Effect of sodium hypochlorite on Fasciola gigantica eggs and the intermediate host, Lymnaea natalensis: A scanning electron microscopy study

The liver fluke Fasciola is one of the commonest causative agents of liver disease in the world. Infection with this organism is of veterinary and medical importance, particularly in areas of high-density cattle and sheep production. Sodium hypochlorite (NaOCl) has been suggested for use in the control of Fasciola transmission. The current study was designed to evaluate the effect of NaOCl on the eggs and their intermediate hosts (Lymnaea natalensis snails) by scanning electron microscopy. Exposure of eggs to NaOCl had markedly deleterious effects on the whole body surface, from smooth to oedematous and disrupted, and on their integrity. These effects were concentration-dependent. Treatment of the intermediate host with various concentrations of NaOCl increased the mortality rate, and the effect was also dependent on concentration and length of exposure. Scanning electron microscopy of the snail foot region showed extensive alterations of the surface, with damage in some areas, after treatment with 10 ppm NaOCl for 15 min. Sodium hypochlorite may therefore be a useful control measure for eliminating both Fasciola eggs and the intermediate snail host.