Bats, Rats, Monkeys... Oh My!
How Animals Impact Human Health
Andrew Clements, Ph.D.
USAID/Bureau for Global Health,
Avian Influenza and Other Emerging Threats Unit
October 8, 2010
USAID Global Health Mini-University
Examples of Common “Human” Pathogens
with Evolutionary Origins in Animals
Disease
AIDS
Dengue fever
Diphtheria
Hepatitis
Influenza
Pathogen
Original Host
HIV-1, HIV-2
Monkeys/apes
Primates
Dengue fever viruses
Corynebacterium diphtheriae bacteria Probably domestic herbivores
Apes
Hepatitis B virus
Influenza A viruses
Wildfowl
Malaria
Plasmodium parasites
Birds and/or monkeys
Measles
Measles virus
Sheep/goats
Plague
Yersina pestis bacteria
Rodents
Trypanosoma brucei parasite
Wild ruminants
Variola virus
Ruminants (possibly camels)
Rickettsia prowazeckii
Rodents
Yellow fever virus
Primates
Sleeping sickness
Small pox*
Typhus
Yellow fever
Source: Wolfe et al. 2007. Nature 447(7142):279-283. * Eradicated in 1980.
Examples of Other Animal Diseases that
Periodically Affect Human Populations
Disease
Avian Influenza
Pathogen
Original Host
H5N1 influenza A virus
Ebola Hemorrhagic Fever
Marburg Hemorrhagic Fever
Ebolavirus
Birds
Bats?
Marburgvirus
Bats?
Monkey pox
Orthopox virus
Squirrels/rodents?
Nipah
Nipah virus
Bats
Rift Valley Fever
RVF virus
Livestock
SARS coronavirus
Bats/palm civets
West Nile virus
Birds
Severe Acute Respiratory Syndrome
West Nile Fever
Sources: Wolfe et al. 2007. Nature 447(7142):279-283; WHO
Emerging Infectious Diseases (EID)
Retrospective analysis of 335
EID events (1940-2004)
• EID events have risen significantly
over time
• ~60% of EIDs originated in
animals
Global distribution of relative risk of an event caused by zoonotic
pathogens from wildlife
 ~70% of these from wildlife
 bats, rodents, non-human
primates most often associated
with EIDs from wildlife
• EID origins significantly correlate
with socio-economic, environmental
and ecological factors
Global distribution of relative risk of an event caused by zoonotic
pathogens from domestic animals
 limited detection/reporting
capacity in geographic “hot spots”
for EID emergence
Global trends in emerging infectious diseases, K. Jones et al, 2008, Nature, Vol 451.21
Current Public Health Systems
• Often use “vertical” programs focused on specific
infectious diseases that commonly affect humans
• Weak linkages with wildlife and domestic animal health
• Emerging infectious diseases in animal populations often
not detected until there is an unusual cluster of human
cases
• Limited ability to adapt to detecting and containing new
diseases in human population
• Slow response to new diseases that efficiently spread
from person to person can result in regional epidemics or
pandemics (e.g. SARS, 2009 H1N1 flu)
Human Pandemics of the
20th and 21st Century
Pandemic*: worldwide epidemic of a disease that may occur when a new
pathogen appears against which the human population has no immunity
Disease
Time
Period
Original Host
Impact
H1N1 influenza A
1918-1919
HIV/AIDS
~1930-2010
Birds?
Monkeys
~50 million deaths
>25 million deaths
H2N2 influenza A
H3N2 influenza A
1957-1958
Birds and mammals?
~1-2 million deaths
1968-1969
Birds and mammals?
~1-2 million deaths
2003
Bats/palm civets
2009-2010
Swine
~800 deaths; >$80 billion
in economic losses
TBD
SARS
H1N1 influenza A
* WHO
Shifting from Public Health to “One Health”
Animal Health
Public Health
Surveillance/Response Surveillance/Response
Wildlife Health
Surveillance/Response
domestic
animal
outbreak
C
A
S
E
S
Crossspecies
transmission
wild
animal
outbreak
wild
animal
outbreak
TIME
Crossspecies
transmission
Crossspecies
transmission
wild
animal
outbreak
wild
animal
outbreak
human
cases
Public Health Benefits of Earlier Detection
Animal Health
Public Health
Surveillance/Response Surveillance/Response
Wildlife Health
Surveillance/Response
C
A
S
E
S
Crossspecies
transmission
wild
animal
outbreak
wild
animal
outbreak
TIME
wild
animal
outbreak
domestic
animal
outbreak
wild
animal
outbreak
Crossspecies
transmission
human
cases
H5N1 Avian Influenza:
“Chasing Chickens for Public Health”
USAID programmed ~$550 million
between 2005 and 2010
10000
Worldwide H5N1
poultry outbreaks
Key outcomes:
1. Faster confirmation times for poultry and
wild bird outbreaks
 decreased outbreak size
 fewer subsequent outbreaks
 fewer people exposed to virus
1000
100
Worldwide H5N1
human cases
2. Cross-sectoral collaboration improved
 Animal outbreaks often used to trigger
search for possible human cases
Public health impact: fewer human cases
and better treatment/containment,
decreases chances of virus acquiring ability
to efficiently move from person to person
10
2003/ 2005 2006 2007 2008 2009 2010
2004
Year
Sources: OIE, FAO, and WHO reports through 8/3/10.
USAID: Expanding Beyond Avian Influenza
Pandemic
Prevention
Pandemic
Preparedness
Pandemic
Response
(2007-2010+)
(2009)
(2005-2010+)
Emerging
Pandemic
Threats
(2009-2014)
mostly Asia; some
Africa and E. Europe
C. Africa, Amazon,
SE Asia, So. Asia
mostly Africa, Asia
mostly Africa, Asia
poultry and
human surveillance
and response,
communications,
commodities for
containment
wildlife and
human surveillance
and response,
risk determination
and reduction
pandemic planning
for civil society
and military;
linked to disaster
preparedness
planning & provision
of equipment needed
for delivery of
donated H1N1
pandemic
vaccine
Avian
Influenza
~$350-400 million over 5 years
AI and Other Emerging Threats Programs managed by USAID/GH’s
Avian Influenza and Other Emerging Threats Unit.
Risk-Based Focusing of USAID Emerging
Pandemic Threats (EPT) Program
EPT Focus:
All
countries
All
pathogens
All
animals
• 4 regional “hot spots”
• diseases from bats,
rodents, non-human
primates
• pathogens TBD
USAID EPT Program
Objective:
• pre-empt or contain diseases that could spark future pandemics
Key Areas of Emphasis:
• Wildlife pathogen detection*: Identification of target pathogens in
wildlife that threaten humans
• Risk Determination*: Characterization of potential risk and method
of transmission for specific diseases of animal origin
• Routine Surveillance and Outbreak Response**: Support for
sustainable country-level response for control of “normative”
diseases
• Risk Reduction**: Promotion of actions that minimize or eliminate
the potential for the emergence and spread of new disease threats
* Represent activities related to wildlife that have generally been missing or underfunded
** Normative functions associated with animal and public health systems
Summary
1.
Over time, a variety of infectious diseases new to humans
have been “crossing over” from animal populations
 trend expected to continue
 some animal diseases cause deadly and/or disruptive human
pandemics
2. In order to adapt to emerging threats, public health systems
need to take a more-proactive approach to surveillance and
response which includes improving linkages to wildlife and
animal health sectors
3.
Promoting a “One Health” approach with USAID’s Emerging
Pandemic Threats program will contribute to improving:
–
–
detection and response to emerging threats
overall public health functions including detection and
response to common diseases