Final Cumulative Maps & Data for 1999–2019

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West Nile virus disease cases reported to CDC by state of residence, 1999-2019

West Nile virus disease cases reported to CDC by state of residence, 1999-2018
State 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Total
Alabama 0 0 2 49 37 16 10 8 24 18 0 3 5 62 9 2 9 19 60 28 5 366
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2
Arizona 0 0 0 0 13 391 113 150 97 114 20 167 69 133 62 107 103 78 111 26 174 1,928
Arkansas 0 0 0 43 25 28 28 29 20 9 6 7 1 64 18 11 18 9 18 8 9 351
California 0 0 0 1 3 779 880 278 380 445 112 111 158 479 379 801 783 442 553 217 225 7,026
Colorado 0 0 0 14 2,947 291 106 345 576 71 103 81 7 131 322 118 101 149 68 96 122 5,648
Connecticut 0 1 6 17 17 1 6 9 4 8 0 11 9 21 4 6 10 1 3 23 1 158
Delaware 0 0 0 1 17 0 2 0 1 1 0 0 1 9 3 0 6 0 1 10 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 11 125
Florida 0 0 12 28 94 41 21 3 3 3 3 12 24 73 7 17 13 8 5 35 2 404
Georgia 0 0 6 44 50 21 20 8 50 8 4 13 22 99 10 13 15 6 48 36 14 487
Hawaii 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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 1,378
Illinois 0 0 0 884 54 60 252 215 101 20 5 61 34 290 117 44 77 154 90 176 28 2,662
Indiana 0 0 0 293 47 13 23 80 24 4 4 13 9 77 23 10 21 18 26 35 4 724
Iowa 0 0 0 54 147 23 37 37 30 6 5 9 9 31 44 15 14 37 12 104 5 619
Kansas 0 0 0 22 91 43 25 30 40 31 13 19 4 56 91 54 34 37 27 47 13 677
Kentucky 0 0 0 75 14 7 5 6 4 3 3 3 5 23 3 1 2 8 10 12 10 194
Louisiana 0 0 1 329 124 109 171 180 40 49 21 27 10 335 54 125 51 59 53 83 20 1,841
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 2 0 4
Maryland 0 0 6 36 73 16 5 11 10 14 1 23 19 47 16 6 45 6 6 45 7 392
Massachusetts 0 0 3 23 17 0 6 3 6 1 0 7 6 33 8 6 10 17 6 49 5 206
Michigan 0 0 0 614 19 16 62 55 17 17 1 29 34 202 36 1 18 43 40 102 12 1,318
Minnesota 0 0 0 48 148 34 45 65 101 10 4 8 2 70 79 21 9 83 30 63 5 825
Mississippi 0 0 0 192 87 51 70 183 136 65 53 8 52 247 45 43 38 43 63 50 15 1,441
Missouri 0 0 0 168 64 36 30 62 77 15 5 3 10 20 29 13 29 11 19 23 5 619
Montana 0 0 0 2 222 6 25 34 202 5 5 0 1 6 38 5 3 6 11 47 3 621
Nebraska 0 0 0 152 1,942 53 188 264 163 47 52 39 29 193 226 142 68 95 68 251 28 4,000
Nevada 0 0 0 0 2 44 31 124 12 16 12 2 16 9 11 3 7 16 67 9 46 427
New Hampshire 0 0 0 0 3 0 0 0 0 0 0 1 0 1 1 0 0 0 1 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 8 321
New Mexico 0 0 0 0 209 88 33 8 60 8 8 25 4 47 38 24 14 6 33 7 40 652
New York 62 14 15 82 71 10 38 24 22 46 7 128 44 107 32 26 57 22 51 98 17 973
North Carolina 0 0 0 2 24 3 4 1 8 3 0 0 2 7 3 0 4 2 8 10 1 82
North Dakota 0 0 0 17 617 20 86 137 369 37 1 9 4 89 125 23 23 85 62 204 9 1,917
Ohio 0 0 0 441 108 12 61 48 23 15 2 5 21 121 24 11 35 17 34 65 3 1,046
Oklahoma 0 0 0 21 79 22 31 48 107 9 10 1 1 191 89 18 89 35 42 18 8 819
Oregon 0 0 0 0 0 3 7 69 26 16 11 0 0 11 16 8 1 4 6 2 9 189
Pennsylvania 0 0 3 62 237 15 25 9 10 14 0 28 6 60 11 13 30 16 20 130 7 696
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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 22
South Carolina 0 0 0 1 6 2 5 1 5 1 3 1 0 29 7 3 0 8 18 15 2 107
South Dakota 0 0 0 37 1,039 51 229 113 208 39 21 20 2 203 149 57 40 152 73 169 11 2,613
Tennessee 0 0 0 56 26 14 18 22 11 19 9 4 18 33 24 16 8 7 30 12 3 330
Texas 0 0 0 202 720 176 195 354 260 64 115 89 27 1,868 183 379 275 370 135 146 32 5,590
Utah 0 0 0 0 1 11 52 158 70 26 2 2 3 5 7 2 8 13 62 11 21 454
Vermont 0 0 0 1 3 0 0 0 0 0 0  0 1 3 2 0 0 2 3 1 0 16
Virginia 0 0 0 29 26 5 1 5 5 1 5 5 9 30 6 7  21 8 13 48 6 230
Washington 0 0 0 0 0 0 0 3 0 3 38 2 0 4 1 12 24 9 13 3 5 117
West Virginia 0 0 0 3 2 0 0 1 0 1 0 0 2 10 1 0 0 1 1 2 0 24
Wisconsin 0 0 0 52 17 12 17 21 13 8 1 2 3 57 21 6 9 13 51 33 2 338
Wyoming 0 0 0 2 375 10 12 65 181 8 12 6 3 7 41 5 8 11 7 4 4 761
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 51,801

