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Year : 2014  |  Volume : 4  |  Issue : 2  |  Page : 119-121  

Subconjunctival dirofilariasis: Case studies with review of literature

1 Department of Microbiology K.V.G. Medical College and Hospital, Kurunjibagh, Sullia, India
2 Consultant Optholmologists, Sharada Nethralaya, Puttur, Karnataka, India

Date of Acceptance01-Mar-2014
Date of Web Publication12-Aug-2014

Correspondence Address:
K Subrahmanya Bhat
Department of Microbiology, K.V.G. Medical College and Hospital, Kurunjibagh, Sullia 574 327, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2229-5070.138541

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Human dirofilariasis is an uncommon zoonotic parasitic infection caused by species of the genus Dirofilaria. Location of the worm is usually confined to the subcutaneous tissues of eyelids, fingers, cheeks and breasts. Ophthalmic involvement is usually periorbital, intraocular or of the eyelids. Subconjunctival localization is rarely observed. We report three cases of subconjunctival dirofilariasis in males, age ranges between 45 and 60 years. All the cases were caused by Dirofilaria repens. The worms were surgically removed under local anesthesia. The cases are discussed in the light of earlier reports on subconjunctival dirofilariasis. In view of frequent reports of dirofilariasis from Karnataka, considering the state endemic for dirofilarasis is also discussed.

Keywords: Dirofilariasis, Dirofilaria repens, subconjunctival dirofilariasis

How to cite this article:
Bhat K S, Kotigadde S, VishwanathaBhat K N, Pare P. Subconjunctival dirofilariasis: Case studies with review of literature. Trop Parasitol 2014;4:119-21

How to cite this URL:
Bhat K S, Kotigadde S, VishwanathaBhat K N, Pare P. Subconjunctival dirofilariasis: Case studies with review of literature. Trop Parasitol [serial online] 2014 [cited 2022 Nov 28];4:119-21. Available from: https://www.tropicalparasitology.org/text.asp?2014/4/2/119/138541

   Introduction Top

Dirofilariasis is an emerging zoonosis in India. Dirofilaria are natural filarial parasites of dogs, cats, foxes and other wild animals. [1] Human dirofilariasis seen world-wide is an accidental infection caused by species of Dirofilaria such as Dirofilaria repens, Dirofilaria immitis, Dirofilaria tenuis and Dirofilaria ursi. [2] Since only immature forms are found in humans, no microfilariae are detected in the circulation. Culex, Aedes, Armigeres and Anopheles mosquitoes are the intermediate hosts of Dirofilaria. The larval stage of Dirofilaria taken up by the mosquito during the blood meal, develop into infective stage in the vector and transmitted to dogs or other hosts including humans during the subsequent blood meal. [1]

Human dirofilariasis has not been widely reported in India, except a focus of human infection with D. repens in Kerala. [1] A few cases of human dirofilariasis have also been reported from Karnataka, a South Indian state. [3],[4],[5] Only one of them was caused by D. tenius, [4] while others were caused by D. repens. [3],[5] Ophthalmic involvement with Dirofilaria may be periorbital, intraocular or subconjunctival. There are a few reports from the western part of peninsular India on dirofilarial involvement of upper or lower eyelid. [4],[5],[6] Though a few solitary cases of sporadic subconjunctival dirofilariasis, were also reported from peninsular India, [3],[4],[5],[6],[7],[8],[9] only one of them [3] was from Karnataka state. Recently we observed a cluster of three cases of subconjunctival dirofilariasis caused by D. repens in males aged between 45 and 60 years of age.

   Case report Top

Three cases of subconjunctival dirofilariasis were presented to ophthalmology clinics in Puttur town of Dakshina Kannada district, Karnataka state. All the three cases were males aged 45, 55 and 60 years respectively. Itching, lacrimation, pain and conjunctival congestion were the prominent manifestations. In the first case an inflamed nodular swelling was observed on the lateral side of the bulbar conjunctiva of the right eye. Slit lamp examination revealed a thin, white worm. Similar thin white worms moving under the conjunctiva of the left eye in the second and on the medial aspect of the scleral conjunctiva of right eye in the third case also were observed. The worms were removed under local anesthesia [Figure 1]. Routine clinical, blood and urine examinations revealed no abnormalities. Blood examination did not reveal any microfilaria. Clinical presentations of the eye were cleared subsequent to removal of the worms.
Figure 1: Extraction of worm from subconjuctival space

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   Conclusions Top

Review of the literature reveals a few reports of subconjunctival dirofilariasis from western peninsular India. The first case of subconjunctival dirofilariasis was reported by Joseph et al., (1976) [7] from Trivandrum town of Kerala, a costal state of western peninsular India. The patient was a 60-year-old Hindu female who complained of a 5-month-old swelling in the right eye with itching, foreign body sensation and excessive watering. A whitish worm of 13.5 cm × 0.5 mm size, extracted from the lesion by surgical procedure was identified as Dirofilaria conjunctivae (D. repens). Another case reported from Kochi, Kerala [8] was a case of subconjunctival dirofilariasis of the left eye caused by D.tenuis in a 75-year-old male, who presented with redness and irritation of the left eye. Another case was reported from Panvel, New Mumbai [9] . The patient was a 48-year-old male who complained of painless swelling and redness of 18 days duration over the white portion of the right eye. Localized conjunctival congestion with yellowish cream, firm, nonmobile and nontender scleral nodule was observed. Two worms removed from the lesion were identified as D. repens. A solitary case of subconjunctival dirofilariasis in a 23-year-old farmer reported from Rothak, Haryana state was caused by D. repens. [10]

