Final Cumulative Maps & Data for 1999–2021

Related Pages

West Nile virus disease cases reported to CDC by state of residence, 1999-2021

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 2021 Total
Alabama 0 0 2 49 37 16 10 8 24 18 0 3 5 62 9 2 9 19 60 28 5 9 12 387
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1 3
Arizona 0 0 0 0 13 391 113 150 97 114 20 167 69 133 62 107 103 78 111 26 174 12 1,715 3,655
Arkansas 0 0 0 43 25 28 28 29 20 9 6 7 1 64 18 11 18 9 18 8 9 1 8 360
California 0 0 0 1 3 779 880 278 380 445 112 111 158 479 379 801 783 442 553 217 225 235 130 7,391
Colorado 0 0 0 14 2,947 291 106 345 576 71 103 81 7 131 322 118 101 149 68 96 122 35 175 5,858
Connecticut 0 1 6 17 17 1 6 9 4 8 0 11 9 21 4 6 10 1 3 23 1 8 7 173
Delaware 0 0 0 1 17 0 2 0 1 1 0 0 1 9 3 0 6 0 1 10 0 0 3 55
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 6 131
Florida 0 0 12 28 94 41 21 3 3 3 3 12 24 73 7 17 13 8 5 35 2 51 5 460
Georgia 0 0 6 44 50 21 20 8 50 8 4 13 22 99 10 13 15 6 48 36 14 8 4 499
Hawaii 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 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 16 1,400
Illinois 0 0 0 884 54 60 252 215 101 20 5 61 34 290 117 44 77 154 90 176 28 42 64 2,768
Indiana 0 0 0 293 47 13 23 80 24 4 4 13 9 77 23 10 21 18 26 35 4 3 14 741
Iowa 0 0 0 54 147 23 37 37 30 6 5 9 9 31 44 15 14 37 12 104 5 3 6 628
Kansas 0 0 0 22 91 43 25 30 40 31 13 19 4 56 91 54 34 37 27 47 13 8 17 702
Kentucky 0 0 0 75 14 7 5 6 4 3 3 3 5 23 3 1 2 8 10 12 10 0 4 198
Louisiana 0 0 1 329 124 109 171 180 40 49 21 27 10 335 54 125 51 59 53 83 20 18 22 1,881
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 2 0 1 0 5
Maryland 0 0 6 36 73 16 5 11 10 14 1 23 19 47 16 6 45 6 6 45 7 1 8 401
Massachusetts 0 0 3 23 17 0 6 3 6 1 0 7 6 33 8 6 10 17 6 49 5 12 11 229
Michigan 0 0 0 614 19 16 62 55 17 17 1 29 34 202 36 1 18 43 40 102 12 32 47 1,397
Minnesota 0 0 0 48 148 34 45 65 101 10 4 8 2 70 79 21 9 83 30 63 5 0 36 861
Mississippi 0 0 0 192 87 51 70 183 136 65 53 8 52 247 45 43 38 43 63 50 15 7 8 1,456
Missouri 0 0 0 168 64 36 30 62 77 15 5 3 10 20 29 13 29 11 19 23 5 1 12 632
Montana 0 0 0 2 222 6 25 34 202 5 5 0 1 6 38 5 3 6 11 47 3 1 2 624
Nebraska 0 0 0 152 1,942 53 188 264 163 47 52 39 29 193 226 142 68 95 68 251 28 15 107 4,122
Nevada 0 0 0 0 2 44 31 124 12 16 12 2 16 9 11 3 7 16 67 9 46 1 1 429
New Hampshire 0 0 0 0 3 0 0 0 0 0 0 1 0 1 1 0 0 0 1 0 0 0 1 8
New Jersey 0 6 12 24 34 1 6 5 1 10 3 30 7 48 12 8 26 11 8 61 8 3 36 360
New Mexico 0 0 0 0 209 88 33 8 60 8 8 25 4 47 38 24 14 6 33 7 40 8 34 694
New York 62 14 15 82 71 10 38 24 22 46 7 128 44 107 32 26 57 22 51 98 17 22 42 1,037
North Carolina 0 0 0 2 24 3 4 1 8 3 0 0 2 7 3 0 4 2 8 10 1 1 8 91
North Dakota 0 0 0 17 617 20 86 137 369 37 1 9 4 89 125 23 23 85 62 204 9 7 30 1,954
Ohio 0 0 0 441 108 12 61 48 23 15 2 5 21 121 24 11 35 17 34 65 3 3 13 1,062
Oklahoma 0 0 0 21 79 22 31 48 107 9 10 1 1 191 89 18 89 35 42 18 8 7 22 848
Oregon 0 0 0 0 0 3 7 69 26 16 11 0 0 11 16 8 1 4 6 2 9 1 5 195
Pennsylvania 0 0 3 62 237 15 25 9 10 14 0 28 6 60 11 13 30 16 20 130 7 11 27 734
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 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 2 24
South Carolina 0 0 0 1 6 2 5 1 5 1 3 1 0 29 7 3 0 8 18 15 2 4 9 120
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 47 2,680
Tennessee 0 0 0 56 26 14 18 22 11 19 9 4 18 33 24 16 8 7 30 12 3 0 4 334
Texas 0 0 0 202 720 176 195 354 260 64 115 89 27 1,868 183 379 275 370 135 146 32 122 143 5,855
Utah 0 0 0 0 1 11 52 158 70 26 2 2 3 5 7 2 8 13 62 11 21 2 28 484
Vermont 0 0 0 1 3 0 0 0 0 0 0  0 1 3 2 0 0 2 3 1 0 0 1 17
Virginia 0 0 0 29 26 5 1 5 5 1 5 5 9 30 6 7  21 8 13 48 6 2 5 237
Washington 0 0 0 0 0 0 0 3 0 3 38 2 0 4 1 12 24 9 13 3 5 2 4 123
West Virginia 0 0 0 3 2 0 0 1 0 1 0 0 2 10 1 0 0 1 1 2 0 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 8 351
Wyoming 0 0 0 2 375 10 12 65 181 8 12 6 3 7 41 5 8 11 7 4 4 1 1 763
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 2,911 55,443

