Worm-Like Parasite Found Living in Woman’s Eye for Two Years; Ocular Pentastomiasis Likely Acquired From Crocodile Meat

A worm-like parasite was found living in a woman's eye for two years, and experts believe it entered her body after she ate crocodile meat.

Unlikely Inhabitant

A 28-year-old woman from Basankusu town in the Democratic Republic of the Congo noticed a mass developing in the corner of her left eye. After getting checked by the doctor, they discovered that the mass was alive.

It turned out to be a living bug that was almost half an inch long. After extracting the mass, it was found to be a pale C-shaped tongue worm larva.

A study revealed that the parasite had grown to about 0.4 inches (1.02 centimeters) and had embedded itself behind the eyelid. The woman's condition was identified as ocular pentastomiasis, named after the parasite pentastomid or tongue worm. Experts linked it to the patient's diet, which included crocodile meat.

The infection of the woman's eye is an unusual place for these parasites to be found, but it made diagnosing and removing the larvae easier.

What is Pentastomiasis?

Pentastomiasis is a rare zoonotic disease caused by the larval stages of pentastomid parasites. It can be transmitted from animals to humans, and most infections occur in the tropics and subtropics.

Pentastomids are worm-like parasites but are modified crustaceans, meaning they are more closely related to shrimp. They are also associated with reptiles such as snakes, lizards, and crocodiles, while they are less associated with amphibians. Both reptiles and amphibians form the parasite's natural host.

Also known as tongue worms, pentastomids live in the upper respiratory tract of their hosts. They can grow between 0.4 and 5.5 inches (1.02 and 13.97 centimeters) long. Their eggs leave the host through its mouth or digestive system, where a rodent can eat them, triggering the eggs to hatch and develop into larvae. A snake or other host eats the rodent, and the cycle starts again.

According to parasite researcher Dennis Tappe from Bernhard Nocht Institute for Tropical Medicine in Germany, humans can get infected by taking up ova from the parasites orally. These eggs are shed by reptiles into the environment through feces and oral secretions.

No case of this type of infection has been reported in individuals who eat crocodile meat, but pentastomids can also infect crocodiles. Crocodile meat can also get contaminated through infected snake meat on a market stall.

When a person becomes infected by pentastomids, the tiny parasites usually burrow into internal organs but rarely cause symptoms. In some cases, the parasites can cause organ perforations, immune reactions, and even death.

Abdominal infections are the most abundant infections encountered during pentastomiasis, but they are still rare and often not symptomatic. In contrast, eye infections are easily visible from the outside and are symptomatic but particularly rare.

These infections are typically treated through surgery, like removing larval parasites from the eye. However, the eye often does not fully recover because of the damage done by the inflammation and scarring of eye tissue.