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Approaches to Community Prevention of West Nile Virus Infection. Emily Zielinski-Gutierrez, DrPH Behavioral Scientist Division of Vector-Borne Infectious Diseases Centers for Disease Control & Prevention. Outline. A little health education and behavior change theory

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approaches to community prevention of west nile virus infection

Approaches to Community Prevention of West Nile Virus Infection

Emily Zielinski-Gutierrez, DrPH

Behavioral Scientist

Division of Vector-Borne Infectious Diseases

Centers for Disease Control & Prevention

  • A little health education and behavior change theory
  • A national perspective on WNV trends
  • Some statistics on WNV protective behaviors
  • Some barriers & opportunities for prevention
    • Lessons from Colorado and elsewhere
lots of different theories
Lots of different theories
  • Theory of Reasoned Action
    • How people decide to take a certain action
  • Health Belief model
    • A person’s behavior can be predicted based upon issues such as perceived susceptibility, perceived severity when making a decision about a particular behavior concerning theirhealth.(Glanz, Lewis, & Rimer, 1990).
  • Transtheoretical model/Stages of Change
    • Precontemplation/ contemplation/ preparation/ action/ maintainence
  • Fear Appeals Theory
      • Some would agree, some not – fear can motivate OR lead to rejection and inaction.
  • And many more

One Theoretical Basis

Risk Communication and Education

Risk Perception

Environmental Factors

MediaDisease history

Local ecology

Demographic factors

Socio-cultural factors

e.g. language, age,

Income, gender, education

Risk Assessment


Barriers to Action

Facilitating Factors for the Action

Desired Action




health communication can
Communication with other strategies can:

Change human behavior

Overcome barriers and systemic problems

Health Communication can:
  • Increase knowledge
  • Increase awareness
  • Prompt action
  • Demonstrate skills
  • Influence attitudes
  • Refute myths

DHHS/NIH/NCI: Making Health Communication Programs Work

health communication questions with west nile virus
Health communication questions with West Nile virus
  • What prevention measures are people using to avoid WNV infection?
  • What are possible reasons that people are not using prevention measures?
  • What communication activities and other interventions might increase use of personal & household prevention?
    • How can communication makes prevention measures more “actionable”/feasible?
plan for the result you want
Plan for the result you want
  • Outcomes:
    • Knowledge about transmission, about risk, about repellents, about prevention
    • Attitudes about personal risk, support of prevention, etc.
  • Impact:
    • Behavior: e.g. increased repellent use, installation of screens
    • Disease reduction: A challenge to measure for WNV/mosquito borne disease
      • Lots of variables ecological and otherwise, serosurveys a huge expensive effort…can use surveillance data for some questions
message receiver behavior change
Message + receiver ≠ behavior change
  • A message w/o supporting context often insufficient
  • There are reasons that people don’t do things that would otherwise seem to make reasonable sense… find out what those reasons are… and address them in your campaign.
  • If there are significant obstacles (income or poor housing, for example) information alone isn’t often going to be enough to counter that alone.
a bigger and bigger problem
A bigger and bigger problem

# Cases # Deaths # States w/ human cases

1999 62 7 1

2000 21 2 3

2001 66 9 10

2002 4071 279 39 states +DC

2003 * 9306 240 45** states+DC

*As of March 3, 2004. Numbers will change.

**No human disease reports in 2003 in WA, OR, ME, HI, AK

this year
This year…
  • 0ver 9000 human cases reported in the US*
    • Severe disease = more than 2700 (30%)
    • West Nile Fever = more than 6300 (~68%)
      • Only about ~25% of all cases in 2002 were Fever
    • Other/unknown = about 163 (2%)

* 2003 cases reported to CDC, as of 3 March 2004

who gets sick from west nile
Who gets sick from West Nile?
  • All ages: 1 mo.–99 years
  • Fever cases tend to be young/middle age adults
  • Severe disease and deaths tend to be people over 50, and especially over 70
  • Kids do get sick, but pretty rarely.
    • Intrauterine infection is possible when a pregnant woman gets infected, but the extent to which this occurs and the health effects on the infant are not yet known.

* 2003 cases reported to CDC, as of 19 November 2003

percent of reported west nile virus cases classified as west nile fever united states 2003
Percent of Reported West Nile Virus Cases Classified as West Nile Fever, United States, 2003

Percent of Cases





* Reported as of 1/29/2004

wnnd county level incidence per million united states 2002
WNND County Level Incidence per Million, United States, 2002*

Incidence per million




* Reported as of 4/15/2003

wnnd county level incidence per million united states 2003
WNND County Level Incidence per Million, United States, 2003*

Incidence per million




*Reported as of 1/20/2004

Human WNV Disease Incidence, by Age Group and Clinical Category, United States, 2003*

* Reported as of 1/30/2004

* *Entire US population

when it s warm in your area do you
When it’s warm in your area, do you…
  • Nationwide: those who report they always/usually…
    • 43.9% look for household standing water
    • 37.6% apply {any} insect repellent
    • 28.5% avoid the outdoors due to mosquitoes
    • 23.9% wear long pants/sleeves

74.5% doing at least one of the above.

