The Wisconsin Department of Health Services (DHS) has found that cases of adult and congenital syphilis are on the rise, with the highest rates being reported in Milwaukee. The number of people diagnosed with syphilis in Milwaukee has increased by nearly 300% compared to pre-pandemic levels. Most of the increase in syphilis cases is in females of reproductive age. The City of Milwaukee has also reported higher numbers of congenital syphilis, or syphilis cases where an infected pregnant person passes syphilis to their fetus.

“The spike in syphilis cases is alarming,” said Dr. Ryan Westergaard, Chief Medical Officer for Bureau of Communicable Diseases. “We are especially concerned with cases of congenital syphilis affecting babies born to mothers with syphilis. Congenital syphilis can have devastating consequences but is preventable with simple screening, early detection, and treatment.”

Syphilis is a sexually transmitted infection (STI) caused by a type of bacteria known as Treponema pallidum. If left untreated in adults, the bacteria can affect many different organ systems, including the heart and blood vessels. Sadly, up to 40% of babies with congenital syphilis may be born stillborn or die from the infection. Congenital syphilis can also cause miscarriage, prematurity, or low birth weight.

“We can achieve our goal of zero cases of congenital syphilis in our state, said Dr. Westergaard, “But we must intensify our efforts to test for and treat the infection in order to get there. We urge all Wisconsin providers to screen all pregnant persons for syphilis.”

Per CDC guidelines, pregnant people who live in areas where there are higher rates of syphilis should be screened at least twice during pregnancy, once in the first trimester and again during the third trimester. DHS has identified six counties where repeat third trimester testing is recommended, based on increased syphilis rates during 2020, these include Brown, Dane, Milwaukee, Racine, Waukesha, and Winnebago counties.

In Wisconsin, the prevalence of syphilis highlights longstanding racial inequities observed across a wide range of health conditions. For example, 65.9% of syphilis cases in the city of Milwaukee diagnosed from 2018-2020 were among Black residents, despite being only 38.7% of the city’s population. 

“It is important to continue efforts addressing the root causes of these inequities,” said Dr. Jasmine Zapata, Chief Medical Officer for Community Health Promotion.

As public health and health care professionals work to decrease the spike in syphilis cases through screening and treatment, work to address factors that make people more at risk for syphilis infection, like combating poverty, increasing access and use of prenatal care services, and building and maintaining trust between patients and health care providers.

For more information, see Wisconsin DHS Health Alert #31.