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West Nile virus neuroinvasive disease cases reported to CDC by state of residence, 1999-2019

West Nile virus neuroinvasive disease cases reported to CDC by state of residence, 1999-2018
State 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Total
Alabama 0 0 2 34 25 15 6 8 17 11 0 1 5 38 3 0 5 13 40 16 4 243
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1
Arizona 0 0 0 0 7 215 52 68 50 62 12 107 49 87 50 80 67 57 98 25 132 1,218
Arkansas 0 0 0 32 23 17 13 24 13 7 6 6 1 44 16 9 16 8 15 6 7 263
California 0 0 0 1 2 291 305 81 154 292 67 72 110 297 237 561 585 335 401 154 147 4,092
Colorado 0 0 0 6 621 41 21 66 99 17 36 26 2 62 90 46 57 59 29 52 52 1,382
Connecticut 0 0 6 10 12 0 4 7 2 5 0 7 8 12 1 3 8 1 2 18 1 107
Delaware 0 0 0 0 12 0 1 0 1 0 0 0 1 2 3 0 0 0 0 8 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 70
Florida 0 0 12 28 61 33 10 3 3 3 2 9 20 52 5 12 12 6 4 30 2 307
Georgia 0 0 6 28 27 14 9 2 23 4 4 4 14 46 4 11 13 4 44 30 9 296
Hawaii 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 5 232
Illinois 0 0 0 553 30 29 137 127 63 12 5 45 22 187 86 36 51 98 72 126 22 1,701
Indiana 0 0 0 180 15 8 11 27 14 3 2 6 7 46 19 9 16 15 18 26 4 426
Iowa 0 0 0 27 81 13 14 22 12 3 0 5 5 11 24 5 4 16 10 59 1 312
Kansas 0 0 0 22 89 18 17 17 14 14 4 4 4 20 34 18 12 18 12 23 7 347
Kentucky 0 0 0 53 11 1 5 5 4 3 3 2 4 13 1 0 1 5 9 9 4 133
Louisiana 0 0 1 204 101 85 117 91 27 18 10 20 6 155 34 61 41 38 38 56 11 1,114
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 0 3
Maryland 0 0 6 22 49 10 4 10 6 6 0 17 10 25 11 6 31 6 5 35 6 265
Massachusetts 0 0 3 19 12 0 4 2 3 1 0 6 5 25 7 5 7 10 5 42 2 158
Michigan 0 0 0 557 14 13 54 43 16 11 1 25 32 141 24 1 16 42 32 80 11 1,113
Minnesota 0 0 0 16 48 13 18 31 44 2 1 4 1 34 31 6 3 38 13 34 2 339
Mississippi 0 0 0 162 34 31 39 89 50 22 31 3 31 103 27 26 25 27 46 31 12 789
Missouri 0 0 0 126 39 27 17 51 61 12 4 3 6 17 24 10 23 9 17 17 4 467
Montana 0 0 0 2 75 2 8 12 37 0 2 0 1 1 10 2 3 3 3 25 3 189
Nebraska 0 0 0 84 194 7 55 45 21 7 11 10 14 42 54 41 19 35 19 124 17 799
Nevada 0 0 0 0 2 25 14 34 2 9 7 0 12 5 8 3 4 13 31 3 34 206
New Hampshire 0 0 0 0 2 0 0 0 0 0 0 1 0 1 1 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 6 215
New Mexico 0 0 0 0 74 32 20 3 39 5 6 21 4 24 24 19 12 6 23 5 30 347
New York 59 14 13 68 57 7 30 16 16 32 6 89 28 61 18 19 42 20 45 77 14 731
North Carolina 0 0 0 2 16 3 2 1 4 2 0 0 2 7 3 0 4 2 8 10 1 67
North Dakota 0 0 0 3 94 2 12 20 49 2 0 2 1 39 64 12 10 24 20 60 2 416
Ohio 0 0 0 310 84 11 46 36 13 14 0 4 10 76 21 10 23 12 23 45 3 741
Oklahoma 0 0 0 16 56 16 17 27 59 4 8 1 1 103 60 9 49 21 34 12 6 499
Oregon 0 0 0 0 0 0 1 7 7 3 1 0 0 0 7 7 0 2 3 2 6 46
Pennsylvania 0 0 3 42 145 10 14 8 5 12 0 19 5 33 6 11 17 12 15 95 5 457
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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 15
South Carolina 0 0 0 1 3 0 5 1 3 0 3 1 0 20 3 3 0 6 16 12 2 79
South Dakota 0 0 0 17 151 6 36 38 48 11 6 4 0 62 57 12 11 35 27 47 0 568
Tennessee 0 0 0 47 21 13 15 16 5 12 4 2 16 19 17 12 5 3 22 11 3 243
Texas 0 0 0 202 431 119 128 233 170 40 93 77 20 844 113 253 196 252 87 108 24 3,390
Utah 0 0 0 0 0 6 21 56 28 6 1 1 1 3 4 1 5 7 39 7 14 200
Vermont 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 2 2 1 0 8
Virginia 0 0 0 16 19 5 0 0 3 0 5 4 8 20 6 5 13 6 12 38 4 164
Washington 0 0 0 0 0 0 0 0 0 2 26 1 0 4 0 7 8 8 10 2 3 71
West Virginia 0 0 0 3 1 0 0 1 0 1 0 0 2 5 1 0 0 0 1 2 0 17
Wisconsin 0 0 0 22 7 5 11 11 7 4 1 0 2 44 17 3 6 10 47 29 0 226
Wyoming 0 0 0 0 92 2 6 15 23 0 4 2 1 3 16 0 3 8 4 3 2 184
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 25,290

