Paul Reno

2) Renibacterium salmoninarum: Assessing the dose of bacteria needed to infect eggs at spawning using ELISA, FAT, and culture methods. Using corticosteriods, determining what effect immunosuppression has on the course of the disease, which produces lesions that are immune-mediated. Determining whether naturally and/or artificially infected fish are specifically tolerant to p57 Renibacterium antigens if they are infected in ovo. Determining whether the bacterium can grow effectively in continuous and finite teleost cell lines, and what adverse effects growth has on the cells.

3) Nadelspora canceri is a new genus and species of microsporidia. Microsporidia are interesting because the organisms have some characteristics of eukaryotic and prokaryotic cells, and they are obligate intracellular parasites. We are currently doing prevalence surveys along the Pacific coast and are determining the methods of transmission and effects of the parasite on its host. We are interested in determining the relationship between this agent on others by RNA analysis. There are many interesting things to do with this new pathogen!

4) Disseminated neoplasia is a lethal disease of bivalves which appears neoplastic in nature. We are currently trying to determine if the disease can be vertically transmitted because very young animals appear to be affected with the disease. We are also trying to determine the biochemical characteristics of the cells involved in order to determine whether they have characteristics of neoplastic cells as found in mammals.

Research Highlights:

1) IPNV: We are finding antigenic stability after long storage of virus and consistent serotypes in particular regions of the world. From other areas, there is considerably more variation.

2) Renibacterium grows well on teleost cells, and at low inocula, better than on specific media designed for its growth. There appears to be little adverse effect on the cells on which the bacterium grows. We have found that it takes a large dose of bacteria (>109/ml) to infect fish at spawning and that infection leads to disease only intermittently. For long periods, bacterial antigen is not detected in the body, but after more than a year, it can be detected again.

3) Nadelspora canceri. We have blocked out the geographic ranges of the diseases (WA, OR, CA) and have found prevalence levels of greater than 40 percent in some populations. It can apparently be transmitted by eating contaminated mussel and a high mortality results from infection. Male crabs, for some reason, are three times more likely to have the disease than females.

4) Disseminated neoplasia has been found extensively in East Coast clams, but not in West Coast clams. We found the West Coast clams were as susceptible, or even more so, to transmission of the tumors than East Coast clams. This indicates that the clams that were transferred to the West left prior to the arrival of whatever inducing agent were involved in the genesis of the disease in the East. These neoplastic cells appear to be unique for each species of bivalves, since there are a number of differences in the DNA composition of diseased clams and mussels.

All of the diseases we are dealing with are capable of causing considerable mortalities in their hosts (which are generally important commercial species). Very little is known about the pathogenesis of these diseases and it is important to be aware of the impact that various factors can have on the development of disease in these animals. Our program is oriented in that direction.