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Toxocariasis is an infection that occurs when a person ingests what is essentially a microscopic roundworm commonly found in cats and dogs. Actually, the person inadvertently ingests larvae of the dog roundworm Toxocara canis, or the cat roundworm Toxocara cati. In the US14% of the population is infected with Toxocara. About 10,000 cases are reported in humans each year. The infection can involve the liver, heart, lung, muscle, eye, and brain. Toxocariasis is predominantly a disease of children aged 2-7 years. Ocular toxocariasis is most common in older children and young adults.

Adult roundworms of the Toxocara species live in the small intestine of cats and dogs. Almost all puppies and kittens are infected soon after birth. When cats and dogs go to the bathroom, the eggs of the worms get into the soil and can survive for years in the environment. Children and young adults are typically exposed after hand to mouth contact with contaminated hands/food. Once ingested the larvae are released into the small intestine. Eventually they can make their way to the muscles, liver, lungs, and sometimes the eyes and brain.

When the eye becomes infected severe retinal swelling occurs resulting in decreased vision and light sensitivity. Most often, a sudden loss of vision occurs because the part of the eye responsible for central vision (macula)is usually involved in Toxocara infections. This results in complete loss of central vision that is typically irreversible. Listening for vague to severe visual symptoms from your children and promptly seeking an eye health evaluation is the only way to have a chance at successful treatment. Do not expect to see signs of atypical “pink eye” infection with redness and mucous discharge because this type of infection manifests on the inside of the eye. Children may only complain of light sensitivity and mild blurry vision in what appears to be an otherwise white, quiet eye.

Treatment includes drugs that kill the roundworm larva. These drugs are called anthelmintics, which means; an agent destructive to worms. Steroids such as prednisone are also used for inflammation and retinal laser therapy is necessary in most cases.

Children and young adults can avoid these infections by using good hygiene after playing outside or in areas where dogs and cats frequent. Eating snacks or meals outside should include hand sanitation prior to eating. In addition, infants and young children should be monitored for putting objects in their mouth while playing outside or in areas where dogs and cats are kept. In other words, reconsider the five-second rule. Finally, for those of you really in love with your animals try to avoid letting your dog or cat lick you or your children on the mouth.

If you or someone you know have vision or eye health related questions and would like more information we invite you to contact us at Cockrell Eyecare Center in Stillwater at 405-372-1715. We also invite you to visit our website at and like us on Facebook at Cockrell Eye Care Center!