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Parasite infectionsFor doctors, trying to figure out whether a person has a parasitic infection is like solving a mystery with few clues or only vague ones.
In the following eight cases, parasites wreaked havoc inside a person's body before being detected. Some of these nasty organisms were picked up by people in strange ways, while others wound up in unusual locations.
All of them caused trouble until their mysteries were solved.
Roundworms camp out in a woman's stomach.Slide 2 of 17
Roundworms camp out in a woman's stomach.A Japanese woman who liked eating raw fish ended up in the hospital after eating raw salmon that was contaminated with parasitic worms, according to a 2016 case in The New England Journal of Medicine.
The roundworms hitched a ride on the uncooked fish and eventually tunneled their way into the walls of her stomach. Within several hours of the meal, the 36-year-old developed stomach and chest pains, along with nausea and vomiting.
But she didn't go to the hospital until two days later. There, doctors inserted a small camera into her stomach and noticed something fishy: 11 anisakis larvae, which are a type of parasitic roundworm. Anisakis worm infections are more common in countries where people eat raw fish or undercooked seafood. But typically, when these parasitic infections happen, one or two worms are usually to blame — not 11 of them, her doctor told Live Science in 2016.
After the worms were fished out of the woman's stomach, her symptoms went away.Slide 3 of 17
Fungal spores infect transplanted organs.Slide 4 of 17
Fungal spores infect transplanted organs.Three people who received transplanted organs from the same donor developed brain problems shortly after the operations due to a rare parasitic infection that originated in the organ donor's body.
One man, who received a kidney, experienced behavior changes. He later died, and his doctors wondered whether the transplanted organ might have been responsible.
Indeed, the man's autopsy revealed his tissue tested positive for a tiny parasite known as Encephalitozoon cuniculi, which belongs to a group of single-celled organisms called Microsporidia.
Doctors tracked down the person who received the donor's liver, and this individual had tremors and difficulty walking. A third person, who received the donor's heart and her other kidney, had been hospitalized with a type of brain inflammation known as encephalitis.
Test results showed that both recipients were infected with Microsporidia. They took medication to treat the parasite and no longer had neurological complaints.
The case series was presented in 2015 at IDWeek, a meeting of several organizations focused on infectious diseases.Slide 5 of 17
Teensy parasite grows on contact lens.Slide 6 of 17
Teensy parasite grows on contact lens.
A young woman in Florida developed a serious infection in her left eye from a parasite that grew on her contact lens, a TV news report from 2013 revealed.
The parasite, called Acanthamoeba, is found in water and soil worldwide, and can enter a person's body through cuts on the skin, contact-lens solution or inhalation, according to the Centers for Disease Control and Prevention (CDC). Anyone who wears contact lenses can become infected with the parasite, though it is incredibly rare, affecting only about 1 in 33 million contact-lens wearers, the CDC estimates.
If the teenager had not sought help for the pain, swelling and redness in her left eye, the infection may have led to permanent vision problems or blindness. She was treated for several months with medication to clear the infection, and said she would be more diligent about cleaning her contacts and not leaving them in her eyes too long.Slide 7 of 17
Beef tapeworm lives in man's small intestine for two years.Slide 8 of 17