Type host: Lagostomus maximus

Type locality: SOUTH AMERICA: Argntina, La Pampa Province, Los Valles Ranch, 39º 11' 0.00" S, 63º 42' 31.9" W.

Geographic distribution: SOUTH AMRICA: Argentina.

Description of oocyst: Oocyst shape: subspheroidal; number of walls: 2; wall thickness: 0.8; wall characteristics: outer layer mostly smooth but may appear slightly rough in some oocysts, yellowish-brown, ~0.4, inner smooth, colorless; L x W: 26.4 x 23.4 (21-27 x 23-31); L/W ratio: 1.1 (1.1-1.2); M: absent; OR: absent; PG: 1-2. Distinctive features of oocyst: none.

Description of sporocysts and sporozoites: Sporocyst shape: elongate ellipsoid; L x W: 14.3 x 9.0 (8-10 x 13-15); L/W ratio: 1.6 (1.4-1.8); SB: absent; SSB: absent; PSB: absent; SR: present; SR characteristics: consists of two bodies of small granules, the larger body lying either between the SP or at one end of the sporocyst and the smaller one always lying at the opposite end, giving the appearance of a SSB; SP: lie side by side with a large RB at posterior end and smaller one at anterior end. Distinctive features of sporocyst: two SR.

Prevalence: 2 of 163 (1%).

Sporulation: Probably exogenous. Oocysts sporulated within 1 wk in 2% (w/v) aqueous potassium dichromate solution at 24 C.

Prepatent and patent periods: Unknown.

Site of infection: Unknown. oocysts recovered from feces.

Materials deposited: Photosyntypes of sporulated oocysts deposited in the USNPC, Beltsville, MD, USNPC no. 90198.

Remarks: Sporulated oocysts of E. vizcacha differ in size from those of E. chinchillae De Vos and Van der Westhuizen, 1968 by being larger 26.4 x 23.4 versus 17.5 x 15.5, and by having 2 SR that E. chinchillae lacks; they differ from those of E. lagostomi by being smaller, 26.4 x 23.4 versus 35.7 x 30.9, by lacking an OR, and by having 2 SR.

References: Couch et al. (2001).