Yard Flooding by Irrigation Canals Increased the Risk of West Nile Disease in El Paso, Texas
Section snippets
Materials and Methods
We conducted a cumulative (“epidemic”) unmatched case-control study (12, p. 125) of 48 new WN virus (WNV) cases reported and investigated by the City of El Paso Department of Public Health from 2009 to 2010 among residents of El Paso County, Texas, who met the definition of confirmed cases (13). The authors conducted the study in October and November of 2010, as part of an ongoing field epidemic investigation. Controls were subjects randomly selected among El Paso County residents who
Results
In 2003 through 2010, 182 confirmed cases of WN disease were reported for an age-adjusted incidence rate of 3.5 cases per 100,000 person-years. Eighteen (or 9.9%) of the 182 confirmed WN disease cases were known to be deceased at the time of report. Cases of WN fever were reported since 2004, and 24 (16%) fell into this category, the rest were considered neuroinvasive. Incidence of WN disease increased 30 times between those in the 0 to 9 years of age and those in the 70 years or older age
Discussion
We tested the hypothesis that proximity to irrigation canals and use of water from canals to flood residential yards is a risk factor for WN disease in El Paso, Texas. The larger 2003 through 2010 case–hypothetical control study showed that persons living closer to irrigation canals were at increased risk of WN, whereas the smaller 2009 through 2010 case-control study, which obtained data through actual interviews, provided insights into one postulated mechanism by which the closeness to canals
Conclusions
We found evidence that living in close proximity to irrigation canals, the use of water from canals and the prevalent practice of flooding residential yards with water from canals in El Paso County, Texas, was a risk factor for WN disease. Furthermore, this study identified two other risk factors: Those at high risk are older individuals with chronic conditions who do not use mosquito repellent. Interventions should target these populations within areas close to irrigation canals.
References (35)
- et al.
Is agricultural activity linked to the incidence of human West Nile virus?
Am J Prev Med
(2006) - et al.
Irrigation linked to a greater incidence of human and veterinary West Nile virus cases in the United States from 2004 to 2006
Prev Vet Med
(2009) - et al.
Epi Info: a general-purpose microcomputer program for public health information systems
Am J Prev Med
(1991) - et al.
Human West Nile virus neuroinvasive disease in Texas, 2003 epidemic: regional differences
Ann Epidemiol
(2006) - et al.
Declining growth rate of West Nile virus in North America
J Virol
(2007) - et al.
West Nile virus in California
Emerg Infect Dis
(2004) - et al.
West Nile Virus in the New World: trends in the spread and proliferation of West Nile Virus in the Western Hemisphere
Zoonoses Public Health
(2009) - et al.
Risk factors associated with human infection during the 2006 West Nile virus outbreak in Davis, a residential community in northern California
Am J Trop Med Hyg
(2008) - et al.
Landscape, demographic, entomological, and climatic associations with human disease incidence of West Nile virus in the state of Iowa, USA
Int J Health Geogr
(2008) - et al.
Irrigated agriculture is an important risk factor for West Nile virus disease in the hyperendemic Larimer-Boulder-Weld area of north central Colorado
J Med Entomol
(2010)
Spatio-temporal analysis of the relationship between WNV dissemination and environmental variables in Indianapolis, USA
Int J Health Geogr
Rapid GIS-based profiling of West Nile virus transmission: defining environmental factors associated with an urban-suburban outbreak in Northeast Ohio, USA
Geospat Health
Spatio-temporal cluster analysis of county-based human West Nile virus incidence in the continental United States
Int J Health Geogr
Modern Epidemiology
Epidemic/Epizootic West Nile Virus in the United States: Guidelines for Surveillance, Prevention, and Control
The next birthday method of respondent selection
Public Opin Q
Evaluation of risk indices for the transmission of dengue
Salud Publica Mex
Cited by (7)
Recurrent West Nile virus outbreak in the United States in 2022: Current challenges and recommendations
2023, Journal of Biosafety and BiosecuritySerological Evidence of Dengue and West Nile Virus Human Infection in Juarez City, Mexico
2019, Vector-Borne and Zoonotic DiseasesSeroprevalence, risk factors and spatial distribution of West Nile virus in Jordan
2019, Transactions of the Royal Society of Tropical Medicine and HygieneEmergence and associated risk factors of vector borne West Nile virus infection in Ilorin, Nigeria
2018, Journal of Arthropod-Borne DiseasesRisk factors for West Nile virus infection and disease in populations and individuals
2015, Expert Review of Anti-Infective Therapy
This study received funding from UT School of Public Health Dr. Cardenas Faculty Incentive Plan and from an NIH National Centers for Research Resources grant (5G12RR008124) to UTEP.