Perkinsus marinus, with 2 matches, is the only bivalve pathogen found within the protozoa (Alveolata) group. Perkinsosis is produced by species from the genus Perkinsus. Both P. marinus and P. olseni have been associated with mortalities in populations of various groups of molluscs around the world and are catalogued as notifiable pathogens by the OIE.