Prophylactic and therapeutic studies on intestinal giant-cystic disease of the Israel carp caused by Thelohanellus kitauei. II. Effects of physical and chemical factors on T. kitauei spores in vitro

Abstract

In a basic attempt to develop the prophylactic and therapeutic measures on intestinal giant-cystic disease of the Israel carp, Cyprinus carpio nudus, the effects of physical and chemical factors on viability or survival of the spores of Thelohanellus kitauei were checked in vitro by means of extrusion test on the polar filament. When the fresh spores suspended with 0.45% and 0.9% sodium chloride solution and distilled water were laid at 5 degrees C and 28 degrees C for short terms, the extrusion rates increased until the 3rd day, meanwhile when some of them were suspended with Tyrode's solution at -70 degrees C the rates increased gradually until the 8th day. Viabilities of the spores suspended with 0.9% saline and added antibiotics to the suspension at 5 degrees C for long terms lasted for 997 days and 1,256 days (presumed values) at maximum, respectively. The spores suspended with distilled water at 28 degrees C for long terms survived 152.4 days, but the spores suspended with Tyrode's solution at -70 degrees C for long terms showed almost the same viable pattern as early freezing stages up to 780 days. The spores suspended with Tyrode's solution, frozen at -70 degrees C and thawed at 5 degrees C, showed the highest rate of extrusion of the polar filament. In the case of frozen spores, the extrusion rates during heating tend to become higher in accordance with the increase of frozen period, and the critical points of 180 day-frozen spores to be killed were generally 78.5 hr. at 60 degrees C, 23.4 hr. at 70 degrees C, 189.1 min. at 80 degrees C or 10.5 min. at 90 degrees C. The longer the spores were frozen, the more time was needed for the death of spores after thawing; 20 days-17.4 days, 100 days-33.2 days, and 400 days-37.8 days. The longer the spores were frozen, the more time was needed for the death of spores at a conventional when they were dried air drying condition, 540 days-23.5 days, 160 days-21.0 days, and 20 days-14.4 days. On the other hand, the longer the spores were frozen, the more spores were dead rapidly when they were irradiated with 10W UV-ray; 100 days-26.0 hr, 300 days-21.9 hr, and 540 days-13.9 hr. The time needed for killing 200 days-frozen spores by various disinfectants at 1,000 ppm was 5.2 min. by calcium oxide, 10.4 min. by potassium permanganate, 27.8 min. by malachite green and 14.3 hr. by formalin.(ABSTRACT TRUNCATED AT 400 WORDS)

Molecular Identification and Real-time Quantitative PCR (qPCR) for Rapid Detection of Thelohanellus kitauei, a Myxozoan Parasite Causing Intestinal Giant Cystic Disease in the Israel Carp

“…Moreover, in cases of IGCD outbreaks, mortality tends to be focused largely in adult (2- and 3-year-old) Israel carps, and can reach levels as high as 10%. Mortality rates such as this can prove to be catastrophic and could severely damage the aquaculture industry [ 2 - 5 ].…”

In vitro studies on viability and proliferation of Enteromyxum scophthalmi (Myxozoa), an enteric parasite of cultured turbot Scophthalmus maximus

“…Siau (1977) carried out short-term studies using cultures of Myxobolus exiguus sporoplasms, after the myxospores of this species had been mechanically broken and the sporoplasms inoculated into cultures of trout cells. The remaining information is limited to some experiments on the in vitro survival of M. cerebralis and Thelohanellus kitauei myxospores exposed to different saline solutions and various physical and chemical factors (Hoffman & Hoffman 1972, Rhee et al 1990, Rhee 1994. Similar studies have also been carried out with actinospores, which have been maintained in vitro for up to 4 wk while longevity, phototaxis and chemotaxis were examined (Yokoyama et al 1995).…”

Occurrence of thelohanellosis caused by Thelohanellus wuhanensis (Myxosporea) in juvenile allogynogenetic silver crucian carp, Carassius auratus gibelio (Bloch), with an observation on the efficacy of fumagillin as a therapeutant

“…It is somewhat similar to T. hovorkai Achmerov, 1960 except for the spore shape and dimensions (Xiao & Chen 1993). Severe disease caused by T. hovorkai is well known (Molnár & Kovács‐Gayer 1986; Yokoyama, Liyanage, Sugai & Wakabayashi 1998, 1999) as is that caused by T. kitauei (Rhee, Kim, Kim & Park 1990; Rhee, Kim & Park 1990, 1993). T. wuhanensis was first found to cause serious disease in juvenile allogynogenetic silver crucian carp on many fish farms around Wuhan City in 1999.…”