26. Epidemiology

Question 1

What is epidemiology?

Answer 1

• scientific study of the distribution and determinative factors related to diseases and other states of human health
  
  • “where” and “when” do these cases occur

Question 2

Define endemic

Answer 2

• number of cases of a particular disease is consistent over time
  
  • within a county/ community

Question 3

Define a epidemic

Answer 3

-increase in cases over a large area, multiple geographical locations in a single continent

Question 4

Define an outbreak

Answer 4

-sudden increase in cases limited to a specific geographical area

Question 5

What are the determinative factors related to disease? (2)

Answer 5

• causes: single event/factor

- risk factors: multiple

Question 6

Define reservoir. Examples?

Answer 6

• location in which the pathogen is found before the host is exposed to the pathogen.
  
  • soil, water in the environment, wildlife, infected person

Question 7

What are two broad categories of transmission modes?

Answer 7

-direct transmission and indirect transmission

Question 8

What is direct transmission and the two modes?

Answer 8

• require a susceptible host come in close contact with and the pathogens reservoir.
  
  • Direct Contact: a skin or mucous membranes of the host touch the reservoir
  • droplet transmission: whenever a person sneezes, coughs, or talks, microscopic droplet of saliva and respiratory secretions are released into the air

Question 9

What is indirect transmission and the 3 modes?

Answer 9

• allow for a pathogen to move from a reservoir to a host by means of an intermediary
  
  • airborne
  • vector
  • vehicle

Question 10

What is airborne transmission?

Answer 10

-occurs when pathogens are carries in the air in suspended particles

Question 11

What are vectors? Types (2)?

Answer 11

• invertebrate animals which carry pathogens
  
  • ex. Mosquitos,ticks, fleas
• Biological vectors:serve part of the lifecycle for the pathogen
  
  • protozoan that cause malaria must first sexually reproduce inside mosquitos
• Mechanical vectors:carry pathogens,but are not required for part of the pathogens life cycle
  
  • ex.fly lands on untreated sewage and lands on your food

Question 12

What is vehicle transmission?

Answer 12

• all other forms of indirect transmission
  
  • food
  • water
  • fomites

Question 13

What is fecal oral transmission?

Answer 13

-a pathogen exits a reservoir host in fecal matter and it eventually enters a new host through the mouth

Question 14

What is vertical transmission?

Answer 14

• special case of direct transmission where a pathogen is transmitted from parent to their child
  
  • can occur in utero if a pathogen crosses the blood placenta barrier

Question 15

What is SFI?

Answer 15

• Staphylococcal food intoxication

- caused by the consumption of food in which S. Aureus bacteria have grown and secreted enterotoxins