Type host: Neurotrichus gibbsii (Baird, 1858), American shrew mole.

Other hosts: None reported to date.

Type locality: NORTH AMERICA: USA, Washington, Clallum Co., 7.9 km S, 1.0 km E of Port Angeles.

Geographic distribution: NORTH AMERICA: USA, Washington.

Description of oocyst: Oocyst shape: subspheroid; number of walls: 3; wall thickness: 1.0; wall characteristics: outer layer smooth, colorless, transparent, ~1/5 of total thickness; middle layer is light yellow, ~3/5 of total thickness; inner is green; L x W: 13.9 x 12.0 (11-16 x 10-15); L/W ratio: 1.1 (1.05 x 1.4); M: absent; OR: absent; PG: 1-3 round lipid-like bodies. Distinctive features of oocyst: small size and 3-layered oocyst wall.

Description of sporocysts and sporozoites: Sporocyst shape: ellipsoid; L x W: 9.2 x 6.1 (8-11 x 5-8); L/W ratio: 1.5 (1.3-1.8); SB: present, small; SSB: absent; PSB: absent; SR: present; SR characteristics: composed of many large globules, often obscuring SP; SP: with central RB. Distinctive features of sporocyst: tiny, inconspicuous SB.

Prevalence: 17/17 (100%).

Sporulation: Exogenous. Oocysts sporulated in 7-10 days in 2.5% aqueous (w/v) potassium dichromate solution at 23 C.

Prepatent and patent periods: Unknown.

Site of infection: Unknown. Oocysts recovered from feces and intestinal contents.

Materials deposited: Skin, skull, skeleton and tissues of the symbiotype host are preserved in the Mammal Division of the Museum of SW Biology, UNM: MSB No. 43543 (NK 3230, female), K. McBee #151. 14 July, 1980. Photosyntypes in the USNPC No. 85993.

Remarks: The sporulated oocysts of this species are most similar in size to those of Isospora neomyi Golemansky, 1978, and to I. sofiae Levine and Ivens, 1979. They differ from the former in shape (always subspheroid vs always spheroid), by having multiple PGs, the presence of a SB, a non-granular SR, and SP with a clear globule that is centrally located rather than at one end. They differ from the latter by having a thicker oocyst wall, by the presence of PGs, the shape of the sporocyst (ellipsoid vs ovoid with a pointed end), the presence of a SB, having a globular (vs granular) SR, and the location of the RB in the SP (central vs terminal).

References: Duszynski (1985).