Community Assessments for Mosquito Prevention and Control Experiences, Attitudes, and Practices — U.S. Virgin Islands, 2017 and 2018
Weekly / June 7, 2019 / 68(22);500–504
Please note: An erratum has been published for this report. To view the erratum, please click here.
Krystal R. Seger, MSPH1; Joseph Roth Jr., MPH2; Amy H. Schnall, MPH3; Brett R. Ellis, PhD1; Esther M. Ellis, PhD1 (View author affiliations)View suggested citation
What is already known about this topic?
Integrated vector management is important to reduce mosquitoborne disease transmission. Community assessments are rarely used to inform mosquito management or understand related community perceptions.
What is added by this report?
Community assessments conducted in the U.S. Virgin Islands during the Zika outbreak response, hurricane response, and hurricane recovery found similar support for mosquito spraying, but support for specific spray methods varied. Concern about acquiring Zika decreased over time.
What are the implications for public health practice?
Mosquito prevention and control community assessment questions can provide rapid, actionable information to advise both community education and mosquito control in emergency response and recovery efforts. Assessments can also be used by vector control programs to enhance routine operations.
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Aedes aegypti, the mosquito that carries dengue, chikungunya, and Zika viruses, is present throughout the U.S. Virgin Islands (USVI). To reduce mosquitoborne disease transmission, the USVI Department of Health (VIDOH) is responsible for integrated mosquito management. During January 2016–January 2018, USVI experienced its first Zika outbreak, with most cases reported during January–December 2016, as well as two Category 5 hurricanes (Irma on St. Thomas/St. John on September 6, 2017, and Maria on St. Croix on September 19, 2017). The hurricanes severely damaged mosquito protection–related building structures (e.g., screens, roofs) and infrastructure (e.g., electricity, air conditioning) and might have created an environment more conducive to mosquito breeding. VIDOH, with requested technical assistance from CDC, conducted three Community Assessments for Public Health Emergency Response (CASPERs) to provide rapid community information at the household level. The three CASPERs were conducted to inform 1) the Zika outbreak response, 2) the hurricane response, and 3) the hurricane recovery. The CASPERs assessed mosquito prevention and control-related experiences, attitudes, and practices; household and environmental conditions associated with mosquito breeding, prevention, and control; and other nonmosquito-related information to inform outbreak and disaster response planning. Approximately 40% of households were very concerned about contracting Zika virus during the Zika outbreak and hurricane responses. Environmental conditions were reported to become more favorable for mosquito breeding between the Zika outbreak and hurricane response. Between 75%–80% of the community supported mosquito-spraying in all assessments. VIDOH used these data to support real-time outbreak and hurricane response planning. Mosquito prevention and control community assessments can provide rapid, actionable information to advise both mosquito education and control and emergency response and recovery efforts. The CASPER design can be used by vector control programs to enhance routine and response operations.
The Zika outbreak response CASPER was conducted during June 26–29, 2017, on the three main islands, St. Croix, St. Thomas, and St. John. The hurricane response CASPER was conducted in two geographically distinct districts (St. Croix on November 7–8, 2017, and St. Thomas/St. John on November 13–14, 2017) to account for the two hurricanes. The same questionnaire was used for both CASPERs, and the results from both locations were similar; therefore, they were considered and analyzed together as one CASPER. The hurricane recovery CASPER was conducted during February 26–March 1, 2018, on the three main islands.
The standard CASPER two-stage cluster sampling methodology was used to select a representative sample of interviewed households (1). The sampling frame was defined as all 43,214 occupied households within USVI, according to the 2010 U.S. Census. Using the Geographic Information Systems CASPER toolkit (1), 30 clusters were selected with probability of selection proportional to the number of households within each cluster. Interview teams were trained to select seven households from each of the selected clusters by systematic random sampling, with a goal of 210 interviews for each assessment. Teams made three attempts to contact one adult resident for an interview in each household before substituting another household.
The three 2-page CASPER questionnaires included the same or similar questions regarding mosquito prevention and control experiences, attitudes, and practices, including mosquito biting activity, repellent use, and household environmental characteristics. Response frequencies and percentages, including completion rates, with 95% confidence intervals (CIs) were calculated using Epi Info (version 220.127.116.11; CDC). Weighted frequencies and percentages based on probability of selection are reported, with weighted analysis only calculated for cells with ≥5 households (1). A preliminary report was presented to VIDOH within 5 days of completion of each assessment.
Teams conducted 201 of the target 210 interviews for the Zika outbreak response CASPER (95.7% completion rate; 62.2% of contacted households); 387 of the target 420 interviews for the hurricane response CASPER, including 195 on St. Croix (92.9% completion rate; 84.1% of contacted households) and 192 on St. Thomas/St. John (91.4% completion rate; 84.2% of contacted households); and 200 of the target 210 interviews for the hurricane recovery CASPER (95.2% completion rate; 81.3% of contacted households). The most represented household member age group in all three CASPERs was persons aged 18–64 years (80.8%, 75.0%, and 76.6% for the Zika outbreak response, the hurricane response, and the hurricane recovery CASPERs, respectively) followed by those aged ≥65 years (41.5% [Zika outbreak], 42.5% [hurricane response], and 42.2% [hurricane recovery]).
During the Zika outbreak response, 72.3% of households were very or somewhat concerned about contracting Zika virus, whereas 25.3% were not concerned; 78.7% were very or somewhat concerned about contracting other mosquitoborne diseases, including malaria, dengue, chikungunya, or yellow fever, and 17.8% were not concerned (Table 1). During the hurricane response, 87% of households noticed an increase in mosquito biting since the storms; however, only 61.5% were very or somewhat concerned about contracting Zika virus, 61.3% were concerned about contracting other mosquitoborne diseases, and 37.4% were not concerned. During hurricane recovery, 39.8% of households noticed an increase in mosquito biting during the preceding 4 weeks; approximately two thirds were very or somewhat concerned about contracting any mosquitoborne disease, and 32.7% were not concerned.
