Acanthamoeba is a genus of amoebae that are commonly recovered from soil, fresh water, and other habitats. Acanthamoeba has two evolutive forms, the metabolically active trophozoite and a dormant, stress-resistant cyst. Trophozoites are small, usually 15 to 25 μm in length and amoeboid in shape. In nature, Acanthamoeba species are free-living bacterivores, but in certain situations, they can cause infections (acanthamebiasis) in humans and other animals. Distribution
Acanthamoeba spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide, and have been isolated from soil, air, sewage, seawater, chlorinated swimming pools, domestic tap water, bottled water, dental treatment units, hospitals, air-conditioning units, and contact lens cases. Additionally, they have been isolated from human skin, nasal cavities, throats, and intestines, as well as plants and other mammals. Role in disease
Diseases caused by Acanthamoeba include keratitis and granulomatous amoebic encephalitis 
(GAE). The latter is often but not always seen in immunosuppressed patients. GAE is caused by the amoebae entering the body through an open wound and then spreading to the brain. The combination of host immune responses and secreted amoebal proteases causes massive brain swelling resulting in death in about 95% of those infected. Granulomatous amoebic encephalitis (GAE)
Granulomatous amoebic encephalitis (GAE) is caused by amoebic infection of the central nervous system (CNS). It is characterized by neurological symptoms including headache, seizures, and mental-status abnormalities. These worsen progressively over weeks to months, leading to death in most patients.
Red, jelly-like sputum - an indicator of possible pneumonia caused by Klebsiella. Green or greenish colored - indicative of potential longstanding respiratory infection (green from degenerative changes in cell debris) as in pneumonia, ruptured lung abscess, chronic infectious bronchitis, and infected bronchiectasis or cystic fibrosis. Rust colored – usually caused by pneumococcal bacteria (in pneumonia), pulmonary embolism, lung cancer or pulmonary tuberculosis. Brownish –potential indicator of chronic bronchitis (greenish/yellowish/brown); chronic pneumonia (whitish-brown); tuberculosis; lung cancer. Yellow, yellowish purulent – an indicator of the sample containing pus. "The sputum color of patients with acute cough and no underlying chronic lung disease does not imply therapeutic consequences such as prescription of antibiotics." The color can provide hints as to effective treatment in chronic bronchitis patients:A yellow-greenish (mucopurulent) color suggests that treatment with antibiotics can reduce symptoms. The green color is caused by degenerating neutrophil verdoperoxidase. Whitish gray sputum color against a white color background (such as a white sink surface) tends to indicate either a specimen from someone who is dehydrated, and/or from an older person, and/or a specimen with a mixed, modest number of eosinophils and maybe some acute inflammatory neutrophil cells (this last choice tends to suggest chronic allergic bronchitis). A white, milky, or opaque (mucoid) appearance means that antibiotics are less likely to be effective in treatment because the likelihood is greater of a viral infection or allergy (even asthma...thick sputum) than of antibiotic-responsive micro-organisms. Foamy white – may come from earlier-phase pulmonary edema. Frothy pink – may indicate more severe pulmonary edema.