A Comparative Study of the Susceptibility and Response of Eight Species of Marine Pelecypods to the Trematode Himasthla quissetensis

Publisher Website
Google Scholar
Abstract
Specimens of 8 spp. of marine pelecypods, Crassostrea virginica, C. gigas, Mytilus edulis, Modiolus demissus, Ensis directus, Mya arenaria, Mercenaria mercenaria, and Tapes philippinarum, were individually challenged with 150 Himasthla quissetensis cercariae in order to study their susceptibility and reactions. Quantitative recovery rates are given. Metacercariae were found encysted in various tissues of all of the pelecypods except C. virginica and C. gigas. In C. virginica few metacercariae were found in blood vessel lumina. Except in T. philippinarum, when metacercariae were found in tissues, they were enveloped by a non-cellular, parasite-secreted inner cyst wall. In T. philippinarum, only those metacercariae found in the testes were enveloped by such a wall. In addition to the inner wall, an outer wall, comprised of host leucocytes and either myofibers or connective tissue fibers, surrounded encysted metacercariae in most instances. The fibrous constituent of the outer wall appeared to be dependent on the type of fibers available in the immediately proximity, while the leucocytes are believed to be attracted by the inner wall. Encysted metacercariae were found on the gill and mantle surfaces of C. virginica and C. gigas and on the palps of M. edulis. These are believed to be inactivated, and thus prevented from invading the molluscs, by some host-elaborated substances.

This publication has 0 references indexed in Scilit: