Two people in Louisiana died in 2011 from a rare brain infection contracted after using neti pots containing tap water to flush their sinuses.
The infection, known as primary amebic meningoencephalitis, occurs after water containing the amoeba Naegleria fowleri enters the nose and travels through the olfactory nerve into the brain.
This is the first time tap water and neti pots have been connected to infection with N. fowleri, according to a report appearing online in Clinical Infectious Diseases.
Neti pots are small vessels that are filled with water and saline solution and used to flush the sinuses.
Although the infection is extremely rare, it is almost uniformly fatal, said Ann Falsey, MD, a professor of medicine at the University of Rochester Medical Center, who was not involved with the study.
According to Jonathan Yoder, MPH, lead author of the paper, 123 cases have been reported since 1962, the year it was discovered. Yoder is coordinator of waterborne diseases and outbreak surveillance at the US Centers for Disease Control and Prevention.
N fowleri is generally found in warmish freshwater ponds, lakes and rivers and can be contracted by swimming, fishing, boating, diving or tubing in such bodies of water.
The first patient to succumb to the infection via a neti pot was a 28-year-old man from southern Louisiana who developed a severe headache along with neck stiffness, back pain and vomiting in June 2011. The next day he arrived at a New Orleans hospital disoriented, confused and combative.
He received a tentative diagnosis of amebic meningoencephalitis, was treated immediately with a combination of drugs but unfortunately died in the neurologic critical care unit.
The man lived with his mother, who reported that he had not been near any freshwater recently but that he did irrigate his sinuses daily with a neti pot. She said he added a commercially sold salt packet to tap water.
A similar case occurred three months later involving a 51-year-old woman in northern Louisiana.
The woman was admitted to a hospital in September 2011 with nausea, vomiting, neck stiffness and altered mental status."
She died in October 2011 and an autopsy revealed amebic meningoencephalitis.
Again, the woman's parents reported that their daughter had had no freshwater exposure in the past two weeks but also regularly used a neti pot.
In both cases, N. fowleri was found in the tap water of the individuals' homes.
Although N. fowleri cannot survive in salt water, the saline solutions used in these neti pots were unable to kill the organisms.
Did You Know? Infections Cause One in Six Cancer Cases Worldwide
Many infections are preventable or treatable. Human papillomavirus can lead to cervical cancer and is preventable through vaccine. Hepatitis affects the liver, leading to inflammation and scarring, which can cause cancer. Hepatitis treatments are available. Helicobacter pylori bacteria can lead to gastric cancer, but the infection can be treated with an antibiotic cocktail.
New Test Quickly Identifies Bacterial Infections
The FDA recently approved a blood test that can identify 12 different types of bacterial infection, such as Staphylococcus, Streptococcus and Listeria, in a few hours after a positive blood culture (instead of the standard two to four days). Results from the new test, called the Verigene Gram-positive Blood Culture (BC-GP) nucleic acid test, were compared with those from traditional tests in 1,642 blood culture samples. Results from the BC-GP test were as accurate as those from the traditional tests. Faster identification of the type of bacteria causing an infection may allow for more effective treatment.
Officials don't know why these two cases occurred in Louisiana, but there is some evidence that N. fowleri may be expanding its reach, particularly into northern areas, which are experiencing warmer weather. A case of primary amebic meningoencephalitis was reported for the first time in Minnesota in 2010 and also in Kansas in 2011.
What Neti-Pot Users Can Do
Despite the severity of the infection, "very simple measures could prevent it," Dr. Falsey said.
Yoder recommended using boiled or filtered water when preparing to use a neti pot.
"Even though tap water is safe...for drinking, showering and bathing, it's certainly not sterile water and we don't think it's appropriate for something like nasal irrigation," he said.
And there are other reasons not to use tap water for nasal irrigation, including the presence of E. coli and the bacteria legionella, Dr. Falsey said.