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Year : 2008  |  Volume : 51  |  Issue : 1  |  Page : 146-148
Ocular thelaziasis in Assam: A report of two cases

1 Department of Microbiology, Assam Medical College, Dibrugarh, India
2 Regional Medical Research Centre, Assam Medical College, Dibrugarh, India
3 Department of Ophthalmology, Assam Medical College, Dibrugarh, India

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Small, white, thread-like, motile worms were recovered from the conjunctival sac of a 13-year-old girl and a 50-year-old woman from Dibrugarh district, Assam, India. They were identified as thelazia species. These two cases have been reported due to their rarity in India and elsewhere.

Keywords: Ocular infestation, thelazia species, upper Assam

How to cite this article:
Nath R, Narain K, Saikia L, Pujari BS, Thakuria B, Mahanta J. Ocular thelaziasis in Assam: A report of two cases. Indian J Pathol Microbiol 2008;51:146-8

How to cite this URL:
Nath R, Narain K, Saikia L, Pujari BS, Thakuria B, Mahanta J. Ocular thelaziasis in Assam: A report of two cases. Indian J Pathol Microbiol [serial online] 2008 [cited 2022 May 16];51:146-8. Available from: https://www.ijpmonline.org/text.asp?2008/51/1/146/40430

   Introduction Top

The genus Thelazia of class Nematoda, order spirurida, contains several species. They are normally recovered from the conjunctival sac and lacrimal duct of animals like dogs, cats, sheep, rabbits, deer and goats. The infection in man is caused by Thelazia callipaeda and Thelazia californiensis . Thelazia callipaeda is an unsegmented worm with distinct anterior and posterior parts and is found in Asia, Middle East and Far East. [1] T. callipaeda , or the oriental eye worm, is primarily a parasite of the conjunctiva of dogs but is also found in rabbits and humans. [2],[3] Its presence in the conjunctiva or ocular tissue can cause excess lacrimation, irritation; and frequent movement across the cornea can cause marked discomfort and corneal scarring. Gravid female worms discharge larvae or embryonated eggs in the lacrimal secretions which are ingested by flies belonging to the genus Fannia and Musca . The infective larvae migrate to the mouth of the fly and from there to a new host when the fly feeds on ocular secretions. [1],[3]

We are reporting two cases of thelaziasis, from which we could recover a total of seven adult worms from the conjunctival sacs of the patients (four males from the first case and one female and two males from the second case). Though thelaziasis has been reported from India, the number of reports is very small.

   Case History Top

Case 1

A 13-year-old girl from Dibrugarh district, Assam, came to a private ophthalmology clinic in August 2000 with a complaint of moving worms in the right eye. Four white, thread-like, tiny worms came out spontaneously, which were sent to the Regional Medical Research Centre, Dibrugarh. The patient also complained of redness and a sensation suggestive of the presence of a foreign body in the affected eye. On examination, mild conjunctival chemosis was found. Orbit, eyelid, lacrimal apparatus, eyeball, cornea, sclera, anterior chamber, iris, pupil, lens, posterior chamber and fundus were found to be normal. The patient's family rears cattle, but there were no pet dogs or cats in the household; also, there was no history of travel to any mountainous region.

Case 2

A 50-year-old female from Dibrugarh, Assam, came to the Ophthalmology Outpatient Department of Assam Medical College and Hospital in April 2006 with a history of spontaneous expulsion of tiny, white worms from the left eye. The patient also complained of redness, excess lacrimation and irritation in the same eye. Two white, tiny worms came out spontaneously. On examination of the eye, another thread-like worm was observed in the upper conjunctival sac. No other abnormality was detected on examination of both the eyes. Orbit, eyelid, lacrimal apparatus, eyeball, cornea, sclera, anterior chamber, iris, pupil, lens, posterior chamber and fundus were found to be normal.

The patient's family rears cattle, but there were no pet dogs or cats at home. The patient did not give any history of travel to any mountainous region. The worms were sent to the microbiology laboratory, Assam Medical College and Hospital.

