Eimeria vilasi Dorney, 1962.
Synonyms: E. dorsalis; E.
morainensis; E. perforoides.
Type host:Eimeria adaensis.
Other hosts: Cynomys leucurus; C.
ludovicianus; Marmota monax; Spermophilus mexicanus; S.
townsendii; Tamias canipes; T. dorsalis; T. merriami; T.
obscurus; T. striatus; T.
Type locality: North America: USA, Wisconsin, Vilas
County, Trout Lake.
Other localities: Central America: Mexico, Baja
California; North America: USA,
Arizona, California, Idaho, Illinois, Massachusetts, New Mexico, New York,
Pennsylvania, Texas, Washington.
Description of oocyst: Oocyst shape: subspheroid to
ellipsoid; wall thickness:
0.7-1.3; layers: 2; outer layer proportion of total thickness: ~3/4; outer layer
colour: yellow-green; outer layer texture: smooth; inner wall characteristics:
smooth, dark tan; micropyle: absent; OR: absent; PG: sometimes present; number of
PGs: 0-6; PG shape: bilobed (in drawing); PG L x W: ~1.5; size: 17.6 x 14.3 (12-23 x
7-19); L/W ratio: 1.2. Distinctive features of oocyst: inner wall thins at one end;
PGs distributed irregularly throughout oocyst; shadow at tapered end (Wilber et al.,
1994; Hill & Duszynski, 1984).
Description of sporocysts and sporozoites:
Sporocyst shape: ellipsoid; size: 10.1 x
5.6; SB: present; SB L x W: not given; SB characteristics: small, can be
inconspicuous; SSB: absent; PSB: absent; SR: present; SR characteristics:
well-defined, tight sphere or elongated mass of granules; SR size: not given; SP:
posterior end slightly curled, clear RB in posterior end. Distinctive features of
Material deposited: USNPC No. 82931
Remarks: Eimeria vilasi was described from
T. striatus by Dorney (1962). In 1965,
Dorney found what he called E. perforoides in M. monax, but we believe
the form he
saw was E. vilasi because he did not observe an oocyst residuum, and the
measurements and qualitative features are similar to those of E. vilasi
7-19 vs. 20-25 x 16-20). Fleming et al. (1979) and McQuistion & Wright (1984 later
reported E. perforoides from M. monax, but they used Dorney (1965) to
identifications; thus, they probably saw E. vilasi.
Hill & Duszynski (1986) described E. dorsalis (17-24 x 14-20) in
Tamias spp., but their photomicrographs and mensural data suggest it is best
synonymize that name with E. vilasi. Likewise, Wilber et al. (1994) described
adaensis (18-26 x 16-22) from S. townsendii. However, E. adaensis
and E. vilasi are
so similar that the former should become a junior synonym. Wilber et al. (1994)
suggested that the eimerian species described as E. morainensis by McAllister
(1991) was E. adaensis (= E. vilasi) because key features of E.
absent from the oocysts of McAllister et al. (1991).
In summary, we suggest that E. adaensis, E. dorsalis, and
(sensu Dorney, 1965) are the same as E. vilasi and should be
synonyms because there is significant similarity in: 1) size of their oocysts and
sporocysts; 2) wall characteristics (dark inner layer, thinning and shadow at
tapered end; this was not reported in E. vilasi, but there was no
and the drawing is of marginal quality); and 3) the sporocyst residuum (compact mass
References: Dorney (1962, 1963, 1965, 1966); Duncan
(1968); Fleming et al. (1979);
Hill & Duszynski (1986); McAllister et al. (1991); McQuistion & Wright (1984);
Seville (1997); Wilber et al. (1994).