First record of Eimeria furonis infection in a ferret, Japan, with notes on the usefulness of partial small subunit ribosomal RNA gene sequencing analysis for discriminating among Eimeria species.

Eimeria is a genus of apicomplexan parasites found in a variety of vertebrates including the weasel. At present, three species have been reported in members of the weasel family, but the presence of weasel Eimeria in Japan have been quite unclear. The identification of Eimeria species has been performed based on oocyst morphology, host species, and habitat in the host, but sometimes discriminating among morphologically similar species under light microscopy is impossible. The present study detected for the first time the weasel coccidium, E. furonis, in a ferret in Japan. Since molecular information for E. furonis has been quite unclear, this species was compared molecularly with other Eimeria species, and also the usefulness of sequencing analysis of the small subunit ribosomal ribonucleic acid gene (SSUrDNA) for discriminating among Eimeria species was examined. About the 350-bp sequence of SSUrDNA of all species including E. furonis compared differed from each other, and its differences found in Eimeria species were also reflected in the phylogram constructed using the partial nucleotide sequences. The sequencing analysis of partial SSUrDNA examined in the present study thus appears useful for discriminating among morphologically similar Eimeria species.