Emerging infectious diseases

Question 1

What percentage of newly emerging diseases are zoonotic?

Answer 1

~ 75%

Question 2

A previously unknow disease that suddenly appears in a population is known as what?

Answer 2

Emerging dz

Question 3

A known disease that suddenly appears in a new population is known as what type of disease?

Answer 3

Emerging

Question 4

What is a re-emerging disease?

Answer 4

A known disease, previously on the decline, that is becoming more common and will likely to continue to do so

Question 5

What are the three steps taken to act against emerging diseases?

Answer 5

Detection: identifies something abnormal or unusual/ dx dilemma
Investigation: communicates dz importance
Response: implementation of dz control/management

Question 6

What are the stages of cross-species disease emergence?

Answer 6

1. pathogen exclusive to an animal reservoir
2. animal reservoir transmits to humans/other animals, but no transmission among them (like a dead end host)
3. animal reservoir transmits to humans/other animals with a few cycles of transmission among them
4. animal reservoir transmits to humans/other animals with sustained transmission among them.
5. pathogen exclusive to humans/new animal reservoir

Question 7

What percentage of known pathogens on have one host?

Answer 7

~ 37%

Question 8

Besides economic costs, what other costs can outbreaks of emerging dz cause?

Answer 8

Emotional, physical (toll on victims, stress on family members of those effected etc), life lost (victims, animals that must be culled, Loss of genetic lines (when culling animals ) etc

Question 9

What two factors are combined to rank the risk of dz/virus spill over? (“anticipating the jump”)

Answer 9

Virus independent traits + Virus specific traits = risk of spill over

Question 10

What are examples of land use changes that drive pathogens to emerge?

Answer 10

Encroaching into natural environments: deforestation and habitat fragmentation

Practices like: fracking, dredging, quarrying, mining beach sand

Question 11

How does urbanization play a role in driving pathogens to emerge?

Answer 11

Increases density of susceptible human populations

Question 12

Changing land use and climate influence _____ borne and ________ borne disease transmission

Answer 12

Waterborne and vector-borne

Question 13

What are some examples of food and agricultural systems practices that drive pathogens to emerge?

Answer 13

Using human sewage as fertilizer (2nd/3rd world countries)
Global trade - carries pathogens across the world
management practices and biosecurity on farms: what happens with animal waste, vaccine protocols, mixing of animals etc

Question 14

What negative effects can an increase in livestock production have in regards to emerging diseases?

Answer 14

Results in uniform genetics, production, and susceptibility to diseases/infections

increased density of herds promotes transmission

Question 15

What are the four major determinants of emergence?

Answer 15

Host: susceptibility
Pathogen: type of agent
Reservoir: phylogenetic distance
Transmission: reservoir size, pathogen prevalence, contact frequency

Question 16

T/F: zoonotic pathogens are twice as likely to be associated with emerging diseases

Answer 16

TRUE

Question 17

What percentage of KNOWN pathogens that infect humans, are zoonotic?

Answer 17

61%

Question 18

What pathogen adaptations promote emergence?

Answer 18

Increased AB resistance
Increased virulence
Mutations that enhance transmissibility within or between species
Evasion of host immunity

Question 19

T/F: Pathogens are less likely to cross between closely related species than distant ones

Answer 19

FALSE

more likely

Question 20

T/F: Pathogens that some how cross between distantly related species often cause very different, often MORE severe disease

Answer 20

TRUE

Question 21

What factors will increase the probability of transmission from a reservoir to a new host?

Answer 21

Increase in abundance of the reservoir
Increasing pathogen prevalence in the reservoir
increasing contact between the reservoir and new host

Question 22

How are animal disease outbreaks typically controlled?

Answer 22

Mass culling
Test and slaughter
Quarantine
Vaccination / ring vaccination
Prophylactic antibiotic use