Emerging Infectious Diseases

Question 1

Define an emerging disease.

Answer 1

Previously UNKNOWN disease that suddenly appears or a KNOWN disease that suddenly appears.

Question 2

Define a re-emerging disease.

Answer 2

A KNOWN disease that was previously declining.

Question 3

How are diseases detected?

Answer 3

Public*
Farmers*
Health care worker
Veterinarian
Pathologist
Epidemiologist
Academic

*Do not overlook these, they are often the first to notice a change.

Question 4

Who investigates (re-)emerging diseases?

Answer 4

State/Provincial and federal agencies.

Question 5

Who responds to (re1)emerging diseases?

Answer 5

National, provincial, international, agencies and industries.

Question 6

What are the 5 stages of cross-species disease emergence?

Answer 6

1. Pathogen is exclusive.
2. Reservoir transmits, but no transmission among new host species
3. Reservoir transmits, with a few cycles of transmission among the new host species.
4. Reservoir transmits, sustained transmission within the new host species.
5. Pathogen exclusive to new host species/reservoir.

Question 7

What are some examples of Stage 2 of cross-species disease emergence?

Answer 7

Rabies (reservoir = carnivore; dead end host = cattle and horses)
WNV, EEEV, WEEV (reservoir = birds; dead-end hosts = humans, horses and dogs)
Influenza H5N1 (reservoir = waterfowl and poultry; dead-end hosts = humans)

Question 8

What are some examples of Stage 3 of cross-species disease emergence?

Answer 8

Mycobacterium bovis (reservoir = cattle, bison, elk; poor human-human transmission)
Nipah Virus (reservoir = fruit bats; human-human and pig-pig transmission)

Question 9

What are some examples of Stage 4 of cross-species disease emergence?

Answer 9

SARS (Reservoir = fruit bats; efficient transmission to humans)
Schmallenberg Virus (resevoir species unknown, efficient transmission in sheep, goats and cattle)
2009 Influenza H1N1 "Swine Flu" (reservoir = swine; very efficient transmission in humans)

Question 10

What are some examples of Stage 5 of cross-species disease emergence?

Answer 10

HIV/AIDs, Measles, Smallpox, Dengue fever, Yellow fever

Question 11

What are the 4 drivers to pathogen emergence?

Answer 11

Land use changes
Food and ag systems
Environmental systems
Human behaviour

Question 12

What are the 4 determinants of emergence?

Answer 12

Pathogen
Reservoir
Transmission
Host

Question 13

What is the most important pathogen type?

Answer 13

Viruses

Question 14

What percentage of known human pathogens are zoonotic?

Answer 14

61%

Question 15

In what ways does a pathogen adapt?

Answer 15

Antibiotic resistance, increased virulence, mutations, evasion of host immunity.

Question 16

How does phylogenetic distance affect the reservoir determinant?

Answer 16

Pathogens are more likely to cross between closely related species. If a pathogen crosses between distantly related species, it often causes very different and more sever disease.

Question 17

What diseases does new host susceptibility apply to?

Answer 17

All diseases.

Question 18

How does intensive agriculture affect new host susceptibility?

Answer 18

Genetically similar hosts managed under the same conditions will have the same susceptibility.

Question 19

What factors increase transmission?

Answer 19

Increasing abundance of the reservoir, increasing pathogen prevalence, increasing contact between reservoir and new host.

Question 20

What are the 4 portals of entry for trans boundary diseases?

Answer 20

Animals/animal products
Vectors
Fomites
People

Question 21

What is a major culprit of increasing transmission?

Answer 21

Animal trade

Question 22

What two ways have development and changing ecosystems increased transmission?

Answer 22

Urbanization increasing population density and changing land use changes the climate.

Question 23

How has travel and tourism increase disease transmission?

Answer 23

More exposure to exotic diseases, animal-based tourism increases contact with both domestic and wildlife species.

Question 24

What is transmission from intentional release?

Answer 24

Bioterrorism, bio-crimes and agroterrorism.

Question 25

How does the veterinary field contribute to emerging disease prevention?

Answer 25

Responsible antimicrobial use, educating clients and public, healthy pets = healthy owners, healthy food animals = reduced pathogen burden at slaughter, food inspection, biosecurity.

Question 26

How does the veterinary field contribute to emerging disease surveillance, identification and prediction?

Answer 26

Vets can detect early-stage outbreaks, vets work in many different fields at different levels to help keep an eye on things and develop better tests and vaccines.

Question 27

How does the veterinary field contribute to emerging disease control?

Answer 27

USDA emergency response corps, VMAT teams (state and local).

Question 28

How are animal disease outbreaks typically controlled?

Answer 28

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