Volume 18, Number 8—August 2012
Research
Comparison of Enzootic Risk Measures for Predicting West Nile Disease, Los Angeles, California, USA, 2004–2010
Jennifer L. Kwan, Bborie K. Park, Tim E. Carpenter, Van Ngo, Rachel Civen, and William K. Reisen
Table 2
Comparison of CMVRA, vector index, and DYCAST for predicting risk for West Nile disease by the calculation threshold applied, validation method, and associated risk, Los Angeles, California, USA, 2004–2010*
| Model | Sensitivity | Specificity | PPV | LRP | LRN | Mantel-Haenszel RR (95% CI) |
|---|---|---|---|---|---|---|
| CMVRA | ||||||
| 2.6 | 0.976 | 0.815 | 0.588 | 5.261 | 0.03 | 403.453 (70.506–2,308.659) |
| 4.1 | 0.317 | 1 | 1 | UND | 0.683 | 38.255 (29.425–49.736) |
| Vector index (percentile) | ||||||
| 0.018 (65) | 0.974 | 0.758 | 0.507 | 4.029 | 0.034 | 25.251 (18.120–35.033) |
| 0.041 (75) | 0.846 | 0.902 | 0.688 | 8.631 | 0.171 | 25.383 (18.350–35.112) |
| 0.095 (85) | 0.564 | 0.954 | 0.759 | 12.33 | 0.457 | 24.284 (17.503–33.692) |
| 0.276 (95) | 0.246 | 0.993 | 0.909 | 36.231 | 0.748 | 23.253 (16.878–32.036) |
| DYCAST | ||||||
| Daily | 0.268 | 0.165 | <0.001 | 0.321 | 4.443 | 10.112 (7.367–13.880) |
| Biweekly | 0.361 | 0.045 | 0.006 | 0.378 | 14.242 | 9.756 (7.764–12.258) |
*CMVRA, California Mosquito-Borne Virus Risk Assessment; DYCAST, Dynamic Continuous-Area Space-Time system; PPV, positive predictive value; LRP, likelihood ratio positive; LRN, likelihood ratio negative; RR, relative risk; UND, undefined due to the high specificity.
