Acanthamoeba Infection

What is an Acanthamoeba infection?

Acanthamoeba are microscopic amoeba commonly found in the environment. Several species of Acanthamoeba have been found to infect humans, A. culbertsoni, A. polyphaga, A. castellanii, A. healyi, A. astronyxis, A. hatchetti, A. rhysodes, and possibly others.

Where are Acanthamoeba found?

Acanthamoeba spp. (spp. means several species) are found worldwide. Most commonly, Acanthamoeba are found in the soil and dust, in fresh water sources such as lakes, rivers, and hot springs and in hot tubs. Acanthamoeba may also be found in brackish water and in sea water. Amoeba can also be found in Heating, Venting, and Air Conditioner units (HVAC), humidifiers, and dialysis units.

Acanthamoeba have been found in the nose and throat of healthy people as well as those with compromised immune systems.

How does infection with Acanthamoeba occur?

Acanthamoeba can enter the skin through a cut, wound, or through the nostrils. Once inside the body, amoeba can travel to the lungs and through the bloodstream to other parts of the body, especially the central nervous system (brain and spinal cord).

Through improper storage, handling, and disinfection of contact lenses, Acanthamoeba can enter the eye and cause a serious infection.

What are the signs and symptoms of Acanthamoeba infection?

There are several ways Acanthamoeba spp. can affect the body.

Each year, many people are infected with Acanthamoeba. Eye infections result from contact lens cases becoming contaminated after improper cleaning and handling. Risk of Acanthamoeba infection is higher for people who make their own contact lens cleaning solution. Acanthamoeba enter the eye via contact lenses or through a corneal cut or sore. Infection or a corneal ulcer results.

In addition, Acanthamoeba spp. can cause skin lesions and/or a systemic (whole body) infection.

Acanthamoeba spp. cause a serious, most often deadly infection called granulomatous amebic encephalitis (GAE). Once infected, a person may suffer with headaches, stiff neck, nausea and vomiting, tiredness, confusion, lack of attention to people and surroundings, loss of balance and bodily control, seizures, and hallucinations. Signs and symptoms progresses over several weeks; death generally occurs.

Who is at risk for infection with Acanthamoeba?

Infections caused by Acanthamoeba spp. occur more frequently in people with compromised immune systems or those who are chronically ill.

Is there treatment for infection with Acanthamoeba?

Yes. Eye and skin infections are generally treatable. However, infections of the brain (CNS) with Acanthamoeba are almost always fatal.

Can infection be spread from person to person?

No cases have ever been reported.

How can I prevent an infection with Acanthamoeba?

Eye infections may be prevented using commercially prepared contact lens cleaning solution rather than using home-made solutions. There is little that can be done to prevent skin and body infection.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.