Counties with the highest STI rates in Wisconsin

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March 18, 2024
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Counties with the highest STI rates in Wisconsin

Sexually transmitted infections are on the rise, putting more people at risk as they spread. Chlamydia rates have nearly doubled since 2000, while the rate of gonorrhea went up by 50% over the same period. The Centers for Disease Control and Prevention reports that syphilis rates are reaching levels last seen in the 1950s.

But some regions of the U.S. are seeing higher rates than others.

Stacker used CDC data to look at which counties reported the highest rate of sexually transmitted infections in Wisconsin. Counties are ranked by the rate of chlamydia infections, the most prominent STI at the national level, with gonorrhea and then syphilis rates serving as tiebreakers. This story focuses on bacterial infections, which can be cured, rather than viral infections such as HIV and herpes. At the county level, 2021 cases are the most recent available from the CDC, but state and national-level data for 2022 are also included. This story focuses on sexual transmissions and does not include congenital syphilis cases that were inherited from the mother.

Condoms are the most effective way to prevent the spread of STIs for people with multiple sexual partners, but research has found a decreasing rate of condom use among straight, bisexual, and gay male populations.

During the HIV/AIDS epidemic throughout the 1980s and 1990s, public health efforts advocating for condom use helped curb the spread of the virus. Today, however, condoms are no longer the only tool. Pills such as PrEP lower the risk of contracting HIV from sex by as much as 99%.

While more recent data is not available, the latest CDC survey from 2011-2015 showed less than half of unmarried men used condoms during the last time they had sex.

Among high school students having sex, the share using condoms has fallen from 60% in 2011 to 52% in 2021. While one-third of sexually active students used hormonal birth control, only 10% used both condoms and birth control. Methods like the pill and IUDs are effective at preventing pregnancy but do not stop the spread of STIs.

Chlamydia, gonorrhea, and syphilis are technically bacterial infections—meaning they can be cured with antibiotics—but they can still have lasting health impacts, including pelvic inflammatory disease and infertility. These risks are heightened when left untreated, which many STIs are as they don't obviously present themselves.

The CDC recommends annual testing for cisgender women, transgender men, and gender-nonconforming people with cervixes. It also recommends annual testing for males with male sexual partners. People in these groups who frequently have sex with anonymous partners should be tested every three to six months. Anyone with symptoms should always get tested according to the guidelines.

The CDC says there is little evidence that screening among straight men lowers the spread, and the agency's limited budget is put towards programs benefiting the most at-risk groups. However, some public health groups advocate for testing among all people regardless of sex and sexual orientation.

Data from the National Survey of Family Growth shows men on average have more opposite-sex sexual partners than women, and some argue that catching STIs throughout a sexual network rather than just for the most at-risk groups could curb their spread.

Soon, a pill may also help counter the spread of STIs. DoxyPEP can be taken 24 to 72 hours after unprotected sex and stops an STI before it becomes spreadable and symptomatic. The CDC has shared proposed guidelines recommending it for men who have sex with men and transgender women. The drug was originally approved for treating inhalation of anthrax, and doctors can prescribe it for off-label use.

Read on to see how STI infection rates in Wisconsin compare nationally, and the top counties.

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Emma Rubin // Stacker

State-level statistics

- Chlamydia cases: 435.7 per 100K (#32 nationally, 25,676 cases)
- Gonorrhea cases: 148.3 per 100K (#30 nationally, 8,740 cases)
- Primary and secondary syphilis cases: 12.6 per 100K (#29 nationally, 742 cases)
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#50. Buffalo County

- Chlamydia cases: 187.9 per 100K people (25 cases)
- Gonorrhea cases: 52.6 per 100K people (7 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#49. Door County

- Chlamydia cases: 191.0 per 100K people (58 cases)
- Gonorrhea cases: 42.8 per 100K people (13 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#48. Sawyer County

