Evaluating Public Housing Residents for Knowledge,Attitudes,and Practices Following Dengue Prevention Outreach in Key West,Florida

Abstract

Background:

In 2009–2010, 93 cases of dengue were identified in Key West, Florida. This was the first outbreak of autochthonous transmission of dengue in Florida since 1934. In response to this outbreak, a multifaceted public education outreach campaign was launched. The aim of this study is to compare dengue prevention knowledge, attitudes, perceptions, and prevention practices among residents of subsidized public housing to the general population in Key West and to assess whether there were barriers preventing effective outreach from reaching specific vulnerable populations.

Methods:

A randomized population-based evaluation of knowledge, attitudes, and behaviors toward dengue prevention consisting of 521 separate household interviews was undertaken in July of 2011. A subset analysis was performed on interviews collected from 28 public housing units within four subsidized public housing complexes. Analysis was performed to determine whether knowledge, attitudes, and behaviors exhibited by public housing residents differed from the non–public housing study population.

Results:

Public housing residents recalled fewer outreach materials (p=0.01) and were 3.4 times (95% confidence interval [CI] 1.4–8.3) more likely not to recall any outreach materials. Public housing residents were less likely to correctly identify how dengue transmission occurs (61% vs. 89%), where mosquitoes lay their eggs (54% vs. 85%), or to identify any signs or symptoms related to dengue (36% vs. 64%). Public housing residents were less likely to perform dengue prevention practices such as removing standing water or always using air conditioning.

Conclusions:

Examination of public housing residents identified an at-risk population that recalled less exposure to outreach materials and had less knowledge about dengue infection and prevention than the randomized study population. This provides public health systems the opportunity to target or modify future health messages and interventions to this group. Differences identified in the demographics of this population suggest that alternative methods or non-English materials may be required to reach desired outcomes.

Introduction

Dengue is the most common vector-borne viral disease worldwide, causing an estimated 50 million new infections each year. Since the 1970s, the incidence of reported dengue infections has risen nearly 30-fold (UNDP/World Bank/WHO 2007). From 1946 to 1980, there were no reported cases of autochthonous transmission of dengue in the continental United States (Centers for Disease Control and Prevention 1996). The last outbreak reported in Florida prior to 2009, was detected in 1934 (Florida Department of Health 2012).

In an urban epidemic cycle, the vector for dengue, Aedes aegypti, has a close association with humans and their built environments. Built environments, including man-made containers and areas with increased vegetation, that can hold water (e.g., bromeliads) are key components in completing development cycles of the mosquitoes (Gubler 1998, Reiter et al. 2003, Ramos et al. 2008, Radke et al. 2011). Furthermore, Ae. aegypti is generally anthropophilic (preferring humans for their bloodmeals) and endophilic (preferring to rest and take bloodmeals inside human dwellings) (Gubler 1998). As a result, actions that reduce the amount of standing water or protective measures such as repellent use, air conditioning use, and having closed or intact screens and doors have been shown to reduce risk for contracting dengue. (Gubler 1998, Reiter et al. 2003, Ramos et al. 2008, Radke et al. 2011, Adalja et al. 2012).

In August of 2009, the index case of this dengue fever outbreak was reported in a New York resident with recent travel to Key West, Florida (Centers for Disease Control and Prevention 2010). A serosurvey in the outbreak area of Key West conducted in 2009 found an approximately 5% recent infection rate with the dengue virus (Radke et al. 2011). Ultimately, 93 reported cases of dengue were associated with Key West during 2009–2010, with none of the reported cases identified residing in public housing (Florida Department of Health 2012).

