Pathogenic Naegleria sp.—Study of a Strain Isolated from Human Cerebrospinal Fluid

SYNOPSIS. Experimental observation of the pathogenicity of some strains of Hartmannella plus the observation of human meningo-encephalitis due to small amebas which had a structure compatible with that of Hartmannella in the tissues has suggested the concept of respiratory amebiasis followed by cerebral and other complications.
Until recently no cultural evidence was available to identify positively the amebas in the human cases. This report summarizes the isolation of Naegleria sp. (HB-1) from human spinal fluid by mouse inoculation followed by tissue culture of the infected mouse brain. C. Butt and his associates, who submitted this material to us, isolated the Naegleria on agar medium with Escherichia coli without antibiotics at 37 C.
The new isolate failed to grow on the medium previously suggested by us for Hartmannella. HB-1 is virulent for laboratory animals and has a structure in the tissues which more resembles the amebas in the human tissue than the amebas in experimental Hartmannella infections of mice.
Naegleria and Hartmannella are both potential pathogens for normal animals and man. A clinical laboratory method to detect Naegleria as well as Hartmannella is herein suggested.