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Acanthamoeba Infection Fact Sheet
(A-kanth-a-ME-buh)
- What is an Acanthamoeba infection?
- Where is Acanthamoeba found?
- How does infection with Acanthamoeba occur?
- Can infection be spread from person to person?
- What are the symptoms of Acanthamoeba infection?
- Who is at risk for infection with Acanthamoeba?
- Is there treatment for infection with Acanthamoeba?
- How can I prevent an infection with Acanthamoeba?
What is an Acanthamoeba infection?
Acanthamoeba is a microscopic, free-living ameba commonly found in the environment that can cause rare but severe illness. Acanthamoeba causes three main types of illness involving the eye (keratitis), the brain and spinal cord (Granulomatous Amebic Encephalitis), and infections that can spread from an entry point to the entire body (disseminated infection).
Where is Acanthamoeba found?
Acanthamoeba is found worldwide. Most commonly, Acanthamoeba is found in the soil and dust, in fresh water sources such as lakes, rivers, and hot springs, in brackish water, and in sea water. Acanthamoeba can also be found in swimming pools, hot tubs, in drinking water systems (e.g., slime layers in pipes, taps), as well as heating, ventilating, and air conditioning (HVAC) systems and humidifiers.
How does infection with Acanthamoeba occur?
Acanthamoeba keratitis infection has been associated with contact lens use, although people who do not use contact lenses can become infected. Contact lens wearers who practice proper lens care can develop infection. However, poor lens hygiene or wearing contact lenses during swimming, hot tub use, or showering might increase the risk of Acanthamoeba entering the eye and causing a serious infection.
Acanthamoeba can also cause disseminated infection by entering the skin through a cut, wound, or through the nostrils. Once inside the body, amebas disperse via the bloodstream to other parts of the body, especially the lungs and brain and spinal cord.
Can infection be spread from person to person?
The spread of Acanthamoeba infection from one person to another has never been reported.
What are the symptoms of Acanthamoeba infection?
The symptoms of Acanthamoeba keratitis can be very similar to the symptoms of other more common eye infections. The symptoms, which can last several weeks to months, are not the same for everybody and might include:
- Eye pain
- Eye redness
- Blurred vision
- Sensitivity to light
- Sensation of something in the eye
- Excessive tearing
Eye infection with Acanthamoeba has never been known to cause infections in other parts of the body.
Acanthamoeba can also cause skin lesions and/or disseminated infection. These infections usually occur in people with compromised immune systems. Acanthamoeba can cause a serious, most often deadly, infection of the brain and spinal cord 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. Symptoms progress over several weeks and death usually occurs. Skin infections do not necessarily lead to disseminated disease.
Who is at risk for infection with Acanthamoeba?
Although infection is very rare, people who wear contact lenses are at increased risk for Acanthamoeba keratitis. Practices among contact lens users that increase the risk of getting Acanthamoeba keratitis include:
- Improper storage and handling of lenses
- Improper disinfection of lenses (such as using tap water or homemade solutions to clean the lenses)
- Swimming, using a hot tub, or showering while wearing lenses
- Coming into contact with contaminated water
- Having a history of trauma to the cornea
Skin or disseminated infection caused by Acanthamoeba occurs 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. If you suspect your eye or skin might be infected with Acanthamoeba, see your health care provider. Medical treatment is most effective when the diagnosis is made promptly.
Most cases of brain and spinal cord infection with Acanthamoeba (Granulomatous Amebic Encephalitis) are fatal.
How can I prevent infection?
These guidelines should be followed by all contact lens users to help reduce the risk of eye infections, including Acanthamoeba keratitis:
- Visit your eye care provider for regular eye examinations.
- Wear and replace contact lenses according to the schedule prescribed by your eye care provider.
- Remove contact lenses before any activity involving contact with water, including showering, using a hot tub, or swimming. Extended-wear contact lens users should discuss concerns with their eye care provider.
- Wash hands with soap and water and dry before handling contact lenses.
- Clean contact lenses according to the manufacturer's guidelines and instructions from your eye care provider.
- Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored. Never reuse or top off old solution.
- Never use saline solution and rewetting drops to disinfect lenses. Neither solution is an effective or approved disinfectant.
- Store reusable lenses in the proper storage case.
- Storage cases should be rinsed with sterile contact lens solution (never use tap water) and left open to dry after each use.
- Replace storage cases at least once every three months.
This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider.