About Parasitic Meningitis

Key points

  • Parasites can cause meningitis or affect the brain or nervous system in other ways.
  • Meningitis from parasites is less common than viral and bacterial meningitis.
  • Some people may have increased risk of infection because of where they live or travel.
  • Diagnosis can be hard and there aren't any specific treatments.
Left: Embryonated B. procyonis egg, showing the developing larva inside. Right: Larva of B. procyonis hatching from an egg.

What it is

Meningitis caused by parasites is called EM which is short for either:

  • Eosinophilic meningitis
  • Eosinophilic meningoencephalitis


The 3 main parasites that cause EM in some infected people are:


People with EM who have symptoms can have typical meningitis symptoms. They also may have an eye infection.

People with EM caused by A. cantonensis often have tingling or painful feelings in their skin.

When to seek emergency care‎

Anyone with symptoms of meningitis should see a healthcare provider right away. A healthcare provider can determine if you have meningitis, what's causing it, and the best treatment.


These parasites can cause severe complications, such as

  • Loss of coordination and muscle control
  • Weakness/paralysis
  • Coma
  • Permanent disability
  • Death

Risk factors

Risk factors vary by parasite, but can include age, animal contact, and geographic location.

A. cantonensis

Most of these infections are diagnosed in Southeast Asia and the Pacific Islands, including in Hawaii.

B. procyonis

This parasite infects raccoons throughout the United States, mainly in the Midwest, Northeast, Middle Atlantic, and West Coast.

People in these areas who spend time around raccoons are at increased risk. Young children are also at risk due to increased likelihood of putting contaminated fingers, soil, or objects in their mouths.

G. spinigerum

This infection is most commonly diagnosed in Southeast Asia, particularly in Thailand, and Japan.

How it spreads

These parasites normally infect animals not people. People get infected primarily by eating infected animals or contaminated foods, or being exposed to infected animals.

Typical source of infection

  • A. cantonensis: Raw or undercooked snails or slugs, contaminated produce
  • B. procyonis: Environments (such as dirt) contaminated with raccoon feces
  • G. spinigerum: Raw or undercooked freshwater fish or eels, frogs, poultry, snakes

How it doesn't spread

Generally, people don't spread parasitic meningitis or the parasites that cause it to other people.

Reducing risk

Visit CDC's website for each parasite to learn specifics on how to prevent infection with these and other parasites. Generally, you can reduce your risk in the following ways:

  • A. cantonensis: Don’t eat undercooked or raw foods that might be infected
  • B. procyonis: Avoid contact with raccoons and their feces
  • G. spinigerum: Don’t eat undercooked or raw foods that might be infected

Testing and diagnosis

In addition to laboratory tests for meningitis, healthcare providers look for evidence of parasitic infection. It's often hard to find these parasites.

The following may be helpful for making a diagnosis:

  • Travel or exposure history
  • Clinical examination
  • Other medical tests, such as brain scans

Treatment and recovery

There's no specific treatment for EM caused by these parasites. However, treatment for the infection might help some people.

Pain medication may be used for headaches.

Medications may also be used to reduce the body’s reaction to the parasite.