Parasitism of the Zweeloo Woman: Dicrocoeliasis evidenced in a Roman period bog mummy

• A bog mummy from the Netherlands contains Dicrocoelium dendriticum eggs.
• This is the oldest known, patent infection of D. dendriticum in humans.
• A new method for analysis of intestine sections is presented.
• Eggs of Ascaris lumbricoides and Trichuris trichiura were also found.

We undertook the analysis of Zweeloo Woman, a bog mummy from the Netherlands, to assess her parasitic state. Evidence of infection came from two areas: (1) liver paraffin sections and (2) microfossils washed from an intestinal section. Although the liver had shrunken considerably, objects consistent with operculated trematode eggs were found. After evaluating the range of trematode species that produce eggs in liver tissue, we arrived at the diagnosis of Dicrocoelium dendriticum. Although only 0.1 ml of sediment was recovered from an intestinal section, eggs of Ascaris lumbricoides and Trichuris trichiura were also identified. No eggs of D. dendriticum were revealed by the intestinal wash although they were observed in the liver. The lancet fluke, D. dendriticum, is a zoonosis that usually infects ruminants such as cattle. Eggs of D. dendriticum may be found in human coprolites if infected cow liver, for example, was eaten. This is false parasitism. Since eggs of D. dendriticum were found in the liver of Zweeloo Woman, we are assured this was a true infection. This find is especially significant because it is the oldest known, patent infection of D. dendriticum in humans.