Final Cumulative Maps & Data for 1999–2018

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West Nile virus disease cases reported to CDC by state of residence, 1999-2018

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 Total
Alabama 0 0 2 49 37 16 10 8 24 18 0 3 5 62 9 2 9 19 60 28 361
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1
Arizona 0 0 0 0 13 391 113 150 97 114 20 167 69 133 62 107 103 78 111 26 1,754
Arkansas 0 0 0 43 25 28 28 29 20 9 6 7 1 64 18 11 18 9 18 8 342
California 0 0 0 1 3 779 880 278 380 445 112 111 158 479 379 801 783 442 553 217 6,801
Colorado 0 0 0 14 2,947 291 106 345 576 71 103 81 7 131 322 118 101 149 68 96 5,526
Connecticut 0 1 6 17 17 1 6 9 4 8 0 11 9 21 4 6 10 1 3 23 157
Delaware 0 0 0 1 17 0 2 0 1 1 0 0 1 9 3 0 6 0 1 10 52
Dist. of Columbia 0 0 0 34 3 2 5 2 0 8 2 6 15 10 1 3 5 1 4 13 114
Florida 0 0 12 28 94 41 21 3 3 3 3 12 24 73 7 17 13 8 5 35 402
Georgia 0 0 6 44 50 21 20 8 50 8 4 13 22 99 10 13 15 6 48 36 473
Hawaii 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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 1,365
Illinois 0 0 0 884 54 60 252 215 101 20 5 61 34 290 117 44 77 154 90 176 2,634
Indiana 0 0 0 293 47 13 23 80 24 4 4 13 9 77 23 10 21 18 26 35 720
Iowa 0 0 0 54 147 23 37 37 30 6 5 9 9 31 44 15 14 37 12 104 614
Kansas 0 0 0 22 91 43 25 30 40 31 13 19 4 56 91 54 34 37 27 47 664
Kentucky 0 0 0 75 14 7 5 6 4 3 3 3 5 23 3 1 2 8 10 12 184
Louisiana 0 0 1 329 124 109 171 180 40 49 21 27 10 335 54 125 51 59 53 83 1,821
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 2 4
Maryland 0 0 6 36 73 16 5 11 10 14 1 23 19 47 16 6 45 6 6 45 385
Massachusetts 0 0 3 23 17 0 6 3 6 1 0 7 6 33 8 6 10 17 6 49 201
Michigan 0 0 0 614 19 16 62 55 17 17 1 29 34 202 36 1 18 43 40 102 1,306
Minnesota 0 0 0 48 148 34 45 65 101 10 4 8 2 70 79 21 9 83 30 63 820
Mississippi 0 0 0 192 87 51 70 183 136 65 53 8 52 247 45 43 38 43 63 50 1,426
Missouri 0 0 0 168 64 36 30 62 77 15 5 3 10 20 29 13 29 11 19 23 614
Montana 0 0 0 2 222 6 25 34 202 5 5 0 1 6 38 5 3 6 11 47 618
Nebraska 0 0 0 152 1,942 53 188 264 163 47 52 39 29 193 226 142 68 95 68 251 3,972
Nevada 0 0 0 0 2 44 31 124 12 16 12 2 16 9 11 3 7 16 67 9 381
New Hampshire 0 0 0 0 3 0 0 0 0 0 0 1 0 1 1 0 0 0 1 0 7
New Jersey 0 6 12 24 34 1 6 5 1 10 3 30 7 48 12 8 26 11 8 61 313
New Mexico 0 0 0 0 209 88 33 8 60 8 8 25 4 47 38 24 14 6 33 7 612
New York 62 14 15 82 71 10 38 24 22 46 7 128 44 107 32 26 57 22 51 98 956
North Carolina 0 0 0 2 24 3 4 1 8 3 0 0 2 7 3 0 4 2 8 10 81
North Dakota 0 0 0 17 617 20 86 137 369 37 1 9 4 89 125 23 23 85 62 204 1,908
Ohio 0 0 0 441 108 12 61 48 23 15 2 5 21 121 24 11 35 17 34 65 1,043
Oklahoma 0 0 0 21 79 22 31 48 107 9 10 1 1 191 89 18 89 35 42 18 811
Oregon 0 0 0 0 0 3 7 69 26 16 11 0 0 11 16 8 1 4 6 2 180
Pennsylvania 0 0 3 62 237 15 25 9 10 14 0 28 6 60 11 13 30 16 20 130 689
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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 22
South Carolina 0 0 0 1 6 2 5 1 5 1 3 1 0 29 7 3 0 8 18 15 105
South Dakota 0 0 0 37 1,039 51 229 113 208 39 21 20 2 203 149 57 40 152 73 169 2,602
Tennessee 0 0 0 56 26 14 18 22 11 19 9 4 18 33 24 16 8 7 30 12 327
Texas 0 0 0 202 720 176 195 354 260 64 115 89 27 1,868 183 379 275 370 135 146 5,558
Utah 0 0 0 0 1 11 52 158 70 26 2 2 3 5 7 2 8 13 62 11 433
Vermont 0 0 0 1 3 0 0 0 0 0 0  0 1 3 2 0 0 2 3 1 16
Virginia 0 0 0 29 26 5 1 5 5 1 5 5 9 30 6 7  21 8 13 48 224
Washington 0 0 0 0 0 0 0 3 0 3 38 2 0 4 1 12 24 9 13 3 112
West Virginia 0 0 0 3 2 0 0 1 0 1 0 0 2 10 1 0 0 1 1 2 24
Wisconsin 0 0 0 52 17 12 17 21 13 8 1 2 3 57 21 6 9 13 51 33 336
Wyoming 0 0 0 2 375 10 12 65 181 8 12 6 3 7 41 5 8 11 7 4 757
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 50,830

