The Humans in Human Ecology:

Studying Society & West Nile Virus

Emily Zielinski Gutierrez,

CDC/Division of Vector-Borne Infectious Diseases

Mary Hayden,

University of Colorado at Colorado Springs

NISSC

Human Ecology & Vector-borne Disease

• People shape local ecology and thus influence vector ecology– Land use and sanitary conditions (trash, breeding

sites)– Control of water resources

• Human patterns and choices affect exposure to vectors– Housing characteristics– Outdoor activities (work & recreation)– Use of prevention measures

Data on Human Behavior

• Land/water use analysis, GIS

• Mapping of housing characteristics

• Surveys to quantify behavior

• Interviews and focus groups to characterize/describe behavior

Qualitative/Quantitative Methods

• Qualitative Data– Often “words”– Inductive– Not intended to be

generalizable– Identify concepts,

issues– How? Why?– Subjective

• Quantitative Data– Often “numbers”– Deductive– Usually generalizable

– Identify frequency/magnitude

– What? How many? – “Objective” (but…)

Qualitative and Quantitative Methods

• Both “scientific,” though from varied disciplines• Role of researcher can vary

– level of involvement, interaction• Ultimately depends on the question(s) you are

trying to answer– Ideally function as complementary approaches to

analysis• Resources

– Qualitative MAY be quicker, cheaper and administratively easier (IRB, OMB) – rapid assessment

Methods – WNV focal areas

• Community discussion groups (e.g. focus groups) – Louisiana (2002), Colorado (2003), Illinois (2003),

California/Mexico border (2004) – Demographically diverse populations– Focus groups were segmented by age, language,

ethnicity/race, and geographic location.

• Interviews transcribed and content analysis conducted to define major themes and interactions

Data Collection

• Topics covered:– concern/risk perception vis-à-vis WNV,

mosquitoes– attitudes towards mosquitoes, repellent, and

mosquito control– information sources– protective actions (repellent, protective

clothing, screening)– housing & lifestyle (e.g., time spent outdoors)

Synthesis

Risk perception was affected by locally- and individually-defined “intensity of WNV transmission”

Factors defining local intensity of transmission include: • personal knowledge about disease • type and credibility of information sources• local government intervention• perception of local ecology

Need for New Models

• Few models of health behavior adequately account for role of local ecology in shaping people’s risk perception

Personal knowledge about diseaseInformation Sources

Locally-defined intensity of transmission

Local ecologyActions of local government

Intense WNV Human Disease 2002 & 2003

WA

OR

CA

MT

ID

NV

WY

COUT

AZ NM

TX

ND

SD

NE

KS

OK

MN

IA

MO

AR

LA

MSAL GA

FL

TNSC

NC

VAIL

WIMI

IN OH

KYWV

PA

MD

DENJ

NY

CTRIMANH

MEVT

> 200 human cases 2003

> 200 human cases 2002

> 200 human cases both years

Includes Fever and neuroinvasive disease as reported to CDC

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

Population perceives limited mosquito infestation

Limited experience w/ & some resistance to mosquito control

Risk perception linked to info from community groups

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: Local Ecology

• “No mosquitoes here”: West– Public lack recent history of dealing with mosquitoes

as a nuisance or comparisons to Midwest/elsewhere– We have a drought, how can we have mosquitoes?

• “We’ve always had mosquitoes…”: South• Home as “Safe Zone”

– Forget repellent in the backyard… 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

• “Hyper-localization” of risk– Individuals try to quantify exactly where and

when the risk exists• We know that (on the whole) Americans have

poor geography skills • 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: 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.

• Can long-term mosquito abatement lead to complacency (and no repellent use) among citizens?

• Local gov’t actions can serve as trigger for citizens

Social Factors Potentially Influencing WNV Risk

• Community Level: – History/use of mosquito abatement– Irrigation practices– Land Use (farming, golf courses…)– Presence of household breeding (trash

collection, tire laws, gardening practices)– Regional adaptation to climate

Social Factors Potentially Influencing WNV Risk

• Household/Personal Level– Presence/lack of air conditioning (vs. swamp

coolers vs. fans vs. none)– Style of housing (open vs. closed)– Type of work (e.g. ag workers, landscaping)– Recreation choices (gardening, golf)– Willingness to engage in repellent use, control

of breeding sites • May depend on experience with other public health

progs, risk perception…

Recommendations

• Short-term:– Educate citizens on local ecology– Help people interpret data through mapping– Housing adaptations, target certain populations with

education on risk mitigation

• Long-term: – Examine factors that influence mosquito breeding &

resistance to control (household and ag irrigation, ag use of pesticides)

• Work toward policy changes