Final Cumulative Maps & Data for 1999–2020

West Nile virus disease cases reported to CDC by state of residence, 1999-2020

West Nile virus disease cases reported to CDC by state of residence, 1999-2020
State 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Total
Alabama 0 0 2 49 37 16 10 8 24 18 0 3 5 62 9 2 9 19 60 28 5 9 375
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 2
Arizona 0 0 0 0 13 391 113 150 97 114 20 167 69 133 62 107 103 78 111 26 174 12 1,940
Arkansas 0 0 0 43 25 28 28 29 20 9 6 7 1 64 18 11 18 9 18 8 9 1 352
California 0 0 0 1 3 779 880 278 380 445 112 111 158 479 379 801 783 442 553 217 225 235 7,261
Colorado 0 0 0 14 2,947 291 106 345 576 71 103 81 7 131 322 118 101 149 68 96 122 35 5,683
Connecticut 0 1 6 17 17 1 6 9 4 8 0 11 9 21 4 6 10 1 3 23 1 8 166
Delaware 0 0 0 1 17 0 2 0 1 1 0 0 1 9 3 0 6 0 1 10 0 0 52
Dist. of Columbia 0 0 0 34 3 2 5 2 0 8 2 6 15 10 1 3 5 1 4 13 11 0 125
Florida 0 0 12 28 94 41 21 3 3 3 3 12 24 73 7 17 13 8 5 35 2 51 455
Georgia 0 0 6 44 50 21 20 8 50 8 4 13 22 99 10 13 15 6 48 36 14 8 495
Hawaii 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1
Idaho 0 0 0 0 1 3 13 996 132 39 38 1 3 17 40 19 13 9 25 16 13 6 1,384
Illinois 0 0 0 884 54 60 252 215 101 20 5 61 34 290 117 44 77 154 90 176 28 42 2,704
Indiana 0 0 0 293 47 13 23 80 24 4 4 13 9 77 23 10 21 18 26 35 4 3 727
Iowa 0 0 0 54 147 23 37 37 30 6 5 9 9 31 44 15 14 37 12 104 5 3 622
Kansas 0 0 0 22 91 43 25 30 40 31 13 19 4 56 91 54 34 37 27 47 13 8 685
Kentucky 0 0 0 75 14 7 5 6 4 3 3 3 5 23 3 1 2 8 10 12 10 0 194
Louisiana 0 0 1 329 124 109 171 180 40 49 21 27 10 335 54 125 51 59 53 83 20 18 1,859
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 2 0 1 5
Maryland 0 0 6 36 73 16 5 11 10 14 1 23 19 47 16 6 45 6 6 45 7 1 393
Massachusetts 0 0 3 23 17 0 6 3 6 1 0 7 6 33 8 6 10 17 6 49 5 12 218
Michigan 0 0 0 614 19 16 62 55 17 17 1 29 34 202 36 1 18 43 40 102 12 32 1,350
Minnesota 0 0 0 48 148 34 45 65 101 10 4 8 2 70 79 21 9 83 30 63 5 0 825
Mississippi 0 0 0 192 87 51 70 183 136 65 53 8 52 247 45 43 38 43 63 50 15 7 1,448
