Isospora saimirae Lainson and Shaw,
Type host: Saimiri sciureus sciureus Linneaus,
1758, Squirrel monkey.
Other hosts: None reported to date.
Type locality: SOUTH AMERICA: Brazil, Pará State,
Island of Tocantins (4º 49' S : 49º 49' W) ~75 km from Tucurui.
Ironically, the type
locality now lies
beneath the waters of the Tucurui Reservoir, a man-made lake formed shortly after
the discovery of this parasite by Lanison and Shaw (1989).
Geographic distribution: SOUTH AMERICA: Brazil,
Pará State, Island of Tocantins.
Description of oocyst: Oocyst shape: subspheroid
to ellipsoid; number of
walls: 1; wall thickness: ~0.6; wall characteristics: smooth, colorless; L x W: 25.5
x 22.2 (24-27.5 x 19-24); L/W ratio: 1.1; M: absent; OR: absent; PG: absent.
Distinctive features of oocyst: thin, 1-layered wall with OR and PG absent.
Description of sporocysts and sporozoites:
Sporocyst shape: ellipsoid; L x W: 15.9 x 11.5 (15-16 x 11-12.5); L/W ratio: 1.4;
SB: absent; SSB: absent; PSB:
absent; SR: large, bulky compact mass composed of granules and spherules lying
between SP; SP: elongate and curved within sporocyst. Distinctive features of
sporocyst: SP without RB, that are longer than sporocyst and curved within
Prevalence: 2/12 (17%).
Sporulation: Exogenous. Oocysts sporulated
24 hr at ~24ºC.
Prepatent and patent periods: Unknown.
Site of infection: Unknown. Oocysts recovered from
Material deposited: None.
Remarks: The fate of the squirrel monkeys and all
other fauna on Tocantins
Island after the flooding is unknown. This species has not been seen since its
Reference: Lainson and Shaw (1989).