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West Nile virus neuroinvasive disease cases reported to CDC by state of residence, 1999-2018

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 Total
Alabama 0 0 2 34 25 15 6 8 17 11 0 1 5 38 3 0 5 13 40 16 239
Alaska 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1
Arizona 0 0 0 0 7 215 52 68 50 62 12 107 49 87 50 80 67 57 98 25 1,086
Arkansas 0 0 0 32 23 17 13 24 13 7 6 6 1 44 16 9 16 8 15 6 256
California 0 0 0 1 2 291 305 81 154 292 67 72 110 297 237 561 585 335 401 154 3,945
Colorado 0 0 0 6 621 41 21 66 99 17 36 26 2 62 90 46 57 59 29 52 1,330
Connecticut 0 0 6 10 12 0 4 7 2 5 0 7 8 12 1 3 8 1 2 18 106
Delaware 0 0 0 0 12 0 1 0 1 0 0 0 1 2 3 0 0 0 0 8 28
Dist. of Columbia 0 0 0 14 3 1 3 0 0 4 2 3 10 8 0 1 3 1 1 7 61
Florida 0 0 12 28 61 33 10 3 3 3 2 9 20 52 5 12 12 6 4 30 305
Georgia 0 0 6 28 27 14 9 2 23 4 4 4 14 46 4 11 13 4 44 30 287
Hawaii 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 10 227
Illinois 0 0 0 553 30 29 137 127 63 12 5 45 22 187 86 36 51 98 72 126 1,679
Indiana 0 0 0 180 15 8 11 27 14 3 2 6 7 46 19 9 16 15 18 26 422
Iowa 0 0 0 27 81 13 14 22 12 3 0 5 5 11 24 5 4 16 10 59 311
Kansas 0 0 0 22 89 18 17 17 14 14 4 4 4 20 34 18 12 18 12 23 340
Kentucky 0 0 0 53 11 1 5 5 4 3 3 2 4 13 1 0 1 5 9 9 129
Louisiana 0 0 1 204 101 85 117 91 27 18 10 20 6 155 34 61 41 38 38 56 1,103
Maine 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 3
Maryland 0 0 6 22 49 10 4 10 6 6 0 17 10 25 11 6 31 6 5 35 259
Massachusetts 0 0 3 19 12 0 4 2 3 1 0 6 5 25 7 5 7 10 5 42 156
Michigan 0 0 0 557 14 13 54 43 16 11 1 25 32 141 24 1 16 42 32 80 1,102
Minnesota 0 0 0 16 48 13 18 31 44 2 1 4 1 34 31 6 3 38 13 34 337
Mississippi 0 0 0 162 34 31 39 89 50 22 31 3 31 103 27 26 25 27 46 31 777
Missouri 0 0 0 126 39 27 17 51 61 12 4 3 6 17 24 10 23 9 17 17 463
Montana 0 0 0 2 75 2 8 12 37 0 2 0 1 1 10 2 3 3 3 25 186
Nebraska 0 0 0 84 194 7 55 45 21 7 11 10 14 42 54 41 19 35 19 124 782
Nevada 0 0 0 0 2 25 14 34 2 9 7 0 12 5 8 3 4 13 31 3 172
New Hampshire 0 0 0 0 2 0 0 0 0 0 0 1 0 1 1 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 44 209
New Mexico 0 0 0 0 74 32 20 3 39 5 6 21 4 24 24 19 12 6 23 5 317
New York 59 14 13 68 57 7 30 16 16 32 6 89 28 61 18 19 42 20 45 77 717
North Carolina 0 0 0 2 16 3 2 1 4 2 0 0 2 7 3 0 4 2 8 10 66
North Dakota 0 0 0 3 94 2 12 20 49 2 0 2 1 39 64 12 10 24 20 60 414
Ohio 0 0 0 310 84 11 46 36 13 14 0 4 10 76 21 10 23 12 23 45 738
Oklahoma 0 0 0 16 56 16 17 27 59 4 8 1 1 103 60 9 49 21 34 12 493
Oregon 0 0 0 0 0 0 1 7 7 3 1 0 0 0 7 7 0 2 3 2 40
Pennsylvania 0 0 3 42 145 10 14 8 5 12 0 19 5 33 6 11 17 12 15 95 452
Puerto Rico 0 0 0 0 0 0 0 0 0 0 0 0 0 1 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 15
South Carolina 0 0 0 1 3 0 5 1 3 0 3 1 0 20 3 3 0 6 16 12 77
South Dakota 0 0 0 17 151 6 36 38 48 11 6 4 0 62 57 12 11 35 27 47 568
Tennessee 0 0 0 47 21 13 15 16 5 12 4 2 16 19 17 12 5 3 22 11 240
Texas 0 0 0 202 431 119 128 233 170 40 93 77 20 844 113 253 196 252 87 108 3,366
Utah 0 0 0 0 0 6 21 56 28 6 1 1 1 3 4 1 5 7 39 7 186
Vermont 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 2 2 1 8
Virginia 0 0 0 16 19 5 0 0 3 0 5 4 8 20 6 5 13 6 12 38 160
Washington 0 0 0 0 0 0 0 0 0 2 26 1 0 4 0 7 8 8 10 2 68
West Virginia 0 0 0 3 1 0 0 1 0 1 0 0 2 5 1 0 0 0 1 2 17
Wisconsin 0 0 0 22 7 5 11 11 7 4 1 0 2 44 17 3 6 10 47 29 226
Wyoming 0 0 0 0 92 2 6 15 23 0 4 2 1 3 16 0 3 8 4 3 182
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 24,657

