Systemic infection of freshwater crayfish Cherax quadricarinatus by hymenostome ciliates of the Tetrahymena pyriformis complex

Abstract

ABSTRACT-A survey of cultured freshwater crayfish Cherax g~~adricarinatus in north Queensland revealed systemic infections by hymenostome clliates in moribund crayfish from one location. The ciliates were identified following protargol impregnation as belonging to the Tetrahymena pyriformis species complex on the basis of their somatic and oral ciliature and morphometric characteristics. Live ciliates were observed in the haemal sinuses of the gills browsing on tissue fragments. H~stological examination revealed the ciliates to have invaded most organs and tissues, causlng extensive necrosis particularly in the hepatopancreas and antenna1 gland. Lipid reserves were not depleted in the hepatopancreas, suggesting the rapid de\telopment of acute disease. This is the flrst record of systeinlc ciliate infections in freshwater decapods.

Description of a presumptive hepatopancreatic reovirus, and a putative gill parvovirus, in the freshwater crayfish Cherax quadricarinatus

“…Edgerton (1996) observed hypertrophic nuclei in gill epithelia1 cells in C. quadricarinatus from 4 farms during a histopathological survey in 1996 at a prevalence of up to 13.6%. The same lesions had not been detected previously by the author, either in a histopathological survey of the same farms conducted in 1992, or in a study of chronic mortality at one of the surveyed farms in northern Queensland in 1993 (Edgerton et al 1995, Edgerton 1996, Edgerton & Owens 1999). The apparent 'emergence' of the lesion in C .…”

“…Both moribund Cherax quadricarinatus collected from the holding tank had good lipid vacuolation in the hepatopancreatic tubule epithelium and systemic haemocytic nodules consistent with bacteraemia (Edgerton et al 1995, Edgerton 1996. One of the C. quadricarinatus was infected by CqBV and CGV.…”

“…Soon after relocation the ern Queensland farms were conducted in 1992 and C . quadricarinatus were used in a failed transmission 1996 (Edgerton 1996, Edgerton & Owens 1999. A trial with the gill-associated virus/lymphoid organ number of pathogens and pathological conditions were virus corona-like virus complex (referred to hereafter observed, and some had a very high prevalence in as GAV) which infects Penaeus monodon in Australia some farms.…”

Daphnia and ciliates: who is the prey?

“…Beside these prey-predator relationships, parasitism and symbiosis have been described between ciliates and several freshwater organisms like perch (Nikolic & Simonovic 1996), crayfish (Edgerton et al 1996), zebra mussels (Molloy et al 1996;Laruelle et al 1999), and chironomids (Golini & Corliss 1981).…”

Molt related mortalities of the Dungeness crab Cancer magister caused by a marine facultative ciliate Mesanophrys pugettensis

“…However, in the last few years, 3 new philasterine scuticociliates, Mesanophrys pugettensis (Morado & Small 1994), M. chesapeakensis (Messick & Small 1996) and Anophryoides haemophila (Cawthorn et al 1996), that infect crustaceans and cause mortalities have been described. In addition, a ciliate identified as Tetrahymena pyriformis was recently found infecting and causing mortalities in the Australian crayfish Cherax quadricarinatus (Edgerton et al 1996).…”