4 - Emerging Infectious Diseases

Question 1

What are Emerging Infectious Diseases (EIDs)

Answer 1

Infections that have recently appeared in a population, or previously existed but are now rapidly increasing in incidence, geographic range, or severity

Question 2

What are examples of EIDs

Answer 2

SARS-CoV-2 (COVID-19)

West Nile virus

Tuberculosis (reemerging)

Smallpox (historically significant, ~1200 years ago)

Question 3

Why is it important to study EIDs

Answer 3

Understand how and why diseases emerge

Improve prediction and preparedness

Prevent future pandemics

Recognise the link between human, animal, and environmental health

Question 4

What historical event is an early example of a deadly outbreak

Answer 4

The Plague of Megiddo (~1350 BC), mentioned in the Amarna Letters: “consumed by death, plague and dust”

Question 5

What is a zoonotic disease

Answer 5

A disease that is transmitted from animals to humans, often due to close contact or ecological disruption

Question 6

Name 4 examples of viral zoonotic diseases

Answer 6

Ebola

Rabies

Zika virus

Influenza

Question 7

Ebola

Answer 7

from bats or primates

Question 8

Rabies

Answer 8

via animal bites

Question 9

Zika virus

Answer 9

from mosquitoes, originally from primates

Question 10

Influenza

Answer 10

often originates in birds or pigs

Question 11

What is the “zoonotic pool”

Answer 11

The reservoir of pathogens in animals that have the potential to spill over into humans

Question 12

What are the two key steps in disease emergence

Answer 12

Introduction of the pathogen into a new host population

Establishment and dissemination within the new population

Question 13

How does deforestation contribute to EIDs

Answer 13

Increases human-wildlife contact, disrupts ecosystems, and alters vector habitats

Question 14

Describe the ecological changes that contribute to the emergence of EIDs

Answer 14

Habitat fragmentation
Biodiversity loss
Altered vector habitats
Responsible for ~31% of outbreaks

Question 15

What virus is linked to ecological change

Answer 15

Zika virus – spread linked to habitat and land use changes

Question 16

How does agricultural development influence EIDs

Answer 16

Creates vector breeding grounds (e.g. rice fields for mosquitoes)
Disrupts natural ecosystems
Linked to 25–50% of human EIDs

Question 17

What example links land use to disease

Answer 17

Malaria outbreaks linked to rice field irrigation

Question 18

How does climate change affect EID emergence

Answer 18

Alters vector/pathogen distribution
Expands habitats of vectors (e.g. ticks, mosquitoes)
Influences human behaviour and exposure risks

Question 19

What disease expanded due to climate change

Answer 19

Lyme disease – in Canada, cases rose from 144 in 2009 to 3,000 in 2022

Question 20

How does urbanisation affect EID risk

Answer 20

Overcrowding increases disease transmission

Half the world lives in urban centres, creating hotspots for outbreaks

Question 21

Give an example of an urban outbreak

Answer 21

Chikungunya in Dhaka, Bangladesh (2017)

Question 22

Globalisation, international travel and trade

Answer 22

Rapid spread of diseases across continents

Over 37 million international arrivals into the USA annually

One day of air travel can spread pathogens worldwide

Question 23

How does microbial mutation contribute to EIDs

Answer 23

Pathogens evolve to infect new hosts or become more virulent

Question 24

Example of a pandemic due to mutation

Answer 24

Spanish Flu (1918) – resulted from influenza virus evolution

Question 25

What is antibiotic resistance

Answer 25

The ability of microbes to survive drugs that previously killed them

Question 26

Example of antibiotic-resistant pathogen

Answer 26

Staphylococcus aureus – caused 130,000 deaths globally in 2021

Question 27

What is the One Health approach

Answer 27

A collaborative strategy across human, animal, and environmental health sectors to improve disease control and prevention

Question 28

Who launched the “One World, One Health” concept

Answer 28

The Wildlife Conservation Society in 2004

Question 29

Why is One Health needed

Answer 29

No single discipline can solve EID challenges alone Encourages cross-sector communication More effective resource use and public health outcomes

Question 30

What are the advantages of the One Health approach (6)

Answer 30

Identifies hotspots for emergence Improves sampling and testing strategies Enhances understanding of disease ecology Strengthens environmental risk assessments Provides evidence for zoonotic risk Maximises resources

Question 31

What is the role of surveillance in EID control

Answer 31

Helps predict emerging epidemics and improve early responses

Question 32

Name two vaccines developed due to EIDs

Answer 32

rVSV-ZEBOV for Ebola (2014) COVID-19 mRNA vaccines (e.g. Moderna)

Question 33

What is AMR and why is it concerning

Answer 33

Antimicrobial resistance – pathogens survive drug treatment Could cause 10 million deaths per year by 2050

Question 34

Give an example of drug-resistant disease

Answer 34

Drug-resistant malaria in Southeast Asia (resistant to artemisinin)