Thelaziasis is an ocular arthropod-borne, zoonotic disease of the eye infecting the conjunctival sac, lacrimal duct, and lacrimal gland caused by a nematode of the genus Thelazia. We report the first case of human ocular thelaziasis in Nepal in a 6-month-old child from a Rukum district, Nepal. The infant presented with conjunctivitis, and his visual acuity and dilated fundal examination were normal. A total of 6 worms were removed for identification. Collected nematodes were identified based on morphological keys as Thelazia callipaeda. The patient’s symptoms improved after removal of the nematodes
We report a rare case of human thelaziasis in a 6-month-old male child from the Rukum district (28o 38’16”N, 84o 27’17”E), Nepal. The district is at an altitude of 1581 meters above sea level, has a subtropical climate zone, an area of 2877 km2, and a population of 207290 (in 2011). The child is from a poor family, and he lives in a village where human and animals live in close proximity to each other. In this part of Nepal, people usually live in wooden houses where domestic cattle live on the ground floor and people live on the first floor. The patient was referred from a local eye hospital to an Ophthalmology clinic at Tribhuvan University Teaching Hospital, Kathmandu, Nepal. His mother noted a whitish, motile, thread-like worm in the lower fornix of the conjunctiva of the right eye. His mother also reported recent history of an insect (fly) sitting over the medial canthus of the right eye of the baby. Because the baby could not protect himself from the flies that sat on his eye, his mother reported that she came to the child, repeatedly leaving her household work, to wave the flies away from her baby’s eyes. On examination, it was noted that the child repeatedly rubbed his right eye. The patient was noted to have excessive lacrimation and conjunctival erythema and suffusion. No purulent discharge or trauma was noted. Visual acuity was within normal limits for age. Slit lamp examination was normal and did not demonstrate corneal abrasions, hypopyon, or retinal changes. A total of 6 worms were removed from the patient’s right eye. The worms were extracted from his right conjunctival sac by using a sterile cotton swab in our hospital, but 2 initial worms were removed by his mother with her bare finger. Ocular symptoms started to resolve rapidly after removal of the sixth worm. Of the 6 worms extracted, 4 were obtained for identification.
All 4 worms were identified as T callipaeda, 1 was male, and 3 were female. The worms were white, thin thread-like, and measured approximately 10–12 mm in length in female and 7–8 mm in male. The female worm had a serrated cuticle, buccal capsule, mouth opening with a hexagonal profile with a long muscular esophagus and a conical tail with the vulva opening located at the anterior portion of the esophagointestinal junction. The vulva opening was visible under high magnification of light microscope as a slight bulges part near the mouth with a smooth surface free of cuticles while tracing laterally from the anterior part. The alimentary canal was well distinguished from the reproductive system, which contained embryonated eggs in the proximal uterus and first-stage larvae in the distal uterus. The anal opening of the worm was demonstrated at the caudal end. The male worm possessed similar buccal cavity but distinct esophageal-intestinal junction and characteristic curved tail end with shorter spicule with pre- and postcloacal papillae. Based on morphological keys, collected nematodes were identified as T callipaeda. For further identification, the microscopic photographic evidence was forwarded to the Centers for Disease Control and Prevention (Atlanta, GA) and confirmed as T callipaeda, based on morphological keys.
The patient was admitted for observation for 3 days, and worms were not observed on serial ocular examinations. He was discharged with tobramycin ophthalmic drop to prevent secondary bacterial infection. Patient followed up occurred in 2 weeks. On follow-up examination, conjunctival congestion was resolved and ophthalmoscopic examination was within normal limits. No worms were observed during this examination.