Field and laboratory comparisons of mortality in normal and neoplastic Mya arenaria

Neoplastic diseases of marine bivalves

“…Farley et al (1986) described a similar bleeding technique for M. arenaria that called ''histocytology'', later referred to as ''hemocytology'' (Peters, 1988). Several studies established scales to quantify the severity and progression of DN based on hemocytological methods (Cooper et al, 1982a;Farley et al, 1986;Barber, 1990;Brousseau and Baglivo, 1991). There is some disagreement as to which methodology, histology or hemocytology, is more precise for detecting DN.…”

“…The disease is progressive and the replacement of normal cells by the neoplastic cells (involving loss of the normal architecture of tissues and organs) often cause the death. However, remission of neoplasia, at least temporally, was detected in some mussels Mytilus edulis, which developed a host response against disease (Elston et al, 1988a), and also in some clams M. arenaria (Brousseau and Baglivo, 1991).…”

Assessment of haemic neoplasia in different soft shell clam Mya arenaria populations from eastern Canada by flow cytometry

“…According to the literature, neoplastic cells have a large nucleus and a high nucleus:cytoplasm ratio. The intensity of HN is generally rated as the percentage of neoplastic cells in the total number of haemocytes examined per slide (Farley et al, 1986), and classified in 3 to 5 different stages, depending on authors' classification criteria (Brousseau and Baglivo, 1991b;Farley et al, 1986;Leavitt et al, 1990;McGladdery et al, 2001). Brousseau and Baglivo (1991b) separated clams into three groups relative to the intensity of the disease: non-affected, low severity (1-50% neoplastic cells) and high severity HN (>51% neoplastic cells) while McGladdery et al (2001) ranged intensity of HN disease as light (1-10%), moderate (11-50%) and heavy (51-100% neoplastic cells).…”

Disseminated neoplasia in flat oysters Ostrea edulis from Galicia (NW Spain): Occurrence, ultrastructural aspects and relationship with bonamiosis

“…However, we could also hypothesize that if haemocytes were almost completely replaced by neoplastic cells in connective tissue and haemolymph, a higher percentage of oysters would be less likely found with moderate and heavy bonamiosis in advanced neoplasia. However, this subject warrants more investigation and it is possible that the knowledge of the course of DN (progression and remission) (Elston et al, 1988;Brousseau and Baglivo, 1991) might also contribute to the understanding of the interaction between these two important diseases. The high prevalence of DN found in this study, in addition to the widespread susceptibility through origins and families within origins of oysters as well as the alteration of tissue, and association with mortality, indicates that this disease is a more important morbidity and mortality cause for oysters cultured in Galicia, than previously recognized.…”