The cellular responses inMarisa cornuarietis experimentally infected withAngiostrongylus cantonensis

The cellular responses in the poorly susceptible ampullariid snailMarisa cornuarietis toAngiostrongylus cantonensis, during a period of 40 days, involved focal and generalized proliferative reactions. The focal reactions appeared around all larvae as accumulations of variable numbers of amoebocytes at 24 h after infection in the loose connective tissues and somewhat later in the dense tissues. This cellular infiltration intensified gradually with time leading to the encapsulation of the parasite. At 18 days after infection a central zone formed mainly of hypertrophic, granular, highly acidophilic amoebocytes and a peripheral zone of fibrous appearance were conspicuous in most capsules.