Transcript M.W. Service (1993) Mosquito Ecology: Field Sampling Methods

Global connections and disease
Laura C. Harrington, PhD
Department of Entomology
Goals for today
•Understand the underlying factors and connections
that lead to global emergence of new infections
•Recognize what types of pathogens are most likely
to emerge
Which of the following general
classes of human pathogens are most
likely to emerge rapidly with
globalization?
a.
b.
c.
d.
e.
Bacteria
Protozoa
Viruses
Fungi
Worms
Red represents newly emerging diseases; blue, re-emerging/resurging diseases; black,
a 'deliberately emerging' disease. Morens et al. 2004. Nature 430, 242-249.
What factors lead to emerging/re-emerging
pathogens?
Mutation of existing pathogens
Ex: Y. pseudotuberculosis - inserting mutations
in lab increases virulence
Host shifting
Influenza virus
H5N1
Highly diverse infecting both humans and animals
Can acquire genes readily from other animal viruses
Re-assortment of viral pathogens
Stevens et al. Nature Reviews Microbiology 4, 857-864 (November 2006) | doi:10.1038/nrmicro1530
Changing weather patterns and climate
Range expansion of vectors and disease
Changes in land use and agricultural practices
Rice paddy irrigation
Banana plantations
Dams
Clear cutting forests
Logging
Road building
unplanned urbanization and poor sanitation
Waste
Poverty
Breakdown of
health care infrastructure
War and conflict
Increasing contact between
humans and animals
rapid global travel
over 760 million international arrivals annually
Changes in human behavior/society
Drug abuse – HIV and other infections among intravenous drug
users in USA
Use of tampons - Toxic shock syndrome and
Staphylococcus aureus infection
Changes in technology
Use of new technology- air conditioning and
water cooling- Legionnaires’ disease (Legionella
pneomophila)
Food processing technology – food borne illness
Chikungunya
Global spread of the Asian Tiger mosquito
Pathogens transmitted by Ae. albopictus
Chikungunya virus
DEN 1-4 virus
Dog heartworm virus
Eastern Equine Encephalitis
Jamestown Canyon virus
Keystone virus
LaCrosse virus
Mayaro virus
Orapouch virus
Potosi virus
Rift Valley Fever virus
Ross River virus
Sinbis virus
Trivittatus virus
West Nile virus
Venezuelan Equine Encephalitis
Dog heartworm
CNN: Thousands hit by Brazil
outbreak of dengue (4/3/08)
Dengue vector
Aedes aegypti
•50-100 million dengue fever cases/year
•500,000 cases of DHF
•2/3 of world’s population at risk
An 11-year-old boy is seen by a military doctor last
weekend at a field hospital west of Rio de Janeiro, Brazil.
•among top global neglected diseases
No vaccine and no treatment for dengue
Cases per thousand
Increasing incidence of Dengue Infections Globally
1000
900
800
884
700
600
500
400
300
200
100
0
482
296
122
1
15
1955-59
1960-69
1970-79
1980-89
Years
1990-99
2000-05
WHO: Dengue Net 2006
Review – factors giving rise to global emergence
of human pathogens
•Mutation, re-assortment and host shifting
•Changing weather patterns and climate
•Changes in land use
•Unplanned urbanization and poor sanitation
•Poverty, war and breakdown of public health infrastructure
•Changes in human behavior and technology
•Increasing contact between humans and animals