<i>Notes from the Field:</i> Neurosyphilis, Ocular Syphilis, and Otic Syphilis — Chicago, January–October 2023

The incidence of syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum, has been increasing in the United States since 2001.*Neurosyphilis, ocular syphilis, and otic syphilis (NOO syphilis), caused by T. pallidum invading the central nervous system, eyes, and ears, respectively, can occur in the primary, secondary, latent, or tertiary stages of syphilis.NOO syphilis manifestations are often debilitating and can include meningitis, stroke, motor or sensory deficits, blindness, and hearing loss.Data from the early to mid-2000s suggested that NOO syphilis was more commonly identified among gay, bisexual, and other men who have sex with men (MSM) and persons with HIV, likely reflecting the syphilis trends at the time these data were collected (1-3).Data collected from Chicago in 2019 showed that 11 of 16 NOO syphilis cases were diagnosed in MSM, and nine cases in persons with HIV.In 2023, health care providers in Chicago reported an increase in NOO syphilis among heterosexual persons without HIV.To assess whether this increase was consistent citywide, this analysis characterized NOO syphilis cases stratified by HIV status to identify factors associated with diagnosis in Chicago during January 1-October 31, 2023. Investigation and Outcomes Data Collection and AnalysesSurveillance data reported to the Chicago Department of Public Health (CDPH) were analyzed to describe NOO syphilis cases diagnosed in 2023.CDPH queried the Chicago Health Information Management System (CHIMS) to identify potential NOO syphilis cases based on 1) cerebrospinal fluid (CSF) test results indicative of neurosyphilis, including reactive CSF Venereal Disease Research Laboratory (VDRL), elevated CSF protein, and elevated CSF leukocyte count, 2) treatment with intravenous penicillin, or 3) any documented NOO syphilis sign or symptom in a Chicago resident during January 1-October 31, 2023.(4).CDPH abstracted clinical information from medical records to identify cases that met the 2018 Council of State and Territorial Epidemiologists' verified, likely, or possible case definitions * https://www.cdc.gov/sti-statistics/annual/index.html