Missouri 0 0 0 168 64 36 30 62 77 15 5 3 10 20 29 13 29 11 19 23 5 1 620
Montana 0 0 0 2 222 6 25 34 202 5 5 0 1 6 38 5 3 6 11 47 3 1 622
Nebraska 0 0 0 152 1,942 53 188 264 163 47 52 39 29 193 226 142 68 95 68 251 28 15 4,015
Nevada 0 0 0 0 2 44 31 124 12 16 12 2 16 9 11 3 7 16 67 9 46 1 428
New Hampshire 0 0 0 0 3 0 0 0 0 0 0 1 0 1 1 0 0 0 1 0 0 0 7
New Jersey 0 6 12 24 34 1 6 5 1 10 3 30 7 48 12 8 26 11 8 61 8 3 324
New Mexico 0 0 0 0 209 88 33 8 60 8 8 25 4 47 38 24 14 6 33 7 40 8 660
New York 62 14 15 82 71 10 38 24 22 46 7 128 44 107 32 26 57 22 51 98 17 22 995
North Carolina 0 0 0 2 24 3 4 1 8 3 0 0 2 7 3 0 4 2 8 10 1 1 83
North Dakota 0 0 0 17 617 20 86 137 369 37 1 9 4 89 125 23 23 85 62 204 9 7 1,924
Ohio 0 0 0 441 108 12 61 48 23 15 2 5 21 121 24 11 35 17 34 65 3 3 1,049
Oklahoma 0 0 0 21 79 22 31 48 107 9 10 1 1 191 89 18 89 35 42 18 8 7 826
Oregon 0 0 0 0 0 3 7 69 26 16 11 0 0 11 16 8 1 4 6 2 9 1 190
Pennsylvania 0 0 3 62 237 15 25 9 10 14 0 28 6 60 11 13 30 16 20 130 7 11 707
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1
Rhode Island 0 0 0 1 7 0 1 0 1 1 0 0 1 4 1 0 0 2 2 1 0 0 22
South Carolina 0 0 0 1 6 2 5 1 5 1 3 1 0 29 7 3 0 8 18 15 2 4 111
South Dakota 0 0 0 37 1,039 51 229 113 208 39 21 20 2 203 149 57 40 152 73 169 11 20 2,633
Tennessee 0 0 0 56 26 14 18 22 11 19 9 4 18 33 24 16 8 7 30 12 3 0 330
Texas 0 0 0 202 720 176 195 354 260 64 115 89 27 1,868 183 379 275 370 135 146 32 122 5,712
Utah 0 0 0 0 1 11 52 158 70 26 2 2 3 5 7 2 8 13 62 11 21 2 456
Vermont 0 0 0 1 3 0 0 0 0 0 0  0 1 3 2 0 0 2 3 1 0 0 16
Virginia 0 0 0 29 26 5 1 5 5 1 5 5 9 30 6 7  21 8 13 48 6 2 232
Washington 0 0 0 0 0 0 0 3 0 3 38 2 0 4 1 12 24 9 13 3 5 2 119
West Virginia 0 0 0 3 2 0 0 1 0 1 0 0 2 10 1 0 0 1 1 2 0 0 24
Wisconsin 0 0 0 52 17 12 17 21 13 8 1 2 3 57 21 6 9 13 51 33 2 5 343
Wyoming 0 0 0 2 375 10 12 65 181 8 12 6 3 7 41 5 8 11 7 4 4 1 762
Total 62 21 66 4,156 9,862 2,539 3,000 4,269 3,630 1,356 720 1,021 712 5,674 2,469 2,205 2,175 2,149 2,097 2,647 971 731 52,532

