Disease progression and mortality in neoplasticMya arenaria in the field

Abstract

Four 6-too mark-and-recapture experiments conducted in Long Island Sound, USA, from 1988 to 1990, involving approximately 2250 individual observations, demonstrated that under natural conditions significantly higher mortality (p<<0.001, chi-square test) occurred among Mya arenaria (L.) with hematopoietic neoplasia than those diagnosed as non-neoplastic. Using a blood-screening technique, the clams were diagnosed and placed in one of three diagnostic groups based on the severity of the disease (the percentage neoplastic cells per total number of blood cells): non-neoplastic (NN), 0%; low-severity neoplastic (LSN), < 50%; high-severity neoplastic (HSN), > 50%. Mortality of those clams initially diagnosed as HSN ranged from 48% to 78%, depending on the test period, as compared to 3% to 21% for the non-neoplastic. Mortality in the LSN treatment varied from 8% to 34%. Both progression and remission were evident in clams at all stages of the disease. Mortality and rates of progression and remission in individuals appeared to be linked to water temperatures. Differential mortality may be responsible for the apparent seasonal cycle of prevalence in populations.

Withdrawn: “A health status survey of clams, Mya arenaria and Ensis siliqua, in the Irish Sea”

“…While varying environmental temperatures would seem to have affected the timing of gametogenesis in this population (Cross et al, 2012), neither energy used for spawning, nor the stress of oscillating environmental temperatures resulted in a disease state, as has been recorded in M. arenaria from other areas (Brousseau & Baglivo, 1991) and other bivalve species (Gagnaire et al, 2006;Harvell et al, 1999;Malham et al, 2009). …”

“…protozoans, have been documented in this species on the Atlantic west coast (Brousseau & Baglivo, 1991;Dungan et al, 2002;Earle & Crisley, 1975 (Perez, 2011;Ruiz et al, 2013).…”

Mya arenaria — an ancient invader of the North Sea coast

“…Mya may be heavily affected by two types of cancer called disseminated neoplasia and germinomas (Landsberg, 1996). Clams categorized into high-severity neoplasia suffered mortalities of up to 78% in Mya in New England (Brousseau & Baglivo, 1991). On the Atlantic east coast no parasites have been found in Mya from the German Wadden Sea (Lauckner, personal communication).…”

Patterns of p53, p73 and mortalin gene expression associated with haemocyte polyploidy in the soft-shell clam, Mya arenaria

“…In 1999, severe mortalities attributed to haemic neoplasia occurred in PEI (McGladdery et al, 2001). Field and laboratory studies had previously established a correlation between high prevalence of haemic neoplasia and mass mortality of clams (Brousseau and Baglivo, 1991). Although the etiology of this disease has still not been clearly established, an association with environmental pollution (Appeldoorn et al, 1984) and/or retroviral infection (House et al, 1998) has been suggested.…”