After years of severe stomach pains and other painful symptoms, Jackie discovers she's been suffering from Schistosomiasis, or snail fever.

Only 20 percent of infected individuals will show symptoms of Zika, making it often misdiagnosed. To make matters worse, it can result in devastating birth defects if a woman catches before or during pregnancy.

Charlye Hebert has been experiencing nausea, vomiting and diarrhea for months. Despite an initial diagnosis and treatment for stomach ulcers, her symptoms have yet to subside.

Doctors and family are stunned when they discover the cause of Kennedy's poor health is due to an extreme allergy to nickel, which can be traced to the metal braces on her teeth.

Xander's condition takes a devastating turn when his skin starts peeling off his body.

Now that doctors know what's wrong with Xander, they put him on life support to give him the best chance of recovery.

After spending two months in a coma as a result of a Group A Streptococcus infection, Katy wakes up to the devastating news that all four limbs had to be amputated in order to keep her alive.

After complaining about pain on his head, 8-year-old Andrew is rushed to the ER, where doctors remove a botfly larva from his scalp.

When doctors cannot find anything in his mouth, biology professor John Allen takes matters into his own hands and extracts a rare parasite called Gongylonema pulchrum.

After suffering from an array of symptoms for months, Al Ceccarelli is diagnosed with Strongyloides, a disease caused by parasitic worms found in tropical climates.

As soon as doctors make an incision near Paul’s eye, out pops a larva.

An ovarian teratoma removed from Kira’s body featured hair, teeth, tissue and other cells, resulting in her erratic behavior and sickness.

Sam's worsening flu-like symptoms takes him to the emergency room, where his urine indicates something dangerously wrong with his renal system.

With Brianna's head abrasion getting worse, her parents rush her to the ER where a dermatologist hears something terrifying coming from her scalp.

When a high school football star begins to experience odd symptoms, his parents take him to the hospital.

Stephanie noticed her 4-year-old son, Alex, came home with less energy than usual. But what seemed like the result of a long day at school quickly turned into a race to the emergency room.

After suffering from an array of symptoms for months, Al Ceccarelli is diagnosed with Strongyloides, a disease caused by parasitic worms found in tropical climates.

A happily married couple's trip to New York becomes a nightmare when they learn that they have been infected with the Bubonic Plague, not only putting their lives in danger but anyone who comes into contact with them.

A fishing trip turns into the vacation from hell when Rick's ankle injury turns into a matter of life or death.

When one woman checks a wound on her leg and sees a tube-like creature MOVE and retract into her body - she heads back to the doctor immediately.

SNEAK PEEK: When a 15-month-old girl has a fever and bloody diarrhea, her frantic parents race her to the hospital. WHAT could be ailing this poor baby?

A young woman's life has been deeply affected for five years by fatigue and illness, when the cause of Lyme Disease is finally discovered.

Lauren is a happy 7-year-old girl… until she begins suffering from tics, anxiety and manic episodes. Her symptoms build up to a terrifying breaking point.

After spending two months in a coma as a result of a Group A Streptococcus infection, Katy wakes up to the devastating news that all four limbs had to be amputated in order to keep her alive.

After a woman suffers having cysts surgically removed from her right breast, things get even worse when surgical sponges are accidentally left inside of her.

When a Dad and soldier has been hospitalized for extreme pain, jaundice and fever, doctors finally diagnose him with a very frightening parasite: 'Babesia.'

It doesn’t look like Lizzie is the only person feeling sick around the house. What happens next to her husband, Anthony, has the couple feeling anxious.

After complaining about pain on his head, 8-year-old Andrew is rushed to the ER, where doctors remove a botfly larva from his scalp.

When bacteria gains access to a woman's brain, it causes an abscess to grow that can lead to fatal results.

A woman's life is turned upside down when a mosquito infects her with an incurable virus, leaving her with no option but to wait and see if she lives or dies.

A man suffering from a deadly infection is medevaced to a hospital for emergency surgery to save his life. They discover dead tissue resulting from necrotizing fasciitis, a flesh-eating disease caused by the bacteria Streptococcus.

Xander's condition takes a devastating turn when his skin starts peeling off his body.