Thelaziasis: an emerging ocular parasite in Northeast of India

Thelazia spp. is a parasitic nematode and the most common cause of “thelaziasis” (oriental eye worm infestation) in humans, dogs and cats. It was first discovered in the eyes of a dog in China in 1910. Infection in man is considered zoonosis. Transmission to humans occurs via the face fly (Musca autumnalis) in T. callipaedia and Fannia canalicularis in T. californiensis. The eye worm commonly parasitizes the tear ducts and conjunctival sacs of the host although intraocular infestations have been reported. Here, we report a case of thelaziasis in a 36-year-old male, from Majuli, Assam. He had a complaint of ‘something’ inside the left eye since one month. The patient was admitted in the Inpatient Department of Ophthalmology and after thorough observation a mild congestion was noticed in the bulbar conjunctiva of left eye. After two days of exploration a small whitish appearing point was seen in deep upper conjunctival cul- de –sac of left eye which was grasped with a forcep and pulled outwards. On further exploration another worm was noticed inside left upper lid in the sub conjunctival space. In total, three worms were received in the Department of Microbiology which were intact, slender, thread-like and creamy white. Based on the site of recovery, gross appearance and microscopical findings, the worms were identified to be Thelazia callipaeda. This study highlights the importance of “thelaziasis” and it required further research to minimize the morbid conditions and sequelae caused by the worm by its presence in the human eye.