Isospora erinacei Yakimoff and Gousseff, 1936

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

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

Geographic distribution: EUROPE: Bulgaria; Russia.

Description of oocyst: Oocyst shape: ovoid (unsporulated), cylindroid (sporoblast stage), spheroid (sporulated); number of walls: 2; wall thickness:unknown, but probably <1; wall characteristics: outer layer colorless to yellowish, apparently smooth; L x W: 30 x 26 (28-34 x 23-27) for ovoid-cylindroid forms (no measurements given for spheroid form); L/W ratio: 1.15; M: absent; OR: absent; PG: present. Distinctive features of oocyst: change in shape during sporulation.

Description of sporocysts and sporozoites: Sporocyst shape: ovoid; L x W: 14.6 x 9.8-12.2; SB: present (?); SSB: absent; PSB: absent; SR: present; SP: without a distinct RB, although this was not stated in the original description. Distinctive features of sporocyst: pointed at one end and do not fill the space within the oocyst; SP lack RB, are very short and do not fill sporocyst.

Prevalence: 1 of 34 (3%).

Sporulation: Unknown.

Prepatent and patent periods: Unknown.

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 some measurements and an original line drawing of a sporulated oocyst were included. However, the original authors reported the shape to vary greatly during sporulation from distinctly ovoid to cylindroid to spheroid when sporulated, but gave no measurements for the spheroid form. It is possible that the spheroid forms represented end-on views of the ovoid/cylindroid forms or even a different species. Whichever the case, the sporulated oocyst has no mensural data. It should be noted that the original line drawing by Yakimoff and Gousseff (1936) is not drawn to the scale of the measurements they provided; thus, we have redrawn the sporulated oocyst to the scale of their measurements. Also, Yakimoff and Gousseff (1936) mentioned the presence of SR, but did not include it in their line drawing. Glebezdin and Kolodenko (1969) said they found this species in hedgehogs in Turkmenia. The oocysts they measured were 31.9 x 27.7 (26-35 x 25.5-29) and sporocysts were 13.6 x 10.3 (9.5-14.5 x 7.5-12). Unfortunately, they did not give a line drawing or a photomicrograph. Golemansky (1979) also found this species in 1/3 E. europaeus from the Sreburna Reserve, Bulgaria; the oocysts measured 24 x 18. Glebezdin (1985) also reported finding I. erinacei in hedgehogs (H. auritus ?) from southeastern Turkmenestan but, again, this seems unlikely.

References: Yakimoff and Gousseff (1936); Glebezdin and Kolodenko (1969); Golemansky (1979); Glebezdin (1985).