Neoparamoeba perurans

Neoparamoeba perurans Young, Crosbie, Adams, Nowak et Morrison, 2007 is a marine amoeba (Arnebozoa, Dactylopodida) which colonizes fish gills resulting in outbreaks of amoebic gill disease (AGD) in fish farmed in the marine environment (Young et al., 2007, 2008a). The transmission is horizontal. Experimental AGD infections are achieved either by cohabitation with infected fish or by exposure to amoebae isolated from the gills of fish affected by AGD. As few as 10 amoebae/1 of water cause AGD in native Atlantic salmon (Salmo salar) (Morrison et al., 2004). There is a positive correlation between the number of amoebae in the water and the severity of the lesions (Zilberg et al., 2001; Morrison et al., 2004). Other members of this genus are free-living amoebae, ubiquitous in the marine environment (Page, 1974, 1983) and have been cultured from marine sediments, water and marine invertebrates both from fish-farming and non-farming areas, ranging from polar to subtropical climate zones (Page, 1973; Crosbie et al., 2003, 2005; Mullen et al., 2005, Dykova et al., 2007; Moran et al., 2007). Massive mortality of American lobster (Homarus americanus) in Western Long Island Sound, which resulted in the collapse of the fishery, was partly attributed to Neoparamoeba pemaquidensis, which was identified on the basis of small-subunit ribosomal RNA (SSU rRNA) fragments having 98% identity with N. pemaquidensis from the gills of Atlantic salmon (Mullen et al., 2005). It was also proposed that Paramoeba invadens, which is a pathogen of sea urchins (Jones and Scheibling, 1985), is a junior synonym of N. pemaquidensis (see Mullen et al., 2005)