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

Abstract

Ichthyophthirius multifiliis Fouquet (Ich) is a fish parasite that causes serious economic loss for aquaculture. A major difficulty in the maintenance of single isolates of Ich for research purposes is the loss of infectivity. After an unknown number of passages or infection cycles the Ich isolate loses its infectivity. This study determined the infectivity of an Ich isolate during 105 infection cycles in channel catfish Ictalurus punctatus over a 2 yr period. The mean percentage of fish infected by Ich, the infection levels and the time to trophont emergence were each compared after 4 cyclic periods

Protozoan infections in farmed fish from Brazil: diagnosis and pathogenesis

“…This parasite is not host specific and any freshwater fish can potentially transmit the parasite (EIRAS, 2013a). Similar to that found for channel catfish (Ictalurus punctatus) in the United States (XU &KLESIUS, 2004), in Brazil it is considered an important parasitic disease in farmed hybrid surubim catfish (Pseudoplatystoma sp.) (ISHIKAWA et al, 2012), including the Central-North region of Brazil where water temperature variations are less frequent.…”

Temperature effects on immune response and hematological parameters of channel catfish Ictalurus punctatus vaccinated with live theronts of Ichthyophthirius multifiliis

“…Water inflow was ceased, and water volume was lowered to 10 l in each tank. Live Ich theronts were added to each tank, and fish were challenged with theronts at 20,000/fish for 1 h [22]. At the end of the challenge, water inflow in each tank was resumed, and temperature was maintained at 25 C. Mortality of fish was recorded for 21 days after theront challenge.…”

Generation and analysis of expressed sequence tags from the ciliate protozoan parasite Ichthyophthirius multifiliis

“…One of the difficulties for the studies of Ich is the problem involved in long-term maintenance of Ich isolates. Ich isolates appear to lose infectivity or become senescent after a certain number of passages [12-15]. Most often a significant decrease in infectivity is observed after about 50 passages [15].…”