Parasitology, Harold W. Manter Laboratory of


Date of this Version


Document Type



Memórias do Instituto Oswaldo Cruz (March 2007) 102(2): 155-157

doi: 10.1590/S0074-02762007005000004

Also available at


Copyright 2007, the author. Open access material

License: CC BY-NC 4.0


The name Theileria electrophori n. sp. is proposed for a small parasite described in the erythrocytes of the electric eel, Electrophorus electricus, from Amazonian Brazil. Division of the organism in the erythrocyte produces only four bacilliform daughter cells which become scattered in the host cell, without a cruciform or rosette-shaped disposition. Exoerythrocytic meronts producing a large number of merozoites were encountered in Giemsa-stained impression smears of the internal organs, principally in the liver, and are presumably the source of the intraerythrocytic forms of the parasite. This developmental pattern is characteristic of piroplasms within the family Theileriidae, where the author considers the parasite of E. electricus to most appropriately belong. It effectively distinguishes the organism from the dactylosomatid parasites Babesiosoma Jakowska and Nigrelli, 1956 and Dactylosoma Labbé, 1894 also found in fishes. This appears to be the second report of Theileria Bettencourt, Franca and Borges, 1907 in a fish.

Included in

Parasitology Commons