Histological and molecular testing of nuclear inclusion X in Pacific Razor clams from select locations in Washington, USA

Nuclear inclusion X (NIX), the etiological agent of bacterial gill disease in Pacific razor clams (Siliqua patula) was associated with host mortality events in coastal Washington, USA during the mid-1980s. Ongoing observations of truncated razor clam size distributions in Kalaloch Beach, Washington raised concerns that NIX continues to impact populations. We conducted a series of spatial and longitudinal NIX surveillances, examined archived razor clam gill tissue, and used population estimates from stock assessments to test whether: a) the prevalence and intensity of NIX infections is higher at Kalaloch Beach relative to nearby beaches b) infected gill tissue has features consistent with historical descriptions of NIX-associated histopathology, and c) annual clam survival is inversely related to NIX infection prevalence and intensity.