As a result of this outbreak, the Florida Department of Health in Monroe County (MCHD) and Florida Keys Mosquito Control District (FKMCD) provided extensive community-wide dengue prevention outreach efforts. This outreach included the “Action to Break the Cycle of Dengue” (ABCD) campaign. The campaign used a variety of approaches, including education from mosquito control inspectors, newspaper articles and advertisements, radio spots, door-hangers, guest speakers, newsletters, and more. The aim of this study was to compare dengue prevention knowledge, attitudes, perceptions, and prevention practices among residents of subsidized public housing to the general population in Key West to determine whether there were barriers preventing effective outreach from reaching specific vulnerable populations. Adult residents of randomly selected households in Key West, Florida, were interviewed using a standardized questionnaire to assess their dengue prevention knowledge, attitudes, and practices as well as recall of dengue prevention outreach materials.

The city of Key West has approximately 24,649 residents, with 9191 reported households (US Census Bureau 2012). Housing is a mix of single-family units, duplexes. and other multifamily units, and large apartment compounds. According to the city's housing authority, there are 903 available public housing units within Key West spread among 11 different public housing compounds that range in size from six to 199 units each (Key West Chamber of Commerce 2008). Eligibility for these public housing units is income based, and eligibility requirements are set by the US Department of Housing and Urban Development and implemented by the Key West Housing Authority.

Methods

The study was conducted from July 17 to August 4, 2011, in Key West, Florida. Samples were selected from residents of subsidized public housing complexes and residents of standard, nonsubsidized residences. Using a property-based geocoded FKMCD database, non–public housing households were selected at random with weighting according to the number of households in the previously designated FKMCD zones (Florida Department of Health 2012). Trained personnel visited selected households to request participation and conduct interviews. Households that were selected for participation in the survey were visited up to three times on different dates and times. Only selected households that had been visited in person but had no one present at the time for an interview were provided a flyer offering the option of completing the same survey over the telephone. Because individual households within public housing residential properties were not enumerated in the FKMCD database, households located within four subsidized public housing complexes were selected using a quota sampling approach. Individual apartments within each selected building were chosen randomly. Surveys were conducted in either English or Spanish by interviewers fluent in those languages.

All respondents were asked what dengue information/outreach they had heard in the previous year. After any spontaneous responses were recorded, respondents were asked which items from a list of 13 dengue prevention outreach sources they recalled having seen/heard, or participated in (Table 1). Respondents could also name any other dengue prevention materials or activities. Respondents not recalling any sources of dengue prevention materials or activities were classified “does not recall any.”

Table 1.

Dengue Prevention Outreach Sources Utilized in Key West in Response to Dengue Outbreak

Door hangers hung on over 10,000 residences

Mosquito control “report cards” detailing where standing water and/or immature mosquitoes were found on the property by an inspector

Mosquito control inspectors where the frequency of inspections at each property increased based on increasing risk for standing water and/or immature mosquitoes on the property

Over 20 newspaper articles in both local newspapers from September, 2009, through November, 2010; the topic frequently covered as a local news item

Radio spots approximately six interviews on multiple local stations

Approximately 10 public meetings or presentations with up to 50 attendees

Clean-up weekend in April, 2011, throughout Key West

Free “Action to Break the Cycle of Dengue” newsletters to partners and subscribing community members

A recurring local public access television program discussing mosquito borne diseases and mosquito control

Water bill inserts

Bus stop marquees

Advertisements at the local cinema

Original cartoon strip by a local artist about “Stan Dingwater”

Household surveys were collected, entered, stored, and processed in QuestionPro, and the residence was geolocated using ArcGIS. Data were analyzed using statistical software, including SAS and SPSS. Individual outreach materials were evaluated by frequency recalled by each population group. Knowledge, attitude, and practice questions were analyzed by comparing the frequency of responses across population groups. The chi-squared test for independence was used to evaluate whether differences in responses were statistically significantly different between residents of subsidized public housing and non–public housing residents.

Results

Surveys were completed by 28 residents of subsidized public housing and 521 residents of non–public housing (general population). Demographics varied considerably between the two groups (Table 2). Non–public housing respondents were primarily white, of non-Hispanic ethnicity, and their primary language was English. Public housing respondents were statistically more likely to be nonwhite, of Hispanic ethnicity, and to speak a primary language other than English (including Spanish and Haitian Creole). Gender, median age, and year-round residence status did not differ significantly between the two groups.

