Minchinia nelsoni n. sp. (Haplosporida, Haplosporidiidae): Causative Agent of the Delaware Bay Oyster Epizoötic

Abstract

Since 1957, oyster popuulations of the Middle Atlantic coast have been ravaged by a new sporozoan parasite that has been called "MSX." This parasite is identified as a new species of Minchinia that invades oysters through epithelial tissues of gill, palp, water tubes, and, occasionally, of the digestive tract. Multinucleate plasmodia are recognized in fresh and fixed preparations.

Declining impact of an introduced pathogen: ­Haplosporidium nelsoni in the oyster Crassostrea virginica in Chesapeake Bay

“…The parasite was introduced from Asia (Burreson et al 2000) sometime prior to 1957, when it emerged in Delaware Bay; by 1959, oysters were dying of H. nelsoni parasitism also in Chesapeake Bay (Andrews 1962, Haskin et al 1966). Oyster mortality due to this parasite exceeded 90% on reefs in lower Delaware and Chesapeake Bays during the early years of the epizootic , Haskin & Andrews 1988, an acute impact that presumably reflected a new encounter between an introduced parasite and a naïve host (Burreson et al 2000).…”

Discrete stochastic marine metapopulation disease model

“…This is the case of the susceptible animal contacting with or filtering infective particles from the environment once are released by living or dead infected individuals; that is, the case of black-band disease (Richardson, 2004;Zvuloni et al, 2009) and Aspergillosis (Jolles et al, 2002) in corals, whithering syndrome (WS) in abalone (Moore et al, 2001(Moore et al, , 2002 and transmission of trematode cercariae (De Montaudouin et al, 1998), shrimps with White-Spot disease (Rudolf and Antonovics, 2007) shedding particles during decay and scavenging processes, OsHV1virus in pacific oysters (Schikorski et al, 2011), MSX (Haskin et al, 1966) and Dermo (Mackin et al, 1950) diseases in oysters; Perkinsosis in clams (Paillard, 2004;Dang et al, 2010). The proliferation of these marine infectious diseases are causing mass mortalities (Ward and Lafferty, 2004;Burge et al, 2014;Lafferty et al, 2015) threatening ecologically valuable habitats and resulting in substantial economic losses in fisheries and aquaculture (Walker and Winton, 2010;Lafferty et al, 2015).…”

Disease in marine aquaculture

“…1). Much has b e e n l e a r n e d about the pathogen, but its life cycle and m e t h o d of transmission are still problematic, despite extensive literature and 25 years of study (Wood & Andrews, 1962;Haskin et al, 1966;Couch et al, 1966;Farley, 1967;A n d r e w s & Frierman, 1974;Andrews, 1979;Haskin & Ford, 1979;and others). The p a t h o g e n is intolerant of e x t e n d e d salinities b e l o w 15 ppt, w h i c h has e n a b l e d the d e v e l o p m e n t of some m a n a g e m e n t methods to r e d u c e mortalities.…”