Free-Living Amoebae as Human Pathogens: Balamuthia mandrillaris

Introduction

Balamuthia mandrillaris has been found in the brain of an 8-month-old pregnant mandrill, who died in the San Diego Zoo (Wildlife Park) developing a meningoencephalitis. The first publication about the causative agent was made by Visvesvara et al. (1993).

General Information

Balamuthia mandrillaris is related to the Acanthamoeba.

Classification

Phylum, Sarcomastigophora (Rhizopoda); subphylum, Sarcodina; class, Lobosea; order, Amoebida (Centramoebida, Acanthopodida); family, Acanthamoebidae; genus, Balamuthia (see also Free-Living Amoebae (FLA), Introduction).

As in many other free-living, heterotrophic amoebae, trophozoites and cysts are the predominant stages within the life cycle. The trophozoites are approximately 10–60 μm in size and multiply by division. The cysts are irregularly round with a thick wall and a diameter of approx. 6–30 μm. They are formed to survive unfavorable environmental conditions.

The ecological niche of Balamuthia mandrillarisis still...