Table 2.

Study Demographics Stratified by Public Housing Status

Demographic	Non–public housing (%)	Public housing (%)
Total number of participants	521 (100%)	28 (100%)
Race
White	412 (79%)	7 (25%)
Non-white	109 (21%)	21 (75%)
Ethnicity
Hispanic	71 (14%)	15 (54%)
Non-Hispanic	435 (86%)	13 (46%)
Primary Language
English	481 (92%)	20 (71%)
Non-English	40 (8%)	8 (29%)
Gender
Male	268 (52%)	10 (36%)
Female	244 (48%)	18 (64%)
Other
Median age in years	53 (N/A)	50 (N/A)
Year-round resident	437 (84%)	25 (89%)

Recall of dengue prevention outreach materials

Only two of the listed prevention materials/activities were recalled by more than 50% of the non–public housing sample, and there were no prevention materials recalled by more than 50% of the public housing sample (Table 3). Mosquito control inspectors (66%) and newspaper materials (66%) were recalled most frequently by non–public housing participants, whereas newspaper materials (43%) were the most frequently recalled dengue prevention outreach material by public housing respondents. Only 9% of general population respondents did not recall exposure to any dengue prevention outreach materials. In contrast, 25% of public housing respondents did not recall any of the same outreach materials, resulting in 3.4 (95% confidence interval [CI] 1.4–8.3) times greater odds that public housing respondents did not recall any outreach materials. Mosquito control inspectors, newspaper materials, door hangers, hearing about the clean-up weekend, and the mosquito control report card were all significantly less likely to be recalled by public housing respondents compared to non–public housing respondents.

Table 3.

Frequency of Recall of Dengue Prevention Outreach Materials/Activities by Housing Status

Activities/materials	Non–public housing (%)	Public housing (%)	Chi-squared
Mosquito control inspector	346 (66%)	8 (29%)	<0.0001
Newspaper materials	343 (66%)	12 (43%)	0.01
Door hanger	204 (40%)	3 (11%)	0.003
Radio	157 (30%)	7 (25%)	0.56
Heard about clean-up weekend	156 (30%)	4 (14%)	0.08
Mosquito control report card	152 (29%)	3 (11%)	0.03
Mosquito control TV show	105 (20%)	8 (29%)	0.28
Does not recall any	47 (9%)	7 (25%)	0.006

Dengue prevention knowledge

Public housing respondents were statistically less likely to answer any of the four knowledge questions posed correctly (Table 4). General population respondents were at 5.1 (95% CI 2.3–11.3) times greater odds of correctly identifying dengue transmission as occurring through a bite from an infected mosquito than public housing respondents. Non–public housing respondents were also 6.0 (95% CI 3.5–10.3) times more likely to correctly identify that the mosquitoes that transmit dengue lay their eggs in standing water. Non–public housing respondents, compared to public housing respondents, were 3.7 (95% CI 1.4–9.9) times more likely to be aware that people with dengue in Key West had been very sick or hospitalized. Last, odds were 3.2 (95% CI 1.5–7.2) times greater that non–public housing respondents could identify at least one sign or symptom of dengue, compared to public housing respondents

Table 4.

