West Nile Virus – Evidence in Alberta 2004
2004 Summary
Surveillance Report 2004
Human cases
There was one confirmed travel-related case of West Nile virus Fever reported in Alberta in 2004. For more information read the 2004 summary report. (* See footnote)
Birds tested
Between May 1, 2004 and September 25, 2004
| Species | Tested this week |
Positive this week |
Tested since May 1/04 |
Total Positive |
Location |
| Blue Jay | 0 tested | 0 positive | 26 tested | 1 | Lethbridge(1) |
| Crow | 0 tested | 0 positive | 335 tested | 7 | Lethbridge(2), Bonnyville(1), Medicine Hat(2) Brooks (1) Vermillion (1) |
|
Magpie |
0 tested | 0 positive | 264 tested | 1 | Medicine Hat(1) |
| Raven | 0 tested | 0 positive | 40 tested | 0 | 0 |
| Other Corvid |
0 tested | 0 positive | 1 tested | 0 | 0 |
| Total | 0 | 0 positive | 666 | 9 |
Further information is available at Alberta Sustainable Resource Development website.
Horses tested
| Week | Number Tested | Number Laboratory Confirmed Positive | Location |
| May 29 - June 4 | 0 | 0 positive | |
| June 5 - 11 | 1 | 0 positive | |
| June 12 - 18 | 1 | 0 positive | |
| June 19 - 25 | 1 | 0 positive | |
| June 26 - July 3 | 2 | 0 positive | |
| July 3 - July 9 | 0 | 0 positive | |
| July 10 - 16 | 2 | 0 positive | |
| July 17 - 23 | 4 | 0 positive | |
| July 24 - 30 | 2 | 0 positive | |
| July 31 - August 6 | 2 | 0 positive | |
| August 7 - 13 | 14 | 1 positive | Picture Butte |
| August 14 - 20 | 4 | 0 positive | |
| August 21 - 27 | 2 | 1 positive | Oyen |
| August 28 - September 3 | 2 | 0 positive | |
| September 4 - 10 | 7 | 1 positive | Pincher Creek |
| September 11- 17 | 3 | 0 positive | |
| September 18- 24 | 4 | 0 positive | |
| September 25- October 1 | 1 | 1 positive | Stettler |
| October 2 - 8 | 2 | 0 positive | |
| October 9 - 15 | 3 | ||
| Total | 57 | 4 positive |
For more information on horse testing, see the Alberta Agriculture, Food and Rural Development website.
Mosquito Pools
| Week | Number of Pools Tested | Number of Positive Pools | Location of Positive Pools |
| June 27- July 3 | 120 | 0 positive | |
| July 4- 10 | 128 | 0 positive | |
| July 11-17 | 163 | 0 positive | |
| July 18-24 | 193 | 0 positive | |
| July 25- 31 | 194 | 0 positive | |
| August 1- 7 | 189 | 1 positive | County of Vulcan |
| August 8 - 14 | 197 | 0 positive | |
| August 15 - 21 | 182 | 0 positive | |
| August 22 - 28 | 160 | 0 positive | |
| August 29 - September 4 | 79 | 0 positive | |
| September 4 - 11 | 38 | 0 positive | |
| September 12 -18 | 36 | 0 positive |
Mosquito pools are tested for West Nile virus in all areas of the province where positive birds have been collected in this or previous years.
*Footnote
Q. Why do the media and Alberta Health and Wellness (AHW) sometimes report different statistics on the number of human West Nile virus cases?
A. The AHW human case count is based on the number of West Nile virus cases that have been officially reported by each regional health authority to AHW. Before a region makes its report to AHW, follow-up laboratory testing and/or contact with the patient may be required to determine whether or not a case fits the case definition for infection with West Nile virus. As AHW has a responsibility to report the most accurate health information possible, we do not count cases of West Nile virus until official case reports are received from the regions. This potential delay required to confirm a case of West Nile virus infection may result in different statistics being reported by the media and AHW.
