Use of laboratory reports as predictors of West Nile virus disease cases, Texas, 2008-2012.
We evaluated laboratory reports as early indicators of West Nile virus (WNV) disease cases in Texas. We compared WNV laboratory results in the National Electronic Disease Surveillance System Base System (NBS) to WNV disease cases reported to the state health department from 2008 to 2012. We calculated sensitivity and positive predictive value (PPV) of NBS reports, estimated the number of disease cases expected per laboratory report, and determined lead and lag times. The sensitivity and PPV of NBS laboratory reports were 86% and 77%, respectively. For every 10 positive laboratory reports, we expect 9·0 (95% confidence interval 8·9-9·2) reported disease cases. Laboratory reports preceded case reports with a lead time of 7 days. Electronic laboratory reports provided longer lead times than manually entered reports (P < 0·01). NBS laboratory reports are useful estimates of future reported WNV disease cases and may provide timely information for planning public health interventions.
Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins, CO,USA.
S J
SJ
Yendell
Infectious Disease Control Unit,Texas Department of State Health Services,Austin, TX,USA.
J
J
Taylor
Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins, CO,USA.
B J
BJ
Biggerstaff
Infectious Disease Control Unit,Texas Department of State Health Services,Austin, TX,USA.
L
L
Tabony
Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins, CO,USA.
J E
JE
Staples
Division of Vector-Borne Diseases,Centers for Disease Control and Prevention,Fort Collins, CO,USA.
M
M
Fischer
D018563:Disease Notification / Q000706:statistics & numerical data*; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D006801:Humans; D007753:Laboratories; D011159:Population Surveillance / Q000379:methods*; D011237:Predictive Value of Tests; D013781:Texas / Q000453:epidemiology; D014901:West Nile Fever / Q000175:diagnosis* / Q000453:epidemiology*; D014902:West Nile virus