Tegumental Studies of Adult Fasciola gigantica (Giant liver fluke) from Philippine Carabaos (Bubalus bubalis) Using Scanning Electron Microscopy for Lead Bio-Indicator Analysis

Recent studies show that parasites such as liver flukes have a capacity to bioaccumulate heavy metals significantly than the liver and muscle tissues of the host without compromising effects on them. One such heavy metal is lead (Pb) which is an abundant pollutant in the environment. Therefore, this study aimed to evaluate the effects of lead in the tegument of Fasciola gigantica (giant liver fluke) isolated from infected livers of carabaos in vitro using the following concentrations of lead: 0ppm, 110ppm, 160ppm, and 210ppm. Results indicate that upon exposure to lead, liver flukes tend to curl and exhibit wrinkled appearance after 15 hours. Furthermore, scanning electron microscopy studies of the tegument showed that chemical exposure of the flukes to lead caused similar alterations observed when flukes are exposed to anthelmintic drugs which are sloughing, blebbing, furrowing, and folding. Moreover, two novel types of alterations were observed in this study which are wrinkling and crumpling of the tegumental surface. In conclusion, distinct morphological and tegumental characteristics observed in liver flukes due to lead tolerance suggests its potential as bio-indicator of environmental pollution and thus promotes its use as a good candidate of an effect indicator.