ABSTRACT The economically important marine bivalve mollusc, Mercenaria mercenaria, (commonly called a northern quahog or hard clam), has endured considerable mortalities caused by a thraustochytrid pathogen called Quahog Parasite X (QPX). Data on the percent prevalence of QPX infections were compiled from published reports along with our data to describe the epizootiology of QPX disease. QPX infections occurred in clams collected from both cultured beds and wild populations, but a ...
<10% for clams from MA, VA, and NJ when all 5 strains were grown in VA. Final, cumulative mortality was highest in FL clams (79%), which was significantly greater than in SC clams (52%), which was significantly greater than in clams from VA (36%) or MA (33%), both of which were significantly greater than in the NJ clams (20%; i.e., FL>