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West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999-2019

West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999-2018
Neuroinvasive disease Non-neuroinvasive disease Total
Year Cases
No.		 Deaths
No. (%)		 Cases
No.		 Deaths
No. (%)		 Cases
No.		 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)
Total  25,290 2,259  (9)   26,511  131  (<1)  51,801 2,390  (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, 1999-2019

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 0.09
20-29 0.15
30-39 0.27
40-49 0.40
50-59 0.56
60-69 0.84
≥70 1.35
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Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by county, 1999-2019

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, 1999-2019

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 0.91
Arkansas 0.43
California 0.52
Colorado 1.30
Connecticut 0.14
Delaware 0.15
District of Columbia 0.55
Florida 0.08
Georgia 0.15
Hawaii 0.00
Idaho 0.70
Illinois 0.63
Indiana 0.31
Iowa 0.49
Kansas 0.58
Kentucky 0.15
Louisiana 1.17
Maine 0.01
Maryland 0.22
Massachusetts 0.11
Michigan 0.54
Minnesota 0.30
Mississippi 1.26
Missouri 0.37
Montana 0.91
Nebraska 2.08
Nevada 0.36
New Hampshire 0.02
New Jersey 0.12
New Mexico 0.80
New York 0.18
North Carolina 0.03
North Dakota 2.94
Ohio 0.31
Oklahoma 0.63
Oregon 0.06
Pennsylvania 0.17
Rhode Island 0.07
South Carolina 0.08
South Dakota 3.31
Tennessee 0.18
Texas 0.64
Utah 0.34
Vermont 0.06
Virginia 0.10
Washington 0.05
West Virginia 0.04
Wisconsin  0.19
Wyoming 1.55
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West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2019

Graph showing West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2018

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
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West Nile virus disease cases reported to CDC by week of illness onset, 1999-2019

Graph showing West Nile virus disease cases reported to CDC by week of illness onset, 1999-2019

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 1
8 1
March 9 8
10 2
11 11
12 5
April 13 4
14 7
15 10
16 12
17 12
May 18 20
19 30
20 53
21 50
June 22 111
23 138
24 184
25 306
July 26 454
27 869
28 1,319
29 1,973
30 2,798
August 31 4,477
32 4,879
33 5,837
34 5,814
September 35 5,569
36 4,767
37 3,957
38 2,658
October 39 1,869
40 1,221
41 727
42 488
43 343
November 44 225
45 169
46 121
47 66
December 48 59
49 60
50 36
51 19
52 37
53 1
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Page last reviewed: November 24, 2020
Content source: Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Vector-Borne Diseases (DVBD)