Genotypic assignment of infection by Dirofilaria repens.

Dirofilariasis is a parasitic disease, which if treated inappropriately due to misdiagnosis, can cause unwanted complications particularly when the infection is located in the breast. The numerous obstacles that can cause misdiagnosis of dirofilariases by standard morphological procedures prompted the development of a Dirofilaria repens-specific direct polymerase chain reaction (PCR)-based diagnostic approach using freshly infected dog blood. Reliable amplification of nematode DNA from formalin-fixed infected human specimens by this method is only possible from relatively fresh biological material, preserved in the fixative for up to 20 days.