A cluster of eye syphilis cases linked to a common sex partner has been reported in Michigan, the Centers for Disease Control and Prevention (CDC) reveals.

Eye syphilis, also known as ocular syphilis, occurs when the sexually transmitted disease of syphilis is left untreated. Around 12 million new cases of the disease are reported worldwide, of which 55,400 are from the United States.

In a first-of-its-kind report of an outbreak linked to a common male sex partner, officials have identified five women with eye syphilis. They believe a new strain of bacteria may have caused the disease.

"A cluster of five cases of ocular syphilis in women with a common male sex partner was identified in Michigan, suggesting that an unidentified Treponema pallidum strain might have been a risk factor for developing systemic manifestations of syphilis," the CDC said in a news release.

The five women, aged 40 to 60 years, reported eye problems between March and July 2022. An investigation revealed that a man had sexual connections to all five women, but he did not initially cooperate with health officials.

When the man sought medical care with complaints of ulcers and lesions in January 2022, he was not tested for syphilis. It was presumed as a case of herpes simplex viral infection and was treated with antiviral medication.

When health officials approached him later in May 2022, he had no signs of syphilis or ocular syphilis. However, the testing revealed he had early latent syphilis, a hidden stage of the disease that occurs when the symptoms appear to resolve. Patients at this stage may not have symptoms for years, but without treatment, it might lead to major complications.

All the patients were treated with penicillin and no additional transmission was known, officials said.

Stages of syphilis:

  • Primary stage - It occurs between two to 12 weeks after exposure to syphilis. The patient develops painless sores on the genitals that might heal on its own.
  • Secondary stage - In one to six months after the primary stage, patients may develop itchy rashes on the skin.
  • Latent stage - The stage of infection in which the patient shows no signs but is infectious.
  • Tertiary stage - It is the late stage when patients may develop complications.

Ocular syphilis can occur at any stage of syphilis, though it is more common in later stages.

Know the symptoms of ocular syphilis:

  • Pain in the eyes
  • Redness in eyes
  • Floating spots in the field of vision
  • Sensitivity to light
  • Blurred vision or blindness

Who is at risk?

People who have unprotected sex with more than one partner or with someone who has tested positive for syphilis are at risk of developing ocular syphilis. Men who have sex with men, and patients with HIV or another sexually transmitted disease are also at risk.

Complications of ocular syphilis

The complications include cataracts, scarring of eye tissue, glaucoma (optic nerve damage), swelling of the macula (the part of the eye that processes central vision) and neovascularization (abnormal development of new blood vessels in the eye), which can lead to decreased vision or complete blindness.