Isospora endocallimici Duszynski and File, 1974.

Type host: Callimico goeldii Thomas, 1904, Goeldi's marmoset.

Other hosts: None reported to date.

Type locality: Unknown (see Remarks).

Geographic distribution: SOUTH AMERICA: Peru; NORTH AMERICA: USA: Louisiana, Delta Regional Primate Research Center in Covington.

Description of oocyst: Oocyst shape: ovoid; number of walls: 2; wall thickness: 2; wall characteristics: outer layer smooth, ~2/3 of total thickness, and may taper at pointed end, inner layer appears as a darker line; L x W: 27.8 x 24.0 (25-31 x 21-27); L/W ratio: 1.2 (1.1-1.4); M: absent; OR: absent; PG: absent. Distinctive features of oocyst: distinctly ovoid shape.

Description of sporocysts and sporozoites: Sporocyst shape: ellipsoid; L x W: 17.3 x 12.5 (15-20 x 10-15); L/W ratio: 1.4 (1.2-1.5); SB: absent; SSB: absent; PSB: absent; SR: present; SR characteristics: granular, usually a compact mass at 1 end of sporocyst; SR L x W: 8 x 5; SP: banana-shaped, 11.3 x 5.4 (10-13 x 5-6), with sub-central N. Distinctive features of the sporocyst: SP appear sausage-shaped within sporocyst, but become clearly banana-shaped when they excyst; also, the compact SR at 1 end of sporocyst.

Prevalence: 5/5 (100 %).

Sporulation: Presumably exogenous. Time and temperature needed are unknown.

Prepatent and patent periods: Unknown.

Site of infection: Unknown. Oocysts recovered from feces.

Material deposited: Photoparatype in the USNPC, No. 88513.

Remarks: Five of 5 marmosets housed at the Delta Regional Primate Research Center, Tulane University, Covington, Louisiana, U.S.A. were found to be passing oocysts in their feces from time to time. Two of the hosts were born at the Center and 3 were imported from Peru so it was not possible to state in which host the infection originated. Host feces were collected at the Primate Center, but were examined at The University of New Mexico, Albuquerque, NM. Oocysts were sporulated upon arrival in Albuquerque. Duszynski and File (1974) described the excystation process of sporozoites of I. endocallimici and documented the unique folding of the sporocyst wall during this process. Speer et al. (1976) describe the ultrastructure of the sporocyst wall during excystation of sporozoites from their sporocysts.

References: Duszynski and File (1974); Speer et al. (1976).