Genetic Variation in the Free-Living AmoebaNaegleria fowleri

Abstract

In this study, 30 strains of the pathogenic free-living amoebaNaegleria fowleri were investigated by using the randomly amplified polymorphic DNA (RAPD) method. The present study confirmed our previous finding that RAPD variation is not correlated with geographical origin. In particular, Mexican strains belong to the variant previously detected in Asia, Europe, and the United States. In France, surprisingly, strains from Cattenom gave RAPD patterns identical to those of the Japanese strains. In addition, all of these strains, together with an additional French strain from Chooz, exhibited similarities to South Pacific strains. The results also confirmed the presence of numerous variants in Europe, whereas only two variants were detected in the United States. The two variants found in the United States were different from the South Pacific variants. These findings do not support the previous hypothesis concerning the origin and modes of dispersal of N. fowleri.

Analysis of the 5.8S rRNA Gene and the Internal Transcribed Spacers in Naegleria spp. and in N. fowleri

“…This finding was first observed by De Jonckheere in some N. fowleri strains (De Jonckheere 1998). Our study demonstrated that all of these variants are present in France confirming the high genetic diversity previously observed in this country (Pelandakis, De Jonckheere, and Pernin 1998; Pelandakis et al 1997). The very long 142 bp ITS1 was found only in the French strain M04.…”

“…In this case, all the data were considered as discrete characters and processed by the parsimony method (DOLMIX). The RAPD data were added to this analysis since the profiles obtained were based on the presence or absence of the fragments (see Pelandakis, De Jonckheere, and Pernin 1998; Pelandakis et al 1997). The parsimony algorithm produced trees showing the same two major groups revealed by the NJ tree (Fig.…”

“… Consensus tree topology within Naegleria fowleri strains inferred by the parsimony method using the RAPD and ITS data. RAPD data (see Pelandakis, De Jonckheere, and Pernin 1998, Pélandakis et al 1997): amplified fragment generated with primer Al was strong (+) or weak (‐); additional amplified fragments generated with primers B18, A15, and B12 were present (+) or absent (‐). The T substitution in the 5.8S gene and the deletion or the repetition events in the ITS 1 region were present or absent in the various strains of N. fowleri.…”

“…THE genus Naegleria includes 14 species, one of which, Naegleria fowleri , is responsible for primary amoebic meningoencephalitis in human beings (Carter 1970). Recently, use of variable DNA markers such as randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphisms (RFLP) demonstrated the existence of different variants of N. fowleri that were not correlated with the geographic origin of the strains (Kilvington and Beeching 1997; Pelandakis, De Jonckheere, and Pernin 1998; Pelandakis et al 1997). The RAPD results also showed an unexpected diversity in Europe, because most of the variants were found in this continent.…”

Occurrence of Naegleria fowleri in Arizona drinking water supply wells

“…N. fowleri is found worldwide (Cabanes et al, 2001; Pélandakis et al, 1998) in soil and freshwaters (Visvesvara et al, 2007). N. fowleri may be found in surface waters following rainfall events or irrigation and may also be found free‐living in warm bodies of water such as ponds, irrigation ditches, cattle tanks, lakes, coastal waters, power plant cooling reservoirs, and hot springs (Huizinga & McLaughlin, 1990; Tyndall et al, 1989).…”