Lewis and Clark County sees chlamydia outbreak as teen cases rise

Lewis and Clark County Public Health recorded 53 chlamydia cases, up from 31 in the same period in 2025, a 71% increase that meets the epidemiological definition of an outbreak. The pattern is moving through adolescent social networks and social media apps, with 44% of cases in people ages 15 to 19 and 58% in females.

Public health nurse supervisor Shelly Maag and health officer Drenda Niemann urged parents and guardians to have direct, honest conversations with teenagers about sexual activity, social media use and the need for testing.

Chlamydia often has no symptoms in men or women, which means people can pass it on without realizing it. Chlamydial infection is the most frequently reported bacterial infectious disease in the United States and is most common among people 24 and younger, according to the Centers for Disease Control and Prevention. Untreated infection in women can lead to pelvic inflammatory disease, ectopic pregnancy and infertility.

In Montana and in the United States, chlamydia is the most common STI, according to the Montana Department of Public Health and Human Services, and untreated infection can cause permanent reproductive damage. For teens, minors in all 50 states and the District of Columbia can consent to STI services, though insurance billing can still make confidentiality complicated, according to the CDC.

Lewis and Clark Public Health offers free and confidential chlamydia testing, along with free rapid HIV testing and affordable treatment for chlamydia and gonorrhea. County nurses investigate STI cases and notify partners of infections. Residents can reach the county’s main line at 406-457-8900, or use confidential texting at 406-431-7470 and 406-594-2949 for STI testing and counseling.