HUMAN DIROFILARIASIS

Background. Subcutaneous and pulmonary dirofilariasis in humans appears to be a frequent disease in endemic areas, notably the Mediterranean region. Following increased air travel in recent years, the incidence of human dirofilariasis has increased in tourists as well. Methods. The clinical and parasitologic aspects in a series of six patients with cutaneous and pulmonary dirofilariasis, seen in a German unit for infectious and tropical diseases, are reviewed. Results. Four patients presented with subcutaneous tumors due to infection with Dirofilaria repens, whereas two patients had pulmonary infiltrates due to the canine heartworm, D. immitis. All infections were acquired in the Mediterranean region. Symptoms were only slight and nonspecific. Eosinophilia in the blood was absent in all patients. The serum IgE levels were normal and signs of a specific humoral response to antigens of Dirofilaria spp. were absent, although slightly elevated antibody levels to antigens of Onchocerca volvulus could be demonstrated in all patients. The diagnosis was established in all patients by the surgical removal of adult worms from the lesions. Oral treatment with diethylcarbamazine (DEC) (2 mg per kg t.i.d.) over a period of 4 weeks was added to the surgical treatment in all patients. In one patient this therapy was preceded by oral ivermectine (150 mg per kg). Conclusions. Dirofilariasis has to be considered as a differential diagnosis in patients presenting with subcutaneous or pulmonary tumors after travels to endemic areas within the last few years. Effective therapy is possible by surgical removal of the adult worms and oral ivermectine plus diethylcarbamazine.