The document discusses emerging and re-emerging viruses. It defines emerging infections as newly appeared in the population or existing infections that are rapidly increasing in incidence or geographic range. Examples are provided. The process of emergence involves the introduction of an agent into a new host population from the environment, another host species, or a variant of an existing human infection, followed by establishment and dissemination in the new host population. Agent-related factors like microbial adaptation and virulence, as well as host-related factors like susceptibility and human behavior, influence emergence. Environmental factors such as changing ecosystems, economic development, technology, and international travel can also drive disease emergence.

1. emerging and re-
emerging viruses
Monday, February 6, 2012

2. what are emerging infections?
Newly appeared in the population
Have existed but are rapidly increasing in
incidence or geographic range
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

3. EXAMPLES
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4. Monday, February 6, 2012

5. Monday, February 6, 2012

6. PROCESS OF EMERGENCE
Introduction of the agent into a new host
population, originating from:
environment
another host species
variant of an existing human infection
Establishment and further dissemination within
the new host population
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

7. AGENT-RELATED FACTORS
Microbial adaptation
Mutation
Natural selection
antibiotic-resistant bacteria
Evolutionary progression
Virulence factors
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

8. HOST-RELATED FACTORS
Human Human behavior
Susceptibility and demographics
immune status Affect disease
dissemination
nutrition
age
occupation, etc.
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

9. environment-related
factors
(#1) Changing ecosystems / land use
Argentine, Bolivian hemorrhagic fever
changes in agriculture (grassland to maize) favoring rodent host
Hantaviruses
Ecological or environmental changes increasing contact with
rodent hosts
Rift Valley fever
agriculture, irrigation
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

10. environment-related
factors
(#2) Economic development
Dengue/DHF
urbanization favoring mosquito vector
Lassa fever
urbanization favoring rodent hosts, increasing
exposure
Rift Valley fever
dam building
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

11. environment-related
factors
(#3) Technology and industry
Hepatitis B and C
transfusions, organ transplants
Influenza (pandemic)
possibly pig-duck agriculture
facilitating reassortment
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

12. environment-related
factors
(#4) International travel and commerce
Dengue/DHF
Ebola, Marburg
In Europe and US, importation of monkeys
HIV
Influenza (pandemic)
SARS
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012

13. environment-related
factors
(#4) International travel and commerce
Dengue/DHF
Ebola, Marburg
In Europe and US, importation of monkeys
HIV
Influenza (pandemic)
SARS
from PH 301 lectures of Lilen Sarol, PhD
Monday, February 6, 2012