West Nile Positive Results

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.

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