* Healthstyles national survey, data licensed from Porter-Novelli, conducted July-Aug 2003

if it s repellent is it deet
If it’s repellent, is it DEET?
  • 40.3% of respondents have repellents containing DEET in the household (another 26.8% not sure)
  • It’s not DEET for everyone:
    • Only 59.3% of repellent “users” confirmed having DEET in the household
  • Other respondents do have DEET, but they don’t use it much
    • 44.6% of those have DEET in the household said that they did NOT always/usually use repellent
West North Central region:

38% in 2002, 49% in 2003

Mountain region:

23% in 2002, 33% in 2003

East South Central region:

39% in 2002

49% in 2003

Red = Regionw/more than 10% increase in “Always/Usually Use Repellent” between 2002-2003

age repellent use
Age & Repellent Use

Bad News:Repellent use (largely) decreases with age

p < .000; n= 4034

age and deet in household
Age and DEET in household
  • Highest age categories may be associated with having children at home
race ethnicity
  • Significant differences in having DEET in household by race/ethnicity (p<.000)
    • “White” respondents most likely to have DEET (44.3%), other respondents less so (<33%)
household income
Household income
  • Poorer people in this sample were less likely to report having DEET-based repellent in the household.

p<.000, n=4008

  • Education level directly related to having DEET in household (p<.000)
    • Non HS graduates <30%, college graduates approaching 50% have DEET
    • Relationship to income bears further attention
the why qualitative complementing quantitative
The “Why”: Qualitative Complementing Quantitative
  • Qualitative research to examine KAP and behavioral factors
    • 2003: Focus group discussions (~12 total) in higher and lower transmission areas [Larimer (high) and El Paso (low) counties]. Data on Cook County forthcoming.
    • 2002: 16 focus groups in Louisiana
    • Topics:
      • Risk perception
      • Attitudes twd mosquitoes, repellents, spraying
      • Information sources and shortcomings
      • Views on responsibility for prevention
barriers questions about deet
Barriers: Questions about DEET
  • Reported infrequent/no use of DEET-based repellents in wk before group
  • Many cited their own sensory experience using repellent
    • smell, feel (“sticky”)
    • skin reactions, “sensitive skin,” I just can’t use that stuff
  • Strong, though often vague, beliefs and feelings about safety of DEET
    • Attribute brain damage, nerve damage, danger to kids
    • Often described by consumers as “something I heard somewhere… read somewhere”
    • Desire for more data, but resources for detailed info often unclear
more on repellents
More on repellents
  • Permethrin never mentioned
  • Use of any repellent on clothing rarely discussed
  • Very little awareness of details about repellent
    • DEET % strength unclear
    • Little about “hierarchy” of alternatives
  • Alternative repellents
    • “They wouldn’t have come up with the other types if there weren’t something wrong with DEET.”
    • Colorado way less interesting than Louisiana
    • Skin-So-Soft & the Avon ladies
    • Trust in “natural” products (regardless)
it s not all about knowledge or about the bug spray
It’s not all about knowledge or about the bug spray
  • The decision to obtain/use repellent is only partly a function of knowledge about WNV, knowledge about prevention, or attitudes toward products.
    • Assessments of risk
      • Temporal, geographical, control/fear/outrage
    • Perceived impact of prevention efforts
      • Would any of these steps make a difference?
    • Individual cost-benefit analysis
      • What is it costing me to take these preventive measures? (not just $)
conceptual framework
Conceptual Framework

Risk perception was affected by locally- and personally-defined intensity of WNV transmission.

Some factors that combine to define local intensity of transmission include:

  • - personal knowledge about disease
  • - perception of local ecology
  • - type and credibility of information sources
  • - local government intervention
Personal knowledge about disease

