Don’t go in the water
Well, it’s summertime, and that means that it’s the season for Naegleria. Via CNN, a story about a 12 year old girl in Arkansas who has been fighting an infection due to Naegleria fowlerii, an amoeba that causes a rare form of meningitis. The disease is actually pretty horrific, and has a poor prognosis for the patient, however it is fortunately pretty rare. I dubbed an episode of House as being “bogus” in its last season, due to the writers re-using a diagnosis of Naegleria in the weekly case, completely ignoring the actual incidence and geographic distribution of the disease.
The current patient was taken to the hospital in mid-July, with symptoms of fever and severe headache. Doctors began treating her with prophylactic antibiotics for meningitis, and found the microorganism in a sample of spinal fluid to get the diagnosis of primary amoebic meningoencephalitis (PAM). The patient was then put on antibiotics to directly target the parasite, and her body temperature was dropped several degrees to reduce the swelling in her brain. Her prognosis as of early August is currently good; she has regained consciousness and is responding to commands, and has been discharged from intensive care. This patient represents only the 3rd reported one to have survived infection by Naegleria.
Naegleria fowlerii is not a rare microorganism; it is found fairly frequently in water, and thrives in warm water during the summer. People do not become infected by simply swimming in the water however, and swallowing or drinking contaminated water poses no health risks at all. The infection is typically acquired when the patient jumps into contaminated water, and the microorganism is forced into the nasal cavity. It is then able to migrate from the back of the sinuses into the brain. Symptoms progress rapidly in patients, generally within two weeks of exposure. Fortunately, although the microorganism is relatively common in the environment, disease due to the organism is not with only 128 cases in the United States in the past 50 years. Three of those cases were on the TV show House, over the course of 6 years, in the state of New Jersey. Epidemiologists think that perhaps the difficult route of entry of the organism, coupled with its low virulence potential to begin with contribute to the extremely low infection rate.