Synonyms: None.

Type host: Boa constrictor

Other hosts: None to date.

Type locality: SOUTH AMERICA: Brazil, Para.

Geographic distribution: SOUTH AMERICA: Brazil.

Description of oocyst: Oocyst shape: spheroidal to sub-shperoidal; number of walls: 1; wall thickness: not given; wall characteristics: colorless, extremely delicate; L x W: 19.0 x 18.0 (15-22 x 15-21.5); L/W ratio: 1.0 (1.0-1.1); M: absent; OR: present; OR characteristics: spheroidal mass of granules and globules, 15.5 x 14.8 (13.5-18.5 x 13.5-17.5); PG: absent. Distinctive features of oocyst: extremely thin wall so that it is “almost invisible” in mature oocysts and OR that measures nearly as wide as the oocyst.

Description of sporozoites: Sporozoite shape: banana-shaped and frequently become irregularly scattered in older oocysts; L x W: 11.0 x 1.8 (8.5-12.5 x 1-2); L/W ratio: not given; RB: 2, one lying anterior and the other posterior to the N; at their more pointed end, the tip of the SZ becomes optically dense (presumably due to the conoid and related organelles). Distinctive features of sporozoites: optically dense tips and 2 RBs.

Prevalence: 1/1 (100%).

Sporulation: Exogenous. Oocysts matured in 8 days when placed in 2% potassium dichromate at 24º C.

Prepatent and patent periods: Unknown.

Site of infection: Kidney. Merogony and gamogony occur on the lumen side of the host cell N, only in epithelial cells of the distal convoluted and collecting tubules.

Endogenous development: Two types of meronts were found in stained smears: larger meronts, up to 30 wide, with 50-100+ tear-shaped merozoites, ~5.0 x 1.75, and smaller meronts, 10-20 wide, with a small number of larger, more slender merozoites, ~12.5 x 2.5. Microgamonts had, (Development ... typical of other members of Eimeriidae, and measured (in tissue smears) 18.6 x 15.8 (12.5-30 x 12.5-20), with angular and densely staining N and comma-shaped microgametes, ~4.0 x 1.0. When microgametes were shed, a bulky residual body remained. Macrogamonts distinguished by delicately staining, pale blue cytoplasm and diffuse, pink N; mature forms, spheroidal to subspheroidal, measured 15-22 x 14-20, with cytoplasm containing numerous granules and diffuse chromatin mass with conspicuous karyosome. Fertilized macrogametes (zygote) compact, stained darkly with spheroidal, intensely staining...wall-forming bodies which appear in cytoplasm. Zygotes rupture into lumen of distal and collecting tubules from where they are expelled into ureters and carried to cloaca.

Pathology: Kidneys of the infected snake were considerably enlarged, compared to those of uninfected specimens of about the same age. Many sections of distal tubules showed every epithelial cell to be occupied by one or more parasite stages, (and it remains highly likely that kidney function was impaired.

Materials deposited: Oocysts in 10% formal-saline and histological sections and smears of the kidney are in the Department of Parasitology, Instituto Evandro Chagas, Belém, Pará, Brazil, No. Boa 01/11.01.93.

Remarks: This species is one of only two Tyzzeria known from Serpentes. A possible adelinid, Klossiella boae Zwart, 1964, was reported to infect the kidneys of Boa constrictor (Zwart, 1964). Oocysts of this genus contain many sporocysts which rupture from the thin-walled oocysts and are passed in the urates. However, the description and photographs by Zwart (1964) are not adequate enough to conclusively identify this organism as a member of the genus Klossiella, and the oocyst photographed along with the measurements given, 14-22 x 36-53, appears to actually represent a meront that may well be one of T. boae.