(CBS) -- The "brain-eating" amoeba, Naegleria fowleri, found in the tap water of neti pots, is believed by researchers to be the cause of two 2011 deaths.
Normally, people get the infection after swimming in warm freshwater lakes and rivers because the amoeba flourishes in those warm conditions. However, the two victims, a 28-year-old male and 51-year-old woman from Louisiana, had not been around freshwater. The man and woman used tap water in their neti pots.
The victims' home plumbing systems were tested and came back positive for the amoeba, but the city water distribution systems tested negative. Naegleria fowleri was found in the woman's bathroom sink and faucet tub, and it was in a tankless water heater in the man's home.
The investigation was published in August 22 issue of Clinical Infectious Dieseases.
The CDC said that the bacteria causes brain swelling and death. About five days after contracting it, symptoms start and may include headache, fever, nausea or vomiting. Symptoms that can follow are stiff neck, confusion, lack of attention to people and surroundings, loss of balance, seizures and hallucinations.
In 99 percent of cases, death occurs and happens after five days. According to the CDC, only one person out of 123 infected individuals in the U.S. from 1962 to 2011 has survived.
Despite success treating the disease in the laboratory, there was limited to no success treating those infected. However, according to the CDC, the disease is rare and only 32 reported cases have happened between 2002 and 2011. These cases are despite millions of people being exposed to sources of water where the amoeba could survive.
The Food and Drug Administration issued warnings about rinsing sinuses with tap water due to improper neti pot use. If swallowed, stomach acid can kill the amoeba, but it can survive in nasal passages, and this is what makes the neti pot so dangerous.
The pots themselves are usually safe according to Dr. Steven Osborne, a medical officer in the FDA's Center for Devices and Radiological Health. It is the water that goes through them that can be contaminated.
"Most important is the source of water," the FDA said. "Some tap water contains low levels of organism, such as bacteria and protozoa, including amoebas, which may be safe to swallow because stomach acid kills them."
To help prevent infection you can clean the neti pot with distilled or sterile water and make sure it is completely dry.
Using water which has been passed through a filter with an absolute pore size of 1 micron or smaller can help get rid of unwanted organisms. Water can also be boiled for three to five minutes then cooled until lukewarm to help clean the neti pot.