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West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999-2018

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)
Total  24,657 2,199  (9)   26,173  131  (<1)  50,830 2,330  (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, 1999-2018

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 0.25
40-49 0.42
50-59 0.52
60-69 0.66
≥70 1.13
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Average annual incidence of West Nile virus neuroinvasive disease reported to CDC by county, 1999-2018

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, 1999-2018

Map of the United States showing average annual incidence of West Nile virus neuroinvasive disease reported to CDC by state, 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 state, 1999-2018
State Average Incidence
Alaska 0.01
Alabama 0.25
Arizona 0.85
Arkansas 0.44
California 0.53
Colorado 1.32
Connecticut 0.15
Delaware 0.16
District of Columbia 0.50
Florida 0.08
Georgia 0.15
Hawaii 0.00
Idaho 0.72
Illinois 0.65
Indiana 0.33
Iowa 0.51
Kansas 0.60
Kentucky 0.15
Louisiana 1.21
Maine 0.01
Maryland 0.22
Massachusetts 0.12
Michigan 0.56
Minnesota 0.32
Mississippi 1.31
Missouri 0.39
Montana 0.94
Nebraska 2.14
Nevada 0.32
New Hampshire 0.02
New Jersey 0.12
New Mexico 0.77
New York 0.18
North Carolina 0.03
North Dakota 3.07
Ohio 0.32
Oklahoma 0.66
Oregon 0.05
Pennsylvania 0.18
Rhode Island 0.07
South Carolina 0.08
South Dakota 3.48
Tennessee 0.19
Texas 0.67
Utah 0.34
Vermont 0.06
Virginia 0.10
Washington 0.05
West Virginia 0.05
Wisconsin  0.20
Wyoming 1.61
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West Nile virus neuroinvasive disease incidence reported to CDC by year, 1999-2018

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
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West Nile virus disease cases reported to CDC by week of illness onset, 1999-2018

Graph showing West Nile virus disease cases reported to CDC by week of illness onset, 1999-2018

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 6
2 5
3 2
4 1
February 5 3
6 3
7 0
8 0
March 9 7
10 2
11 11
12 4
April 13 4
14 6
15 8
16 12
17 10
May 18 18
19 29
20 51
21 47
June 22 107
23 134
24 177
25 294
July 26 429
27 841
28 1,275
29 1,925
30 2,734
August 31 4,417
32 4,821
33 5,769
34 5,737
September 35 5,479
36 4,672
37 3,886
38 2,596
October 39 1,831
40 1,198
41 702
42 475
43 329
November 44 217
45 164
46 118
47 64
December 48 59
49 59
50 36
51 18
52 35
53 1
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Page last reviewed: October 9, 2019
Content source: Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Vector-Borne Diseases (DVBD)