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West Nile virus neuroinvasive disease cases reported to CDC by state of residence, 1999-2020

West Nile virus neuroinvasive disease cases reported to CDC by state of residence, 1999-2020
State 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Total
Alabama 0 0 2 34 25 15 6 8 17 11 0 1 5 38 3 0 5 13 40 16 4 7 250
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1
Arizona 0 0 0 0 7 215 52 68 50 62 12 107 49 87 50 80 67 57 98 25 132 8 1,226
Arkansas 0 0 0 32 23 17 13 24 13 7 6 6 1 44 16 9 16 8 15 6 7 1 264
California 0 0 0 1 2 291 305 81 154 292 67 72 110 297 237 561 585 335 401 154 147 179 4,271
Colorado 0 0 0 6 621 41 21 66 99 17 36 26 2 62 90 46 57 59 29 52 52 17 1,399
Connecticut 0 0 6 10 12 0 4 7 2 5 0 7 8 12 1 3 8 1 2 18 1 5 112
Delaware 0 0 0 0 12 0 1 0 1 0 0 0 1 2 3 0 0 0 0 8 0 0 28
Dist. of Columbia 0 0 0 14 3 1 3 0 0 4 2 3 10 8 0 1 3 1 1 7 9 0 70
Florida 0 0 12 28 61 33 10 3 3 3 2 9 20 52 5 12 12 6 4 30 2 44 351
Georgia 0 0 6 28 27 14 9 2 23 4 4 4 14 46 4 11 13 4 44 30 9 7 303
Hawaii 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Idaho 0 0 0 0 0 1 3 139 11 4 9 0 1 5 14 6 5 3 16 10 5 5 237
Illinois 0 0 0 553 30 29 137 127 63 12 5 45 22 187 86 36 51 98 72 126 22 36 1,737
Indiana 0 0 0 180 15 8 11 27 14 3 2 6 7 46 19 9 16 15 18 26 4 3 429
Iowa 0 0 0 27 81 13 14 22 12 3 0 5 5 11 24 5 4 16 10 59 1 2 314
Kansas 0 0 0 22 89 18 17 17 14 14 4 4 4 20 34 18 12 18 12 23 7 6 353
Kentucky 0 0 0 53 11 1 5 5 4 3 3 2 4 13 1 0 1 5 9 9 4 0 133
Louisiana 0 0 1 204 101 85 117 91 27 18 10 20 6 155 34 61 41 38 38 56 11 14 1,128
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 0 1 4
Maryland 0 0 6 22 49 10 4 10 6 6 0 17 10 25 11 6 31 6 5 35 6 1 266
Massachusetts 0 0 3 19 12 0 4 2 3 1 0 6 5 25 7 5 7 10 5 42 2 9 167
Michigan 0 0 0 557 14 13 54 43 16 11 1 25 32 141 24 1 16 42 32 80 11 29 1,142
Minnesota 0 0 0 16 48 13 18 31 44 2 1 4 1 34 31 6 3 38 13 34 2 0 339
Mississippi 0 0 0 162 34 31 39 89 50 22 31 3 31 103 27 26 25 27 46 31 12 4 793
Missouri 0 0 0 126 39 27 17 51 61 12 4 3 6 17 24 10 23 9 17 17 4 1 468
Montana 0 0 0 2 75 2 8 12 37 0 2 0 1 1 10 2 3 3 3 25 3 1 190
Nebraska 0 0 0 84 194 7 55 45 21 7 11 10 14 42 54 41 19 35 19 124 17 9 808
Nevada 0 0 0 0 2 25 14 34 2 9 7 0 12 5 8 3 4 13 31 3 34 0 206
New Hampshire 0 0 0 0 2 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 5
New Jersey 0 5 12 16 21 1 3 2 1 6 3 15 2 22 10 6 23 11 6 44 6 3 218
New Mexico 0 0 0 0 74 32 20 3 39 5 6 21 4 24 24 19 12 6 23 5 30 7 354
New York 59 14 13 68 57 7 30 16 16 32 6 89 28 61 18 19 42 20 45 77 14 18 749
North Carolina 0 0 0 2 16 3 2 1 4 2 0 0 2 7 3 0 4 2 8 10 1 1 68
North Dakota 0 0 0 3 94 2 12 20 49 2 0 2 1 39 64 12 10 24 20 60 2 2 418
Ohio 0 0 0 310 84 11 46 36 13 14 0 4 10 76 21 10 23 12 23 45 3 3 744
Oklahoma 0 0 0 16 56 16 17 27 59 4 8 1 1 103 60 9 49 21 34 12 6 6 505
Oregon 0 0 0 0 0 0 1 7 7 3 1 0 0 0 7 7 0 2 3 2 6 0 46
Pennsylvania 0 0 3 42 145 10 14 8 5 12 0 19 5 33 6 11 17 12 15 95 5 7 464
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1
Rhode Island 0 0 0 1 5 0 1 0 0 1 0 0 1 2 1 0 0 2 1 0 0 0 15
South Carolina 0 0 0 1 3 0 5 1 3 0 3 1 0 20 3 3 0 6 16 12 2 4 83
South Dakota 0 0 0 17 151 6 36 38 48 11 6 4 0 62 57 12 11 35 27 47 0 10 578
Tennessee 0 0 0 47 21 13 15 16 5 12 4 2 16 19 17 12 5 3 22 11 3 0 243
Texas 0 0 0 202 431 119 128 233 170 40 93 77 20 844 113 253 196 252 87 108 24 101 3,491
Utah 0 0 0 0 0 6 21 56 28 6 1 1 1 3 4 1 5 7 39 7 14 1 201
Vermont 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 2 2 1 0 0 8
Virginia 0 0 0 16 19 5 0 0 3 0 5 4 8 20 6 5 13 6 12 38 4 1 165
Washington 0 0 0 0 0 0 0 0 0 2 26 1 0 4 0 7 8 8 10 2 3 0 71
West Virginia 0 0 0 3 1 0 0 1 0 1 0 0 2 5 1 0 0 0 1 2 0 0 17
Wisconsin 0 0 0 22 7 5 11 11 7 4 1 0 2 44 17 3 6 10 47 29 0 5 231
Wyoming 0 0 0 0 92 2 6 15 23 0 4 2 1 3 16 0 3 8 4 3 2 1 185
Total 59 19 64 2,946 2,866 1,148 1,309 1,495 1,227 689 386 629 486 2,873 1,267 1,347 1,455 1,309 1,425 1,658 633 559 25,849

