Meeting Abstract
29.1 Friday, Jan. 4 Evidence that Perkinsus marinus is acquired by oysters during rejection of waterborne particles as pseudofeces ALLAM, B*; CARDEN, W; WARD, JE; RALPH, GM; WINNICKI, S; PARVEZ, N; PALES ESPINOSA, E; Stony Brook University, Stony Brook; Stony Brook University, Stony Brook; University of Connecticut, Groton; University of Connecticut, Groton; Stony Brook University, Stony Brook; Stony Brook University, Stony Brook; Stony Brook University, Stony Brook Bassem.Allam@stonybrook.edu
One of the most common mechanisms for non-vector transmitted parasites to reach the internal host environment is through feeding. In this study, we investigated the mechanisms of oyster host colonization by the Alveolate Perkinsus marinus and focused on how oysters process infective waterborne P. marinus cells during feeding in an attempt to reveal the portal and mechanisms of entry of this parasite to its host. We also compared the uptake of freely-suspended P. marinus with that of aggregated parasite cells to link changes in particle processing by the feeding organs with infection success and route. Finally, we evaluated the effect of oyster secretions (mucus) covering the feeding organs on P. marinus physiology because these host factors are involved in the processing of waterborne particles. The ensemble of results shows a unique mechanism for infection by which P. marinus is mostly acquired during the feeding process, but not via ingestion. Rather, infection occurs during the rejection of material as pseudofeces before reaching the mouth. The pseudofeces discharge area, a specialized area of the mantle where unwanted particles are accumulated for rejection as pseudofeces, showed significantly higher parasite loads than other host tissues including other parts of the mantle. Aggregated P. marinus cells caused significantly higher disease prevalence and infection intensities when compared to freely-suspended parasite cells. Mucus covering the mantle caused a quick and significant increase in parasite replication rates suggesting rapid impact on P. marinus physiology. A new model for P. marinus acquisition in oysters is proposed.