Frequency of Responses to Knowledge, Attitudes, and Practices Questions by Housing Status

Category	Non–public housing (%)	Public housing (%)	Chi-squared
Knowledge^a
Mosquitoes transmit dengue	462 (89%)	17 (61%)	<0.0001
Lay eggs in standing water	443 (85%)	15 (54%)	<0.0001
Hospitalizations in Key West	229 (45%)	5 (18%)	0.005
Any sign or symptom of dengue	335 (64%)	10 (36%)	0.002
Attitudes^a
Serious problem for Key West	308 (60%)	15 (58%)	0.82
Discuss dengue with family/friends	301 (58%)	6 (21%)	0.0002
Responsible for control of dengue in the Keys
Mosquito control	291 (56%)	13 (46%)	0.33
Health department	62 (12%)	4 (14%)	0.71
Residents/Individuals	220 (42%)	6 (21%)	0.03
Don't know	22 (4%)	5 (18%)	0.001
Practices
Remove standing water	363 (70%)	14 (50%)	0.03
Always use air conditioning^b	423 (82%)	18 (67%)	0.04
All doors/windows have intact screens	323 (62%)	18 (64%)	0.81
Never use repellent	220 (42%)	13 (50%)	0.44

For knowledge questions, frequency and percentages are for those correctly answering the knowledge questions. For attitudes or practices, frequency and percentages are displayed for those who agreed with the statements or identified with the actions.

Eight non–public housing and one public housing households sampled did not have air conditioning units.

Attitudes and perceptions about dengue

Despite recalling fewer outreach materials and being statistically less likely to correctly answer the knowledge-based questions, public housing respondents and non–public housing respondents both perceived dengue as a serious problem for Key West (58% vs. 60%) (Table 4). Likewise, public housing and non–public housing respondents had similar perceptions that government agencies, FKMCD (46% vs. 56%) and MCHD (14% vs. 12%), were responsible for control of dengue in the Keys. However, public housing respondents were 4.9 (95% CI 1.7–14.2) times less likely to be able to identify a person or agency who was responsible for the control of dengue than non–public housing respondents. Moreover, non–public housing respondents were 2.7 (95% CI 1.1–6.7) times more likely to identify residents/individuals as personally responsible for dengue control. The odds a non–public housing respondent discussed dengue with their family or friends were 5.0 (95% CI 2.0–12.6) times greater than public housing respondents.

Dengue prevention practices

Nearly 70% of non–public housing respondents reported taking actions to remove standing water on their property, compared to only 50% of public housing respondents (Table 4). Over 80% of non–public housing respondents reported always using air conditioning compared to only 64% of public housing respondents, making non–public housing respondents 2.4 (95% CI 1.1–5.4) times more likely to always use air conditioning than public housing respondents. Of the homes that had any air conditioning, non–public housing respondents were 4.6 (95% CI 2.0–10.8) times more likely to utilize central air conditioning rather than window units, when compared to public housing respondents. Public housing respondents and non–public housing respondents reported a similar likelihood to have all doors and windows with intact screens (64% vs. 62%), and both groups reported at least some use of mosquito repellent (50% vs. 58%).

Discussion

Dengue is an important re-emerging health threat and a sentinel for future risks such as chikungunya virus and other arboviral infections. This evaluation of dengue prevention outreach suggests that residents of subsidized public housing in Key West are a population in need of future targeted and tailored outreach. Respondents who were residents of subsidized public housing recalled significantly fewer outreach materials and demonstrated less knowledge about dengue infection. Prevention and many of their dengue prevention practices were more limited than that of non–public housing respondents in Key West.

Exposure to certain outreach materials, in particular newspaper materials, was associated with an increase in dengue prevention knowledge among non–public housing residents (Florida Department of Health 2012). There was no source of outreach recalled by more than 50% of the public housing population, and one in four public housing respondents did not recall any outreach material. The rate of those having no exposure to dengue prevention outreach among public housing respondents was nearly three times higher than non–public housing respondents. Therefore, the employed outreach methods were not effective in disseminating messaging to public housing residents, and alternative methods to reach this population are needed. Because outreach materials were not field-tested among residents of public housing, a survey or focus groups among this population prior to commencing large outreach campaigns could be valuable in determining the most effective methods and messages for outreach among this populations.