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West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999-2020

West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999-2020
Year Neuroinvasive disease
Cases
No.
Neuroinvasive disease
Deaths
No. (%)
Non-neuroinvasive disease
Cases
No.
Non-neuroinvasive disease
Deaths
No. (%)
Total
Cases
No.
Total
Deaths
No. (%)
1999 59 7  (12) 3 0  (0) 62 7  (11)
2000 19 2  (11) 2 0  (0) 21 2  (10)
 2001  64  10  (16)  2  0  (0)  66  10  (15)
 2002  2,946 276  (9)  1,210  8  (1)  4,156  284  (7)
2003 2,866 232  (8) 6,996 32  (<1) 9,862 264  (3)
2004 1,148 94  (8) 1,391 6  (<1) 2,539 100  (4)
2005 1,309 104  (8) 1,691 15  (1) 3,000 119  (4)
2006 1,495 162  (11) 2,774 15  (1) 4,269 177 (4)
2007 1,227 117  (10) 2,403 7  (<1) 3,630 124  (3)
2008 689 41  (6) 667 3  (<1) 1,356 44  (3)
2009 386 32  (8) 334 0  (0) 720 32  (4)
2010 629 54  (9) 392 3  (1) 1,021 57  (6)
2011 486 42  (9) 226 1  (<1) 712 43  (6)
 2012  2,873 270  (9)  2,801  16  (1)  5,674 286  (5)
 2013  1,267 111  (9)  1,202  8  (<1)  2,469 119  (5)
 2014  1,347 87  (6)  858  10  (1)  2,205 97  (4)
 2015  1,455 142  (10)  720  4  (<1)  2,175 146  (7)
2016  1,309 105  (8)  840  1  (<1)  2,149 106  (5)
2017 1,425 146  (10) 672 0  (0) 2,097 146  (7)
2018 1,658 165  (10) 989 2  (<1) 2,647 167  (6)
2019 633 60 (9) 338 0  (0) 971 60 (6)
2020 559 66 (12) 172 0  (0) 731 66 (6)
Total  25,849 2,325  (9)   26,683  131  (<1)  52,532 2,456  (5) 

Source: ArboNET, Arboviral Diseases Branch, Centers for Disease Control and Prevention

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Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by age group, 1999-2020

Graph depicting Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by age group, 1999-2018

Source: ArboNET, Arboviral Diseases Branch, Centers for Disease Control and Prevention

