Dirofilaria repens microfilariae from a human node fine-needle aspirate: a case report.
Human dirofilariosis is still a little known infection even in endemic areas. Dirofilariosis is zoonotic infection usually abortive in humans; instead, we report a very rare case (the 4th in the world), the first in Italy, in which at least two infective larvae became mature adults that mated and produced active microfilariae even though they did not reach peripheral blood.



A 30-year-old Italian woman presented with a transient oedematous swelling on the left abdominal wall with a creeping eruption followed by the occurrence of a subcutaneous nodular painless mass in the iliac region. One month later, a similar temporary swelling appeared on the contralateral inguinal region associated with intermittent joint discomfort in both knees. The patient had recently travelled abroad, therefore many possible diagnoses were to be ruled out. Routine laboratory investigations revealed eosinophilia. An ultrasound examination of the iliac swelling evidenced a well-defined cyst with a big filamentous formation in continuous movement. A fine-needle aspiration of the lesion was performed for parasitological, cytological and histological exams. The prompt microscopic examination of the aspired material showed the presence of numerous microfilariae that were initially morphologically attributed to Mansonella ozzardi. Subsequently, the revision of the Giemsa stained film and molecular analyses of the biological material, allowed to identify Dirofilaria repens as etiological agent of infection.



We report of a case in whom microfilariae were detected in fine-needle aspirate of subcutaneous node, without evidence of microfilaraemia, and the infection failed to become fully patent. Therefore we confirm that complete development and fertilization of D. repens worms in human hosts may occur, at variance with what is commonly believed, that Dirofilaria worms cannot fully develop in humans.
"Dipartimento di Medicina Clinica (Clinica Malattie Infettive e Tropicali)" "Sapienza" Università di Roma, Rome, Italy. lucia.sulekova@gmail.com.|Policlinico Umberto I, Viale del Policlinico, 155, 00161, Rome, Italy. lucia.sulekova@gmail.com.
Lucia
L
Fontanelli Sulekova
Policlinico Umberto I, Viale del Policlinico, 155, 00161, Rome, Italy.|"Dipartimento di Sanità pubblica e Malattie infettive (Unità Operativa Dipartimentale di Diagnostica delle Parassitosi)" "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Simona
S
Gabrielli
"Dipartimento di Medicina Clinica (Clinica Malattie Infettive e Tropicali)" "Sapienza" Università di Roma, Rome, Italy.|Policlinico Umberto I, Viale del Policlinico, 155, 00161, Rome, Italy.
Maurizio
M
De Angelis
Policlinico Umberto I, Viale del Policlinico, 155, 00161, Rome, Italy.|"Dipartimento di Sanità pubblica e Malattie infettive (Unità Operativa Dipartimentale di Diagnostica delle Parassitosi)" "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Giovanni L
GL
Milardi
Ospedale Civile di Legnano, Via Papa Giovanni Paolo II, 20025, Legnano, MI, Italy.
Carlo
C
Magnani
Ospedale Civile di Legnano, Via Papa Giovanni Paolo II, 20025, Legnano, MI, Italy.
Biancamaria
B
Di Marco
"Dipartimento di Medicina Clinica (Clinica Malattie Infettive e Tropicali)" "Sapienza" Università di Roma, Rome, Italy.|Policlinico Umberto I, Viale del Policlinico, 155, 00161, Rome, Italy.
Gloria
G
Taliani
Policlinico Umberto I, Viale del Policlinico, 155, 00161, Rome, Italy.|"Dipartimento di Sanità pubblica e Malattie infettive (Unità Operativa Dipartimentale di Diagnostica delle Parassitosi)" "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Gabriella
G
Cancrini
D000328:Adult; D000818:Animals; D044963:Biopsy, Fine-Needle; D003937:Diagnosis, Differential; D060348:Dirofilaria repens / Q000235:genetics / Q000302:isolation & purification*; D004184:Dirofilariasis / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007558:Italy; D008198:Lymph Nodes / Q000469:parasitology*; D008366:Mansonella; D008368:Mansonelliasis / Q000175:diagnosis*; D008842:Microfilariae; D009339:Needles; D016133:Polymerase Chain Reaction
Dirofilaria repens; Fine-needle aspirate; Immunodiagnostics; Italy; Microfilariae; Microscopy; Molecular diagnostics