ORLANDO , Florida ( CNN ) -- Something in the lakes around Orlando , Florida , has claimed the lives of three boys this summer . Will Sellars ' family says he died after being exposed to a deadly amoeba on a Florida lake . `` This thing is just there . It 's lurking like some deadly thing in the water which can take our children 's lives and we all have to be aware , '' said Orange County Health Department Director Dr. Kevin Sherin . The `` thing '' is n't a fish or alligator . It is so small it can not be seen with the naked eye . The killer that lives in the hot , fresh water is a single cell amoeba that once exposed to the human brain through the nasal passages is almost always fatal . At first people exposed to the amoeba , naegleria fowleri , suffer from flu-like symptoms . Very quickly , in from one to 14 days , the symptoms worsen , Sherin said . `` There 's a downhill course . Folks lapse into a coma ; there are abnormal movements of the eyes and a terrible cascade of events leading to the actual death of parts of the brain . '' Sherin said exposure to the amoeba can be detected by an MRI and it can be treated with antibiotics if caught early enough , but Sherin said he believes medical personnel are not in the habit of looking for the disease . That is because the amoeba is very rare . The Centers for Disease Control in Atlanta , Georgia , has documented 24 cases in the United States since 1989 . Health officials do not know what caused three cases in Orlando in one summer . Theories range from warmer temperatures to a drought that has lowered lake levels . Sherin said officials considered closing access to the lakes , but concluded they did not have the authority . Even if public lakes had been closed , private lakes would have remained open . So , at 15 parks and lakes around the city , warnings about the amoeba have been posted . The signs urge bathers to wear nose clips or stay out of water warmer than 80 degrees Fahrenheit , which can be a breeding ground for the amoeba . The warnings provide little solace for Steve Sellars . Health investigators said they believe Sellars ' 11-year old son , Will , was exposed to the amoeba during an August weekend spent learning to wakeboard on Orlando 's Lake Jessamine . `` You think it wo n't happen to me , it wo n't happen to my family . '' Sellars said . `` You 're wrong '' `` [ Will 's ] symptoms were like a flu bug , '' Sellars said , `` We rushed him to the hospital and two days later he 's passed away . It 's like a nightmare . '' A month later , a 10-year-old boy died from exposure to the amoeba . Investigators have not determined where he was exposed . The death of a 14 year-old boy in June in the Orlando area also is being blamed on the amoeba . As he investigates the deaths of the three boys from the amoeba , Sherin is concerned these type of deaths may be underreported . Health departments in Florida are not required to report amoeba infections to the state . The illness is so rare , he said , it may be commonly misdiagnosed in the United States and internationally . He said anyone who exhibits flu-like symptoms who has been in a lake recently should see a doctor immediately . Speaking in Will 's old bedroom , which Steve Sellars has decorated with photographs of his son , Sellars said he hopes he can help get the word out . He does not want anyone to lose a family member as quickly and mysteriously as he did . `` It 's the worst thing we ever had to go through and I hate to see any other parent go through this and another child lose his life , '' Sellars said . E-mail to a friend .
3 boys die from deadly amoeba in Orlando-area lakes this summer . Bathers warned to stay out of water warmer than 80 degrees Fahrenheit . Comment: