Isospora rastegaievae (Yakimoff and Matikaschwili, 1933) emend. Pellerdy, 1974

Synonym:> Isospora rastegaiev Yakimoff and Matikaschwili, 1933.

Type host: Erinaceous europaeus Linnaeus, 1758, Eurasian hedgehog.

Type locality: EUROPE: Russia, Polotzk District, Leningrad Zoo.

Geographic distribution: EUROPE: Austria; Czechoslovakia;Germany; Russia.

Description of oocyst: Oocyst shape: subspheroid (unsporulated) to asymmetrically cylindroid (sporulated); number of walls: 2 (?); wall thickness: unknown, but probably ~1.0; wall characteristics: outer layer colorless, apparently smooth; L x W: 19.1 x 17.4 (16-21 x 15-20); L/W ratio: 1.1 M: absent OR: absent PG: absent. Distinctive features of oocyst: presumably changing shape during sporulation and lack of M, OR and PG.

Description of sporocysts and sporozoites: Sporocyst shape: subspheroid to ellipsoid (from drawing); L x W: 12-14.5 x 6.9012.1; SB: absent; SSB: absent; PSB: absent; SR: present; SR characteristics: compact mass of granules in center of sporocyst; SP: sausage-shaped, 11-12 x 2-4, without a distinct RB (from drawing). Distinctive features of sporocyst: compact SR of granules and sausage-shaped SP without RB.

Prevalence: 1 of 2 (50%) in Russia; 1 of 3 (33%) in Czechoslovakia; up to 45% (38 of 85) in Germany.

Sporulation: 1-2 days.

Prepatent and patent periods: Prepatent unknown; patent, 6-7 days.

Site of infection: Unknown. oocysts recovered from feces.

Materials deposited: None.

Remarks: The description of this species is only marginally useful; it is retained as valid only because an original line drawing of a sporulated oocyst was included and because several later investigators have reported it and clarified some of the details. Yakimoff and Matikaschwili, (1933) reported the shape to vary greatly during sporulation from distinctly round to ovoid or subspheroid when sporulated, although this seems unlikely to us. The possibility exists that they may have been looking at more than one species. They also said the oocyst wall was double contoured, but illustrated it as a single layer. Rysavy (1957) reported this species in E. europaeus from Czechoslovakia and added a line drawing; the oocysts were spheroid and measured 19-23 x 17-21. Kheissin (1959) studied the fate of residual bodies of I. rastegaievae and other Eimeria and Isospora species when the oocysts were kept in 2% K2Cr2O7 at 18-25 C and found that residual bodies (glycogen and fat) disintegrated faster in Isospora than in Eimeria species. There are several reports of I. rastegaievae from "hedgehogs" (host species name never stated) worth mentioning: Barutzki et al. (1987) reported the oocysts of this species to be the predominant parasite of hedgehogs maintained in animal homes (38/85, 45%) and in private homes as pets (175/542, 32%), whereas it was much less prevalent in fecal samples of wild hedgehogs living outdoors (1-13% of 127 from several areas); Saupe (1988) noted that this species was present in hedgehogs and mentioned several treatment regimes; and Löwenstein et al. (1991), reporting data from their small animal practice in Austria, found I. rastegaievae in 21.5% of 341 hedgehogs between 1984-1989. They also provided the following observations: 1.) outer wall colorless; 2.) sporulation occurs in 1-2 days; 3.) patency lasts 6-7 days and results in a chronic coccidiosis; 4.) this species could cause liquid feces and occasionally bloody diarrhea; and 5.) that coccidiosis regularly appeared in the spring after hibernation and was less common in the fall. Finally, a number of other authors have made occasional reference to this species (Yakimoff and Gousseff, 1940; Matuschka, 1984; Glebezdin, 1985; Epe et al., 1993).

References: Yakimoff and Matikaschwili (1933); Yakimoff and Gousseff (1940); Rasavy (1957); Kheissin (1959); Pellérdy (1974); Matuschka (1984); Glebezdin (1985); Barutzki et al. (1987); Saupe (1988); Löwenstein et al. (1991); Epe et al. (1993)