Tegumental surface changes in adult Paramphistomum microbothrium (Fischoeder 1901) following in vitro administration of artemether.

The treatment of paramphistomiasis, a neglected tropical disease, has been carried out with different fasciolicidal compounds, all showing weak efficacy. Therefore, the search for alternative paramphistomicidal drugs is warranted. In the present study, the in vitro effects of artemether on adult Paramphistomum microbothrium were evaluated, for the first time, using scanning electron microscopy. After 24 h of incubation with 10 microg ml(-1) artemether, tegumental damage of both anterior and posterior ends of the fluke had occurred in the majority of the specimens examined. Sensory papillae surrounding the oral aperture were ruptured, while those at the acetabular region appeared to be sunken due to tegumental swelling. The tegumental disruption became more pronounced and both oral sucker and acetabulum were severely distorted, on increasing the concentration to 20 microg ml(-1). With higher concentration of 30 microg ml(-1), gross swellings of the body of the fluke, clearly visible to the naked eye, were observed, and damage to both oral sucker and acetabulum was so extreme that little recognizable structure remained.