Nasal rinsing could lead to deadly amoeba brain infections
The Centers for Disease Control and Prevention (CDC) has issued a new report that highlights a potential danger of nasal rinsing with tap water: amoeba infections of the skin, eyes, lungs or brain. In the report, the agency detailed cases of ten US patients who were infected with a type of amoeba called Acanthamoeba between 1994 and 2022. Nine of the cases occurred in the past decade. All of the patients had rinsed out their nasal passages before falling ill. They did so for various reasons, including to relieve symptoms of chronic sinusitis. The patients experienced a range of health complications as a result of their amoeba infections. Six people developed skin diseases and six experienced a rare nervous system infection called granulomatous amoebic encephalitis (GAE) that affects the brain and spinal cord.
All of the infected patients had weakened immune systems, most commonly because they had cancer and were undergoing treatment. Of the five people who reported what kind of water they had used for nasal rinsing, four said they used tap water and one said they’d used sterile water but submerged their device in tap water. Tap water typically contains small amounts of microbes that are usually killed by the acid in the stomach. However, these microorganisms can survive in the nose and cause infections if they end up in there.
GAE starts with symptoms of confusion, headaches and seizures. Acanthamoeba are found worldwide and live in both soil and bodies of water, including in lakes, rivers and tap water. The findings of the new report serve as a reminder to those who practise nasal rinsing to do so safely. The CDC recommends that anyone who conducts nasal rinsing use boiled, sterile or distilled water. Tap water, for instance, should be boiled for at least one minute to sterilise it, or for three minutes if you are located above 2,000 metres. It should always be cooled before use.
Acanthamoeba can enter the body in numerous ways, including through the eyes, broken skin or the respiratory tract. It is a type of opportunistic pathogen, meaning it doesn’t normally harm healthy people but can seize the opportunity if someone has a weakened immune system or if it can enter the body through damaged tissue. People who are most at risk of infection are those who have had an organ transplant, cancer,
HIV or diabetes. Acanthamoeba are found everywhere, so it is often hard to determine how a person may become infected or to identify ways to prevent infection. As such, with the data they have, the researchers cannot confirm that all ten of the highlighted individuals became infected from unsterile tap water.