Evaluation of methods using ray's fluid thioglycollate medium for diagnosis of Perkinsus marinus infection in the eastern oyster, Crassostrea virginica

Host-parasite interactions among broadly distributed populations of the eastern oyster Crassostrea virginica and the protozoan Perkinsus marinus

“…Cultures were maintained a s described by La Peyre et al (1993) except that buffers were modified according to Freshney (1987) for maintenance in ambient air rather than a 5' Yn CO2 atmosphere. Because oysters become infected by filtering P marinus from the water (Ray 1954), and heavily infected oysters can harbor more than 10h P marinus cells per gram wet tissue (Choi et al 1989, Gauthier & Fisher 1990, Bushek et al 1994b, it is not likely that a particular oyster would be infected by a single clone. Since in vitro cultures were initiated from heavily infected oysters, each isolate is likely to be a population of many clones rather than a monoclonal culture.…”

“…Waste water was sterilized with a minimum of 10 ppt Cl, prlor to disposal, as recommended by Elston (1990). Weightstandardized Perkinsus marinus body burden (Bushek et al 1994b) was determined for all oysters that died dunng the experiment, for a subsample of 5 NJ oysters from each tank in the first replicate on Day 80 postinoculation, and for all remaining oysters on Day 94 post-inoculation.…”

“…5). Most infections were still well below the level of the inoculum, but some had reached levels typically observed during mortalities in natural populations (10' cell g-' wet tissue weight; see Choi et al 1989, Bushek et al 1994b). Two-way ANOVA indicated no interaction between oyster popula- tiOn and parasite isO1atel but both main effects per isolate (22 ME + 48 NJ + 20 VA + 36 TX) were significant (Table 4, Fig.…”

“…As systemic infections intensify, parasite proliferation causes lysis and sloughing of tissues that ultimately kdl the oyster (Maclun 1951). During P marinus epizootics, 100 %, of the adult oysters on a bed are likely to be infected (Bushek et al 1994b) and up to 90% may die from those infections (Andrews 1988) Parasites can have important roles in ecological communities. They can limit species distributions and abundance by altering survival, reproductive output, behavior, and intra-or interspeciflc interactions (e.g.…”

First record of protozoan parasites, Tetrahymena rostrata and Callimastix equi from the edible oyster in Sundarbans region of West Bengal, India

“…Transmission occurs over large distances and can be rapid under favorable climatic conditions, resulting in rapid parasite proliferation and elevated adult mortalities (Andrews and Wood 1967;Lafferty and Kuris 1993;Burreson and Ragone-Calvo 1996;Ford and Tripp 1996). Throughout the region in which the disease organism can exist, most hosts are exposed to the disease organism and probably become infected, even though infections may be undetected (Bushek et al 1994;Stokes et al 1995;Culloty et al 2003). The spread and intensification of infections can result in epizootics, which are disease epidemics in nonhuman animal populations.…”