Article

Modifiable Risk Factors for West Nile Virus Infection during an Outbreak - Arizona, 2010

Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 80521, USA.
The American journal of tropical medicine and hygiene (Impact Factor: 2.7). 05/2012; 86(5):895-901. DOI: 10.4269/ajtmh.2012.11-0502
Source: PubMed

ABSTRACT

West Nile virus (WNV) is the leading cause of mosquito-borne disease in the United States; however, risk factors for infection are poorly defined. We performed a case-control study to identify modifiable risk factors for WNV infection. Case-patients (N = 49) had laboratory evidence of recent WNV infection, whereas control-subjects (N = 74) had negative WNV serology. We interviewed participants, surveyed households, and assessed environmental data. WNV infection was associated with living in or near Water District X within Gilbert Township (adjusted odds ratio [aOR] 5.2; 95% confidence interval [95% CI] = 1.5-18.1), having water-holding containers in their yard (aOR 5.0; 95% CI = 1.5-17.3), and not working or attending school outside the home (aOR 2.4; 95% CI = 1.1-5.5). During this outbreak, WNV infection was likely primarily acquired peri-domestically with increased risk associated with potential mosquito larval habitats around the home and neighborhood.

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    • "Notwithstanding differences in mosquito abundance and diversity between and within regions, climatic conditions that drive extrinsic incubation periods within mosquitoes may vary with the relationship between environmental temperature and dissemination rates of infection.123 With recent epidemics of WNV in Europe and North America, studies have identified environmental conditions as potentially important drivers of virus activity, including case-controlled studies in North America that have identified a high risk associated with urban environments.119,124,125 Changing environmental conditions may also influence reservoir host populations, including the migration of bird populations into new regions or other changes that bring avian host, mosquito vectors, and susceptible human populations into close proximity. "
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