Isospora brevicauda Hertel and Duszynski, 1987
Type host: Blarina brevicauda (Say, 1823), Short-tailed shrew.
Other hosts: None reported to date.
Type locality: NORTH AMERICA: USA, Ohio, Ashtabula County, 4 km W,
2.7 km S, Ashtabula.
Geographic distribution: NORTH AMERICA: USA, Ohio.
Description of oocyst:
Oocyst shape: spheroid to slightly subspheroid;
number of walls: 2;
wall thickness: <1.0;
wall characteristics: outer, generally with a few small bumps, irregularly spaced, ~1/2 of total thickness and with a
striated appearance in optical cross section;
L x W: 16.5 x 16.2 (15-18 x 15-18);
L/W ratio: 1.0 (1.0-1.05);
PG: 4-6 fragments of irregular shape.
Distinctive features of oocyst: small size, spheroid shape, with striated outer wall.
Description of sporocysts and sporozoites:
Sporocyst shape: ovoid;
L x W: 11.6 x 7.6 (10-12 x 7-8);
L/W ratio: 1.5 (1.4-1.7);
SSB: present, ~2x wider than SB;
SR characteristics: many lipid-like globules that obscure SP;
SP: probably have 1 large RB at rounded end, which was not reported in the original description.
Distinctive features of sporocyst: lipid-like SR globules.
Prevalence: 2/21 (10%).
Sporulation: Exogenous. Oocysts sporulated in 7-10 days in 2.5% aqueous (w/v) potassium
dichromate solution at ~23 C.
Prepatent and patent periods: Unknown.
Site of infection: Unknown. Oocysts recovered from feces and intestinal contents.
Materials deposited: Skin, skull, skeleton and tissues of the symbiotye
host are preserved in the Mammal Division of the Museum of SW Biology, UNM: MSB No. 43415 (NK 3122, female),
K. McBee #121, 29 June 1980. Photosyntypes in the USNPC No. 86356.
Remarks: This was the first Isospora sp to be described from
Blarina spp. Oocysts and sporocysts of this form are similar in size to those of Isospora aranei Golemansky (1978),
but differ by the striated nature of the oocyst wall and by the presence of a SB and SSB.
References: Hertel and Duszynski (1987).