It’s important to count the number of mosquitoes that have tested positive for West Nile virus. We share our test results with public health officials and community residents throughout the year.
2020 West Nile Virus Positive Mosquito Batches
The table below reflects test results through September 25, 2020.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| # of positive mosquito batches | # of batches tested | |
| Evanston | 199 | 549 |
| Glencoe | 24 | 75 |
| Glenview/Golf | 74 | 206 |
| Kenilworth | 23 | 86 |
| Lincolnwood | 43 | 146 |
| Morton Grove | 42 | 127 |
| Niles | 34 | 103 |
| Northbrook | 15 | 71 |
| Northfield | 24 | 117 |
| Skokie | 133 | 404 |
| Wilmette | 39 | 127 |
| Winnetka | 32 | 142 |
| Total | 682 | 2153 |
2019 West Nile Virus Positive Mosquito Batches
The table below reflects test results through September 27, 2019.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| # of positive mosquito batches | # of batches tested | |
| Evanston | 99 | 495 |
| Glencoe | 10 | 120 |
| Glenview/Golf | 80 | 238 |
| Kenilworth | 11 | 82 |
| Lincolnwood | 6 | 98 |
| Morton Grove | 33 | 97 |
| Niles | 21 | 124 |
| Northbrook | 7 | 88 |
| Northfield | 7 | 82 |
| Skokie | 102 | 379 |
| Wilmette | 49 | 158 |
| Winnetka | 14 | 109 |
| Total | 439 | 2070 |
2018 West Nile Virus Positive Mosquito Batches
The table below reflects test results through September 28, 2018.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| # of positive mosquito batches | # of batches tested | |
| Evanston | 102 | 372 |
| Glencoe | 16 | 62 |
| Glenview/Golf | 90 | 186 |
| Kenilworth | 16 | 51 |
| Lincolnwood | 32 | 111 |
| Morton Grove | 38 | 103 |
| Niles | 30 | 91 |
| Northbrook | 27 | 78 |
| Northfield | 25 | 84 |
| Skokie | 130 | 357 |
| Wilmette | 18 | 75 |
| Winnetka | 57 | 135 |
| Total | 581 | 1705 |
2017 West Nile Virus Positive Mosquito Batches
The table below reflects test results through September 29, 2017.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| # of positive mosquito batches | # of batches tested | |
| Evanston | 139 | 394 |
| Glencoe | 6 | 47 |
| Glenview/Golf | 68 | 173 |
| Kenilworth | 41 | 100 |
| Lincolnwood | 46 | 140 |
| Morton Grove | 36 | 80 |
| Niles | 6 | 52 |
| Northbrook | 25 | 63 |
| Northfield | 20 | 61 |
| Skokie | 140 | 344 |
| Wilmette | 18 | 59 |
| Winnetka | 8 | 52 |
| Total | 553 | 1565 |
2016 West Nile Virus Positive Mosquito Batches
The table below reflects cumulative test results through October 1, 2016.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| # of positive mosquito batches | # of batches tested | |
| Evanston | 130 | 365 |
| Glencoe | 30 | 116 |
| Glenview/Golf | 68 | 189 |
| Kenilworth | 17 | 68 |
| Lincolnwood | 19 | 74 |
| Morton Grove | 9 | 66 |
| Niles | 13 | 43 |
| Northbrook | 29 | 72 |
| Northfield | 17 | 67 |
| Skokie | 106 | 279 |
| Wilmette | 23 | 79 |
| Winnetka | 24 | 95 |
| Total | 485 | 1513 |
2015 West Nile Virus Positive Mosquito Batches
The table below reflects test results through September 29, 2015.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| # of positive mosquito batches | # of batches tested | |
| Evanston | 22 | 139 |
| Glencoe | 11 | 72 |
| Glenview/Golf | 67 | 183 |
| Kenilworth | 19 | 81 |
| Lincolnwood | 22 | 97 |
| Morton Grove | 22 | 104 |
| Niles | 15 | 60 |
| Northbrook | 9 | 58 |
| Northfield | 3 | 60 |
| Skokie | 44 | 131 |
| Wilmette | 8 | 50 |
| Winnetka | 16 | 83 |
Testing Notes
1,118 RAMP tests – 258 positives
2014 West Nile Virus Positive Mosquito Pools
The table below reflects the test results for 2014.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| RAMP® Test | RT-PCR Test* | |
| Evanston | 17 | 5 |
| Glencoe | 3 | 0 |
| Glenview/Golf | 17 | 1 |
| Kenilworth | 7 | 3 |
| Lincolnwood | 10 | 3 |
| Morton Grove | 14 | 3 |
| Niles | 9 | 2 |
| Northbrook | 6 | 2 |
| Northfield | 14 | 3 |
| Skokie | 4 | 0 |
| Wilmette | 7 | 1 |
| Winnetka | 2 | 1 |
Testing Notes
970 samples via RAMP® test – 110 positives.
