Bats, Rats, Monkeys... Oh My! How Animals Impact Human Health

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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

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Examples of Common Human Pathogens with
Evolutionary Origins in Animals
Disease Pathogen Original Host
AIDS HIV-1, HIV-2 Monkeys/apes
Dengue fever Dengue fever viruses Primates
Diphtheria Corynebacterium diphtheriae bacteria Probably domestic herbivores
Hepatitis Hepatitis B virus Apes
Influenza Influenza A viruses Wildfowl
Malaria Plasmodium parasites Birds and/or monkeys
Measles Measles virus Sheep/goats
Plague Yersina pestis bacteria Rodents
Sleeping sickness Trypanosoma brucei parasite Wild ruminants
Small pox Variola virus Ruminants (possibly camels)
Typhus Rickettsia prowazeckii Rodents
Yellow fever Yellow fever virus Primates
Source Wolfe et al. 2007. Nature
447(7142)279-283. Eradicated in 1980.
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Examples of Other Animal Diseases that
Periodically Affect Human Populations
Disease Pathogen Original Host
Avian Influenza H5N1 influenza A virus Birds
Ebola Hemorrhagic Fever Ebolavirus Bats?
Marburg Hemorrhagic Fever Marburgvirus Bats?
Monkey pox Orthopox virus Squirrels/rodents?
Nipah Nipah virus Bats
Rift Valley Fever RVF virus Livestock
Severe Acute Respiratory Syndrome SARS coronavirus Bats/palm civets
West Nile Fever West Nile virus Birds

Sources Wolfe et al. 2007. Nature
447(7142)279-283 WHO
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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
• ? 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
• ? limited detection/reporting
• capacity in geographic hot spots
• for EID emergence

Global distribution of relative risk of an event
caused by zoonotic pathogens from wildlife
Global distribution of relative risk of an event
caused by zoonotic pathogens from domestic animals
Global trends in emerging infectious diseases, K.
Jones et al, 2008, Nature, Vol 451.21
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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)

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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 Birds? 50 million deaths
HIV/AIDS 1930-2010 Monkeys gt25 million deaths
H2N2 influenza A 1957-1958 Birds and mammals? 1-2 million deaths
H3N2 influenza A 1968-1969 Birds and mammals? 1-2 million deaths
SARS 2003 Bats/palm civets 800 deaths gt80 billion in economic losses
H1N1 influenza A 2009-2010 Swine TBD
WHO
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Shifting from Public Health to One Health
Public Health Surveillance/Response
CASES
human cases
TIME
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Public Health Benefits of Earlier Detection
Wildlife Health Surveillance/Response
CASES
wild animal outbreak
wild animal outbreak
wild animal outbreak
wild animal outbreak
TIME
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H5N1 Avian Influenza Chasing Chickens for
Public Health

• USAID programmed 550 million between 2005 and
  2010
• Key outcomes
• 1. Faster confirmation times for poultry and wild
  bird outbreaks
• decreased outbreak size
• fewer subsequent outbreaks
• fewer people exposed to virus
• 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

Sources OIE, FAO, and WHO reports through
8/3/10.
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USAID Expanding Beyond Avian Influenza
Pandemic Preparedness
Pandemic Response
Pandemic Prevention
Avian Influenza (2005-2010) mostly Asia
some Africa and E. Europe poultry and human
surveillance and response, communications,
commodities for containment
Emerging Pandemic Threats (2009-2014) C. Africa,
Amazon, SE Asia, So. Asia wildlife and human
surveillance and response, risk determination
and reduction
(2009) mostly Africa, Asia planning provision
of equipment needed for delivery of donated
H1N1 pandemic vaccine
(2007-2010) mostly Africa, Asia pandemic
planning for civil society and military linked
to disaster preparedness
350-400 million over 5 years

• AI and Other Emerging Threats Programs managed by
  USAID/GHs
• Avian Influenza and Other Emerging Threats Unit.

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Risk-Based Focusing of USAID Emerging Pandemic
Threats (EPT) Program
All countries
All pathogens
All animals
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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
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• Summary
• 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
• Promoting a One Health approach with USAIDs
  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