Isospora rothschildi Upton, Wilson, Norton and Greiner, 2001
Type host: Leucospar rothschildi
Type locality: NORTH AMERICA: USA; Kansas, Topeka Zological Park.
Geographic distribution: NORTH AMERICA: USA; Kansas, Florida, Illinois, North Carolina, Texas.
Description of oocyst: Oocyst shape: spherical to subspherical;
number of walls: 2;
wall thickness: 1.5-1.7;
wall characteristics: thick outer layer with light-moderate pitting external and thinner, 1.0-1.2, smooth inner layer, c. 0.5;
L x W: 22.3 x 21.6 (20-26 x 19-23);
L/W ratio: 1.03 (1.0-1.15);
Distinctive features of oocyst: none.
Description of sporocysts and sporozoites:
Sporocyst shape: ovoidal;
L x W: 15.9 x 10.6 (15-18 x 9.5-11);
L/W ratio: 1.5 (1.4-1.65);
SB: present, c. 1.0 high x 1.5-2.5 wide;
SSB: present. 2.0-3.0 high x 3.0-4.0 wide;
SR characteristics: ellipsoidal, 8.0 x 5.8 (6.5-11 x 5-8), composed of hundreds of granules;
SP: elongate, 18.1 x 3.4 (17-20 x 3-4), reflexed back along ends of sporocysts, each with spherical, rarely suspherical anterior RB, 3.0 (2.5-4.0) and elongate posterir RB, 6.3 x 3.2 (5-8 x 3-3.5); nucleus situated between RBs.
Distinctive features of sporocyst: highly granulated SR and reflexed SPs.
Prevalence: 5 of 5 (100%).
Sporulation: Exogenous. oocysts were passed unsporulated and became fully sporulated within 1 wk at 23º C when placed in 2.5% (w/v) potassium dichromate solution.
Prepatent and patent periods: Unknown.
Site of infection: Unknown. oocysts recoverd from feces.
Materials deposited: Phototypes deposited in the USNPC, Beltsville, MD, collection #89296.
Remarks: Oocysts of I. rothschildi are similar in size to several other sturnid isosporans. However, oocysts of I. ginginiana Chakravarty & Kar, 1944 from Acridotheres ginginianus have a diffuse rather compact SR and a PG is neither depicted nor described. Oocysts of I. malabarica Swarup & Chauhan, 1975 from Sturnus malabarica have an OR, unlike I. rothschildi, a diffuse rather than compact SR, and the sporocysts are slightly more elongate. Oocysts of I sturniae Chakravarty & Kar, 1946 from Sturnus malabarica tend to be larger, while those of I. tenemuchi Chakravarty & Kar, 1944 form Sturnus pagodarum have a smaller, more compact SR, shorter SPs and apparently lack a PG. Morphologically similar oocysts have been described previously from Bali mynahs (Partington et al., 1989), and it is likely that these coccidia represent I. rothschildi.
References: Upton, Wilson, Norton & Greiner, 2001.