- Chlamydia cases: 191.3 per 100K people (35 cases)
- Gonorrhea cases: 109.3 per 100K people (20 cases)
- Syphilis cases (non-congenital): 76.5 per 100K people (14 cases)
--- Primary and secondary syphilis: 54.7 per 100K people (10 cases)
--- Nonprimary and nonsecondary early syphilis: 21.9 per 100K people (4 cases)
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Barbara Smits // Shutterstock

#47. Lafayette County

- Chlamydia cases: 196.6 per 100K people (33 cases)
- Gonorrhea cases: 17.9 per 100K people (3 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#46. Green County

- Chlamydia cases: 197.4 per 100K people (73 cases)
- Gonorrhea cases: 24.3 per 100K people (9 cases)
- Syphilis cases (non-congenital): 2.7 per 100K people (1 case)
--- Primary and secondary syphilis: 2.7 per 100K people (1 case)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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Sam Wagner // Shutterstock

#45. Jackson County

- Chlamydia cases: 203.6 per 100K people (43 cases)
- Gonorrhea cases: 66.3 per 100K people (14 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#44. Burnett County

- Chlamydia cases: 209.0 per 100K people (35 cases)
- Gonorrhea cases: 47.8 per 100K people (8 cases)
- Syphilis cases (non-congenital): 6.0 per 100K people (1 case)
--- Primary and secondary syphilis: 6.0 per 100K people (1 case)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#43. Kewaunee County

- Chlamydia cases: 209.3 per 100K people (43 cases)
- Gonorrhea cases: 38.9 per 100K people (8 cases)
- Syphilis cases (non-congenital): 9.7 per 100K people (2 cases)
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 9.7 per 100K people (2 cases)
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#42. Oconto County

- Chlamydia cases: 213.4 per 100K people (84 cases)
- Gonorrhea cases: 22.9 per 100K people (9 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#41. Chippewa County

- Chlamydia cases: 215.4 per 100K people (144 cases)
- Gonorrhea cases: 79.3 per 100K people (53 cases)
- Syphilis cases (non-congenital): 1.5 per 100K people (1 case)
--- Primary and secondary syphilis: 1.5 per 100K people (1 case)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#40. Pierce County

- Chlamydia cases: 216.0 per 100K people (92 cases)
- Gonorrhea cases: 42.3 per 100K people (18 cases)
- Syphilis cases (non-congenital): 4.7 per 100K people (2 cases)
--- Primary and secondary syphilis: 4.7 per 100K people (2 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#39. Calumet County

- Chlamydia cases: 228.4 per 100K people (120 cases)
- Gonorrhea cases: 40.0 per 100K people (21 case)
- Syphilis cases (non-congenital): 7.6 per 100K people (4 cases)
--- Primary and secondary syphilis: 5.7 per 100K people (3 cases)
--- Nonprimary and nonsecondary early syphilis: 1.9 per 100K people (1 case)
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Henryk Sadura // Shutterstock

#38. Langlade County

- Chlamydia cases: 230.7 per 100K people (45 cases)
- Gonorrhea cases: 15.4 per 100K people (3 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#37. Trempealeau County

- Chlamydia cases: 231.1 per 100K people (71 case)
- Gonorrhea cases: 39.1 per 100K people (12 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#36. Lincoln County

- Chlamydia cases: 238.3 per 100K people (68 cases)
- Gonorrhea cases: 14.0 per 100K people (4 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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John Touscany // Shutterstock

#35. Wood County

- Chlamydia cases: 240.3 per 100K people (178 cases)
- Gonorrhea cases: 54.0 per 100K people (40 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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Suzanne Tucker // Shutterstock

#34. Waupaca County

- Chlamydia cases: 242.4 per 100K people (125 cases)
- Gonorrhea cases: 33.0 per 100K people (17 cases)
- Syphilis cases (non-congenital): 3.9 per 100K people (2 cases)
--- Primary and secondary syphilis: 3.9 per 100K people (2 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#33. Columbia County

