Since only monokaryotic nuclei have been reported from infections
of E. bieneusi in vertebrates, it is conceivable that other life
cycle stages such as diplokaryotic forms and gametes might occur
in an alternative host, and that shrimp could constitute such a host.
However, the fact that the spores in P. mondon are also monokaryotic
and that they develop in a manner similar to those of E. bieneusi
rather than developing from diplokaryotic or meiotic nuclei
(Flegel and Pasharawipas, 1995) argues against this possibility. In
addition, work on possible sources of E. bieneusi in human infections
has implicated birds and mammals rather than shrimp, and
fresh water sources rather than marine (Dowd et al., 1998; Didier
et al., 2004; Lobo et al., 2006). All this information argues in favor
of our contention that E. hepatopenaei is distinct from E. bieneusi.