Willaertia magna is a thermophilic amoeba (optimal growth temperature: 43 °C) measuring 50 to 100 µm in diameter in its trophozoic form, and around 18 to 21 µm in diamenter when encysted (Studies conducted by CIQLE, Lyon 1 University, March 2016). The genus Willaertia was first described by de Jonckheere et al. in 1984.
Although the morphology of this genus resembles that of the Vahlkamphiidae family, with its eruptive pseudopods in its vegetative form, there are a number of significant differences. In particular, the trophozoites of the Vahlkamphiidae family do not have a flagellate stage, whereas Willaertia magna C2c Maky does, with 4 flagellae; in addition, results of serological and isoenzyme analysis confirm that Willaertia is distinct from members of the Vahlkamphiidae genus (which includes Vahlkamphia, Naegleria and Tetramitus). Finally, and significantly, in contrast to members of the Naegleria genus, Willaertia magna C2c Maky is non-pathogenic, non-toxic nor is it eco-toxic. Because of these differences, a new genus and species name was proposed in memory of Dr. E. Willaert : Willaertia magna.
While most free-living amoeba are permissive to bacterial contamination, the Willaertia magna C2c Maky strain behaves very differently, targeting many different organisms through phagocytosis. We demonstrated that the biocidal activity of Willaertia magna C2c Maky is not due to cytotoxicity against its putative prey; phagocytosis is its mode of action and is the basis of its biocidal properties. Willaertia magna C2c Maky was demonstrated to internalize both Legionella pneumophila bacterium and its putative protozoan vectors in the environment, including free-living amoeba, such as Vermamoeba. Unlike many free-living amoeba, phago-lysosomal fusion is not inhibited in Willaertia magna C2c Maky by parasitic bacteria such as Legionella pneumophila. This property makes it an effective and robust biocide.
The non-toxic, non-pathogenic and no eco-toxic properties of Willaertia magna C2c Maky mean it is classed as non-hazardous (no physical hazard, no hazards on human and animal health, no environmental hazards) according to EC-regulation No. 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP).