Host-to-host transmission of Perkinsus marinus in oyster (Crassostrea virginica) populations by the ectoparasitic snail Boonea impressa (Pyramidellidae)

Perkinsus (= Dermocystidium) marinus is a primary cause of oyster mortality in the Gulf of Mexico. In a laboratory study, the ectoparasitic snail Boonea impressa was capable of transmitting P. marinus from one oyster to another. Thirty-six percent of oysters previously free of P. marinus contracted the disease when parasitized by B. impressa which had previously fed on infected oysters. P. marinus was subsequently found in the tissue of these snails. Feeding by B. impressa also resulted in the intensification of P. marinus infection in previously infected oysters. Consequently, B. impressa may be a determining factor in the impact of P. marinus in oyster populations.