B. mandrillaris is the only known species belonging to the genus Balamuthia. The amoeba was recognized as both a new genus and species in 1993. Like the other previously discussed free-living amoeba, it is also an opportunistic pathogen. There are a number of similarities between B. mandrillaris and Ancanthamoeba species. Their life cycles are similar, they look very similar in fixed tissues, they both cause GAE which runs a similar course, and they are both found in soil and water (although B. mandrillaris is more commonly associated with soil than water). To date there have been approximately 200 cases worldwide. The nearly 90 cases in the United States have mostly been in the Southern states.