Tailoring of messages is important for another reason: There are some differences between the prevention actions to be taken by non–public housing residents, many of whom have responsibility for yards (and their water-holding containers), and public housing residents, who typically have little if any “personal” outdoor space. Additionally, public housing areas are often more open with limited vegetation and therefore with less ideal Ae. aegypti habitat available. Non–public housing residents of Key West may interact with mosquito control inspectors who request permission to access their property to inspect for mosquito oviposition sites, whereas inspectors do not typically knock on individual doors to inspect communal public housing areas. This difference could account for some of the reported variation in whom respondents named as the entity responsible for control of dengue, and perhaps may account for lower reported actions to reduce standing water among public housing residents.

Although some outreach materials were translated into Spanish, there was a need for increased outreach using a variety of media for non-English speakers to improve exposure to and recall among residents of subsidized public housing. It is notable that insect repellents were used by less than 60% of residents of Key West overall. This suggests the need to better understand how use of this personal prevention option can be increased.

There was no difference between public housing residents and non–public housing residents in the perceived seriousness of dengue as a problem for Key West. This may be a result of the survey methodology and lack of knowledge on the subject, because participants not recalling any outreach materials were significantly more likely to perceive greater seriousness of dengue for Key West (Florida Department of Health 2012).

Dengue prevention practices such as removal of standing water, use of mosquito repellent, air conditioning use, and having intact screens on doors and windows were either identical or reported less frequently by subsidized public housing residents. This study did show lower access to air conditioning among the public housing respondents, and air conditioning has been shown to be protective against dengue infection in other settings. However, whether the difference in consistent use or type of air conditioning (e.g., window unit or central) plays a role in risk reduction has been conjectured but not well defined (Ramos et al. 2008). Public housing residents may have less control over their built environment than non–public housing residents, but appropriate protection actions can be determined. A route forward may be development of a multidisciplinary group (i.e., the public housing authority, local health department, and mosquito control agencies) to assess epidemiological risks for public housing residents and other vulnerable populations that may differ from the general population and tailor interventions accordingly.

The true vulnerability of public housing residents in the United States to infection with dengue viruses is not known. No cases among public housing residents were identified during the outbreak. This may be a result of geographic distance from high seroprevalence areas or possibly risk-reducing factors, such as limited vegetation on the property. In addition, public housing residents may face barriers, such as cost, access to reaching medical assessment and laboratory testing needed to meet the reportable case definition for dengue surveillance, and limited awareness of (and care-seeking for) symptoms pertaining to dengue. On the basis of these survey results, public housing residents often take fewer protective action against dengue compared to other Key West residents; however, risk can be quite heterogeneous on the basis of the ecology of the vector mosquito and specific evaluation of vector densities near public housing are lacking (Favier et al. 2005, Flauzino et al. 2009). Lack of reported dengue cases does not obviate the possible risk to this population; the serosurvey results from 2009 suggest that many more dengue infections occurred in Key West than were reported (Radke et al. 2011). The prior residence of many public housing residents in dengue-endemic areas of Latin America or the Caribbean also suggests that the risk for dengue hemorrhagic fever may be present among this population if infection with a novel serotype were to occur.

Conclusions

This study identified important limitations in the reach of education about dengue to residents in Key West's public housing areas and provides an important baseline for future outreach in this community. The data also provide local agencies working with this and other potentially vulnerable communities the opportunity to modify health messages and interventions to target such groups effectively. The significant differences in race, ethnicity, and primary language spoken between residents of subsidized public housing and non–public housing residents may require health information to be provided by alternative methods or languages to reach desired outcomes in this target population (Eng et al. 1998, Andrullis and Brach 2007, Quinn 2008). Formative research and pretesting can provide important insights into what methods and materials may be most effective with this population.

Communicating health information to community stakeholders is not only important when an emerging disease is detected, but also during routine health events and preparedness activities in every community (Eng et al. 1998, Andrullis and Brach 2007, Quinn 2008). This study was able to provide insight into the needs, improvements, planning, and evaluation for future health-related communication in the public housing resident population.