Print only version [PDF – 3 pages]

 Top of Page

West Nile virus neuroinvasive disease cases reported to CDC by state of residence, 1999-2021

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 2021 Total
Alabama 0 0 2 34 25 15 6 8 17 11 0 1 5 38 3 0 5 13 40 16 4 7 9 259
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 2
Arizona 0 0 0 0 7 215 52 68 50 62 12 107 49 87 50 80 67 57 98 25 132 8 1,140 2,366
Arkansas 0 0 0 32 23 17 13 24 13 7 6 6 1 44 16 9 16 8 15 6 7 1 6 270
California 0 0 0 1 2 291 305 81 154 292 67 72 110 297 237 561 585 335 401 154 147 179 96 4,367
Colorado 0 0 0 6 621 41 21 66 99 17 36 26 2 62 90 46 57 59 29 52 52 17 101 1,500
Connecticut 0 0 6 10 12 0 4 7 2 5 0 7 8 12 1 3 8 1 2 18 1 5 5 117
Delaware 0 0 0 0 12 0 1 0 1 0 0 0 1 2 3 0 0 0 0 8 0 0 3 31
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 4 74
Florida 0 0 12 28 61 33 10 3 3 3 2 9 20 52 5 12 12 6 4 30 2 44 5 356
Georgia 0 0 6 28 27 14 9 2 23 4 4 4 14 46 4 11 13 4 44 30 9 7 3 306
Hawaii 0 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 12 249
Illinois 0 0 0 553 30 29 137 127 63 12 5 45 22 187 86 36 51 98 72 126 22 36 49 1,786
Indiana 0 0 0 180 15 8 11 27 14 3 2 6 7 46 19 9 16 15 18 26 4 3 11 440
Iowa 0 0 0 27 81 13 14 22 12 3 0 5 5 11 24 5 4 16 10 59 1 2 4 318
Kansas 0 0 0 22 89 18 17 17 14 14 4 4 4 20 34 18 12 18 12 23 7 6 10 363
Kentucky 0 0 0 53 11 1 5 5 4 3 3 2 4 13 1 0 1 5 9 9 4 0 4 137
Louisiana 0 0 1 204 101 85 117 91 27 18 10 20 6 155 34 61 41 38 38 56 11 14 17 1,145
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 0 1 0 4
Maryland 0 0 6 22 49 10 4 10 6 6 0 17 10 25 11 6 31 6 5 35 6 1 7 273
Massachusetts 0 0 3 19 12 0 4 2 3 1 0 6 5 25 7 5 7 10 5 42 2 9 9 176
Michigan 0 0 0 557 14 13 54 43 16 11 1 25 32 141 24 1 16 42 32 80 11 29 38 1,180
Minnesota 0 0 0 16 48 13 18 31 44 2 1 4 1 34 31 6 3 38 13 34 2 0 27 366
Mississippi 0 0 0 162 34 31 39 89 50 22 31 3 31 103 27 26 25 27 46 31 12 4 5 798
Missouri 0 0 0 126 39 27 17 51 61 12 4 3 6 17 24 10 23 9 17 17 4 1 11 479
Montana 0 0 0 2 75 2 8 12 37 0 2 0 1 1 10 2 3 3 3 25 3 1 2 192
Nebraska 0 0 0 84 194 7 55 45 21 7 11 10 14 42 54 41 19 35 19 124 17 9 69 877
Nevada 0 0 0 0 2 25 14 34 2 9 7 0 12 5 8 3 4 13 31 3 34 0 1 207
New Hampshire 0 0 0 0 2 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 1 6
New Jersey 0 5 12 16 21 1 3 2 1 6 3 15 2 22 10 6 23 11 6 44 6 3 26 244
New Mexico 0 0 0 0 74 32 20 3 39 5 6 21 4 24 24 19 12 6 23 5 30 7 31 385
New York 59 14 13 68 57 7 30 16 16 32 6 89 28 61 18 19 42 20 45 77 14 18 35 784
North Carolina 0 0 0 2 16 3 2 1 4 2 0 0 2 7 3 0 4 2 8 10 1 1 8 76
North Dakota 0 0 0 3 94 2 12 20 49 2 0 2 1 39 64 12 10 24 20 60 2 2 12 430
Ohio 0 0 0 310 84 11 46 36 13 14 0 4 10 76 21 10 23 12 23 45 3 3 11 755
Oklahoma 0 0 0 16 56 16 17 27 59 4 8 1 1 103 60 9 49 21 34 12 6 6 19 524
Oregon 0 0 0 0 0 0 1 7 7 3 1 0 0 0 7 7 0 2 3 2 6 0 1 47
Pennsylvania 0 0 3 42 145 10 14 8 5 12 0 19 5 33 6 11 17 12 15 95 5 7 22 486
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 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 1 16
South Carolina 0 0 0 1 3 0 5 1 3 0 3 1 0 20 3 3 0 6 16 12 2 4 6 89
South Dakota 0 0 0 17 151 6 36 38 48 11 6 4 0 62 57 12 11 35 27 47 0 10 18 596
Tennessee 0 0 0 47 21 13 15 16 5 12 4 2 16 19 17 12 5 3 22 11 3 0 3 246
Texas 0 0 0 202 431 119 128 233 170 40 93 77 20 844 113 253 196 252 87 108 24 101 130 3,621
Utah 0 0 0 0 0 6 21 56 28 6 1 1 1 3 4 1 5 7 39 7 14 1 21 222
Vermont 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 2 2 1 0 0 1 9
Virginia 0 0 0 16 19 5 0 0 3 0 5 4 8 20 6 5 13 6 12 38 4 1 2 167
Washington 0 0 0 0 0 0 0 0 0 2 26 1 0 4 0 7 8 8 10 2 3 0 4 75
West Virginia 0 0 0 3 1 0 0 1 0 1 0 0 2 5 1 0 0 0 1 2 0 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 7 238
Wyoming 0 0 0 0 92 2 6 15 23 0 4 2 1 3 16 0 3 8 4 3 2 1 0 185
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 2,008 27,857

