Volume 10, Number 9—September 2004
Dispatch
Year-round West Nile Virus Activity, Gulf Coast Region, Texas and Louisiana
Robert B. Tesh*
, Ray Parsons†, Marina Siirin*, Yvonne Randle†, Chris Sargent†, Hilda Guzman*, Taweesak Wuithiranyagool†, Stephen Higgs*, Dana L. Vanlandingham*, Adil A. Bala†, Keith Haas‡, and Brian Zerinque§
, Ray Parsons†, Marina Siirin*, Yvonne Randle†, Chris Sargent†, Hilda Guzman*, Taweesak Wuithiranyagool†, Stephen Higgs*, Dana L. Vanlandingham*, Adil A. Bala†, Keith Haas‡, and Brian Zerinque§Table 1
Monthly summary of dead birds and mosquitoes tested for West Nile virus (WNV) in Harris County, Texas
| Year/month | Mean temperature (°C)a | Total birds tested | No. WNV-positive (% positive) | Total mosquitoes tested | No. WNV-positive mosquito poolsb | WNV minimum infection rate |
|---|---|---|---|---|---|---|
| 2003 | ||||||
| January | 10.6 | 46 | 0 | 2,164 | 0 | 0.00 |
| February | 12.5 | 62 | 0 | 1,146 | 0 | 0.00 |
| March | 16.7 | 80 | 0 | 5,304 | 0 | 0.00 |
| April | 21.4 | 98 | 1 (1.0) | 39,000 | 0 | 0.00 |
| May | 27.1 | 213 | 4 (1.9) | 58,698 | 2 | 0.03 |
| June | 27.9 | 219 | 33 (15.1) | 42,041 | 40 | 0.95 |
| July | 28.2 | 205 | 72 (35.1) | 54,582 | 203 | 3.72 |
| August | 28.9 | 164 | 83 (50.6) | 40,184 | 128 | 3.19 |
| September | 25.5 | 127 | 38 (29.9) | 34,691 | 21 | 0.61 |
| October | 22.2 | 73 | 11 (15.1) | 41,465 | 4 | 0.10 |
| November | 18.7 | 20 | 2 (10) | 7,562 | 2 | 0.13 |
| December | 12.6 | 7 | 1 (14.3) | 8,411 | 0 | 0.00 |
| 2004 | ||||||
| January | 13.2 | 26 | 1 (3.8) | 12,816 | 0 | 0.00 |
| February | 12.3 | 146 | 3 (2.1) | 9,790 | 0 | 0.00 |
| March | 19.5 | 137 | 1 (0.7) | 14,714 | 0 | 0.00 |
| Total | – | 1,623 | 250 (15.4) | 372,568 | 400 | 1.07 |
aMean monthly temperature in Houston (Harris County) (11).
bMean pool size was 28.2 mosquitoes/pool.
