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Year : 2015  |  Volume : 33  |  Issue : 4  |  Page : 593--594

Oral dirofilariasis

RS Desai1, N Pai2, AP Nehete1, JS Singh1,  
1 Department of Oral Pathology, Nair Hospital Dental College, Parel, Mumbai, Maharashtra, India
2 Department of Dentistry, KEM Hospital, Parel, Mumbai, Maharashtra, India

Correspondence Address:
R S Desai
Department of Oral Pathology, Nair Hospital Dental College, Parel, Mumbai, Maharashtra
India

Abstract

Dirofilaria is parasitic nematodes of domestic and wild animals that can infect humans accidentally via vectors. Its occurrence in the oral cavity is extremely rare. The most frequent presentation of human dirofilariasis is a single submucosal nodule without signs of inflammation. We hereby, report a case of human dirofilariasis affecting the buccal mucosa in a 32-year-old farmer caused by D. repens.

How to cite this article:
Desai R S, Pai N, Nehete A P, Singh J S. Oral dirofilariasis.Indian J Med Microbiol 2015;33:593-594

How to cite this URL:
Desai R S, Pai N, Nehete A P, Singh J S. Oral dirofilariasis. Indian J Med Microbiol [serial online] 2015 [cited 2020 Aug 12 ];33:593-594
Available from: http://www.ijmm.org/text.asp?2015/33/4/593/167342

Full Text

 Introduction



Human dirofilariasis is a rare helminthic zoonosis caused by a nematode Dirofilaria. Dirofilaria is parasitic nematodes commonly affecting dogs and cats, which are the habitual hosts. The habitual hosts are infected after a bite by various arthropods, fleas or mosquitoes, all of which are biological carriers of Dirofilaria.[1] Humans are accidental hosts of this nematode, which is not able to reproduce in the human and will eventually degenerate. D. repens and D. immitis are the two most common Dirofilaria species affecting the humans.[2] Clinically, the lesions are usually presented as single non-tender submucosal nodules. Intra-oral dirofilarial infections are extremely uncommon. So far, only 11 cases of intra-oral dirofilariasis have been documented in the literature.[1],[3],[4],[5],[6]

 Case Report



A 32-year-old male farmer presented with a painless submucosal mass in his right buccal mucosa since 1-month [Figure 1]. Intra-oral examination revealed a solitary, painless, mobile, firm, submucosal nodule measuring about 1 cm × 2 cm located in the right buccal mucosa. There was no sinus or discharge from the swelling. The overlying mucosa was normal in colour. His medical and family history was non-contributory. A complete haemogram was normal. Differential diagnosis of salivary gland neoplasm, lipoma, neurofibroma, calcified lymph node and infected epidermoid cyst were considered. Since the clinical diagnosis was a soft tissue lesion, a radiograph was not taken.{Figure 1}

The lesion was excised under local anaesthesia through intraoral approach. Microscopic examination of the specimen showed a cystic cavity lined by fibrous connective tissue composed of inflamed granulation tissue containing cross-sections of a nematode. Higher magnification showed a thick-multi-layered cuticle, a central intestinal tube and well-developed somatic musculature [Figure 2]. Based on these morphological features, an infection with a D. repens was diagnosed. Patient underwent stool and sputum analysis, which was negative for cysts or ova. The chest radiograph was normal. Patient has remained free of local and systemic disease after 2 years of follow-up.{Figure 2}

 Discussion



Dirofilariasis is a rare parasitic infection caused by a nematode that can infect humans accidently via vectors and have been implicated in zoonotic infections worldwide. Though not widely recognised in India, dirofilariasis has been reported to occur widely throughout Asia Minor, Central Asia, Southern and Eastern Europe and Sri Lanka.[1]Dirofilaria is common parasites of domestic and wild animals, which constitute the main reservoir of infection, and tend to localise in the heart, pulmonary arteries or subcutaneous nodule. The condition is regarded as a form of occult dirofilariasis as microfilaria is not seen in the blood. 6 out of 40 species of Dirofilaria are known to cause diseases in humans; they are D. immitis, D. repens, D. striata, D. tenuis, D. ursi and D. Spectans.[6] Intra-oral dirofilarial infections are extremely uncommon, with cheek and buccal mucosa being the most common site of infection. Clinically, the infection caused by D. repens usually present with localised symptoms of painless submucosal mass with a short clinical history exhibiting no systemic symptoms. Once the infective larvae enter through the wound made by the vector's biting, they migrate into the submucosal tissue. In the present case, submucosal nodule in the buccal mucosa may be due to migration of the nematode from the facial subcutaneous tissue inwards to the buccal mucosa. As humans are not the natural host for this parasite, its development fails to progress to produce microfilaria and adult lesions will eventually disintegrate if left untreated. No specific anti-helminth treatment is therefore needed.[7] Surgical removal of the worm or lesion is the treatment of choice with a good prognosis. There is no need for chemotherapy as microfilaraemia is extremely rare. Although intra-oral dirofilarial infections are extremely uncommon, it should be considered in the differential diagnosis of a solitary symptomless submucosal nodule in the oral cavity. It is very important for the pathologists to be familiar with the histopathological characteristics of nematode since the demonstration of adult dirofilarial worm in the tissue section remains the gold standard for the diagnosis of dirofilarisis.[8] Due to globalisation, there are many diseases, which have become prominent in emigrants. Travel history is important when building a differential diagnosis and often may be overlooked. Human dirofilariasis is most probably underreported because many of them remain undiagnosed or unpublished. Increased awareness of this infection among clinicians may improve the patient care, especially if the patient is coming from an endemic area.

References

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