Table 2.
Summary of first dates of detection of West Nile virus in Los Angeles County for each surveillance indicator by year*
| Indicator | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 |
|---|---|---|---|---|---|---|
| First dead bird report | Jan 16 | Jan 4 | Jan 4 | Jan 3 | Jan 1 | Jan 1 |
| First positive dead bird | Sep 3 | Feb 24 | Feb 1 | Jan 9, Apr 6 | Apr 5 | Jan 29 |
| Sentinel chicken | ND | Jul 13 | Jun 18 | Jul 22 | Aug 11 | Jul 13 |
| Positive mosquito pools | ||||||
| Culex tarsalis | ND | May 24 | Jun 21 | ND | Aug 22 | Jun 25 |
| Cx. p. quinquefasciatus | Sep 26 | May 6 | Jun 1 | May 10 | Jan 11, May 15 | May 15 |
| Cx. stigmatosoma | ND | Jul 16 | Jun 22 | ND | Aug 3 | Aug 1 |
*
First positive dead bird = virus detection in a bird carcass by reverse transcription–polymerase chain reaction; ND = none detected in that surveillance year.