The first case of subconjunctival dirofilariasis from Karnataka was reported by Nadgir et al. (2001). [3] The patient was a 42-year-old farmer from Karwar, a coastal town of Karnataka. He presented with pain and excessive watering of left eye for a month. An inflamed nodular swelling with marked hyperemia was noticed at the inferomedial quadrant of the left eye. A whitish worm extracted from the lesion was identified as D. repens. All cases of subconjunctival dirofilariasis including the present report are from peninsular western India except the solitary report from Rothak, Haryana. [10] Swelling, redness, excessive lacrimation and/or foreign body sensation, hyperemia and localized pruritus were observed in these cases. In India, D. repens has been more commonly incriminated in dirofilariasis, irrespective of anatomical sites involved, although D. tenuis was the etiological agent in two cases. [4],[8]

Diagnosis of dirofilariasis based on symptoms or by resorting to serological methods is not reliable. Surgical removal of the worm from lesions and subsequent identification by morphological and anatomical features and biopsy, aid establish the diagnosis and treatment. All dirofilaria have fine transverse striations on the cuticle and abundant somatic musculature. All except D.immitis and a few others have prominent external longitudinal ridges. [11] D. repens has beaded longitudinal ridges and transverse striations [12] [Figure 2]. D. repens is found in dogs and cats in Asia, Europe and Africa. [3] Surgical extraction of the worm is the treatment of choice for dirofilarisis. Chemotherapeutic agents are ineffective. Identification is essential to avoid treatment with antihelmintics and for documentation.
Figure 2: Microphotograph of Dirofilaria repens showing transverse striations

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Recently dirofilariasis has been increasingly reported from India. Kerala state has been recognized as endemic area for dirofilariasis. [1] Dirofilaria are natural parasites of mammals such as dogs, cats, foxes and raccoons and are transmitted to man by hematophagous, anthropophilic mosquitoes of the genera Culex, Aedes, Armigera and Anophelis, [1] carrying the infective stage larvae, acquired from natural infection in animal hosts. Of the 40 recognized species of Dirofilaria, a few species such as D. repens, D. tenuis, D. ursi and D. immitis have been found to cause human infections. [11] Man is the suboptimal host. Dirofilaria cannot develop into fully mature stage in the human host and majority of them die before producing microfilaria. Ocular involvement is usually associated with localized pruritus, pain, swelling, edema, hyperemia of the conjunctiva and sensation of movement under the conjunctiva or skin. Allergic manifestation with fever, urticarial and facial edema may occur. [13]

All the three present cases are from rural areas surrounding Puttur, a town situated at a distance of 50 km from the costal belt of Dakshina Kannada District of Karnataka state. Two cases reported earlier [4],[5] as well hailed from this area. Therefore, it appears that this part of Karnataka is a focus of human dirofilariasis. Since every house hold in this area rear dogs and cats which are natural hosts for D. repens, screening them for dirofilariasis, creating awareness among medical practitioners, proper preservation and identification of worms extracted from cases and documentation of cases are necessary, probably to consider this geographical area endemic for dirofilariasis.

   References Top

1.Sabu L, Devada K, Subramaniam H. Dirofilariasis in dogs and humans in Kerala. Indian J Med Res 2005;121:691-3.  Back to cited text no. 1
2.Pampiglione S, Canestri Trotti G, Rivasi F. Human dirofilariasis due to Dirofilaria (Nochtiella) repens: A review of world literature. Parassitologia 1995;37:149-93.  Back to cited text no. 2
3.Nadgir S, Tallur SS, Mangoli V, Halesh LH, Krishna BV. Subconjunctival dirofilariasis in India. Southeast Asian J Trop Med Public Health 2001; 32:244-6.  Back to cited text no. 3
4.Bhat KG, Wilson G, Mallya S. Human dirofilariasis. Indian J Med Microbiol 2003;21:223.  Back to cited text no. 4
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5.Kotigadde S, Sathyavathi AR, Kariyappa TM. Human dirofilariasis due to Dirofilaria repens in southern India. Trop Parasitol 2012;2:67-8.  Back to cited text no. 5
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6.Sekhar HS, Srinivasa H, Battu RR, Mathai E, Shariff S, Macaden RS. Human ocular dirofilariasis in Kerala Southern India. Indian J Pathol Microbiol 2000;43:77-9.  Back to cited text no. 6
[PUBMED]  Medknow Journal  
7.Joseph A, Thomas PG, Subramaniam KS. Conjunctivitis by Dirofilaria conjunctivae. Indian J Ophthalmol 1977;24:20-2.  Back to cited text no. 7
8.Bhat S, Sofia O, Raman M, Biswas J. A case of subconjunctival dirofilariasis in South India. J Ophthalmic Inflamm Infect 2012;2:205-6.  Back to cited text no. 8
9.Sangit VA, Haldipurkar SS. Subconjunctival dirofilariasis mimicking scleritis: First report from Western India. Indian J Ophthalmol 2012;60:76-7.  Back to cited text no. 9
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10.Gautam V, Rustagi IM, Singh S, Arora DR. Subconjunctival infection with Dirofilaria repens. Jpn J Infect Dis 2002;55:47-8.  Back to cited text no. 10
11.Wong MM, Brummer ME. Cuticular morphology of five species of Dirofilaria: A scanning electron microscope study. J Parasitol 1978;64:108-14.  Back to cited text no. 11
12.Garcia LS (editors). Diagnostic Medical Parasitology. 5 th ed. Ch. 12. Washington: ASM Press; 2007.p. 348-51.  Back to cited text no. 12
13.Jelinek T, Schulte-Hillen J, Löscher T. Human dirofilariasis. Int J Dermatol 1996;35:872-5.  Back to cited text no. 13


  [Figure 1], [Figure 2]

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