Isospora natalensis Elsdon-Dew, 1953.

Type host: Homo sapien Linneaus, 1758, Humans.

Other hosts: None reported to date.

Type locality: AFRICA: South Africa, Durban.

Geographic distribution: AFRICA: South Africa, Durban.

Description of oocyst: Oocyst shape: spheroid to subspheroid; number of walls: 1 (in line drawing); wall characteristics: smooth, thin; L x W: 25-30 x 21-24; M: absent; OR: absent; PG: absent. Distinctive features of oocyst: subspheroidal shape distinguishes it from I. belli.

Description of sporocysts and sporozoites: Sporocyst shape: ellipsoid; L x W: 17 x 12; L/W ratio: 1.4; SB: absent; SSB: absent; PSB absent; SR: present; SR characteristics: large, coarse granules loose and irregularly distributed in sporocyst and without limiting membrane; SP: "smaller than one would expect" without RB or N visible. Distinctive features of the sporocyst: "they take up an equatorial position in the oocyst."

Prevalence: Found in 2 individuals in Durban, South Africa, but the sample size was not stated.

Sporulation: Exogenous. Oocysts sporulated in 24 hrs when left "in the open," but in a closed container, development did not take place in 7 days. However, when the container was reopened, "maturation took place as usual (Elsdon-Dew, 1953)."

Prepatent period: Unknown.

Patent period: 4 days in 1 individual in whom the oocysts were produced in large numbers (Dodds and Elsdon-Dew, 1955).

Site of infection: Unknown. Oocysts recovered from feces.

Material deposited: None.

Remarks: This species has not been reported since its original description. Its oocysts resemble those of the I. ohioensis complex in dogs, I. rivolta in cats, and I. suis in pigs, but they are slightly larger than these species (Lindsay et al., 1997). The oocysts also closely resemble those of I. arctopitheci in almost every mensural and qualitative way (cf. Figs. 14, 20). Given the unusually broad host range of I. arctopitheci, it may be the same species and, thus, would be its junior synonym.

References: Dodds and Elsdon-Dew (1955); Elsdon-Dew (1953); Lindsay et al. (1997).