"The pathologist was able to look at it under a microscope and see the characteristic, actually the amoeba, in the tissue", said Dr. Charles Cobbs, Swedish Neuroscience Institute. The publication doesn't identify the victim.
Despite the surgeons' best efforts, the woman died a month later.
Amoebic brain infections are more common in warmer waters in the South, but might become more common in northern states thanks to global warming, experts say. It can only grow on mammalian cells and other amoebas, the report said. Although extremely rare, B. mandrillari is deadly, with nearly 90 percent of cases of infection resulting in death.
The specific amoeba that killed the Seattle woman moves slowly, which is why it went undetected for a year.
In order to prevent any risk of infection, people should always read the instructions on a neti pot and only use saline or sterile water.
The woman's doctors say they think her death was ultimately tied to her use of the Neti pot.
Kristen Maki, a spokeswoman for the Washington State Department of Health, said in an email that "Large municipal water supplies. have robust source water protection programs" and treatment programs, and she noted that "Well protected groundwater supplies are logically expected to be free of any such large amoeba" such as Balamuthia.
Normally, an extra effort is required to bring on an infection; it can not be contracted by drinking contaminated water.
Eventually she reportedly developed a rash on her nose and raw skin near her nostrils, which was misdiagnosed as rosacea, a skin condition.
"It's so exceedingly rare that I'd never heard of it", Cobbs said. At first doctors thought the woman had a tumor, as she had been previously diagnosed with breast cancer.
The woman's infection is the first to be linked to improper nasal lavage, according to Piper. The woman turned out to have an infection with a "brain-eating" amoeba called Balamuthia mandrillaris.
But they would soon learn that what was inside the woman's skull was not a tumor at all. The other slow-acting amoeba is called Acanthamoeba spp.