Volume 17, Number 8—August 2011
Research
Early Warning System for West Nile Virus Risk Areas, California, USA
, Sean C. Ahearn, Alan McConchie2, Carol A. Glaser, Cynthia Jean, Chris Barker, Bborie Park, Kerry Padgett, Erin Parker, Ervic Aquino, and Vicki L. Kramer
Table 3
Reported human West Nile virus cases predicted by DYCAST system by county, California, 2005–2009*
| 2005† | 2006 | 2007 | 2008 | 2009 | |
|---|---|---|---|---|---|
| Alameda | NR | 0/1 (0) | NR | 0/1 (0) | NR |
| Amador | 0/1 (0) | NR | NR | NR | NR |
| Butte | 0/1 (0) | 4/29 (13.8) | 2/14 (14.3) | 0/4 (0) | 0/2 (0) |
| Calaveras | – | NR | NR | 0/1 (0) | NR |
| Colusa | – | 0/3 (0) | 0/2 (0) | 0/1 (0) | NR |
| Contra Costa | – | 4/8 (50.0) | 3/3 (100.0) | 3/3 (100.0) | 0/5 (0) |
| El Dorado | – | 0/2 (0) | NR | 0/1 (0) | 0/1 (0) |
| Fresno | – | 6/9 (66.7) | 9/17 (52.9) | 0/2 (0) | 2/11(18.2) |
| Glenn | – | 2/10 (20.0) | 0/1 (0) | 0/1 (0) | NR |
| Imperial | NR | 0/1 (0) | 0/2 (0) | NR | NR |
| Kern | – | 2/45 (4.4) | 74/126 (58.7) | 2/2 (100.0) | 0/15 (0) |
| Kings | – | 0/1 (0) | 0/6 (0) | 0/1 (0) | 0/3 (0) |
| Lake | NR | 0/1 (0) | NR | NR | NR |
| Los Angeles | – | 0/12 (0) | 2/31 (6.5) | 18/147 (12.2) | 1/16 (7.1) |
| Madera | – | NR | 0/2 (0) | NR | NR |
| Marin | NR | 0/1 (0) | NR | NR | NR |
| Mendocino | NR | NR | 0/2 (0) | NR | NR |
| Merced | 15/24 (62.5) | 0/4 (0) | 0/3 (0) | 0/1 (0) | 0/4 (0) |
| Mono | NR | 0/1 (0) | NR | NR | NR |
| Monterey | NR | NR | NR | NR | 0/1 (0) |
| Napa | NR | 0/1 (0) | 0/1 (0) | NR | NR |
| Nevada | – | 0/1 (0) | NR | NR | NR |
| Orange | – | 0/5 (0) | 0/9 (0) | 18/60 (30) | 0/2 (0) |
| Placer | 29/32 (90.6) | 3/8 (37.5) | 1/4 (25.0) | 1/5 (20.0) | NR |
| Riverside | 0/10 (0) | 0/4 (0) | 0/16 (0) | 0/55 (0) | 0/2 (0) |
| Sacramento | 142/152 (93.4) | 9/15 (60.0) | 7/22 (31.8) | 4/12 (33.3) | NR |
| San Bernardino | 0/6 (0) | 0/3 (0) | 0/3 (0) | 5/29 (17.2) | 0/2 (0) |
| San Diego | – | NR | 0/12 (0) | 1/30 (3.3) | 0/4 (0) |
| San Joaquin | 25/34 (73.5) | 4/8 (50.0) | 3/8 (37.5) | 3/9 (33.3) | 0/8 (0) |
| San Luis Obispo | NR | 0/1 (0) | NR | NR | NR |
| San Mateo | 0/1 (0) | NR | NR | NR | NR |
| Santa Clara | – | 3/5 (60.0) | 1/3 (33.3) | 0/1 (0) | NR |
| Shasta | – | 2/4 (50.0) | 1/9 (11.1) | 0/1 (0) | NR |
| Solano | 4/5 (80.0) | 6/8 (75.0) | NR | 1/1 (100.0) | NR |
| Sonoma | 0/1 (0) | NR | 0/1 (0) | NR | NR |
| Stanislaus | 67/79 (84.8) | 3/10 (30.0) | 7/20 (35.0) | 6/16 (37.5) | 0/12 (0) |
| Sutter | – | 0/12 (0) | 0/2 (0) | NR | NR |
| Tehama | – | 0/6 (0) | 0/3 (0) | 0/4 (0) | NR |
| Tulare | – | 0/5 (0) | 0/9 (0) | 2/3 (66.7) | 0/3 (0) |
| Tuolumne | – | NR | NR | NR | NR |
| Ventura | NR | 1/2 (50.0) | 0/1 (0) | NR | NR |
| Yolo | 7/8 (87.5) | 18/26 (69.2) | 0/1 (0) | 0/1 (0) | 0/2 (0) |
| Yuba | – | 0 (0/3) | NR | NR | NR |
| Total | 289/354 (81.6) | 67/255 (26.3) | 110/333 (33.0) | 64/392 (16.3) | 3/93 (3.2) |
*DYCAST, Dynamic Continuous-Area Space-Time; NR, no reported human West Nile virus cases; –, nonparticipating counties with reported cases in 2005. Records without a geocodable address or onset of illness cannot be included in the DYCAST model and are therefore not included in these totals. Counties with no reported cases from 2005–2009 are not shown.
†Analysis regions (Figure 1) consisted of the 16 agencies that participated in the 2005 DYCAST program. The participating region within El Dorado County had no reported cases in 2005.
1Current affiliation: Brown University, Providence, Rhode Island, USA.
2Current affiliation: University of British Columbia, Vancouver, British Columbia, Canada.