Acanthamoeba is an opportunistic protozoan that is widely distributed in the environment. Acanthamoeba has two stages in its life cycle, an active trophozoite stage during which Acanthamoeba reproduces, and a dormant cyst stage during which Acanthamoeba remains inactive with little metabolic activity, but viable, for years. During the last few decades, Acanthamoeba has become increasingly appreciated as an important microbe and now well-recognized to produce serious human infections, including a vision-threatening keratitis (called Acanthamoeba keratitis) and a rare but fatal encephalitis, known as granulomatous amoebic encephalitis. Initially the term "granulomatous amoebic encephalitis" was coined specifically to describe brain infection due to Acanthamoeba. However, with the discovery of a number of amoebae that can produce granulomatous encephalitis, including Acanthamoeba, Balamuthia mandrillaris, Sappinia diploidea, and perhaps other unidentified amoebae, it is necessary to differentiate the disease according to its causative agent. "Granulomatous amoebic encephalitis due to Acanthamoeba" can be referred to as "Acanthamoeba granulomatous encephalitis".

The true burden of keratitis and encephalitis due to Acanthamoeba on the human health is not known. Furthermore, the pathogenesis and pathophysiology associated with Acanthamoeba infections, as well as the molecular identification of virulence traits of Acanthamoeba, which may be potential targets for therapeutic interventions and/or the development of preventative measures remain incompletely understood. In recent years, there has been a tremendous interest in this pathogen by the scientific and the medical community. This is due to (i) an increasing number of Acanthamoeba infections, associated with a rise in the number of immunocompromised individuals and contact lens wearers, (ii) the potential role in ecosystems, and (iii) the ability to act as a host or reservoir for microbial pathogens, including viruses, prokaryotes, other protozoa and fungi.

from Naveed Khan in Acanthamoeba: Biology and Pathogenesis

See also: Acanthamoeba pictures, illustrations and figures

Labels: Acanthamoeba, amoeba, protozoa