Wisconsin regularly ranks among the states with the lowest prevalence of sexually transmitted diseases, or STDs, in the United States. But the state’s relatively low rates of several different common STDs are under risk of being undone thanks to recent increases of chlamydia, gonorrhea, syphilis and HIV — even some in the double digits, a trend that largely tracks with national growth in STDs.

What types of sexually transmitted diseases and infections are most common in our state, how have rates here changed over time, and which parts of the state have the highest frequency of chlamydia, gonorrhea, and primary and secondary syphilis? To answer those questions, we’ll look at data from the Wisconsin Department of Health Services and the federal Centers for Disease Control and Prevention.

Chlamydia Rates in Wisconsin

Wisconsin’s rate of chlamydia cases relative to the state’s population size puts Wisconsin in the bottom half of the country with a rate more than 8% lower than the overall national rate.

Chlamydia infections per 100,000 people

Highest
Alaska 799.8
Louisiana 742.4
Mississippi 707.6
New Mexico 651.6
South Carolina 649.8
Georgia 623.7
Alabama 615.5
North Carolina 612.2
New York 591.6
Illinois 589.9
Total 528.8
Lowest
Wisconsin 485
Minnesota 426.4
Massachusetts 425.7
New Jersey 392
Idaho 368.4
Wyoming 365.8
Maine 342.1
Utah 332.2
New Hampshire 330.5
Vermont 297.5
West Virginia 226.1

While Wisconsin ranks 30th overall among all states for population-adjusted rates of chlamydia, the state has seen its rate of chlamydia go up every year since 2014, climbing more than 30% between 2007 and 2017.

Wisconsin chlamydia rate by year (cases per 100,000 people)

2007 354
2008 368
2009 371
2010 409
2011 431
2012 413
2013 412
2014 406
2015 425
2016 470
2017 485

Illinois is the only Midwestern state that ranks among the top 10 for chlamydia prevalence, and Wisconsin ranks in the middle of the region.

Chlamydia infection rate, Midwestern states (cases per 100,000 people)

Illinois 589.9
Missouri 536.4
Ohio 528.6
Indiana 514.2
South Dakota 512.7
Michigan 511.9
Wisconsin 485
Kansas 466.2
Nebraska 450.7
Iowa 443.2
North Dakota 432.5
Minnesota 426.4

 Gonorrhea Rates in Wisconsin

Wisconsin ranks 33rd in the country for its population-adjusted rate of gonorrhea with a rate that’s more than 20% lower than the overall U.S. rate for gonorrhea.

Gonorrhea infections per 100,000 people

Highest
Mississippi 309.8
Alaska 295.1
Louisiana 256.7
South Carolina 254.4
Alabama 245.7
Oklahoma 231.4
Arkansas 224.5
North Carolina 220.9
Georgia 217.5
Ohio 216.3
Total 171.9
Lowest
Wisconsin 135
Rhode Island 102.9
Hawaii 95.1
Utah 83.3
Montana 75
West Virginia 70.8
Wyoming 70.4
Idaho 58.6
Maine 46.6
New Hampshire 38.4
Vermont 32.5

Gonorrhea has become more prevalent in Wisconsin every year since 2014, nearly doubling since that time.

Wisconsin gonorrhea rate by year (cases per 100,000 people)

2007 121
2008 107
2009 93
2010 90
2011 85
2012 83
2013 81
2014 72
2015 93
2016 115
2017 135

Six Midwestern states are among the states with the 25 highest rates of gonorrhea, but Wisconsin has the fourth-lowest gonorrhea rate in the region.

Gonorrhea infection rate, Midwestern states (cases per 100,000 people)

Ohio 216.3
Missouri 214.8
Illinois 186.4
Indiana 177.5
Kansas 156.3
Michigan 154.7
South Dakota 149.1
Nebraska 139.1
Wisconsin 135
North Dakota 127.4
Iowa 119.9
Minnesota 118.1

Syphilis Rates in Wisconsin

Wisconsin has the fifth-lowest population-adjusted rate of syphilis infections in the country, with a rate that’s about a third the overall U.S. level.

Primary and secondary syphilis infections per 100,000 people

Highest
Nevada 20
California 17.1
Georgia 14.5
Louisiana 14.5
Arizona 13.1
Maryland 12.2
New York 11.9
Florida 11.6
North Carolina 10.6
Mississippi 10.4
Total 9.5
Lowest
South Dakota 3.8
West Virginia 3.4
New Hampshire 3.2
Iowa 3.2
Connecticut 3.1
Wisconsin 3
Nebraska 2.3
Vermont 2.1
Alaska 1.8
Wyoming 0.7

While Wisconsin’s rate of syphilis remains relatively low, the prevalence of primary and secondary syphilis in Wisconsin doubled between 2015 and 2017.

