DNA sequence polymorphisms in two strains of Fasciola hepatica from Egypt and Europe

A new PCR based system was used that had broad detection capability among parasites based on a conserved region of the 18 S ribosomal DNA gene. Five samples each of European and Egyptian Fasciola hepatica of bovine origin were obtained and DNA was isolated. The target of the PCR primers was a fragment of approximately 600 nucleotides in length corresponding to a region of the 18 S rRNA gene. Sequences were compared over a 107 base pair region that identified polymorphism between the strains. All five Egyptian isolates were identical. Likewise all of the European isolates had identical sequence. There were polymorphisms between the two strains and also with F. hepatica isolates from North America. Both the European and Egyptian isolates have a single base addition in the polymorphic region. In addition there is a single base substitution in the Egyptian isolates when compared to the others. This region is a small target that can be used to identify the origins of different F. hepatica isolates.