Two year study on the infectivity of Ichthyophthirius multifiliis in channel catfish Ictalurus punctatus.

摘要: Ichthyophthirius multifiliis Fouquet (Ich) is a fish parasite that causes serious economic loss for aquaculture. A major difficulty in the maintenance of single isolates Ich research purposes infectivity. After an unknown number passages or infection cycles isolate loses its This study determined infectivity during 105 channel catfish Ictalurus punctatus over 2 yr period. The mean percentage infected by Ich, levels and time to trophont emergence were each compared after 4 cyclic periods: 1-25, 26-60, 61-90 91-105 cycles. Results this demonstrated was significantly more infective (p < 0.05) at 1-25 than 26-105 Channel ratio 1 8 naive 26-60 higher occurred Trophont noted be longer cycles, 7 5 d respectively, 23.4 +/- 1.1 degrees C. results present indicate I. started decrease 25 predominant