Acanthamoeba is a microscopic, free-living ameba, or amoeba (single-celled living organism), that can cause rare, but severe infections of the eye, skin, and central nervous system. The ameba is found worldwide in the environment in water and soil. The ameba can be spread to the eyes through contact lens use, cuts, or skin wounds or by being inhaled into the lungs. Most people will be exposed to Acanthamoeba during their lifetime, but very few will become sick from this exposure.
The three diseases caused by Acanthamoeba are:
Acanthamoeba keratitis: An infection of the eye that typically occurs in healthy persons and can result in permanent visual impairment or blindness.
Granulomatous Amebic Encephalitis (GAE): A serious infection of the brain and spinal cord that typically occurs in persons with a compromised immune system.
Disseminated Infection: A widespread infection that affects the skin, sinuses, lungs and other organs independently or in combination. It is also more common in persons with a compromised immune system.
Where is Acanthamoeba found?
Acanthamoeba is found worldwide. Most commonly, Acanthamoeba is found in soil, dust, fresh water sources (such as lakes, rivers, and hot springs), in brackish water (such as a marsh), and sea water. Acanthamoeba can also be found in swimming pools, hot tubs, drinking water systems (for example, slime layers in pipes and taps), as well as in heating, ventilating, and air conditioning (HVAC) systems and humidifiers.
How does infection with Acanthamoeba occur?
Acanthamoeba keratitis infection has been linked to contact lens use, although people who do not use contact lenses can also become infected. Poor contact lens hygiene or wearing contact lenses during swimming, hot tub use, or showering may increase the risk of Acanthamoeba entering the eye and causing a serious infection. However, contact lens wearers who practice proper lens care can also develop infection.
Who is at risk for infection with Acanthamoeba?
Acanthamoeba keratitis is most common in people who wear contact lenses, but anyone can develop the infection. For people who wear contact lenses, certain practices can increase the risk of getting Acanthamoeba keratitis:
Storage and handling lenses improperly
Disinfecting lenses improperly (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
Is there treatment for infection with Acanthamoeba?
Eye and skin infections caused by Acanthamoeba are usually treatable. It is important to see your health care provider immediately if you think you have Acanthamoeba infection of the eye or skin as medical treatment is most effective when started early. Unfortunately, most cases of brain and spinal cord infection with Acanthamoeba (Granulomatous Encephalitis) are fatal.
How can you prevent an infection with Acanthamoeba?
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.
Wash hands with soap and water and dry before handling contact lenses.
Clean contact lenses according to instructions from your eye care provider and the manufacturer’s guidelines.
Never reuse or top off old solution. Use fresh cleaning or disinfecting solution each time lenses are cleaned and stored.
Never use saline solution or re wetting drops to disinfect lenses. Neither solution is an effective or approved disinfectant.
Be sure to clean, rub, and rinse your lenses each time you remove your lenses. Rubbing and rinsing your contact lenses will aid in removing harmful microbes and residues.
Store reusable lenses in the proper storage case.
Storage cases should be rubbed and rinsed with sterile contact lens solution (never use tap water), emptied, and left open to dry after each use.
Replace storage cases at least once every three months.
Contact lens users with questions regarding which solutions are best for them should consult their eye care providers. They should also consult their eye care providers if they have any of the following symptoms: eye pain or redness, blurred vision, sensitivity to light, sensation of something in the eye, or excessive tearing.