- Chlamydia cases: 246.2 per 100K people (144 cases)
- Gonorrhea cases: 53.0 per 100K people (31 case)
- Syphilis cases (non-congenital): 10.3 per 100K people (6 cases)
--- Primary and secondary syphilis: 8.5 per 100K people (5 cases)
--- Nonprimary and nonsecondary early syphilis: 1.7 per 100K people (1 case)
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Emmy_ann // Shutterstock

#32. Rusk County

- Chlamydia cases: 247.8 per 100K people (35 cases)
- Gonorrhea cases: 42.5 per 100K people (6 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#31. Barron County

- Chlamydia cases: 250.4 per 100K people (117 cases)
- Gonorrhea cases: 59.9 per 100K people (28 cases)
- Syphilis cases (non-congenital): 2.1 per 100K people (1 case)
--- Primary and secondary syphilis: 2.1 per 100K people (1 case)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#30. Marathon County

- Chlamydia cases: 257.2 per 100K people (354 cases)
- Gonorrhea cases: 67.6 per 100K people (93 cases)
- Syphilis cases (non-congenital): .7 per 100K people (1 case)
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: .7 per 100K people (1 case)
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B View // Shutterstock

#29. Iron County

- Chlamydia cases: 259.0 per 100K people (16 cases)
- Gonorrhea cases: 0 cases
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#28. Jefferson County

- Chlamydia cases: 260.2 per 100K people (221 case)
- Gonorrhea cases: 51.8 per 100K people (44 cases)
- Syphilis cases (non-congenital): 2.4 per 100K people (2 cases)
--- Primary and secondary syphilis: 2.4 per 100K people (2 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#27. Grant County

- Chlamydia cases: 261.0 per 100K people (136 cases)
- Gonorrhea cases: 48.0 per 100K people (25 cases)
- Syphilis cases (non-congenital): 7.7 per 100K people (4 cases)
--- Primary and secondary syphilis: 7.7 per 100K people (4 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#26. Shawano County

- Chlamydia cases: 264.3 per 100K people (108 cases)
- Gonorrhea cases: 34.3 per 100K people (14 cases)
- Syphilis cases (non-congenital): 2.4 per 100K people (1 case)
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 2.4 per 100K people (1 case)
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#25. Richland County

- Chlamydia cases: 267.3 per 100K people (46 cases)
- Gonorrhea cases: 52.3 per 100K people (9 cases)
- Syphilis cases (non-congenital): 11.6 per 100K people (2 cases)
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 11.6 per 100K people (2 cases)
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#24. Walworth County

- Chlamydia cases: 289.3 per 100K people (309 cases)
- Gonorrhea cases: 46.8 per 100K people (50 cases)
- Syphilis cases (non-congenital): 6.6 per 100K people (7 cases)
--- Primary and secondary syphilis: 5.6 per 100K people (6 cases)
--- Nonprimary and nonsecondary early syphilis: .9 per 100K people (1 case)
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#23. Manitowoc County

- Chlamydia cases: 289.6 per 100K people (236 cases)
- Gonorrhea cases: 49.1 per 100K people (40 cases)
- Syphilis cases (non-congenital): 4.9 per 100K people (4 cases)
--- Primary and secondary syphilis: 2.5 per 100K people (2 cases)
--- Nonprimary and nonsecondary early syphilis: 2.5 per 100K people (2 cases)
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#22. Ashland County

- Chlamydia cases: 291.8 per 100K people (47 cases)
- Gonorrhea cases: 31.0 per 100K people (5 cases)
- Syphilis cases (non-congenital): 12.4 per 100K people (2 cases)
--- Primary and secondary syphilis: 12.4 per 100K people (2 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#21. Sheboygan County

- Chlamydia cases: 293.9 per 100K people (346 cases)
- Gonorrhea cases: 91.7 per 100K people (108 cases)
- Syphilis cases (non-congenital): 17.8 per 100K people (21 case)
--- Primary and secondary syphilis: 11.9 per 100K people (14 cases)
--- Nonprimary and nonsecondary early syphilis: 5.9 per 100K people (7 cases)
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Patrick Lansing // Shutterstock