Wisconsin primary and secondary syphilis rate by year (cases per 100,000 people)

2012 1.6
2013 1.8
2014 1.5
2015 1.5
2016 2.4
2017 3

Wisconsin has the second-lowest rate of syphilis cases among all Midwestern states.

Primary and secondary syphilis infection rates, Midwestern states (cases per 100,000 people)

Illinois 9.6
Missouri 8.3
Ohio 6.3
North Dakota 5.8
Minnesota 5.3
Michigan 4.8
Indiana 4.8
Kansas 4.6
South Dakota 3.8
Iowa 3.2
Wisconsin 3
Nebraska 2.3

HIV & Other STD Rates in Wisconsin

HIV

More than 250 people were newly diagnosed with HIV in Wisconsin in 2017, and the state’s population-adjusted rate is among the lowest in the nation. But Wisconsin has seen a troubling increase in HIV — a 15% jump between 2016 and 2017. See How to Test for HIV

Hepatitis B & C

Wisconsin’s rate of acute hepatitis B infections is far below the national level, but the state’s rate of acute hep C cases is significantly higher than the national rate, and acute cases of both types of hepatitis virus disease have gone up recently. Wisconsin’s hep B infection rate doubled between 2015 and 2016, while the prevalence of acute hep C more than tripled between 2012 and 2016. See How to Test for Hepatitis

HPV

While it’s not known exactly how many people in our state are infected with human papillomavirus, looking at the rates of certain types of cancer can help fill in the blanks. That’s because HPV causes the vast majority of several cancers, including cervical, penile, anal and vulvar cancers. Wisconsin’s HPV-related cancer rate is about 11.1 per 100,000, slightly lower than the national median of 11.7 per 100,000. See How to Test for HPV

STDs in Wisconsin Cities & Counties

The Milwaukee metro area accounts for a large majority of several different STDs, and the area ranks highly among all major cities in the U.S. for certain diseases.

Chlamydia

Milwaukee accounted for at least a third of all cases of chlamydia in Wisconsin in 2017, but several other areas of the state also had rates near the overall state level. Additionally, the Milwaukee metro area has the fourth-highest chlamydia rate of any major metro in the country.

Wisconsin counties by chlamydia infection rate (cases per 100,000 people), top 10

Milwaukee 1,148
Menominee 1,006
Rock 557
Dane 549
Kenosha 539
Eau Claire 515
Racine 472
Brown 460
La Crosse 440
Dunn 412

Gonorrhea

More than 60% of gonorrhea cases in Wisconsin were diagnosed among those living in Milwaukee. The greater Milwaukee metro has the second-highest rate of gonorrhea of all major U.S. metro areas, behind only Memphis.

Wisconsin counties by gonorrhea infection rate (cases per 100,000 people), top 10

Milwaukee 496
Rock 192
Racine 157
Kenosha 137
Dane 125
Sheboygan 113
Brown 80
Menominee 66
Eau Claire 65
Winnebago 64

Primary and secondary syphilis

More than half of all syphilis cases in Wisconsin were diagnosed among individuals in Milwaukee.

Wisconsin counties by syphilis infection rate (cases per 100,000 people)*

Milwaukee 30
Dane 13
Chippewa 13
Kenosha 12
Burnett 12
Eau Claire 11
Trempealeau 11
Saint Croix 10
Calumet 9
Dodge 9

 * Includes all stages

Conclusion

While Wisconsin has relatively low rates of most major sexually transmitted diseases and infections, the trends in our state are moving in the wrong direction. Lowering the prevalence of STDs benefits everybody in Wisconsin, which is a big reason why anybody who could be at risk of having an STD (which is anybody who has ever had sex) get tested so they can be sure they’re not unwittingly passing STDs along.

Additional References

Note: Some states have published more recent data for chlamydia, gonorrhea, and primary and secondary syphilis. For states in which that’s the case, we have substituted the individual state data for 2018 and used that in our rankings, while other states’ rankings are based on 2017 numbers. In some cases, we assume that when the full national dataset is published by the CDC, states’ positions relative to other states will change some, though those changes are unlikely to be dramatic, since the CDC data comes from the states.