Footnotes

Acknowledgments

We thank the Florida Department of Health in Monroe County, the Florida Keys Mosquito Control District, and Florida Keys Community College for all of their time and assistance in this evaluation.

This study/report was supported in part by an appointment to the Applied Epidemiology Fellowship Program administered by the Council of State and Territorial Epidemiologists (CSTE) and funded by the Centers for Disease Control and Prevention (CDC) Cooperative Agreement Number 5U38HM000414.

Author Disclosure Statement

No competing financial interests exist.

References

Adalja

, Sell

, Bouri

, Franco

. Lessons learned during dengue outbreaks in the United States, 2001–2011. Emerg Infect Dis, 2012; 18:608–614.

Andrullis

, Brach

. Integrating literacy, culture, and language to improve health care quality for diverse populations. Am J Health Behav, 2007; 31(Suppl 1):S122–S133.

Centers for Disease Control and Prevention. Dengue fever at the US–Mexico border, 1995–1996. MMWR Morb Mortal Wkly Rep, 1996; 45:841–844.

Centers for Disease Control and Prevention. Locally acquired dengue—Key West, Florida, 2009–2010. MMWR Morb Mortal Wkly Rep, 2010; 59:577–581.

Eng

, Maxfield

, Patrick

, Deering

, et al. Access to health information and support: A public highway or a private road?. JAMA, 1998; 280; 15:1371–1375.

Favier

, Schmit

, Müller-Graf

CDM

, Cazelles

, et al. Influence of spatial heterogeneity on an emerging infectious disease: The case of dengue epidemics. Proc Biol Sci, 2005; 272:1171–1177.

Flauzino

, Souza-Santos

, Barcelllos

, Gracie

, et al. Spatial heterogeneity of dengue fever in local studies, City of Niterói, Southeastern Brazil. Rev Saúde Pública, 2009; 43:1035–1043.

Florida Department of Health. Evaluation of a Dengue Prevention Outreach Campaign on Public Knowledge, Attitudes, and Practices. Draft report. Tallahassee: Florida Department of Health, 2012a.

Florida Department of Health. Surveillance and Control of Selected Arthropod-borne Diseases in Florida, 2012 Guidebook. Tallahassee: Florida Department of Health, 2012b.

10.

Gubler

. Dengue and dengue hemorrhagic fever. Clin Microbiol Rev, 1998; 11:480–496.

11.

Key West Chamber of Commerce. Key West Vision 2020: Ten Year Progress Review. Draft report, 2008.

12.

Quinn

. Crisis and Emergency Risk Communication in a Pandemic: A Model for Building Capacity and Resilience of Minority Communities. Health Promot Pract, 2008; 9(Suppl 4):18S–25S.

13.

Radke

, Gregory

, Kintziger

, Sauber-Schats

, et al. Dengue outbreak in Key West, Florida, USA, 2009. Emerg Infect Dis, 2011; 18:135–137.

14.

Ramos

, Mohammed

, Zielinski-Gutierrez

, Hayden

, et al. Epidemic dengue and dengue hemorrhagic fever at the Texas–Mexico Border: Results of a household-based seroepidemiologic survey, December 2005. Am J Trop Med Hyg, 2008; 78:364–369.

15.

Reiter

, Lathrop

, Bunning

, Biggerstaff

, Singer

, et al. Texas lifestyle limits transmission of dengue virus. Emerg Infect Dis, 2003; 9:86–89.

16.

UNDP/World Bank/WHO. Special Programme for Research and Training in Tropical Diseases. Report of the Scientific Working Group meeting on Dengue, Geneva, 1-5 October 2006. Geneva: World Health Organization, 2007.

17.

US Census Bureau. “Key West (city), Florida.” State and County QuickFacts. U.S. Census Bureau, December 6, 2012. Available at http://quickfacts.census.gov/qfd/states/12/1236550.html