Epidemiology and Infection

West Nile virus/encephalitis

Completeness of West Nile virus testing in patients with meningitis and encephalitis during an outbreak in Arizona, USA

I. B. WEBERa1 c1, N. P. LINDSEYa1, A. M. BUNKO-PATTERSONa2, G. BRIGGSa3, T. J. WADLEIGHa2, T. L. SYLVESTERa2, C. LEVYa4, K. K. KOMATSUa4, J. A. LEHMANa1, M. FISCHERa1 and J. E. STAPLESa1

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

SUMMARY

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)

Correspondence:

c1 Author for correspondence: Dr I. B. Weber, CDC/DVBD, 3150 Rampart Road, Fort Collins, Colorado 80521, USA. (Email: ggv8@cdc.gov)

Metrics