Thirty cases of human subcutaneous dirofilariasis reported in Rostov-on-Don (Southwestern Russian Federation)

Abstract

Introduction: Different species of the genus Dirofilaria, mainly D. immitis and D. repens, are responsible for emergent vector borne transmitted zoonotic diseases in the Old World. Human D. repens infections are characterized by the appearance of benign subcutaneous nodules that mimic skin malignant tumors or due to live worms in the ocular area.

Methods: Thirty patients presenting superficial or deep nodules were treated at the Rostov Regional Diagnostic Center (Southwestern Russian Federation). Anatomical characteristics of the nodules were studied by non-invasive ultrasound and color and power Doppler techniques. Worms were surgically removed from every nodule and their DNA analyzed by polymerase chain reaction (PCR).

Results: Twenty-four out of the 30 nodules were located in the hypodermis, two in a retro-ocular location and four in scrotal location. Image techniques allowed the identification of the helminthic origin of all nodules, based on their oval and regular shape, peripheral vasculature, and the existence of internal linear winding hyperechoic structures with or without movements, indicating the presence of live or dead worms, respectively. Specific adscription to D. repens was achieved by the PCR analysis.

Conclusion: The series described in the present paper confirms the increasing risk of infection by D. repens in humans living in endemic areas of Eastern Europe. The use of non-invasive ultrasounds and Doppler techniques can contribute to an appropriate management of human dirofilariasis. Moreover, awareness of the medical community in the endemic areas influences the report of cases, and consequently the current epidemiological picture of human dirofilariasis.

Keywords: Dirofilaria repens; Dirofilariosis subcutánea/ocular; Doppler; Polymerase chain reaction; Reacción en cadena de la polimerasa; Subcutaneous/ocular dirofilariasis; Ultrasonidos; Ultrasound.