Ocular Toxocariasis

Excerpt

Helminths have been causing disease in human beings for since long. Helminths are divided into phylum, Nemathelminthes, and Platyhelminths. Nematodes are a class of Nemathelminthes that include human worms (Ascaris lumbricoides, Trichuris trichiura), animal worms (Toxocara canis, Toxocara catis), and filarial worms (Wuchereria bancrofti). Platyhelminths are divided into trematodes (Schistosoma mansoni) and cestodes (Taenia solium). Worldwide around 1 billion people are infected with helminths.

They are pathogenic to humans. They parasitize the intestine and cause tissue damage by direct invasion. Ocular toxocariasis is a zoonotic infection. It is caused by the nematode Toxocara canis and Toxocara cati. In 1950, Wilder described the ocular infection caused by a nematode. She studied 46 enucleated eye specimens and found nematode larva in 24 of them. Beaver, in 1952, identified the Toxocara larva in the liver biopsies of children. Nichols in 1956 demonstrated T. canis in 24 enucleated eye specimens.

These findings implicated Toxocara as a common etiology for systemic and ocular pathology. Ocular toxocariasis may present with peripheral granuloma, posterior granuloma, or endophthalmitis. This review discusses etiology, epidemiology, pathophysiology, clinical features, investigations, differential diagnoses, management, complications, and the role of interprofessional coordination for patients with ocular toxocariasis.