History

Fact Explanation
Red eye Thelaziasis is a nematode infection of ocular tissue that is caused by Thelazia callipaeda. Human becomes infested after infected flies feed on tears or other lacrimal secretions. The parasite resides in the conjunctival sac, and lacrimal gland and canal. This causes in an inflammation of the conjunctiva which is characterized by redness in the white of the eye or inner eyelid, increased amount of tears, burning or itching sensation of the eyes. Patients may complain of a foreign body sensation. The disease usually involves one eye. [1,2,3,4,5]
Visual disturbances In severe infections, patients may present with blurring of the vision, photophobia or blindness. [2,3,4]
At risk population Thelaziasis occurs worldwide. But it is more common in regions like United States, China, Russia, India, Japan, and Thailand. [1,2,3]
References
  1. KRISHNACHARY PS, SHANKARAPPA VG, RAJARATHNAM R, SHANTHAPPA M. Human ocular Thelaziasis in Karnataka. Indian J Ophthalmol [online] 2014 Jul, 62(7):822-4 [viewed 22 August 2014] Available from: doi:10.4103/0301-4738.138183
  2. SINGH TS, SINGH KN. Thelaziasis: report of two cases. Br J Ophthalmol [online] 1993 Aug, 77(8):528-9 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/8025054
  3. 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 [online] 2008 Jan-Mar, 51(1):146-8 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18417889
  4. OTRANTO D, DUTTO M. Human thelaziasis, Europe. Emerg Infect Dis [online] 2008 Apr, 14(4):647-9 [viewed 22 August 2014] Available from: doi:10.3201/eid1404.071205
  5. OTRANTO D, EBERHARD ML. Zoonotic helminths affecting the human eye. Parasit Vectors [online] 2011 Mar 23:41 [viewed 22 August 2014] Available from: doi:10.1186/1756-3305-4-41

Examination

Fact Explanation
Conjunctivitis Infestation of the eyes results in inflammation of the conjunctiva. This is characterized by redness in the conjunctiva, epiphora and greenish/ yellowish/ whitish eye discharge. [1,2,3,4]
Corneal changes In severe disease the parasite can migrate to the cornea from the conjunctivae causing corneal opacity, or corneal ulcers (ulcerative keratitis) [3,4,5]
Visual disturbances Vision examination will reveal blurring of vision to blindness. [2,3,4,5]
Worm The conjunctival examination may show the parasite in the conjunctival sac. Adult worm may measure up to 2.0 cm in length. [1,3,5]
References
  1. KRISHNACHARY PS, SHANKARAPPA VG, RAJARATHNAM R, SHANTHAPPA M. Human ocular Thelaziasis in Karnataka. Indian J Ophthalmol [online] 2014 Jul, 62(7):822-4 [viewed 22 August 2014] Available from: doi:10.4103/0301-4738.138183
  2. OTRANTO D, DUTTO M. Human thelaziasis, Europe. Emerg Infect Dis [online] 2008 Apr, 14(4):647-9 [viewed 22 August 2014] Available from: doi:10.3201/eid1404.071205
  3. 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 [online] 2008 Jan-Mar, 51(1):146-8 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18417889
  4. SINGH TS, SINGH KN. Thelaziasis: report of two cases. Br J Ophthalmol [online] 1993 Aug, 77(8):528-9 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/8025054
  5. OTRANTO D, EBERHARD ML. Zoonotic helminths affecting the human eye. Parasit Vectors [online] 2011 Mar 23:41 [viewed 22 August 2014] Available from: doi:10.1186/1756-3305-4-41

