MMWR Clinical Pearls

April 2025

Neuro-, ocular, and otic syphilis

The incidence of syphilis has been increasing in the United States since 2001, and is more common in persons with HIV infection. Neurosyphilis, ocular syphilis, and otic syphilis (NOO syphilis) can occur at any syphilis stage with or without HIV coinfection. NOO syphilis manifestations often are debilitating and can include meningitis, stroke, motor or sensory deficits, blindness, and hearing loss. During January 1–October 31, 2023, 40 NOO syphilis cases were reported in Chicago, 68% of which occurred in persons without HIV infection compared with 44% in 2019. Among 33 (83%) NOO syphilis patients whose sex and that of their sexual partners were reported, 18 (55%) were not men who have sex with men (MSM) compared with four of 15 patients (27%) in 2019.

Bottom Line:

Clinicians should consider NOO syphilis in patients who present with unexplained neurologic, visual, or auditory complaints, even in persons who do not have HIV and who are not MSM.

Learn more:
Notes from the Field: Neurosyphilis, Ocular Syphilis, and Otic Syphilis — Chicago, January–October 2023
Neurosyphilis, Ocular Syphilis, & Otosyphilis
Neurosyphilis, Ocular Syphilis, and Otosyphilis – STI Treatment Guidelines

Hepatitis C in Alaska

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, hepatocellular carcinoma, and liver-related death and is targeted for global elimination as a public health threat by 2030. In Alaska, the average annual rate of newly reported chronic hepatitis C (cases per 100,000 adults) during 2016–2023 was 121; the rate decreased a relative 30% from 142 (2016–2019) to 99 (2020–2023). Rates decreased for most groups but were higher overall among males, persons aged 18–39 years, residents of rural areas, and American Indian or Alaska Native persons.

Bottom Line:

Universal hepatitis C screening is recommended for all U.S. adults aged ≥18 years (at least once during their lifetime) and pregnant women during each pregnancy; periodic risk-based screening also is recommended.
Persons with evidence of current infection should be linked to antiviral treatment, which usually results in a virologic cure within 8–12 weeks.

Learn more:
Newly Reported Chronic Hepatitis C Among Adults — Alaska, 2016–2023
CDC Recommendations for Hepatitis C Screening Among Adults — United States, 2020

Acanthamoeba encephalitis after nasal irrigation and CPAP use

Acanthamoeba, a free-living ameba, can cause encephalitis and disseminated disease that are nearly always fatal. Immunocompromised people are at highest risk. In November 2023, a patient died from an Acanthamoeba infection, likely acquired by using tap water in electronic medical devices. Acanthamoeba was detected in the patient’s brain tissue, an electronic nasal irrigator, and a continuous positive airway pressure (CPAP) machine; all strains were of the same genotype.

Bottom Line:

Counsel patients to always follow manufacturer recommendations when using medical devices, including CPAP machines.
For nasal irrigation, patients should use distilled, sterile, or boiled and cooled tap water.
CDC offers a 24-hour, 7 days-a-week free-living ameba clinical consultation service to provide diagnostic and treatment advice to health care providers.

Learn more:
Notes from the Field: Fatal Acanthamoeba Encephalitis in a Patient Who Regularly Used Tap Water in an Electronic Nasal Irrigation Device and a Continuous Positive Airway Pressure Machine at Home — New Mexico, 2023
CDC – DPDx – Free Living Amebic Infections
CDC – DPDx – Contact Us

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