PREDICT: Emerging Pandemic Threats Program New Initiatives in Surveillance: The USAID EPT “PREDICT” Project Stephen S. Morse Co-Director, PREDICT Columbia University & University of California, Davis IOM Symposium on “Emerging Infections, Microbial Threats to Health, and the Microbiome” December 12, 2012
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PREDICT: Emerging Pandemic Threats Program
New Initiatives in
Surveillance: The USAID
EPT “PREDICT” Project
Stephen S. Morse Co-Director, PREDICT
Columbia University & University of California, Davis
IOM Symposium on “Emerging Infections,
Microbial Threats to Health, and the Microbiome” December 12, 2012
• Increasing changes in land use, allowing more opportunities
for exposure to previously unfamiliar species and pathogens
• Likely result: Increase in emerging infections
PREDICT: Emerging Pandemic Threats Program
Host Jumping: What Determines Host
Range?
• No simple answer, likely varies with the
pathogen and the host interaction
For example:
• Flu: Receptor binding necessary but not
sufficient
• Coronaviruses: Receptor binding seems
sufficient
• HIV: Requires co-receptor (chemokine
receptor)
PREDICT: Emerging Pandemic Threats Program
Predicting Pandemic Potential:
Host-Pathogen Interactions
• Host-receptor interactions: Necessary but not always sufficient – Changing receptor affinity (from avian to mammalian-type)
was the first step in the recent laboratory work adapting H5N1 avian influenza virus to mammalian transmission
– But other mutations were also required
– However, highly host-specific receptor structures may provide a significant barrier to infection of a new host
• Why are some viruses relatively benign in their natural hosts, but induce hyperinflammatory responses in a new host? (E.g., Ebola or Nipah viruses in humans) – Research to test in cell cultures, humanized mice
PREDICT: Emerging Pandemic Threats Program
Predicting Pandemic Potential:
Requirements for Human Infection
• Relative importance (or “success rate”) of
host relatedness versus contact frequency:
– e.g., HIV-1 (from chimpanzees), vs. SARS (from bats and civets), Nipah (from bats and pigs), or influenza (from pigs and birds)
• Is an animal virus that is more closely related to a known human pathogen more likely to infect people?
– Paramyxoviruses possible examples
– But most viral families’ potential recognized only after the fact
PREDICT: Emerging Pandemic Threats Program
Predicting Pandemic Potential:
Pathogen Factors
• Association between emergence and a broad host
range?
• Estimates of viral ‘evolvability’: Role of high mutability
in pathogen success?
• Patterns of host-virus co-evolution. Relationships
can be assessed by genetic sequence comparisons
– Strong patterns of co-evolution over recent evolutionary
time suggest stable long term interactions
• Is history destiny? Require better understanding
of the pathogen’s history
PREDICT: Emerging Pandemic Threats Program
Transmissibility
• Essential for pathogen success
• Possible relation to virulence
• Genetics and evolution of transmissibility
poorly understood
• In many cases, even mechanisms of
transmission poorly understood
• Human behavior very important factor
PREDICT: Emerging Pandemic Threats Program
Crossing the Animal-Human Interface
• To evaluate public health importance,
need the other side of the story: identifying
which of these animal microbes infect
humans
• What mechanisms promote or inhibit
transfer across interfaces?
• Commonalities: What do the successful
pathogens have in common?
PREDICT: Emerging Pandemic Threats Program
“Pathogen discovery” is
only one part of PREDICT
Other key objectives include:
• Surveillance: Sampling, testing, data
collection
• Building capacity for surveillance in
developing countries
• Better understanding the biology and
ecology of emergence and microbial
background
PREDICT: Emerging Pandemic Threats Program
It’s Not Only Technical Challenges
Besides continuing improvement in
technology and surveillance coverage:
• Sustaining capacity
• Political will
• Avoiding complacency
• Maintaining resources
PREDICT: Emerging Pandemic Threats Program
THANK YOU …
Sincere thanks to all our colleagues
USAID and the PREDICT team
• Drs. Dennis Carroll, Murray Trostle, Andrew Clements, Alisa
Pereira, Rob Henry, August Pabst, Julian Brown, USAID EPT
mission liaisons
• Dr. Jonna A.K. Mazet (Co-Director & PI, University of
California, Davis); Drs. Peter Daszak, William Karesh, and
colleagues at EcoHealth Alliance; Dr. Damien Joly and
colleagues at WCS; Drs. Nathan Wolfe, Joseph Fair and
colleagues at Global Viral/Metabiota; Drs. Suzan Murray, Chris
Whittier, and colleagues at SI; PREDICT Country
Coordinators; and many others
• Drs. Mark Woolhouse, Colin Parrish (Cornell), Ralph Baric
(UNC), Ian Lipkin, and Mark Buller (St. Louis University)