#20. Dunn County

- Chlamydia cases: 311.8 per 100K people (142 cases)
- Gonorrhea cases: 79.0 per 100K people (36 cases)
- Syphilis cases (non-congenital): 2.2 per 100K people (1 case)
--- Primary and secondary syphilis: 2.2 per 100K people (1 case)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#19. Marinette County

- Chlamydia cases: 317.6 per 100K people (133 cases)
- Gonorrhea cases: 28.7 per 100K people (12 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#18. Outagamie County

- Chlamydia cases: 318.5 per 100K people (610 cases)
- Gonorrhea cases: 82.0 per 100K people (157 cases)
- Syphilis cases (non-congenital): 7.3 per 100K people (14 cases)
--- Primary and secondary syphilis: 4.2 per 100K people (8 cases)
--- Nonprimary and nonsecondary early syphilis: 3.1 per 100K people (6 cases)
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#17. Monroe County

- Chlamydia cases: 337.7 per 100K people (156 cases)
- Gonorrhea cases: 52.0 per 100K people (24 cases)
- Syphilis cases (non-congenital): 8.7 per 100K people (4 cases)
--- Primary and secondary syphilis: 6.5 per 100K people (3 cases)
--- Nonprimary and nonsecondary early syphilis: 2.2 per 100K people (1 case)
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#16. Douglas County

- Chlamydia cases: 348.4 per 100K people (154 cases)
- Gonorrhea cases: 119.9 per 100K people (53 cases)
- Syphilis cases (non-congenital): 6.8 per 100K people (3 cases)
--- Primary and secondary syphilis: 6.8 per 100K people (3 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#15. Fond Du Lac County

- Chlamydia cases: 351.7 per 100K people (367 cases)
- Gonorrhea cases: 97.7 per 100K people (102 cases)
- Syphilis cases (non-congenital): 4.8 per 100K people (5 cases)
--- Primary and secondary syphilis: 4.8 per 100K people (5 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#14. Dodge County

- Chlamydia cases: 357.2 per 100K people (319 cases)
- Gonorrhea cases: 42.5 per 100K people (38 cases)
- Syphilis cases (non-congenital): 5.6 per 100K people (5 cases)
--- Primary and secondary syphilis: 4.5 per 100K people (4 cases)
--- Nonprimary and nonsecondary early syphilis: 1.1 per 100K people (1 case)
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#13. Juneau County

- Chlamydia cases: 365.6 per 100K people (98 cases)
- Gonorrhea cases: 26.1 per 100K people (7 cases)
- Syphilis cases (non-congenital): 3.7 per 100K people (1 case)
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 3.7 per 100K people (1 case)
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#12. Eau Claire County

- Chlamydia cases: 378.6 per 100K people (403 cases)
- Gonorrhea cases: 117.4 per 100K people (125 cases)
- Syphilis cases (non-congenital): 7.5 per 100K people (8 cases)
--- Primary and secondary syphilis: 5.6 per 100K people (6 cases)
--- Nonprimary and nonsecondary early syphilis: 1.9 per 100K people (2 cases)
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#11. Sauk County

- Chlamydia cases: 392.7 per 100K people (258 cases)
- Gonorrhea cases: 73.1 per 100K people (48 cases)
- Syphilis cases (non-congenital): 4.6 per 100K people (3 cases)
--- Primary and secondary syphilis: 1.5 per 100K people (1 case)
--- Nonprimary and nonsecondary early syphilis: 3.0 per 100K people (2 cases)
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#10. Portage County

- Chlamydia cases: 414.4 per 100K people (292 cases)
- Gonorrhea cases: 52.5 per 100K people (37 cases)
- Syphilis cases (non-congenital): 2.8 per 100K people (2 cases)
--- Primary and secondary syphilis: 2.8 per 100K people (2 cases)
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#9. Winnebago County

