Ocular toxocariasis--United States, 2009-2010.

Ocular toxocariasis (OT) is caused by the zoonotic parasites Toxocara canis and Toxocara cati, roundworms of dogs and cats. Persons become infected with Toxocara when they unintentionally ingest embryonated eggs that have been shed in the feces of infected animals. Although OT is uncommon, it most often affects young children and can cause debilitating ophthalmologic disease, including blindness. Previous studies of OT in the United States have been conducted in single institutions. This report describes the results of a web-based survey distributed to uveitis, retinal, and pediatric ophthalmology specialists nationwide to collect epidemiologic, demographic, and clinical information on patients with OT. A total of 68 patients were newly diagnosed with OT from September 2009 through September 2010. Among the 44 patients for whom demographic information was available, the median patient age was 8.5 years (range: 1-60 years), and 25 patients (57%) lived in the South at the time of diagnosis. Among 30 patients with reported clinical data, the most common symptom was vision loss, reported by 25 (83%) patients; of these, 17 (68%) suffered permanent vision loss. The results of this first national level survey demonstrate that OT transmission continues to occur in the United States, frequently affecting children and causing permanent vision loss in the majority of reported patients. Good hygiene practices, timely disposal of pet feces, and routine deworming of pets are strategies necessary to reduce OT in humans.