An unexpected guest in follicular fluid.

Parasitic infection as the only or concomitant cause of infertility in Caucasian women is rare. A parasitic infection may also present itself quite unexpectedly as a coincidental finding as shown with this case report. Moving microfilariae of Mansonella perstans were found in the aspirated follicular fluid of a patient who underwent in-vitro fertilization (IVF) with embryo transfer because of tubal pathology due to Chlamydia trachomatis. The patient also appeared to have a Schistosoma infection. To our knowledge, the presence of parasites in follicular fluid has never been reported before. We expect that infertility physicians may be confronted with parasitic infections more often, not only in patients originating from tropical countries but also in Western women as a result of a tendency to travel more frequently to exotic and (sub)tropical countries.