Barriers to use of mosquito repellent differed between the Zika outbreak and hurricane responses (Table 2). During the Zika outbreak response, approximately half (49.0%) of households had no barriers to mosquito repellent use, although nearly a quarter (23.5%) did not like the feel or smell, and one in five (19.4%) was concerned about their health when using it; 3.9% said it was too expensive. During the hurricane response, a larger percentage (59.3%) had no barriers, and fewer did not like the feel or smell (12.5%) or were concerned about their health when using it (10.8%); more than twice as many (8.9%) said it was too expensive.
Reported environmental conditions became more favorable for mosquito breeding and exposure to mosquito bites between the Zika outbreak and hurricane responses. For example, the percentages of households with undamaged window screens, undamaged door screens, and air conditioning were 64.4%, 39.9%, and 41.0%, respectively, during the Zika outbreak response. These percentages declined to 30.0%, 22.7%, and 19.8% during the hurricane response.
Community support for VIDOH to spray for mosquitoes was similar during the Zika outbreak response and hurricane recovery (76.3% each) and the hurricane response (79.2%) (Table 3), although support for specific spray methods varied. Support for truck spraying increased from 63% of households during Zika outbreak response to 78.1% during hurricane response and returned to 63% during hurricane recovery. Outdoor backpack spraying was supported by only 29.6% of households during the Zika outbreak response, increasing to 44.8% during the hurricane response and to 61.9% during hurricane recovery. Aerial spraying was supported by 12.8% of households during Zika outbreak response, 28.8% during hurricane response, and 16.4% during hurricane recovery.
These community assessments conducted during the Zika outbreak, hurricane responses, and hurricane recovery in USVI found that households were more concerned about contracting mosquitoborne diseases shortly after the Zika outbreak than during the hurricane response and hurricane recovery, even though reported mosquito biting activity increased, and environmental conditions were more favorable for mosquito breeding and exposure to bites following the hurricanes. In addition, although mosquitoborne diseases are endemic in USVI, and the population might be aware of the risk, households had concerns after the hurricanes that did not exist during the Zika outbreak, such as lack of shelter, clean water, and electricity (2). These differing levels of concern did not, however, change the community’s support for mosquito spraying, although support for specific spray methods varied.
VIDOH used the CASPER data to make real-time outbreak and hurricane response decisions to improve mosquito bite prevention, mosquito control, and community education. For example, because the percentage of households concerned about contracting mosquitoborne diseases declined after the hurricanes compared with during the Zika outbreak response, VIDOH hurricane response education campaigns prioritized household-level mosquito bite prevention. The differing levels of support for various spray methods were also recognized and considered during decision-making. For example, these data, along with unique environmental considerations, were used by the administration in place during the responses and recovery to determine backpack spraying to be the only acceptable option.
The CASPER is a useful tool for assessing mosquitoborne disease risk factors and creating immediately useable data to guide vector-related public health campaigns (3). According to CDC’s internal CASPER database (4), a limited number of CASPERs have been conducted that assess mosquito bite prevention- and control-related factors, such as knowledge of mosquitoborne diseases; ways to protect against mosquito bites; and how to identify, quantify, and manage potential mosquito breeding sites. Even fewer CASPERs have focused solely on mosquitoes. A CASPER in Long Beach, California, during a Zika outbreak identified the need for increased mosquito abatement (5). In two areas of Texas, CASPERs successfully assessed the prevalence of vectorborne disease risk factors and the communities’ knowledge of mosquito bite prevention and Zika virus (6,7). A CASPER conducted in American Samoa identified increased vector problems and the need for vector control after a tsunami (8).
Not only is CASPER an important tool for emergency response and recovery, it is also useful for collecting community public health information unrelated to an emergency (4,9). Vector control programs can use CASPERs during nonemergency situations to enhance and increase operation efficacy by evaluating the effectiveness of community campaigns and understanding community knowledge, attitudes, and practices.
The findings in this report are subject to at least three limitations. First, data generated from the CASPERs represent discrete points in time, which should be considered when interpreting the results to guide outbreak and hurricane response and recovery efforts. Second, the age distribution of the survey respondents is skewed, with a larger proportion of persons aged ≥65 years represented in the CASPERs than that reported by the U.S. Census; therefore, households without persons aged ≥65 years might be underrepresented. Finally, some questions were asked differently or not at all among the three CASPERs presented and are not directly comparable.
CASPERs that include mosquito prevention- and control-related questions are an important tool to inform both routine and response vector control operations and to understand how a community’s perceptions and behaviors might vary by adverse event and over time.
U.S. Virgin Islands Department of Health executive team members; Emory University summer practicum students; U.S. Virgin Islands Department of Health staff members; National Center for Environmental Health, CDC; Center for Preparedness and Response, CDC; University of Michigan Public Health Action Student Team; University of the Virgin Islands nursing students; AmeriCorps volunteers; Oak Ridge Institute for Science and Education fellows; Health and Human Services Incident Response Coordination Team and Emergency Support Function 8; CASPER respondents; Council of State and Territorial Epidemiologists.
Corresponding author: Krystal R. Seger, email@example.com, 340-718-1311.
All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.
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Suggested citation for this article: Seger KR, Roth J Jr., Schnall AH, Ellis BR, Ellis EM. Community Assessments for Mosquito Prevention and Control Experiences, Attitudes, and Practices — U.S. Virgin Islands, 2017 and 2018. MMWR Morb Mortal Wkly Rep 2019;68:500–504. DOI: http://dx.doi.org/10.15585/mmwr.mm6822a3external icon.
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