Behavioral Risks for West Nile Virus Disease, Northern Colorado, 2003

Larimer County Department of Health and Environment, Fort Collins, Colorado 80521, USA.
Emerging infectious diseases (Impact Factor: 6.75). 04/2007; 13(3):419-25. DOI: 10.3201/eid1303.060941
Source: PubMed


In 2003, residents in 2 adjacent cities in northern Colorado (Loveland and Fort Collins) had severe outbreaks of human West Nile virus (WNV) disease. Unexpectedly, age-adjusted neuroinvasive disease rates were higher in Loveland (38.6 vs. 15.9 per 100,000), which had a more extensive mosquito control program and fewer mosquitoes. A survey was conducted to assess differences in personal protection and risk practices by each city's residents. During May and June 2004, a random-digit dial telephone survey was conducted among adults to assess personal protection behavioral practices used to prevent WNV infection during the 2003 outbreak. After we adjusted for identified risk factors, Loveland residents were 39% more likely to report seldom or never using N,N-diethyl-m-toluamide (DEET), and approximately 30% were more likely to report being outdoors during prime mosquito-biting hours than Fort Collins residents. Personal protective practices may directly influence rates of WNV infection and remain important even when comprehensive community mosquito control measures are implemented.

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    • "In studies focused on spatial or temporal risk of illness from WNv, the response variable typically includes data from human disease cases [13,14,16,20,27-29], vector abundance or infection [15,17,30-34], evidence of infection in non-human hosts [21-24,26], or a combination of vector and host data [1,12,25,35-37]. When human case data are the response variable, inconsistencies between WNv risk and environmental factors have been attributed to: exposure occurring away from the home residence; time outdoors; use of insect repellent; socioeconomic differences, and even variable case definition [38-41]. An analysis in Indianapolis, IN, with similar climatic features and spatial scale as the current study, identified a relationship with both low precipitation and higher temperatures and increased numbers of human WNV cases [36]. "
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