Chlamydia cases in Brown County have been increasing, keeping pace with the rise in numbers in the rest of the state, according to the department of health.
Brown County's numbers account for 3.7 percent of the cases in South Dakota since 2006.
Since 2006, there have been 655 cases of chlamydia reported in the county, with numbers fluctuating from year to year. Chlamydia is the most commonly reported sexually transmitted disease throughout the state and nation, said State Epidemiologist Lon Kightlinger.
Cases of chlamydia reported in Brown County, according to the state health department:
- 97 cases reported to date this year.
- 128 in 2011.
- 159 in 2010.
- 88 in 2009.
- 84 in 2008.
- 85 in 2007.
- 111 reported cases in 2006.
Numbers for the surrounding counties for the same period of time were significantly less. The most notable was Walworth County, which reported 167 cases. Day and Spink counties reported fewer than 100 cases of chlamydia. Campbell, Edmunds, Faulk, Marshall, McPherson and Potter each reported fewer than 50 cases since 2006.
Gonorrhea rates, which saw a spike throughout the state in 2012, were relatively low in the region. Since 2006, there have been 39 total reported cases in Brown County. Walworth County reported 23 total cases for the same time frame. Other counties reported seven or fewer. Statewide, 558 cases were reported, according to data from the health department.
Kightlinger said the explanation for the lower infection rate in the area could be the sparse population in the counties.
"There's not a lot of people to spread it around," he said. "But it could take hold of some small counties. We do have some counties in the state with fairly high numbers."
As for HIV, 12 cases were reported in Brown County from 1985 to 2011. Marshall, Day, Spink, Walworth and Potter each reported five or fewer cases in the same period.
South Dakota has a low rate for the virus and is one of the four lowest among states, Kightlinger said. The rate is 2.9 cases per 100,000 people over the last five years, according to state data.
No cases of syphilis were reported in the area, with most of the cases concentrated near Sioux Falls, Kightlinger said. Statewide, 17 cases have been reported since 2006.
But he cautioned people not to become complacent: "Don't think it's just a Sioux Falls thing; it can happen in Aberdeen, too."
Overall, Kightlinger said, people should still be vigilant and cautious.
"The interpretation could be that STDs are common in South Dakota, and there's no region of the state that does not have STDs," he said.