CARTER COUNTY, Okla. - A local family is sending out a warning before you head out to the lake.
That's after their daughter was killed by a brain-eating amoeba after a day at Lake Murray.
Since 1962, only 4 people have survived the effects of Naegleria fowleri.
News 4 first reported this story three years ago, but since then, the family has worked hard to prevent this from happening to anyone else.
Mike and Alonie McKown still get emotional talking about their daughter Elizabeth Knight.
"I miss her terribly," Alonie said.
The 24-year-old's health - declined rapidly a day after visiting Lake Murray.
"Developed severe headaches, migraines," Mike recalled.
Knight was treated and released at the local ER for what doctors thought were migraines.
The next day, things went from bad to worse.
"She had difficulty walking, talking, increased headache that had gotten a lot worse," Mike said. "Fever, nausea vomiting."
Knight went back to the ER where she was diagnosed with bacterial meningitis - a second misdiagnosis.
She didn't respond to treatment and was put on a ventilator the next day. It wasn't until then was there any mention of exposure to freshwater or a deadly amoeba.
"It was too late," Alonie said. "She had no brain activity."
The young mother - leaving behind two very young children.
"Kameron actually has a picture of his mom that he carries around the house and he puts it up to eat cereal with him, to watch cartoons," Alonie said. "I see so much of Elizabeth in both of them. It puts a smile on my face, but it also breaks my heart."
In the days following Knight's death, her family has worked with other amoeba victims' families on a nation-wide effort to raise awareness about this vicious, and little-known danger lurking in fresh water.
"It's 98-99% fatal, but it's 100% preventable if you take the necessary precautions," Mike said.
According to the CDC, this amoeba is prevalent in warm bodies of fresh water. They encourage swimmers to use nose clips.
"It actually works its way up through your nasal cavity to your brain and starts to deteriorate the brain tissue," Alonie said.
In the last few years, there's been a medication approved to help treat the disease, but in order for it to work, you still have to be diagnosed early.
The McKowns also are pushing to make checking for the Naegleria fowleri amoeba a mandatory report in hospitals and educate doctors about it - because the McKowns - themselves - are in the medical field and had never heard about this until it happened to their daughter.
"We just don't want other families to have to learn what it's like to live without her child," Mike said.
Just because you visit a chlorinated pool or water park that doesn't mean you're in the clear.
The CDC encourages you to check the pH levels and never let water get up your nose.
Knight's family has set up a website with all the information you need to know.