Isospora callimico Hsu and Melby, 1974.

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

Other hosts: None reported to date.

Type locality: Unknown. This marmoset was obtained from a "commercial source" and the parasite was found while the host was maintained in the Division of Lab Animal Medicine, Johns Hopkins University, Baltimore, Maryland, U.S.A.

Geographic distribution: NORTH AMERICA: USA: Maryland, Johns Hopkins University in Baltimore.

Description of oocyst: Oocyst shape: broadly ellipsoid to subspheroid, occasionally spheroid; number of walls: 2; wall thickness: 1.2; wall characteristics: outer layer smooth, colorless to faint green-yellow; inner layer, dark brown; L x W: 16.9 x 14.9 (13-21 x 11.5-17); L/W ratio: 1.1 (1.0-1.2); M: absent; OR: absent; PG: absent. Distinctive features of oocyst: dark inner layer of oocyst wall.

Description of sporocysts and sporozoites: Sporocyst shape: ellipsoid; L x W: 11.3 x 7.5 (10-13 x 7-9); L/W ratio: 1.5 (1.3-1.7); SB: absent; SSB: absent; PSB: absent; SR: present; SR characteristics: scattered, coarse granules or a compact mass; SP: banana-shaped, with a clear, subcentral N and 1 faint RB at 1 end. Distinctive features of the sporocyst: ellipsoid shape without SB, but with a centrally located N in SP.

Prevalence: 1/1 (100 %).

Sporulation: Exogenous. Oocysts sporulated in 48 hr at 26ºC.

Prepatent and patent periods: Unknown.

Site of infection: Unknown. Oocysts recovered from feces.

Material deposited: None.

Remarks: The host was a female adult C. goeldii obtained from a commercial source; no other host information was given. Although the authors describe the shape of the sporulated oocysts to be ellipsoid to subspheroid, the photomicrograph (their Fig. 2) and line drawing (their Fig. 3) show oocysts that are distinctly ovoid (slightly pointed at one end).

Reference: Hsu and Melby, 1974.