A Cluster of Ocular Syphilis Cases with a Common Sex Partner — Southwest Michigan, 2022

Untreated syphilis can lead to ocular syphilis, otosyphilis, and neurosyphilis, conditions resulting from Treponema pallidum infection of the eye, inner ear, or central nervous system. During March-July 2022, Michigan public health officials identified a cluster of ocular syphilis cases. The public health response included case investigation, partner notification, dissemination of health alerts, patient referral to a public health clinic for diagnosis and treatment, hospital care coordination, and specimen collection for T. pallidum molecular typing. Five cases occurred among southwest Michigan women, all of whom had the same male sex partner. The women were aged 40-60 years, HIV-negative, and identified as non-Hispanic White race; the disease was staged as early syphilis, and all patients were hospitalized and treated with intravenous penicillin. The common male sex partner was determined to have early latent syphilis and never developed ocular syphilis. No additional transmission was identified after the common male partner's treatment. Due to lack of genetic material in limited specimens, syphilis molecular typing was not possible. A common heterosexual partner in an ocular syphilis cluster has not been previously documented and suggests that an unidentified strain of T. pallidum might have been associated with increased risk for systemic manifestations of syphilis. A high index of clinical suspicion and thorough sexual history are critical to diagnosing ocular syphilis, otosyphilis, and neurosyphilis. Coordination of disease surveillance with disease intervention specialist investigation and treatment referral can interrupt syphilis transmission.