a1 Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, USA
a2 Maricopa County Department of Public Health, Phoenix, AZ, USA
a3 Pinal County Division of Public Health, Florence, AZ, USA
a4 Arizona Department of Health Services, Phoenix, AZ, USA
Accurate data on West Nile virus (WNV) cases help guide public health education and control activities, and impact regional WNV blood product screening procedures. During an outbreak of WNV disease in Arizona, records from patients with meningitis or encephalitis were reviewed to determine the proportion tested for WNV. Of 60 patients identified with meningitis or encephalitis, 24 (40%) were tested for WNV. Only 12 (28%) of 43 patients aged <50 years were tested for WNV compared to 12 (71%) of 17 patients aged ≥50 years (P<0·01). Patients with clinical signs of weakness or paralysis, elevated CSF protein, admitted to an inpatient facility, or discharged to a rehabilitation facility were also more likely to have WNV testing performed. The lack of testing in younger age groups and in those with less severe disease probably resulted in substantial underestimates of WNV neuroinvasive disease burden.
(Accepted November 03 2011)
(Online publication November 29 2011)