Injection of Lymnaea stagnalis with miracidia of Trichobilharzia ocellata

Since D6nges (1963) mentioned the feasibility of injecting trematode rediae in Lymnaea stagnalis, several authors have reported on injections of snails with different trematode stages or with other organisms and materials (e.g. Heyneman 1966; Chernin 1966; D6nges 1968; Jourdane and Th6ron 1980). Reports on methods of injecting miracidia in snails (Heyneman 1966; D6nges and G6tzelmann 1977) are brief and few. Heyneman (1966) used fine glass pipettes but found it "impossible to penetrate the fleshy snail foot without damage to the parasite". The description of the method used by D6nges and G6tzelmann (1977), who injected two or three echinostome miracidia into L. stagnalis with a shell length of 19-42 ram, is confined to a reference to D6nges (1968), i.e. to a figure showing a micro-precisionsyringe with a glass cannula. The procedure described here for injection of miracidia of Trichobilharzia ocellata into L. stagnalis has been developed to meet the following requirements : injection of a predetermined number of miracidia in a small volume of fluid; injection into the desired place of the body of even the smallest snails; no need for deep anaesthesia; no harmful effects on the host or parasite.