Epidemiology & Control

Question 1

What is epidemiology?

Answer 1

branch of medical science that studies factors which determine the presence & absence of diseases & disorders

Question 2

Why is Ascaris a relatively simple parasite to model?

Answer 2

direct, no IH, no amplification

Question 3

Define per capita reproductive rate.

Answer 3

r: # of eggs produced per worm

Question 4

Define net reproductive rate.

Answer 4

rA

Question 5

Define per capita transmission rate.

Answer 5

beta: likelihood eggs will get into a host & develop into adults

Question 6

Which model components describe parasite reproduction and transmission?

Answer 6

rA = net reproduction & beta = transmission

Question 7

Which model components describe parasite elimination?

Answer 7

u1 and u2

Question 8

What balance must be maintained for the parasite to survive in the host population?

Answer 8

reproduction (rA) & transmission (beta) > elimination (u1 & u2)

Question 9

What host behaviors must be considered in the development of a model?

Answer 9

1. contact 2. # of eggs 3. # of hosts

Question 10

How can our model be applied to the eradication of Ascaris?

Answer 10

increase parasite elimination (Au1 with drugs) and decrease beta (behavior education and drugs)

Question 11

Would you target parasite elimination or transmission?

Answer 11

transmission

Question 12

What is Ro?

Answer 12

basic reproductive ratio: avg # of secondary cases that a typical single infected case will cause

Question 13

How is Ro related to our success in eradication specific diseases?

Answer 13

Ro = 1 is the threshold of parasite survival

Question 14

Define control.

Answer 14

pathogen continues to exist, but prevalence reduced as consequence of intervention

Question 15

Define eradication.

Answer 15

pathogen no longer exists anywhere in the world…seldom realistic

Question 16

Define elimination.

Answer 16

localized eradication: pathogen no longer exists in a specific geographical region

Question 17

When was smallpox eradicated?

Answer 17

1980

Question 18

Explain why the smallpox eradication campaign was so successful.

Answer 18

1. because Ro is only 2 2. long lasting immunity 3. vaccine 4. absence of animal reservoir 5. gov cooperation 6. funding

Question 19

What was the one key factor in smallpox eradication?

Answer 19

vaccine: 1. long lasting protective immunity 2. single dose 3. easily administered 4. easy delivery & edu campaign 5. fear of disease -> public acceptance

Question 20

Have any vaccines against parasites been developed?

Answer 20

no

Question 21

Why is Dracunculus so close to possible eradication?

Answer 21

education & other control methods

Question 22

What factors in developed countries have contributed to elimination of many human parasites?

Answer 22

1. increased living standards 2. sanitation & hygiene 3. effective waste disposal 4. improved meat inspection

Question 23

What are the 2 best approaches for most campaigns which are aimed at eliminating or eradication parasites?

Answer 23

education and control