Type host: Tadpole of Hyperolius viridiflavus (Dumeril & Bibron, 1841), Common reed frog.

Other hosts: None reported to date.

Type locality: AFRICA: Kenya, Sagana fish ponds.

Geographic distribution: AFRICA: Kenya.

Description of oocyst: Oocyst shape: subspheroidal; number of walls: initially a typical plasma membrane (see Remarks), but as the oocyst matures this envelope seems to merge with the wall of the parasitophorous vacuole (PV) that surrounds it; wall thickness: not given; wall characteristics: membranous; L x W: 7.7 (7-10) or 7-9 x 6-8; L/W ratio: 1.1-1.3; M: absent; OR: absent; PG: absent. Distinctive features of oocyst: the plasma membrane of the oocyst merges with the membrane of the PV and them becomes surrounded and enclosed by a yellow body, which may be an accumulation of degenerate intraepithelial lymphocytes resulting as part of a host defense process.

Description of sporocysts and sporozoite: Sporocyst shape: ellipsoidal (line drawing); L x W: 7.2 x 4.9 (6-8 x 4-6); L/W ratio: 1.5; SB: absent; SSB: absent; PSB: absent; SR: present; SR characteristics: a ball of large granules/globules that gradually disintegrates and disappears once SZ differentiation is completed; SZ: 7 x 1.4-2, with a RB ~4.2-5.6 x 2.8. Distinctive features of sporocysts: a double-layered wall, 7.7-8.5 (?) thick, with distinct longitudinal sutures characteristic of the genus, and a SR that disappears once the SZ differentiate.

Prevalence: 8 of 13 (61.5%) tadpoles, 0 of 4 (0%) post-metamorphosis, and 0 of 11 (0%) adult frogs.

Sporulation: Endogenous.

Prepatent and patent periods: Unknown.

Site of infection: Variable. Early developmental stages are found located in cells of the gut epithelium between the N and the brush border (Paperna et al. 1997, p. 82), while the host cells of oocyst stages in the tadpoles resemble intraepithelial leuckocytes rather than ordinary mucosal epithelial cells (Paperna et al. 1997, p. 87)

Endogenous development: Early meronts were 4.5–5 x 2–4 and these later formed merozoites that the authors first said were 9.5 x 4 (Paperna et al. 1997, p. 80), but later (Paperna et al. 1997, p. 82) said were “very elongated,” 7–8 long. Young macrogamonts were 7–9 x 4–5 and contained within a PV. Microgamonts were not seen.

Materials deposited: None.

Remarks: In addition to the discrepancy noted above, regarding length of the merozoites, there are a few other discrepancies by Paperna et al. (1997) that make our interpretation of some of their data tenuous. First, Paperna et al. stated that “early oocysts...were 7.7 (7.0–9.8) and sporoblasts 9.45 (8.4–10.6) in diameter.” Our view is that early oocysts and sporoblasts are one and the same. Second, early in their results they stated “Neither refractile nor crystalloid bodies could be identified in the newly formed sporozoites,” but later they said that SZs contained a RB, 4.2–5.6 x 2.8. A number of Eimeria species described from anurans have very thin walled oocysts that undergo endogenous sporulation and some of these have sporocysts with longitudinal sutures rather than a SB. This led Molnár (1995) to place E. neglecta, which he redescribed, into the genus Goussia, of mostly piscine coccidian (see Steingagen 1991 and Steingagen & Körting 1990), but the members of which all share this unique sporocyst feature. This is only the second eimeriid coccidium described from tadpoles; both are Goussia species and both seem to share some unique developmental features. Nöller (1920), who first described E. neglecta (= G. neglecta), noticed the disappearance of infection from the tadpoles as they neared metamorphosis into frogs. Likewise, Paperna et al. (1997) found that the infections in H. viridiflavus also were found naturally only in tadpoles (8 of 13), but never in young post metamorphosis frogs (0 of 4) or in adult frogs (0 of 11). They also noted that infections terminated in tadpoles which failed to develop to the metamorphosis stage, suggesting to them that infection is time-restricted and expires independently of the metamorphosis process. The sporulated oocysts of this species are similar in size to those of G. neglecta described from P. rhidibundus and P. esculenta tadpoles in Hungary. However, the sporocysts of this species are smaller (6.6 x 4.8) and have a smaller L/W ratio, 1.4, than those of G. neglecta, which are larger (8.8 x 4.8) with a larger L/W ratio, 1.8. This was the first coccidium described from anurans on the African continent.