(CNN)An unidentified patient in Florida is being treated after being infected with a brain-eating amoeba last week, according to the Florida Department of Health. It is the fourth known case this year of infection by the parasite Naegleria fowleri.

"We believe that the individual contracted the infection after swimming in unsanitary water on a single private property," said Mara Gambineri, the health department's communications director, noting that there is no risk to the general public.

The parasite is almost always deadly. According to the Centers for Disease Control and Prevention, between 1962 and 2015 there were 138 known cases of primary amebic meningoencephalitis, the infection caused by the amoeba, and only three of those patients survived.

Individuals become infected when swimming in warm freshwater, such as a lake or river. The amoeba enters the nose and then goes to the brain, where it destroys brain tissue, causing swelling and death. Symptoms begin between one and nine days after exposure and include headache, fever, nausea and vomiting.

It can be confused with meningitis at first. Then a stiff neck, seizures and hallucinations begin as the infection becomes worse. Those infected die between one and 18 days after symptoms begin.An anti-parasitic drug called miltefosine (sold as Impavido) has been used to treat patients and even, in two cases in 2013, saved victims' lives.In March, the drug was approved for the treatment of another parasitic infection called leishmaniasis. Now, the drug company, Profounda Inc., can provide it for other uses (called off-label use), including treatment of primary amebic meningoencephalitis.

Previously, the drug was considered investigational for all purposes and could be obtained only from the CDC. Now, Orlando-based Profounda can provide the medication directly to hospitals, although the CDC said it still helps coordinate in these instances.

Profounda CEO Todd MacLaughlan said he is optimistic about the survival and recovery of the patient in Florida, although he could not give details, citing patient privacy.

He was contacted by a pharmacist at the hospital where the patient is being treated after a physician identified the possibility that the person was infected with Naegleria fowleri. MacLaughlan was able to get the treatment to the hospital in less than 30 minutes so treatment could begin even before testing confirmed the presence of the amoeba.

"This is the most optimistic, cautiously optimistic, I've been so far as compared to other cases because of how fast [the patient was] diagnosed and how quickly treated in combination with other drugs," he said.The protocol for treating patients is based on the case of Arkansas teen Kali Hardig, who survived primary amebic meningoencephalitis in 2013. She was 12 at the time and infected while swimming at a water park.

After nearly seven weeks in the hospital, she was home by the time that dreadful summer was over and returned to school in the fall. Doctors attributed her recovery to the speed with which she was diagnosed and treated: According to the CDC, she was diagnosed 30 hours after her symptoms began, and treatment began within 36 hours.

That treatment began with an induced coma and lowering of body temperature, MacLaughlan said, while they were waiting for the drug to arrive.

Miltefosine is an oral medication given two to three times a day for 28 days. It's given via feeding tube to patients who cannot swallow the drug independently. The antifungal drug amphotericin and steroids are also given, along with other supportive care.

MacLaughlan said it's not known whether, or how much, the other drugs help, but because they were used to treat Hardig, this is what is practiced.

Most patients don't make it beyond 12 or 13 days, he said. "The idea is to maintain the coma and raise the body temperature once you are sure the amoeba is gone."

Also in 2013, an 8-year-old boy in Texas who was treated with miltefosine survived, although he suffered brain damage. That outcome was believed to be due to the fact that he was not treated until "several days after his symptoms began" and his body temperature was not lowered, according to the CDC.

The only other known survivor in the United States, who was not treated with miltefosine, was a patient in California in 1978.

Miltefosine costs $16,000 per pack, and each patient usually needs two or three packs, according to MacLaughlan. Amphoterin can cost as much as $60,000.The statistics are grim. There have been three other cases of Naegleria fowleri infection this year, all of them fatal. Miltefosine was requested for each of them, according to the CDC.

On August 5, CNN affiliate WCSC reported the death of 11-year-old Hannah Katherine Collins, who had become infected with the parasite while swimming a river in her home state of South Carolina. MacLaughlan provided the drug, but she did not survive. No other details were available.In June, an 18-year-old Ohio woman died after becoming infected while visiting a water park in North Carolina.

This summer, the Texas Department of State Health Services confirmed the death of a teen from Harris County. CNN affiliate KPRC identified him as Hudson Adams. He was working as a lifeguard at a summer camp with a lake, which is where he was probably infected.

According to the CDC, there are typically up to eight cases per year, so the four cases this year are considered average.Even though it's rare, officials offer some recommendations to reduce the risk of becoming infected, especially during the warm summer months. These include limiting the amount of water entering the nose when jumping into rivers or lakes, by holding the nose or wearing a nose plug, or keeping your head above the water. When in the water, don't stir up sediment from the bottom in shallow areas.

Education is also crucial. MacLaughlan said more can be done to prepare and raise awareness among emergency room physicians so they will consider the possibility of primary amebic meningoencephalitis and ask about exposure to fresh water in patients who exhibit suspicious symptoms.