Differential Diagnoses

Fact Explanation
Allergic conjunctivitis Allergic conjunctivitis is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Allergens differ among patients. Symptoms consist of redness, edema of the conjunctiva, itching, and increased lacrimation. If this is combined with rhinitis, the condition is termed "allergic rhinoconjunctivitis". [1,2,3,4]
Viral conjunctivitis Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, and/or a sore throat. Its symptoms include excessive watering and itching. The infection usually begins with one eye, but may spread easily to the other. Viral conjunctivitis shows a fine, diffuse pinkness of the conjunctiva, which is easily mistaken for the ciliary injection of iritis, but there are usually corroborative signs on microscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis. Some other viruses that can infect the eye include Herpes simplex virus and Varicella zoster. [1,2,3,4]
Bacterial conjunctivitis Bacterial conjunctivitis causes the rapid onset of conjunctival redness, swelling of the eyelid, and mucopurulent discharge. Typically, symptoms develop first in one eye, but may spread to the other eye within 2–5 days. Bacterial conjunctivitis due to common pyogenic (pus-producing) bacteria causes marked grittiness/irritation and a stringy, opaque, greyish or yellowish mucopurulent discharge that may cause the lids to stick together, especially after sleep. Severe crusting of the infected eye and the surrounding skin may also occur. The gritty and/or scratchy feeling is sometimes localized enough for patients to insist they must have a foreign body in the eye. The more acute pyogenic infections can be painful. Common bacteria responsible for non-acute bacterial conjunctivitis are Staphylococci and Streptococci. [1,2,4]
References
  1. AZARI AA, BARNEY NP. Conjunctivitis: a systematic review of diagnosis and treatment. JAMA [online] 2013 Oct 23, 310(16):1721-9 [viewed 22 August 2014] Available from: doi:10.1001/jama.2013.280318
  2. LA ROSA M, LIONETTI E, REIBALDI M, RUSSO A, LONGO A, LEONARDI S, TOMARCHIO S, AVITABILE T, REIBALDI A. Allergic conjunctivitis: a comprehensive review of the literature. Ital J Pediatr [online] 2013 Mar 14:18 [viewed 22 August 2014] Available from: doi:10.1186/1824-7288-39-18
  3. WADHWANI M, D'SOUZA P, JAIN R, DUTTA R, SAILI A, SINGH A. Conjunctivitis in the newborn- a comparative study. Indian J Pathol Microbiol [online] 2011 Apr-Jun, 54(2):254-7 [viewed 22 August 2014] Available from: doi:10.4103/0377-4929.81584
  4. BURD EM, SHARP SE. Photo quiz: A 36-year-old with recurrent conjunctivitis. J Clin Microbiol [online] 2012 Feb, 50(2):215, 543 [viewed 22 August 2014] Available from: doi:10.1128/JCM.06019-11

Investigations - for Diagnosis

Fact Explanation
Microscopic examination After finding the adult worm in the conjunctival sac, worms has to be removed with forceps. The parasite is examined under the microscopy for the confirmation of the diagnosis. Its cuticle has coarse striations, often giving the worms a serrate appearance. The mouth is without lips and the esophagus is short. The tail of the male is recurved and without caudal alae. The tail of the female is bluntly rounded. [1,2,3]
References
  1. OTRANTO D, DUTTO M. Human thelaziasis, Europe. Emerg Infect Dis [online] 2008 Apr, 14(4):647-9 [viewed 22 August 2014] Available from: doi:10.3201/eid1404.071205
  2. 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 [online] 2008 Jan-Mar, 51(1):146-8 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18417889
  3. SINGH TS, SINGH KN. Thelaziasis: report of two cases. Br J Ophthalmol [online] 1993 Aug, 77(8):528-9 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/8025054

Management - General Measures

Fact Explanation
Prevention Thelaziasis can be prevented by controlling of the fly vector by use of bed nets to protect children while they are sleeping and by keeping their faces and eyes clean. [1,2,3]
References
  1. 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 [online] 2008 Jan-Mar, 51(1):146-8 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18417889
  2. SINGH TS, SINGH KN. Thelaziasis: report of two cases. Br J Ophthalmol [online] 1993 Aug, 77(8):528-9 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/8025054
  3. OTRANTO D, DUTTO M. Human thelaziasis, Europe. Emerg Infect Dis [online] 2008 Apr, 14(4):647-9 [viewed 22 August 2014] Available from: doi:10.3201/eid1404.071205

Management - Specific Treatments

Fact Explanation
Physical extraction of the adult worm This is the only definitive treatment in human. The adult worm is removed from the conjunctival sac using topical anesthesia and antibiotic eye drops. [1,2,3]
References
  1. KRISHNACHARY PS, SHANKARAPPA VG, RAJARATHNAM R, SHANTHAPPA M. Human ocular Thelaziasis in Karnataka. Indian J Ophthalmol [online] 2014 Jul, 62(7):822-4 [viewed 22 August 2014] Available from: doi:10.4103/0301-4738.138183
  2. OTRANTO D, DUTTO M. Human thelaziasis, Europe. Emerg Infect Dis [online] 2008 Apr, 14(4):647-9 [viewed 22 August 2014] Available from: doi:10.3201/eid1404.071205
  3. 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 [online] 2008 Jan-Mar, 51(1):146-8 [viewed 22 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18417889