Print only version [PDF – 2 pages]

 Top of Page

West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999-2021

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)
2021 2,008 225 (11) 903 2  (<1) 2,911 227  (8)
Total  27,857 2,550  (9)   27,586  133  (<1)  55,443 2,683  (5) 

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

Print only version [PDF – 1 page]

 Top of Page

Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by age group, 1999-2021

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

Print only version [PDF – 1 page]

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 0.14
30-39 0.23
40-49 0.41
50-59 0.54
60-69 0.63
≥70 1.03
 Top of Page

Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by county, 1999-2021

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

Print only version [PDF – 1 page]

 Top of Page

Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by state, 1999-2021

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

Print only version [PDF – 1 page]

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 1.55
Arkansas 0.41
California 0.51
Colorado 1.23
Connecticut 0.15
Delaware 0.15
District of Columbia 0.49
Florida 0.08
Georgia 0.13
Hawaii 0.00
Idaho 0.67
Illinois 0.63
Indiana 0.30
Iowa 0.46
Kansas 0.57
Kentucky 0.14
Louisiana 1.11
Maine 0.01
Maryland 0.21
Massachusetts 0.12
Michigan 0.54
Minnesota 0.30
Mississippi 1.21
Missouri 0.36
Montana 0.84
Nebraska 2.09
Nevada 0.32
New Hampshire 0.02
New Jersey 0.12
New Mexico 0.84
New York 0.18
North Carolina 0.03
North Dakota 2.58
Ohio 0.29
Oklahoma 0.61
Oregon 0.05
Pennsylvania 0.17
Rhode Island 0.07
South Carolina 0.08
South Dakota 3.14
Tennessee 0.17
Texas 0.59
Utah 0.33
Vermont 0.07
Virginia 0.09
Washington 0.05
West Virginia 0.04
Wisconsin  0.19
Wyoming 1.44
 Top of Page

West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2021

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

Print only version [PDF – 1 page]

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
2021 0.61
 Top of Page

West Nile virus disease cases reported to CDC by week of illness onset, 1999-2021

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

Print only version [PDF – 1 page]

West Nile virus disease cases reported to CDC by week of illness onset, 1999-2017 
Month Week of Onset Number of Cases
January 1 10
2 4
3 4
4 2
February 5 6
6 4
7 1
8 1
March 9 12
10 1
11 12
12 6
April 13 6
14 8
15 11
16 14
17 13
May 18 23
19 38
20 59
21 59
22 118
June 23 157
24 203
25 343
26 482
July 27 927
28 1,373
29 2,027
30 2,890
August 31 4,592
32 5,079
33 6,053
34 6,067
September 35 5,814
36 5,094
37 4,241
38 2,931
October 39 2,164
40 1,509
41 1,001
42 704
43 464
November 44 335
45 203
46 131
47 74
48 59
December 49 48
50 30
51 12
52 21
53 1
 Top of Page