The United States has seen four consecutive years of rising rates of several common sexually transmitted diseases, according to the federal Centers for Disease Control and Prevention. Trends in South Dakota largely mirror what’s happening at the national level, though South Dakota generally is not one of the states with the highest rates of STDs.

Just how common are STDs here in South Dakota? How much more common have certain STDs grown over the past few years, and which areas of the state are the most prone to high rates of STDs? To answer those questions and more, we’ll dig deep into STD data published by the CDC.

Chlamydia Rates in South Dakota

South Dakota ranks just among the top half of the 50 states when it comes to how common chlamydia is in the state. South Dakota’s population-adjusted rate of 512.7 per 100,000 people is high enough for No. 23 overall among the states but is nearly one-third lower than that of Alaska, the state with the highest rate. It’s also lower than the overall U.S. rate, but by a smaller margin of just a few percent.

Chlamydia infections per 100,000 people, top 25

Alaska 799.8
Louisiana 742.4
Mississippi 708.7
South Carolina 649.8
New Mexico 645
Georgia 623.7
Alabama 615.5
North Carolina 612.2
New York 591.6
Illinois 589.9
Maryland 586.3
Arkansas 576.7
Arizona 571.8
Delaware 566.3
California 557.4
Oklahoma 554.4
Nevada 544.7
Texas 543.9
Missouri 536.4
Ohio 528.6
Tennessee 522.5
Indiana 514.2
South Dakota 512.7
Michigan 511.9
Rhode Island 500
Total 528.8

The chlamydia rate has varied quite a bit in South Dakota over the past several years, but it stands today at nearly 10% higher than it was in 2012.

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

2012 470.9
2013 464.8
2014 488.3
2015 460
2016 504.5
2017 512.7

Illinois is the only Midwestern state to place in the top 10 nationally, and South Dakota’s rate puts the state in the top half 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
Kansas 488.9
Wisconsin 485
Iowa 467
Nebraska 450.7
Minnesota 444
North Dakota 432.5

Gonorrhea Rates in South Dakota

South Dakota’s population-adjusted gonorrhea rate of 149.1 per 100,000 ranks the state at No. 29 overall, coming in both below the national rate (-13%) and well below the state with the highest rate, Mississippi (-52%).

Gonorrhea infections per 100,000 people, bottom 25

Iowa 154
Florida 153.7
Colorado 151.1
South Dakota 149.1
Virginia 143.3
Minnesota 142
Nebraska 139.1
Washington 137.1
Wisconsin 135
North Dakota 127.4
Oregon 121.3
Pennsylvania 119.2
Connecticut 109.4
Massachusetts 106.5
New Jersey 105.5
Rhode Island 102.9
Hawaii 95.1
Utah 81.2
Montana 75
West Virginia 70.8
Wyoming 70.4
Idaho 58.6
Maine 46.6
New Hampshire 38.4
Vermont 32.5
Total 171.9

The gonorrhea rate has risen steadily in South Dakota since 2012, climbing by more than 75% between 2012 and 2017.

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

2012 84.8
2013 92.8
2014 104.6
2015 122.1
2016 147.8
2017 149.1

Ohio is the only state in the Midwest with a gonorrhea rate that is among the 10 highest, and South Dakota’s rate is low enough to place in the bottom half of the region.

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

Ohio 216.3
Missouri 214.8
Illinois 186.4
Kansas 180.8
Indiana 177.5
Michigan 154.7
Iowa 154
South Dakota 149.1
Minnesota 142
Nebraska 139.1
Wisconsin 135
North Dakota 127.4

Syphilis Rates in South Dakota

South Dakota is tied for the 10th-lowest rate of primary and secondary syphilis in the nation, posting a rate of 3.8 per 100,000 people, far lower than both the national leader, Nevada (-80%), and the overall U.S. rate (-60%).

Primary and secondary syphilis infections per 100,000 people

Highest
Nevada 19.7
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
Total 9.5
Lowest
South Dakota 3.8
Utah 3.7
West Virginia 3.4
New Hampshire 3.2
Connecticut 3.1
Wisconsin 3
Iowa 2.7
Nebraska 2.3
Vermont 2.1
Wyoming 0.7

South Dakota recorded a recent high in the syphilis rate in 2014, and the rate had been falling since then, but 2017 marked a slight increase. Still, since 2012, the syphilis rate is up by a total of 72%.

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

2012 2.2
2013 5.2
2014 6.2
2015 4.5
2016 3
2017 3.8

Four of the states with the 10 lowest rates in the country are in the Midwest, and South Dakota has the fourth-lowest rate in the region.

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 5.5
Kansas 5
Michigan 4.8
Indiana 4.8
South Dakota 3.8
Wisconsin 3
Iowa 2.7
Nebraska 2.3

HIV & Other STD Rates in South Dakota

HIV

New cases of HIV are relatively rare in South Dakota, with less than 40 people being diagnosed in 2017. South Dakota’s population-adjusted rate of 4.3 per 100,000 is tied for 11th-lowest in the country, and the state saw the HIV rate drop by 10% between 2016 and 2017. See How to Test for HIV

Hepatitis B & C

Cases of acute hepatitis B are far less common in South Dakota than the rest of the country, but it’s an opposite picture for acute hep C. South Dakota’s hep B rate of 0.2 per 100,000 is much lower than the overall U.S. rate of 1 per 100,000, and the state’s rate has been cut in half since 2014. Acute hep C, on the other hand, occurs about twice as frequently here than in the U.S. as a whole. Historic data on hep C infections is not available. See How to Test for Hepatitis

HPV

Because it’s incredibly common, it’s difficult to pinpoint the precise number of people who are infected with human papillomavirus, or HPV, at any given time. But looking at the rates of certain cancers can help provide some context. That’s because for several cancers, HPV is the primary cause. This famously included cervical cancer but also anal, penile and several other types of cancers. The HPV-caused cancer rate in South Dakota is 11.4 per 100,000, just under the national median of 11.7 per 100,000. See How to Test for HPV

STDs in South Dakota Cities & Counties

While South Dakota generally is not among the states with the highest rates of many types of STDs, several of the state’s counties do have very high rates, and the states two major cities, Rapid City and Sioux Falls, account for a large percentage of cases.

Chlamydia

About 42% of chlamydia cases in South Dakota in 2017 were diagnosed among people in Rapid City and Sioux Falls.

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

Dewey 2,603
Todd 2,018
Corson 1,835
Buffalo 1,432
Roberts 1,164
Bennett 1,110
Mellette 1,073
Lyman 1,006
Ziebach 927.6
Charles Mix 884.6

Gonorrhea

Sioux Falls accounted for nearly 30% of gonorrhea cases, and Rapid City added another 22%.

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

Dewey 1,108
Todd 1,084
Lyman 645
Ziebach 642.2
Buffalo 572.8
Bennett 496.6
Mellette 487.8
Charles Mix 405
Corson 309.7
Pennington 261.3

Primary and secondary syphilis

Nearly 3 in 4 cases of primary and secondary syphilis occurred in the Sioux Falls area.

South Dakota counties by primary and secondary syphilis infection rate (cases per 100,000 people)

Corson 71.5
Clay 14.3
Minnehaha 9.7
Lake 7.9
Brookings 3
Lincoln 1.9

Conclusion

South Dakota may not be among the states with STD rates that cause the highest degree of concern. But that doesn’t mean the states rates and increases don’t deserve attention. As the trends in South Dakota and across the country illustrate, a statistical increase here or there can quickly turn into a major public health problem. The best way for individuals to make an impact on the state of STDs here in South Dakota is to get tested so that they can be sure they are not passing STDs along to their sexual partners.

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.