Human dirofilariosis in Hungary:: an emerging zoonosis in central Europe

Introduction: In the temperate regions of Europe, mainly Italy, France, Greece, and in recent years Hungary, a specific filarioid worm, Dirofilaria (Nochtiella) repens, a parasite of dogs, cats and some other carnivores, transmitted by mosquitoes, has occasionally been contracted, causing dirofilariosis in humans. We report a case of dirofilariosis and review all previously observed cases in Hungary. Materials, methods and results: The authors present a case of human subconjunctival dirofilariosis in a 56-year-old man with mild itching and a burning sensation in his right eye. A slow-moving, whitish, thread-like worm was detected by slit-lamp examination. The worm was surgically removed and parasitological examination identified it as an immature male Dirofilaria repens. A review of Hungarian cases from 1880 to 2000 is presented, with updates of earlier reports. In addition, 16 new cases (8 men; 8 women) diagnosed between 2001 and 2006 are reviewed. The mean age of these 16 patients was 60 years; eight cases had ocular localization, seven were subcutaneous and one was diagnosed in a histopathological section of removed axillary lymph node in a patient with lymphoid leukemia. Twelve of the 16 identified Dirofilariae were females, four were males. According to their recorded histories the patients had not traveled internationally. Conclusion: Most of the above cases of dirofilariosis are certainly autochthonous infections. The increasing number of diagnosed cases suggests that this zoonosis is becoming more important in central Europe and that the incidence may increase with the improvement of clinical diagnosis.