2013 Annual Report
Costing tool: This tool will help vector control managers estimate the additional cost associated with recommended Aedes albopictus control strategies.
Household surveys: The willingness to pay (WTP) survey was conducted in 2010 for 400 randomly selected households in the six study sites. The cooperation rate was 67.5%. The majority (54.6%) of respondents considered mosquitoes a problem. Mosquitoes prevented 59.5% of respondents from enjoying their outdoor activities to some extent. During a summer week, 51% of respondents reported being bitten on average 7.1 bites per week, 77.7% were bitten outdoors compared to 22.3% indoors. Of those bitten, 49.6% used existing products at home to treat their bites, 34.7% bought new products, and 4.2% saw a health care provider. The average amount paid out-of-pocket per person on treatment over the summer for mosquito bite products was $9.10 and $9.71 on medical providers, while insurance paid on average $13.14.
The survey asked respondents to rate the importance (1-5) of key aspects of living in a neighborhood. Respondents rated the mean importance of enjoying porch and yard outdoors activities without mosquitoes (4.7) equal to that of neighborhood safety and higher than that of a clean neighborhood (4.6). Getting 7 mosquito bites in a week is rated as the most unpleasant (1-5) event (4.7) followed by having trash in their block (4.6), and having mosquitoes outside their residence (4.5). When asked for the maximum amount respondents are WTP for one additional work-free, mosquito-free hour per summer week to engage in yard and porch activities, 92.4% reported WTP>0 for this imaginary hour. The mean WTP for eating or cooking outside was $10.43, for playing in yard or porch was $7.26, for relaxing and socializing was $10.75, for gardening was $7.74, and for maintaining a house or car was $6.47. Residents rated their mean mosquito experience during that summer on a scale of 100 (no mosquitoes) to 0 (mosquitoes’ invasion) at 56.7 and their overall utility (0 to.
Benefit-cost analysis: To estimate the cost of controlling Aedes albopictus, Brandeis University analyzed financial documents and the time allocated by staff implementing the programs in 2009 and 2011, and estimated the net cost of the program to be $33.34 per capita per year. Random samples of households in area wide pest management (AWPM) and control areas were surveyed each fall from 2008 through 2011. Hours lost were differences between actual hours of yard and porch activities in an average summer week compared to potential hours if there had been no mosquitoes. Net estimated benefits of AWPM were based on a difference-in-difference analysis. Reductions in hours lost were valued based on respondents’ WTP for a hypothetical extra hour free of mosquitoes they could spend in yard or porch activities. Numbers of hours lost per adult respondent due to mosquitoes in AWPM areas between the base year (2008) and the second and third intervention years (2010-2011) declined by 2.05 hours/week in intervention areas compared to control areas. However, the decline was not significant (p=0.19). This improvement translated to 26.70 hours gained over the 13-week summer. Residents’ WTP averaged $9.54/hour, indicating a monetary valuation per resident of $255/year (range: $226-$283).
These results give a net benefit per resident of $221/year (range: $189-$254) and a benefit-cost ratio of 7.6 (range: 6.8-8.5). Our analysis shows positive net benefit of the AWPM program.