|Year : 2013 | Volume
| Issue : 1 | Page : 64-65
Subcutaneous nodule: A case of Dirofilaria
Reshmina D'Souza1, Ramakrishna Pai Jakribettu2, H Sunil Sudharsana1, P Sathyamoorthy Aithala1
1 Department of Surgery, Father Muller Medical College, Mangalore, Karnataka, India
2 Department of Microbiology, M.E.S. Medical College, Perinthalmanna, Malappuram District, Kerala, India
|Date of Submission||01-Aug-2012|
|Date of Acceptance||12-Mar-2013|
|Date of Web Publication||18-May-2013|
Department of Surgery, Fr. Muller Medical College, Mangalore - 575 006, Dakshina Kannada District, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Human subcutaneous dirofilariasis is a rare helminthic infection. It is caused by filarial worms of the Genus Dirofilaria, which is the natural parasites of dogs, cats, foxes, and wild mammals. Zoonotic filariasis caused by Dirofilaria species is rarely seen in the region of Dakshina Kannada. Most of them are seen in patients who are along the border of the district which shares its boundary with the state of Kerala, where dirofilariasis is constantly reported to occur. Here, we report a case of subcutaneous dirofilariasis, presenting as a subcutaneous nodule on the left cheek of a 28-year-old male from Cochin (Ernakulam), Kerala, South India. Two live worms were recovered from the subcutaneous nodular swelling.
Keywords: Dirofilariasis, subcutaneous nodule, zoonotic filariasis
|How to cite this article:|
D'Souza R, Jakribettu RP, Sudharsana H S, Aithala P S. Subcutaneous nodule: A case of Dirofilaria. Int J App Basic Med Res 2013;3:64-5
|How to cite this URL:|
D'Souza R, Jakribettu RP, Sudharsana H S, Aithala P S. Subcutaneous nodule: A case of Dirofilaria. Int J App Basic Med Res [serial online] 2013 [cited 2019 Sep 16];3:64-5. Available from: http://www.ijabmr.org/text.asp?2013/3/1/64/112243
| Introduction|| |
Human subcutaneous dirofilariasis is a rare helminthic infection. It is caused by filarial worms of the genus Dirofilaria species, which is the natural parasites of dogs, cats, foxes, and wild mammals.  Dirofilaria species belongs to the filarial nematodes, causes zoonotic infections in man, occasionally. Subcutaneous dirofilariasis is caused mainly by Dirofilaria repens, which causes subcutaneous nodules in and around the eye. It is a common parasite of dog, seen mainly in the subcutaneous tissue. The mosquitoes Culex, Aedes, and even Anopheles species form the vector for this nematode.
| Case Report|| |
A 28-year-old male hailing from Cochin, South India presented with a subcutaneous nodule on the left cheek of duration of 2 weeks, which was gradually increasing. On clinical examination, he had a firm oval swelling on the left cheek measuring 1.5 cm × 1 cm, which was non-tender and freely mobile. The systemic examination was unremarkable. A clinical diagnosis of a subcutaneous swelling/Sebaceous cyst was made, and the swelling was excised as an out-patient procedure under local anaesthesia. On excision two live thread like cylindrical worms, 0.5 mm thick measuring about 10-25 cm were found, coiled to each other. On macroscopic examination, of both the worms it was found that both the worms had a short and rounded tail [Figure 1]. No lips were seen in the mouth. Under the microscope, the outer surface of the nematode's cuticle was found to have fine transverse striations and prominent longitudinal ridges [Figure 2]. Shorter worm had unequal caudal spicules hence identified as male dirofilarial worm. The longer worm had oesophagus anterior to the vulva and was identified female dirofilarial worms. On the basis of macroscopic and, microscopic examination, worm was thus identified as D. repens.
|Figure 2: Microscopic picture of the worm showing Cuticle and transverse striation|
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The hemogram showed hemoglobin 13 g%, total leucocyte count 10,200/mm 3 and differential count showed eosinophilia, with absolute eosinophil count 2060/mm 3 . The peripheral smear showed relative eosinophilia without any parasite. No microfilaria were seen in peripheral blood. The patient did not review after the excision of the nodular swelling for follow-up.
| Discussion|| |
Human subcutaneous dirofilariasis is a rare helminthic infection, caused by filarial worms Dirofilaria species. It is an occasional zoonosis disease. The worm is a natural parasites of dogs, cats, foxes, and wild mammals.  Dirofilaria parasites are transmitted to man by mosquitoes. Most of the dirofilariasis cases are asymptomatic. The symptomatic ones typically manifests as either subcutaneous nodules or lung parenchymal disease. Excision of the subcutaneous lesion is both diagnostic and therapeutic. The clinical implication of human dirofilariasis is that, these subcutaneous lesions may be initially misidentified as malignant tumors, requiring invasive investigation and surgery before the correct diagnosis is made. The pathology of the condition results from the aberrant localization of immature worms intended for nonhuman hosts. Among the documented cases of human dirofilariasis in India, most of them had ocular infections. ,, In India and the Asian subcontinent D. repens is the main causative agent of subcutaneous human dirofilariasis. , The Coastal Kerala is endemic for dirofilariasis due to the presence of the suitable vector and climatic condition.  Most of the cases of Dirofilariasis reported from the northern  and western parts  of India is caused by D. repens. Few cases of Dirofilaria immitis have been also reported from India. ,
The cause of endemicity in Southern-India and Sri Lanka is mainly due to drastic changes in climatic conditions especially humidity and rainfall pattern, which favor the development of vector mosquitoes and the larval phase of the nematode in the mosquitoes. Recently two more cases have been reported from the Southern-India presenting as subcutaneous nodules.  Most cases are diagnosed retrospectively, when the histopathological sections of biopsy or excision material are viewed. , As microfilaremia is rarely seen in dirofilariasis chemotherapy is not called for. , Thus, this case emphasizes that Subcutaneous Dirofilariasis should be considered as the differential diagnosis in case of a single subcutaneous swelling, especially, when the patient is coming from an endemic area.
| Acknowledgment|| |
We would like to acknowledge Dr. B. Sanjeev Rai, Chief of Medical Services, Fr. Muller Charitable Institutions and Fr. Denis D'Sa, Administrator, Fr. Muller Medical College, Mangalore for their constant support for our research projects.
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[Figure 1], [Figure 2]