title: Human west nile virus neuroinvasive disease in Texas, 2003 epidemic: regional differences.
abstract: OBJECTIVE
  Arboviral diseases, such as West Nile virus (WNV) epizootics, tend to be geographically unique because of the biomes that support the vector(s) and reservoir host(s). Understanding such details aids in preventive efforts. We studied the 2003 epidemic of human West Nile neuroinvasive disease (WNND) in Texas because it initially appeared that incidence was not uniform across regions of the state.
  
  
  METHODS
  The epidemic was described by age, sex, and region of residence. These variables were used to compare age-specific incidence, standardized cumulative incidence, and age-adjusted relative risk (RR). We verified case data and used routine software, with population estimates from the US Census Bureau.
  
  
  RESULTS
  Regardless of sex, risk increased with age. Males had the greater risk (RR, 1.69); however, males aged 5 to 17 years had the greatest RR. Of the five regions compared, two posed more (RRs, 7.98 and 2.14) and one posed less (RR, 0.40) risk than the remainder of the state. Proportions of Culex vector species differed significantly between regions.
  
  
  CONCLUSIONS
  During 2003, the risk for WNND varied considerably across Texas. This suggests that various risks for WNV infection deserve additional research for preventive interventions to be regionally appropriate and effective.
authors.affiliation: Texas Tech University Health Sciences Center, School of Medicine, Lubbock, TX, USA. ronald.warner@ttuhsc.edu
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Warner
authors.forename: Robert C
authors.initials: RC
authors.lastname: Kimbrough
authors.forename: James L
authors.initials: JL
authors.lastname: Alexander
authors.forename: J
authors.initials: J
authors.lastname: Rush Pierce
authors.forename: Tigi
authors.initials: T
authors.lastname: Ward
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Martinelli
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000368:Aged; D000818:Animals; D002648:Child; D002675:Child, Preschool; D009033:Culicidae; D005260:Female; D006801:Humans; D008297:Male; D012306:Risk; D012737:Sex Factors; D013781:Texas / Q000453:epidemiology; D014901:West Nile Fever / Q000453:epidemiology* / Q000635:transmission