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   Table of Contents      
Year : 2015  |  Volume : 63  |  Issue : 2  |  Page : 173

Human ocular thelaziasis in Karnataka

Department of Ophthalmology, IGMC, Shimla, Himachal Pradesh, India

Date of Web Publication1-Apr-2015

Correspondence Address:
Dr. M L Pandey
Department of Ophthalmology, IGMC, Shimla, Himachal Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0301-4738.154415

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How to cite this article:
Pandey M L, Sharma R L, Sharma A. Human ocular thelaziasis in Karnataka. Indian J Ophthalmol 2015;63:173

How to cite this URL:
Pandey M L, Sharma R L, Sharma A. Human ocular thelaziasis in Karnataka. Indian J Ophthalmol [serial online] 2015 [cited 2020 Jun 1];63:173. Available from: http://www.ijo.in/text.asp?2015/63/2/173/154415

Dear Editor,

We have read with interest the brief communication on human ocular thelaziasis by Krishnachary et al. [1] . They have quoted a case report from Himachal Pradesh, but have not cited the reference. A case on thelaziasis was reported from this hill state in 2006, and it was published [2] where five different worms 2 males and 3 females with larvae in their uterus were identified. As we have pointed out that human involvement is not uncommon, but is under reported. These cases are occasionally seen in our  out patient department (OPD) particularly during or after rainy seasons in the hilly region. Transmission of larvae occurs in sleeping host in unhygienic surrounding by tear seeking flies. [3]

The adult worms of Thelazia species discovered so far inhabit only the eyes of various mammals, birds, including humans. [4] and hence called eye worms. In the uterus of the adult female, the embryos develop into first-stage larvae (L1), which remain in the eggshell (sheath). [5] The female deposits these sheathed larvae in the tears of the mammal or bird definitive host and the larvae are ingested by tear-feeding flies. In the fly, the larvae "hatch," to penetrate the gut wall and migrate to the fat body, testes or egg follicles (depending on the species). There they develop into third-stage larvae (L3), which migrate to the head of the fly. The infective L3 larvae wiggle out of the straw-like feeding apparatus of the fly when it feeds on the tears of another mammal or bird host. The L3 larvae develop into adults in the eye or surrounding tissues of the host, where they may live for over 1-year. Hence, it is unlikely that transmission could take place with contaminated towel with cow dung or trauma as mentioned in this case report. The vectors are biological for Thelazia species, and they are tear-feeding flies of the genera Musca, Phortica (family Drosophilidae), or Fannia (family Fanniidae).

The symptoms are irritation and redness of the eyes until they bury in the tissues, but it should not be mistaken for conjunctivitis as parasite are likely to enter in deeper tissue. For the treatment of human cases, removal of the worm under topical anaesthesia is suggested. Because most, if not all, species of Thelazia are spread by flies, sanitary practices, which reduce the contact with the flies will also reduce the spread of thelaziasis.

  References Top

Krishnachary PS, Shankarappa VG, Rajarathnam R, Shanthappa M. Human ocular thelaziasis in Karnataka. Indian J Ophthalmol 2014;62:822-4.  Back to cited text no. 1
[PUBMED]  Medknow Journal  
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. 2
[PUBMED]  Medknow Journal  
Anderson RC. Thelazia. Nematode parasites of vertebrates: Their development and transmission. 2 nd ed. Wallingford, England: CABI Publishing; 2000. p. 404-7.   Back to cited text no. 3
Otranto D, Lia RP, Buono V, Traversa D, Giangaspero A. Biology of Thelazia callipaeda (Spirurida, Thelaziidae) eyeworms in naturally infected definitive hosts. Parasitology 2004;129:627-33.  Back to cited text no. 4
Hong ST, Lee SH, Kim SI. A human case of Thelazia callipaeda. Korean J Parasitol 1995;33:139-44.  Back to cited text no. 5


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