Transcript Protocol for Cryptosporidium Risk Communication for Drinking

Protocol for Cryptosporidium
Risk Communication for
Drinking Water Utilities
Mitch Small, Baruch Fischhoff, Claire Palmgren, Felicia Wu, Elizabeth Casman
Center for Integrated Study of the Human
Dimensions of Global Change,
Carnegie Mellon University
CIS oƒ HDGC
Carnegie Mellon
Sponsored by a grant from the
American Water Works Association
Research Foundation
What is cryptosporidiosis?
Acute gastrointestinal disease
Caused in humans by an intracellular
protozoan parasite, Cryptosporidium
parvum
Symptoms include explosive watery
diarrhea, nausea, low-grade fever
Self-limiting in otherwise healthy hosts
Can be fatal in people with AIDS
No cure currently available
Small concentrations of Cryptosporidium
are likely to be found in many drinkingwater source and finished waters.
How should utilities report this information
to avoid misunderstandings?
• How can utilities communicate risk and uncertainty
while maintaining customer confidence?
• How can the utility be sure customers understand the
information?
Mental Models Methodology
• Depicts an individual’s beliefs regarding a
risk process and the options for addressing
the risk
• Identifies crucial gaps in information and
misunderstandings by contrasting the
mental model with an expert model
Mental Models Protocol
• Develop expert model of Cryptosporidium transmission
• Interview public about Cryptosporidium risk
• Develop lay public mental model of Cryptosporidium risk
• Compare lay knowledge with expert model to identify
significant gaps
• Create structured questionnaire incorporating critical facts
and gaps
• Create communication instrument
• Test success of communication
• Iteratively refine communication
CIS oƒ HDGC
Carnegie Mellon
Expert Model
Contamination of
Drinking Water
Health Effects
timestep = 1 week
Consumption of
treated water
Utility
treatment
options
Medical
Awareness
Averting
behavior
for public
systems
Routine
testing results
Health
Department
awareness
Utility
awareness
Utility
Communique
Consumption of
well water
Tap
test
Averting
behavior
for private
wells
Well
test
Info sources
Consumer
awareness for
public systems
Consumer
awareness
for private
wells
Trigger
Event
Special
studies
Joint task
force
Media
coverage
Top Level Diagram: Awareness, Communication, and Behavior
Present in
surface water
Contamination of Drinking Water
timestep = 1 week
Module
Source of
Cryptosporidium
Government
enforcement
actions
Present in
utility intake
Present in
finished water
Present at tap
Distribution
system
contamination
Source water
type
Well
vulnerability
Access to
ground
water
Subsurface
attenuation
Present in
ground water
Present in
private wells
timestep = 1 week
Proportion
HIV+
Mortality
Proportion
on Public
System
Endemic rate
HIV+
Endemic rate
HIV -
Epidemic
Morbidity
Other Sources
Secondary
Transmission
Total
Endemicity
Herd
Immunity
Health Effects Module
Outbreaks caused
by Other Factors
eaters
exposed
Person to
Person and
Zoonotic
people
exposed
Sexual
contact
Animal
Contact
Foodborne
prepared foods
and meat
swimmers
exposed
Recreational
Water
fresh fruits,
vegetables
and drinks
Day
Care
Hospital and
Nursing Home
handler
irrigation
water
feces
wash
water
Other Sources Module
lakes, ponds
rivers, streams
swimming
pools, beaches
Progress to date:
•Completion of Expert Model
•External Review of Expert Model
•Review of existing communication instruments
(brochures and websites) for content, form, and
accessibility
•Development of lay elicitation materials
•Pre-testing of lay elicitation protocol
•Completed plan for in-depth interviews
CIS oƒ HDGC
Carnegie Mellon