the study concluded after 309 interviews were completed , a predetermined endpoint based on allowable resources . we measured the frequency ( 1 = never to 5 = always ) with which participants said they practiced protective behaviors ( applied mosquito repellent , eliminated standing water , and avoided mosquitoes ) . the following predictor items measured concepts of the health belief model : knowledge ( mode of transmission , risk groups ) , susceptibility to illness , severity of illness , barriers to action ( safety concerns , cost ) , benefits of action , and cues to action ( behavior of relatives , sources of information ) . response options for predictors were measured on a 5-point likert scale and signified the respondent 's agreement with a statement ( 1 = strongly disagree to 5 = strongly agree ) or belief that an event would occur ( 1 = not at all likely to 5 = very likely ) . response options for predictors measured with multiple - choice questions were scored as correct or incorrect . the subscore for a concept was calculated by averaging the scores obtained from questions specific to that concept . the subscore for the knowledge concept was calculated by counting the number of correct responses . we ascertained the participant 's sex , age , ethnicity , education , and income . participants were also asked to report the level of mosquito activity near their residence ( low , medium , high ) . a response rate of 64.6% ( 307 of 477 ) was calculated by dividing the number of completed surveys by the number of persons contacted . respondents were more likely to be women , older , more educated , and in a higher income bracket than the general population . most respondents said they obtained information about wnv by watching television ( n = 180 , 62.9% ) . while almost all ( n = 285 , 98.6% ) were aware that wnv was transmitted by mosquitoes , 57.9% ( n = 159 ) were aware that adults > 50 years of age are at greatest risk for serious illness . of those unaware of this fact , 52.0% ( n = 63 ) were > 50 years of age . at least occasional practice of the following specific protective behaviors was reported : 197 ( 68.2% ) removed standing water , 168 ( 58.1% ) practiced mosquito avoidance behavior , and 162 ( 56.0% ) used deet - based mosquito repellents ( figure ) . when asked if information about wnv had influenced them to remove standing water , agreement or strong agreement was reported by 213 ( 73.7% ) respondents , 147 ( 50.9% ) for using deet ( n , n - diethyl - m - toluamide and related compounds)-based mosquito repellent , and 110 ( 38.1% ) for avoiding mosquitos . the most prominent barriers to practicing protective behaviors were perception that deet is a health and environmental hazard , the time required to remove standing water , and participating in outdoor leisure activities during peak mosquito hours . approximately half ( n = 113 , 45.9% ) of respondents claiming to have spent time outdoors during peak mosquito hours did so to participate in leisure activities ( walking , playing with kids , gardening ) . more than one third ( n = 101 , 35.1% ) agreed or strongly agreed that removal of standing water was time consuming . more than one third ( n = 101 , 35.1% ) believed deet is hazardous to the environment , and more than one quarter ( n = 78 , 27.1% ) disagreed or strongly disagreed that it is safe for human use . the proportional odds ordinal regression model was fit to model the frequency at which persons reported avoiding mosquitoes , applying deet , and removing standing water ( table ) . predictors that were investigated included the composite scores for each of the health belief model concepts , demographic variables ( sex , age , area code , education , income , ethnicity ) , and residential mosquito activity level . or , odds ratio ; ci , confidence interval ; deet , n , n - diethyl - m - toluamide and related compounds . barriers to action and cues to action were important predictors in each of the three models . in addition , perceived susceptibility was significant in modeling the frequency of practicing avoidance of mosquitoes ( p < 0.01 ) and had an associated odds ratio of 1.61 ( confidence interval 1.222.12 ) . all other investigated predictors were not significant in multivariate models at the  = 0.05 level . before the study , the british columbia centre for disease control and prevention issued three formal press releases and provided 110 interviews with local or provincial media outlets about wnv and associated protective behaviors . most respondents in our study cited television as their main source of information , which demonstrates the ability of public health messaging to reach audiences through broadcast media . this finding is consistent with findings from other studies ( 10 ) and underscores the important role that this medium plays in educating the public ( 11 ) . the proportion of respondents who said they used deet - based mosquito repellent or practiced mosquito avoidance behavior was comparable to the proportion found in similar studies conducted in connecticut ( 2,10 ) . eliminating standing water was not specifically investigated in these studies . a national u.s . study reported smaller proportions of respondents who said that they avoided the outdoors during dawn or dusk ( 24% ) , used deet - based mosquito repellent ( 31% ) , and eliminated standing water ( 31% ) ( 12 ) . differences may be the result of the varying levels of wnv activity throughout the united states . regular systematic evaluations of the knowledge , attitudes , and behaviors of the public are needed to ensure the effectiveness of public health messages ( 2 ) . by using the health belief model as a theoretical framework the fear that deet - based mosquito repellents are hazardous to human health and the environment is a barrier of particular concern . these repellents are a mainstay for the personal prevention of wnv ( 11 ) and were demonstrated to be an important protective behavior option , given the participation of many respondents in outdoor activities during peak mosquito hours . instructions for the safe use of deet are outlined in the literature ( 13 ) and should be conveyed to address public fears . deet does not readily degrade by hydrolysis at environmental phs ( 14 ) and has been identified as a ubiquitous pollutant in aquatic ecosystems , but the effect of this is unknown ( 15 ) . a deficiency was also observed in the proportion of respondents who were aware that persons > 50 years of age were at greatest risk for serious illness from wnv . making perceptions of susceptibility and severity in this population more consistent with the actual susceptibility and severity could help to influence the adoption of wnv protective behaviors ( 9 ) . our study supports the ability of public health education campaigns to influence the practice of wnv protective behaviors . specifically , we found that most respondents reported that information about wnv influenced them to engage in protective behaviors , and cues to action significantly increased the odds that respondents practiced protective behaviors more frequently . together , these findings suggest the potential for public health messages that endorse wnv protective behaviors to have a " snowball effect " ; public health education can influence persons to practice protective behaviors , and these persons can influence friends and family to do the same . a number of limitations were associated with our study . first , we depended on self - reporting to measure frequency of practicing wnv protective behaviors , and no effort was made to validate the participants ' responses . if participants attempted to please interviewers , the frequency of protective behavior practice may have been overestimated . second , administering the interview by telephone excluded persons who did not have telephones or only had cellular phones , which may have contributed to the observed demographic differences between our study population and the general population . consequently , findings may not be generalizable outside the study population . third , information on nonrespondents was not obtained , and differences between them and the study population could not be ascertained . thus , the effects of this bias could not be determined . despite these limitations , this study will help public health officials achieve the goal of promoting wnv protective behaviors and reducing the risk for infection .
we investigated personal protective behaviors against west nile virus infection . 
 barriers to adopting these behaviors were identified , including the perception that deet ( n , n - diethyl - m - toluamide and related compounds ) is a health and environmental hazard . 
 televised public health messages and knowing that family or friends practiced protective behaviors were important cues to action .