology

Question 1

Opportunistic pathogen

Answer 1

Pathogen that only causes disease when host is weakened in some way
-usually from a shift in microbiota or weakened immune system
Ex: Candida albicans and Clostridium difficile

Question 2

True pathogen

Answer 2

Pathogen does not require a weakened host

Ex: Salmonella, Listeria, E.Coli

Question 3

Communicable disease

Answer 3

Diseases that are able to mutate and spread human to human

Ex: Ebola, Influenza, Mumps, Norovirus, Coronavirus, Pertussis, Tuberculosis

Question 4

Noncommunicable disease

Answer 4

Chronic diseases not passed human to human
-long duration
-slow progression
Ex: diabetes, cancer, cardiovascular diseases

Question 5

Acute disease

Answer 5

Any illness or disease that develops quickly, is intense or severe, and lasts a short period.
-Usually responds to therapy
Ex: pneumonia, SARS, appendicitis, strep throat

Question 6

Chronic disease

Answer 6

Disease or illness that has a slow onset and progression
-lasts for 3 months or longer
-requires ongoing medical treatment
-limits daily activities
Ex: diabetes mellitus, cancer, heart disease, Alzheimer’s, stroke

Question 7

Endemic

Answer 7

Disease or illness that is always present in a certain population or region in low levels
Ex: malaria in Brazil, chicken pos in U.S.

Question 8

Sporadic disease

Answer 8

Disease that happens irregularly and is separated widely in time and place

• may be starting point of an epidemic
• ex: CJD and other prion diseases, plague, rabies, tetanus, Ebola

Question 9

Pandemic

Answer 9

Epidemic that spreads to numerous countries

Question 10

Epidemic

Answer 10

Widespread disease outbreak in a particular region during a specific time frame

Question 11

Emerging disease

Answer 11

A disease that is newly appeared or is already existing yet has spread to new regions/populations
Ex: Zika, HIV, SARS, Lyme, West Nile, E.Coli

Question 12

Re-emerging disease

Answer 12

Was previously under control due to prevention efforts and treatment yet is resurfacing
-has mutated to withstand previous treatments
Ex: multi-drug resistant tuberculosis, malaria, cholera, pertussis, influenza, gonorrhea

Question 13

Koch’s 4 postulates of disease

Answer 13

1. Same organism must be present in every case of disease
2. Organism must be isolated from the diseased host and grown as a pure culture
3. Isolated organism should cause the disease in question when inoculated into a susceptible host
4. Organism must then be re-isolated from the inoculated diseased animal

Question 14

Limitations of Koch’s postulates

Answer 14

1. Doesn’t apply to non infectious diseases (not caused by pathogens)
2. Not all infectious agents can be grown in a lab setting
3. Obligate intracellular pathogens cannot be cultured due to needing host cells
4. Cultured microbes are able to attenuate/lose disease causing ability
5. Cannot be used on human specific agents (HIV)
6. Not every microbe leads to active infection and signs/symptoms may never emerge

Question 15

6 different categories of pathogens

Answer 15

Helminths
Protozoan
Fungi
Bacteria
Viruses
Prion

Question 16

Helminths

Answer 16

Eukaryotic, parasitic worms (multi-cellular)

-hookworms, pinworms, trichinosis

Question 17

Protozoan

Answer 17

Eukaryotic, parasites (unicellular)
-possess animal like behavior (motility, lack cell wall, ingest food particles)
Ex: amoeba

Question 18

Fungi

Answer 18

Eukaryotic, multicellular or unicellular

Ex: histoplasmosis, tines pedis (athelete’s foot)