Physiological and histochemical observations on the adult liver fluke, Fasciola hepatica L. I. Survival in vitro

Abstract

1. In an alkaline inorganic solution containing borate, no bacterial disintegration of tissues occurs in a week.2. Survival is prolonged by adding sugars to this solution, but not by the addition of bile salt or peptone. Monosaccharides are more effective than disaccharides, and both may enter the worm through its body wall.3. The effect of variations in certain physicochemical conditions was studied. Wide ranges of osmotic pressure, of the K/Naratio, and of the Ca/Na ratio, have little effect on the worms. The optimum pH is c. 8.4, and t h e optimum temperature c. 36° C. Approximately anaerobic conditions decrease the survival time.4. The effect of various bactericides, bacteriostatics and anthelmintics upon the worm were investigated in a preliminary manner. Many bactericides are toxic, certain anthelmintics are not. Survival is prolonged by 1/5000 trypan blue.5. A satisfactory medium for large-scale ‘culturing’ is: NaCl 150 mM., KC1 10 mM., CaCl2 1 mM., borax 6 mM., glucose 30 mM. (pH 8.6). In this the worms survive for c. 60 hr. at a temperature of 36° C.