504 samples via RT-PCR test – 24 positives.
*As of August 13, 2014, RT-PCR tests were not available due to equipment issues.
2013 West Nile Virus Positive Mosquito Pools
The table below reflects the test results through October 4, 2013.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| RAMP® Test | RT-PCR Test | |
| Evanston | 36 | 47 |
| Glencoe | 1 | 3 |
| Glenview/Golf | 41 | 48 |
| Kenilworth | 26 | 27 |
| Lincolnwood | 29 | 34 |
| Morton Grove | 16 | 23 |
| Niles | 21 | 24 |
| Northbrook | 14 | 23 |
| Northfield | 22 | 23 |
| Skokie | 24 | 34 |
| Wilmette | 20 | 26 |
| Winnetka | 17 | 23 |
Testing Notes
1242 samples via RAMP® test – 267 positives.
1219 samples via RT-PCR test – 335 positives.
2012 Positive Results
The extreme hot and dry conditions the area experienced from June to September were significant factors in the 56.35% increase in the Culex population in 2012 from 2011. We tested 1443 mosquito pools for West Nile Virus, of which 435 were positive.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| *RAMP® Test | **RT-PCR Test | |
| Evanston | 60 | 64 |
| Glencoe | 15 | 19 |
| Glenview/Golf | 67 | 72 |
| Kenilworth | 22 | 28 |
| Lincolnwood | 36 | 44 |
| Morton Grove | 28 | 34 |
| Niles | 25 | 28 |
| Northbrook | 21 | 29 |
| Northfield | 21 | 24 |
| Skokie | 76 | 94 |
| Wilmette | 37 | 43 |
| Winnetka | 27 | 32 |
Testing Notes
- 30.14% of the total number of mosquito pools tested were positive for West Nile Virus
- The week of July 20 – July 27, saw 90.7% of mosquito pools tested positive
- Experts consider a level of 10% positive mosquitoes to be of greater risk for transmission to humans
2011 Positive Results
During the 2011 season, 1135 mosquito pools were tested for West Nile Virus, of which 149 were positive. The following table lists the number of mosquito pools that tested positive for West Nile virus in each municipality.
| Location | # of Positive Results for West Nile Virus | |
|---|---|---|
| *RAMP® Test | **RT-PCR Test | |
| Evanston | 13 | 19 |
| Glencoe | 6 | 9 |
| Glenview/Golf | 27 | 32 |
| Kenilworth | 11 | 16 |
| Lincolnwood | 2 | 5 |
| Morton Grove | 5 | 7 |
| Niles | 7 | 10 |
| Northbrook | 9 | 14 |
| Northfield | 5 | 8 |
| Skokie | 51 | 58 |
| Wilmette | 8 | 9 |
| Winnetka | 5 | 9 |
Testing Notes
- Overall 13.13% of the total number of mosquito pools tested were positive for West Nile Virus
- Experts consider a level of 10% positive mosquitoes to be of greater risk for transmission to humans.
*RAMP® – Rapid Analyte Measurement Platform
**RT-PCR – means Real Time Polymerase Chain Reaction