- Chlamydia cases: 428.8 per 100K people (736 cases)
- Gonorrhea cases: 125.9 per 100K people (216 cases)
- Syphilis cases (non-congenital): 4.1 per 100K people (7 cases)
--- Primary and secondary syphilis: 2.9 per 100K people (5 cases)
--- Nonprimary and nonsecondary early syphilis: 1.2 per 100K people (2 cases)
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#8. Kenosha County

- Chlamydia cases: 467.0 per 100K people (788 cases)
- Gonorrhea cases: 155.3 per 100K people (262 cases)
- Syphilis cases (non-congenital): 7.7 per 100K people (13 cases)
--- Primary and secondary syphilis: 5.9 per 100K people (10 cases)
--- Nonprimary and nonsecondary early syphilis: 1.8 per 100K people (3 cases)
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#7. Brown County

- Chlamydia cases: 475.5 per 100K people (1,282 cases)
- Gonorrhea cases: 133.2 per 100K people (359 cases)
- Syphilis cases (non-congenital): 7.0 per 100K people (19 cases)
--- Primary and secondary syphilis: 4.8 per 100K people (13 cases)
--- Nonprimary and nonsecondary early syphilis: 2.2 per 100K people (6 cases)
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#6. Dane County

- Chlamydia cases: 512.3 per 100K people (2,889 cases)
- Gonorrhea cases: 199.7 per 100K people (1,126 cases)
- Syphilis cases (non-congenital): 14.5 per 100K people (82 cases)
--- Primary and secondary syphilis: 8.5 per 100K people (48 cases)
--- Nonprimary and nonsecondary early syphilis: 6.0 per 100K people (34 cases)
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#5. Rock County

- Chlamydia cases: 520.1 per 100K people (855 cases)
- Gonorrhea cases: 270.7 per 100K people (445 cases)
- Syphilis cases (non-congenital): 4.3 per 100K people (7 cases)
--- Primary and secondary syphilis: 2.4 per 100K people (4 cases)
--- Nonprimary and nonsecondary early syphilis: 1.8 per 100K people (3 cases)
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#4. La Crosse County

- Chlamydia cases: 532.2 per 100K people (641 case)
- Gonorrhea cases: 131.2 per 100K people (158 cases)
- Syphilis cases (non-congenital): 8.3 per 100K people (10 cases)
--- Primary and secondary syphilis: 5.8 per 100K people (7 cases)
--- Nonprimary and nonsecondary early syphilis: 2.5 per 100K people (3 cases)
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#3. Racine County

- Chlamydia cases: 632.3 per 100K people (1,245 cases)
- Gonorrhea cases: 279.3 per 100K people (550 cases)
- Syphilis cases (non-congenital): 15.2 per 100K people (30 cases)
--- Primary and secondary syphilis: 9.6 per 100K people (19 cases)
--- Nonprimary and nonsecondary early syphilis: 5.6 per 100K people (11 case)
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#2. Menominee County

- Chlamydia cases: 979.2 per 100K people (42 cases)
- Gonorrhea cases: 139.9 per 100K people (6 cases)
- Syphilis cases (non-congenital): 0 cases
--- Primary and secondary syphilis: 0 cases
--- Nonprimary and nonsecondary early syphilis: 0 cases
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#1. Milwaukee County

- Chlamydia cases: 1,175.8 per 100K people (10,912 cases)
- Gonorrhea cases: 594.6 per 100K people (5,518 cases)
- Syphilis cases (non-congenital): 82.5 per 100K people (766 cases)
--- Primary and secondary syphilis: 53.9 per 100K people (500 cases)
--- Nonprimary and nonsecondary early syphilis: 28.7 per 100K people (266 cases)

This story features data reporting and writing by Emma Rubin and is part of a series utilizing data automation across 49 states.

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