Acanthamoeba infection

Overview

Acanthamoeba infection is a cutaneous condition resulting from Acanthamoeba that may result in various skin lesions. Acanthamoeba strains can also infect human eyes causing acanthamoebic keratitis. 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.

Symptoms

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.

Causes

Keratitis:

  • Wearing contact lenses
  • Using homemade sodium chloride solutions to clean contact lenses
  • Wearing contacts while swimming
  • Cleaning contact lenses less frequently than recommended by the manufacturer

Granulomatous amebic encephalitis and disseminated disease:

Acanthamoeba is ubiquitous; most persons are exposed to this organism. Although rare cases have been described in immunocompetent adults and children, the main risk factors for the development of disease include immunocompromising conditions and factors associated with immunosuppression, such as the following:

  • AIDS
  • Liver disease
  • Transplantation
  • Diabetes mellitus
  • Steroid use
  • Systemic lupus erythematosus
  • Cancer that requires chemotherapy
  • Malnutrition