A trip to a Florida beach with friends turned into a "nightmare" for a Tennessee teenager after he became infected with hookworm. 

Michael Dumas, 17, from Memphis was on a mission trip to south Florida in June, when he and some friends buried each other in the sand on Pompano Beach, north of Fort Lauderdale. Towards the end of the vacation, he started to feel very tired, and his ears began to ache, his mother Kelli Dumas told Fox 13.

A series of bumps then appeared on his right thigh, and he was later diagnosed with hookworm.

“He was buried in the sand for fun and it has become our nightmare,” Kelli Dumas wrote in a Facebook post detailing her son’s ordeal. 

Four other people on the trip to were also infected with parasites, but Kelli says her son's condition was the worst. Photos of Michael’s feet show track marks where the parasites burrowed under his skin. 

Kelli told Newsweek due to the severity of his infection and the fact his condition was worsening despite taking medication, he was referred to a dermatologist.

"He had cryofreezing done with liquid nitrogen on both feet and both calves. The tracts from some of the worms were two to three inches long. It is horrifying."

Michael is now housebound, must soak his feet in bleach water every day, and will have permanent scarring, she said. 

The incident has also hit the family financially, racking up $1,356 in medical bills.

Kelli urged other parents to buy water shoes to wear to the beach. "Never walk barefoot on a beach again. Never be buried in the sand or allow someone else to. It can result in  a parasitic invasion, pain, agony, scars, expense and a traumatic experience you never dreamed possible," she said. 

She claimed the Health Department in charge of Pompano Beach told her "everyone knows to wear shoes on the beach because you can get parasites."

"I can assure you, no one knows to wear shoes on the beach," said Kelli. 

Florida Health Department did not immediately respond to a request for comment.

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According to the Centers for Disease Control and Prevention, hookworms are parasites which live inside the small intestine. Estimates suggest up to 740 million people in the world are infected with hookworm at any given time. 

Once prevalent in the U.S., particularly in the southeast, improvements in living conditions have reduced infections.

Hookworm eggs are carried in the feces of infected people. If someone defecates outside or their feces is used as fertilizer, the eggs can hatch in soil or sand, and the mature larvae can burrow into the skin of humans. Most hookworm infections occur when a person walks barefoot across contaminated soil.

In most cases, people with hookworms in their intestines will have no symptoms, but some people may experience stomach aches if they are infected for the first time. In serious cases, the infection can lead to anemia due to blood loss.

But if the larvae penetrate the skin, a rash may appear and the individual may experience stomach pains, diarrhea, weight loss, and a poor appetite. This can affect the physical and brain development of children.

As was the case with Michael, the infection can be treated with special medicine. 

This article has been updated with comment from Kelli Dumas.