Amebic Meningitis / Encephalitis
Amebic CNS infections (amebic meningitis/encephalitis) are caused by microscopic, free-living amebae (single-celled living organisms).
Amebic CNS infections (amebic meningitis/encephalitis) are caused by microscopic, free-living amebae (single-celled living organisms).
Amebic meningitis/encephalitis infections are not spread from person to person. The amebae that cause amebic meningitis/encephalitis enter the body through different routes, depending on the specific ameba:
Balamuthia
Acanthamoeba
Sappinia
The symptoms of Granulomatous Amebic Encephalitis (GAE) vary depending on the infecting ameba:
Balamuthia mandrillaris infection is very rare and serious, with a death rate of more than 89%. The disease might appear mild at first but can become more severe over weeks to several months. Early diagnosis and treatment may increase the chances of survival.
Disease begins with a skin wound and can then travel to the brain causing GAE. Diagnosis of Balamuthia GAE can be difficult, but some early symptoms might include:
Other signs of Balamuthia GAE might include:
Acanthamoeba species: This is a serious, most often deadly, infection of the brain and spinal cord. Symptoms progress over several weeks and death usually occurs.
Sappinia species: There is only one known case of Sappinia encephalitis in a human. A scan of the one known infected patient’s brain revealed a 2-centimeter tumor-like mass on the back left section of the brain. Symptoms of Sappinia infection may include:
Some groups have a higher risk of infection or disease:
Currently, there are no known ways to prevent infection with Balamuthia or Acanthamoeba. Since persons with weakened immune systems are more susceptible to Acanthamoeba infection, they should follow the advice of their treating physician carefully.
Other Amebic Meningitis and Encephalitis including Granulomatous Amebic Encephalitis (GAE):
From 1972-2020, 19 other amebic meningitis/encephalitis cases were reported to DSHS, 11 caused by Balamuthia mandrillaris, 5 caused by Acanthamoeba species, and 1 by a Sappinia species. Texas’ 1998 Sappinia pedata encephalitis case is the only known case of amebic encephalitis caused by Sappinia, worldwide. In 2012, Texas confirmed a case of Acanthamoeba healyi, a species not previously reported to cause human amebic encephalitis.
Although GAE infections and other amebic meningitis and encephalitis cases have always been reportable to Texas health departments as exotic diseases, before 2012, PAM was the only amebic infection of the central nervous system that was listed on the Texas Notifiable Conditions list.
There is no vaccine for amebic meningitis or encephalitis, including Primary Amebic Meningoencephalitis and Granulomatous Amebic Encephalitis.
Report any CNS infection, including Naegleria fowleri, Acanthamoeba spp. & Balamuthia mandrillaris within one week to DSHS at (512) 776-7676.
Several Texas laws (Tex. Health & Safety Code, Chapters 81, 84 and 87) require specific information regarding notifiable conditions be provided to the Texas Department of State Health Services (DSHS). Health care providers, hospitals, laboratories, schools, and others are required to report patients who are suspected of having a notifiable condition (25 Tex. Admin. Code §97.2).
Reports from healthcare providers and laboratories may be submitted using the EPI-2 Initial Provider Disease Report Form. Health Departments may use the Investigation Form.
NOTE: Prior to shipping you must call 512-776-7676 and speak with the epidemiologist for Amebic Meningitis/Encephalitis in the Emerging and Acute Infectious Disease Branch(EAIDB) of the Department of State Health Services (DSHS).
Instructions for submitting photos through DPDx are available at the DPDx Contact Us page.
For additional information about specimen submission and shipping contact the DSHS Medical Parasitology Team at 512-776-7560.
Infectious Disease Prevention Section
Mail Code: 1927
PO BOX 149347
Austin, TX 78714-9347
United States
1100 West 49th Street
Suite G401
Austin, TX 78714
United States