West Nile Virus – Evidence in Alberta 2007
2007 Summary
Surveillance Report 2007
Human cases
There were 320 cases of WNv reported in Alberta in 2007. West Nile Non-Neurological Syndrome accounted for 296 (92.5 per cent) of cases, while there were 21 cases (6.5 per ent) of West Nile Neurological Syndrome. There were three asymptomatic cases. For more information read the 2007 summary report.
Regional rates of WNv in Alberta to October 27, 2007:
| RHA | All Cases | Cases* (excluding known travel) | Population | Local Rate | Standard Error | Rate |
| Chinook | 55 | 54 | 156,562 | 34.5 | 4.69 | 35.1 |
| Palliser | 191 | 182 | 102,387 | 177.8 | 13.16 | 186.5 |
| Calgary | 37 | 19 | 1,207,814 | 1.7 | 0.37 | 3.1 |
| David Thompson | 14 | 7 | 300,246 | 2.3 | 0.88 | 4.7 |
| East Central | 11 | 8 | 111,197 | 7.2 | 2.54 | 9.9 |
| Capital | 8 | 1 | 1,027,553 | 0.1 | 0.10 | 0.8 |
| Aspen | 3 | 1 | 177,420 | 0.6 | 0.56 | 1.7 |
| Peace Country | 0 | 0 | 139,009 | 0.0 | 0.00 | 0.0 |
| Northern Lights | 1 | 0 | 75,547 | 0.0 | 0.00 | 1.3 |
| Alberta | 320 | 272 | 3,297,735 | 8.0 | 0.49 | 9.7 |
* All cases are considered to be locally acquired unless there is definitive evidence of acquisition during travel.
Mosquito pools
A cumulative total of 223 WNv positive Culex tarsalis mosquito pools have been found in Alberta since July 15, 2007. Five health regions, Chinook, Palliser, Calgary, David Thompson and East Central, reported positive mosquito pools in 2007.
| Week | Number of Pools Tested | Number Laboratory Confirmed Positive |
| August 26 – September 1 | 26 | 4 |
| August 19–25 | 59 | 23 |
| August 12–18 | 126 | 53 |
| August 5–11 | 164 | 62 |
| July 29 – August 4 | 167 | 43 |
| July 22–28 | 135 | 25 |
| July 15–21 | 127 | 13 |
| July 8–14 | 55 | 0 |
| July 1–7 | 38 | 0 |
| June 24–30 | 20 | 0 |
| June 17–23 | 12 | 0 |
| 2007 Total | 929 | 223 |
Horses tested
Forty-five horses tested positive for West Nile virus in 2007.
For more information on horse testing, see the Alberta Agriculture and Food website.