The worm

Macroscopically, all the worms were white, tiny and thread-like. The length of all male worms recovered from the first case varied from 9.58 mm to 10.1 mm, and the breadth was within the range of 0.25 mm to 0.41 mm. But the length of the male worms recovered from the second case varied from 11 mm to 11.2 mm, and the width was around 0.3 mm. Transverse cuticular striations were seen in the whole body in all the worms. The buccal cavity was rectangular with no lips or teeth-like structures. The long spicule protruded from the cloaca, the length of which varied from 0.85 mm to 1.31 mm. All the preanal papillae were not visible because of the spiral coiling of the posterior end. The testes were located in the region extending from the mid portion of the body to the tails. The female worm was 17 mm in length and 0.4 mm in width. The anterior end was similar to that in the male. The esophagus was about 0.6 mm similar to male worm in morphology. The vaginal opening was indistinguishable. Posterior part of the worm was filled with eggs and larvae-like structures. Transverse cuticular striations were found all over the body of the worm [Figure - 1],[Figure - 2],[Figure - 3].

The morphological features of the worm were consistent with the genus Thelazia. Species identification could not be done as the position of the vaginal opening was indistinguishable in the female worm, and the anal papillae in the male worm could not be counted.

   Discussion Top

T. callipaeda and T. californiensis are common parasites of sheep, dogs, cats, rabbits, and deer. Human beings are occasional and accidental hosts. As the patients were from rural areas, they might have acquired the infection from some farm or domestic animal. The difference in sizes of the male worms in the two cases might be due to difference in stages of maturity.

There are a few cases of Thelazia infestation among humans reported from India. Probably, the first case of Thelazia callipaeda infection was reported from Salem District, India, in 1948. [4] Subsequently, four cases were reported by various authors from Manipur, Assam, and Himachal Pradesh. [5],[6],[7] All these reports are of Thelazia callipaeda infestation except the report by Mahanta et al. , where the case was reported as Thelazia species as the worm isolated was an immature male and for which species differentiation could not be done. The present case is also from the same district of Assam. Therefore, it may be speculated that more cases of Thelazia infestation may be present in Assam, particularly in Dibrugarh district, which may not have been recorded. On many occasions, the patients do not seek medical treatment because of the spontaneous exit of the worm and cure without specific treatment. Most of the cases reported from China, Japan, India, Russia, Thailand, Korea, as well as the present two cases, were extra-ocular. However, Zakir et al. reported a case of Thelazia infestation of the vitreous cavity from China. [2] Though travel to mountaineous region has been implicated as a risk factor in some of the reports, [7],[8],[9] this has not been found in the present case. In another case reported from Assam [6] by Mahanta et al . also this history was not found. Therefore it seems that vector and reservoir may be present in plains itself. This relation of vector and reservoir in plains needs further epidemiological study.

   Acknowledgment Top

The authors are thankful to the DPDx team, Division of Parasitic Diseases, Center for Disease Control, Atlanta, for helping in the preliminary identification of the worm.

   References Top

1.Beaver PC, Jung RC, Cupp EW. The spirurida. Clinical parasitology, 9 th ed. Lea and Febiger: Philadelphia; 1984. p. 344-5.  Back to cited text no. 1    
2.Zakir R, Zhong-Xia Z, Chiodini P. Intraocular infestation with the worm, Thelazia callipaeda. Br J Ophthalmol 1999;83:1194.  Back to cited text no. 2    
3.Levine ND. Spiruroids. Nematode parasites of domestic animals and man. 2 nd ed. Burgess Publishing Company: Minneapolis; 1980. p. 321-3.  Back to cited text no. 3    
4.Friedman M. Thelazia callipaeda, the "Oriental eye worm". Antiseptic 1948;45:620-6.  Back to cited text no. 4    
5.Singh TS, Singh KN. Thelaziasis: Report of two cases. Br J Ophthalmol 1993;77:528-9.  Back to cited text no. 5    
6.Mahanta J, Alger J, Bordoloi P. Eye infestation with Thelazia species. Indian J Ophthalmol 1996;44:99-101.  Back to cited text no. 6    
7.Sharma A, Pandey M, Sharma V, Kanga A, Gupta ML. A case of human thelaziasis from Himachal Pradesh. Indian J Med Microbiol 2006;24:67-9.  Back to cited text no. 7    
8.Hong ST, Lee SH, Kim SI. A Human case of Thelazia callipaeda infection with reference to its internal structures. Korean J Parasitol 1988;26:136-9.  Back to cited text no. 8    
9.Hong ST, Park YK, Lee SK, Yoo JH, Kim AS, Chung YH, et al . Two human cases of Thelazia callipaeda infection in Korea. Korean J Parasitol 1995;33:139-44.  Back to cited text no. 9    

Correspondence Address:
Reema Nath
Department of Microbiology, Assam Medical College, Dibrugarh - 786 002
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.40430

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  [Figure - 1], [Figure - 2], [Figure - 3]

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