Morphometries and Redescription of Trypanoplasma borreli Laveran & Mesnil, 1901 (Mastigophora, Kinetoplastida) from Experimentally Infected Common Carp (Cyprinus carpio L.)

.Morphological development of cloned Trypanoplasma borreli was studied during the course of experimental infections in common carp. During the course of infection the cell dimensions of T. borreli showed high variability. At the beginning of parasitemia at day 8 p.i. (post inoculation) small and slender T. borreli predominated: surface area (SA, determined using a polar planimeter) 48.9 ± 13.1 Mm²; shape index (SI, length/width) 7.8 + 2.1 (n = 110). During the exponential growth phase until day 13 p.i. the size further decreased significantly (P < 1%): SA 29.9 ± 9.5 μm^: (n = 109). During the transition of parasitemia from exponential growth to the chronic phase the size of T. borreli enlarged significantly (P < 1%) and it became stumpy in shape. Day 15 p.i.: SA 63.2 ± 15.8 μm²; SI 4.2 ± 1.0 (n = 51). During the chronic phase significantly (P < 1%) larger trypanoplasms predominated: day 41 p.i. SA 90.6 ± 22.7 μm², SI 4.9 ± 1.1 (n = 221). Further samples showed only moderate variability of cell dimensions during this phase of parasitemia. Measurements of dimensions of lrinetoplast and nucleus and length of flagella varied in a similar manner. The position of the kinetoplast remained unchanged, while the nucleus had a more anterior position in the chronic phase. Experimental infections of various cyprinids were successful, perch and rainbow trout were not susceptible to experimental infections with T. borreli. Using these data a redescription of T. borreli is given.