What do we know by now about the genus Naegleria?

In this short overview of the genus Naegleria a brief historical sketch is given since the discovery of this amoeboflagellate in 1899 and the finding in 1970 that one species, Naegleria fowleri causes primary amoebic meningoencephalitis in man. Eight different types of this pathogen are known which have an uneven distribution over the world. Until now 47 different Naegleria spp. are described, of which two other species cause disease in experimental animals, and their geographical dispersal is indicated. The presence of group I introns in the SSU and in the LSU rDNA in the genus is discussed, as well as the possibility of sex or mating. It is also mentioned that the genome of N. fowleri should not be compared to that of Naegleria gruberi, to know why the former is pathogenic, but to the genome of its closest relative Naegleria lovaniensis.