Information Sources

Actions of local


Local ecology

Locally-defined intensity of transmission

Intense WNV Human Disease 2002 & 2003















Population perceives limited mosquito infestation

Limited experience w/ & some resistance to mosquito control

Risk perception linked to info from community groups



































Long history of mosquito infestations and nuisance

Experience with and general support for mosquito control as a public service

Risk perception linked to info from community groups

Includes Fever and neuroinvasive disease as reported to CDC

> 200 human cases 2003

> 200 human cases 2002

> 200 human cases both years

risk personal knowledge of disease
Risk: personal knowledge of disease
  • Knowing some who was ill
    • Increased recognition of WNV Fever cases during 2003*, more residents knew of someone infected
  • Concern about severity of Fever
    • Not the same impact as ND, but people missed school, work, described prolonged headache ache and fatigue
      • “No one told us it was going to be this bad.”
defining risk disease age
Defining Risk:disease & age
  • No one is “old.”
  • Perspective: participants > 60 y.o. pointed out their experience with other illnesses
    • Lived through polio
    • I had malaria and I figured I must be immune
  • Risk roulette for younger people:
    • “One of my younger neighbors, he thought that he ought to go ahead and get it so he would build up an immunity…”
personal view of disease fear and control
Personal view of disease: fear and control
  • Concern fueled by sense of powerlessness
    • felt that personal options were limited
    • “I can’t spend time outside anymore”
  • Risk may seem ‘unquantifiable’ to general public
    • hard to make decisions about prevention--what to do, what to give up
  • Difficulty conceptualizing how a single mosquito bite can be fatal or life-changing
defining risk local ecology
Defining Risk: Local Ecology
  • “No mosquitoes here”
    • Public lacks history of dealing with mosquitoes as a nuisance or makes qualitative comparisons to Midwest/elsewhere
      • “I just don’t see where all these mosquitoes can be coming from…”
  • Home as “Safe Zone”
    • Don’t use repellent when “just in the backyard”… some disinclination to regard home as dangerous
      • “Most of us [retirees] who are living here are so happy to be in this particular environment that we think we’ve got it made and… we’re kind of invulnerable to any sort of thing.”
defining risk perception of ecology local geography
Defining Risk: perception of ecology/local geography
  • “Hyper-localization” of risk
    • Desire to quantify exactly where and when the risk exists
      • People try to downgrade their risk – e.g. that dead bird was 3 blocks from here…
      • “We hear about the deaths… I wish they would go into a bit more history [of where they were bit.]”
defining risk use of outdoors
Defining Risk: use of outdoors
  • The culture of outdoor recreation
    • Golfing, fishing, walking, gardening
    • Neighborhood visiting in PM (cities, south)
  • Resources
    • People without air-conditioning have a v. different relationship to outdoors
    • Age/quality/preferences in housing stock
      • Again western states very different than South and Midwest
defining risk info sources
Defining Risk: Info sources
  • People get most of information from media
    • Passive
    • Subject to the vagaries of how issues are covered – to what makes the “front page”
  • Respondents suspicious… media “hypes everything”
    • “I think there was confusion over how much is this really a problem and how much is media hype?”
    • Public’s inherent distrust (or at least ambivalence) regarding the media affected level of concern
defining risk media and controversy
Defining Risk: media andcontroversy
  • Adulticiding in Larimer county became major and divisive distraction from other prevention messages
  • On the other hand it keep it in the forefront of people’s minds…

Hard to know the sum effect

of controversy.

defining risk info sources52
Defining risk: Info sources
  • Some Hispanic residents reported hearing little to nothing about WNV in the media sources to which they were exposed
    • Some folks may be accessing Univision more than local media
  • “Worry fatigue”:
    • “… it felt like, OK, so this year it’s West Nile, last year was something and next year will be something else to be afraid of.”
  • All areas: People expressed interest in hearing from community representatives, relevant leaders, “people like them”
      • “I figured if it were really important my pastor would have mentioned it.” – urban LA resident
defining risk people look at what government is doing
Defining risk: people look at what government is doing
  • Mosquito Control actions can create controversy.
      • The decision to declare a public health emergency also was noted as influencing people’s concern over the issue.
  • Some question whether long-term mosquito control can lead to complacency among citizens and how to combat
  • Local gov’t actions can serve as trigger for citizens
opportunities cues to action
Opportunities: Cues to Action
  • High profile repellent sales in retail locations triggered purchase
    • “[they] had [repellent] right when you walk in the door… we bought some right then, and I don’t know if I would have right then [otherwise]… I thought that was wise and caring.”
    • Approach to bring in private elements of the community
  • Hearing about & knowing people around them who were ill
  • A minority of the US population is using repellent but most are doing something.
    • But important gaps related to population (age, SES) and possible geographic risk factors
    • The “something” might provide limited protection.
opportunities future steps
Opportunities/Future steps
  • “Socially market” repellents with greater savvy
    • DEET and more effective alternatives
    • Distribution points (where people already go)
    • Encourage industry to look at some of the things people really don’t like about DEET
    • Address safety straight on
  • Use the fact that nearly half the population already report looking for breeding sites
    • Encourage, and evaluate
opportunities future steps57
Opportunities: future steps
  • Identify maintenance vs. emergency strategies
  • A lesson from the Avon ladies
    • Personal messages engage people on a different level than TV, a website or a flyers.
    • Who are your partners?
final opportunities
(Final) Opportunities
  • As WNV epidemiology and ecology evolve, messages must similarly evolve.
  • Local ecology and history w/ mosquitoes important in construction of risk
    • considered in adapting prevention efforts
  • Involve community groups and local officials in prevention messages and planning
    • Supplement media and health department personnel