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Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by age group, 1999-2018
Age Group Average Incidence
<10 0.03
10-19 0.08
20-29 0.13
30-39 0.22
40-49 0.40
50-59 0.52
60-69 0.59
≥70 0.92

Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by county, 1999-2020

This map shows the average annual incidence of human West Nile virus neuroinvasive disease (e.g., meningitis, encephalitis, or acute flaccid paralysis) by county from 1999-2017 with shading ranging from 0.01‐0.49, 0.50‐0.99, 1.00‐1.49, 1.50‐1.99, and greater than 2.00 per 100,000 population.  The heaviest concentration of incidents are found in the midwest region of the U.S. and the lightest concentration in the eastern half of the U.S.

Source: ArboNET, Arboviral Diseases Branch, Centers for Disease Control and Prevention

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Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by state, 1999-2020

Map of the United States showing average annual incidence of West Nile virus neuroinvasive disease reported to CDC by state, 1999-2019

Source: ArboNET, Arboviral Diseases Branch, Centers for Disease Control and Prevention

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Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by state, 1999-2018
State Average Incidence
Alaska 0.01
Alabama 0.24
Arizona 0.87
Arkansas 0.41
California 0.52
Colorado 1.26
Connecticut 0.14
Delaware 0.14
District of Columbia 0.52
Florida 0.08
Georgia 0.14
Hawaii 0.00
Idaho 0.68
Illinois 0.61
Indiana 0.30
Iowa 0.47
Kansas 0.56
Kentucky 0.14
Louisiana 1.13
Maine 0.01
Maryland 0.21
Massachusetts 0.11
Michigan 0.53
Minnesota 0.29
Mississippi 1.21
Missouri 0.35
Montana 0.87
Nebraska 2.00
Nevada 0.35
New Hampshire 0.02
New Jersey 0.11
New Mexico 0.78
New York 0.18
North Carolina 0.03
North Dakota 2.82
Ohio 0.29
Oklahoma 0.61
Oregon 0.05
Pennsylvania 0.17
Rhode Island 0.00
South Carolina 0.08
South Dakota 3.22
Tennessee 0.17
Texas 0.63
Utah 0.33
Vermont 0.06
Virginia 0.09
Washington 0.05
West Virginia 0.04
Wisconsin  0.18
Wyoming 1.49

West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2020

Graph showing West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2020

Source: ArboNET, Arboviral Diseases Branch, Centers for Disease Control and Prevention

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West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2018
Year Incidence per 100,000 population
1999 0.02
2000 0.01
2001 0.02
2002 1.02
2003 0.99
2004 0.39
2005 0.44
2006 0.50
2007 0.41
2008 0.23
2009 0.13
2010 0.20
2011 0.16
2012 0.92
2013 0.40
2014 0.42
2015 0.45
2016 0.41
2017 0.44
2018 0.51
2019 0.19
2020 0.17

West Nile virus disease cases reported to CDC by week of illness onset, 1999-2020

Graph showing West Nile virus disease cases reported to CDC by week of illness onset, 1999-2020

Source: ArboNET, Arboviral Diseases Branch, Centers for Disease Control and Prevention

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West Nile virus disease cases reported to CDC by week of illness onset, 1999-2017 
Month Week of Onset Number of Cases
January 1 7
2 5
3 2
4 1
February 5 4
6 3
7 3
8 1
March 9 9
10 2
11 12
12 5
April 13 4
14 7
15 10
16 13
17 12
May 18 22
19 32
20 54
21 53
June 22 114
23 140
24 184
25 311
July 26 459
27 872
28 1,329
29 1,983
30 2,810
August 31 4,497
32 4,904
33 5,878
34 5,876
September 35 5,627
36 4,866
37 4,030
38 2,726
October 39 1,904
40 1,266
41 761
42 507
43 360
November 44 232
45 178
46 126
47 73
December 48 62
49 64
50 37
51 19
52 45
53 29