L & R: Trophozoites of N. fowleri in brain tissue, stained with H&E.
Center: Ameboflagellate trophozoite of N. fowleri. Credit: DPDx
Of the many and varied infections reported in North America each year, Naegleria Fowleri is among the rarest, and almost certainly one of the deadliest, that we know of. Sometimes called the `brain eating amoeba’ in the media, this parasite lurks in warm, often stagnant fresh water, and is usually responsible for 2 or 3 infections every summer.
Just last month the CDC held a COCA Call On Naegleria Fowleri & Cryptosporidium for clinicians, with guidance on a new investigational drug called miltefosine, which – for the first time on record - was used to successfully treat a victim of PAM or Primary amebic meningoencephalitis last summer (see MMWR: CDC Imports Investigational Drug For Amoebic Infections).
Although infections usually occur while swimming in warm, freshwater lakes and streams, last year we saw a 4 year-old infected in Louisiana, through contact with the municipal water supply. Subsequently we saw the St. Bernard Parish Water Supply Tests Positive For Naegleria Fowleri, which prompted an increase in chlorination.
Also, in 2011 we saw a new wrinkle when 2 people in Louisiana became infected through the introduction of tap water into their sinuses using a neti pot. These incidents caused the Louisiana Health Department to recommend that people `use distilled, sterile or previously boiled water to make up the irrigation solution’ (see Neti Pots & Naegleria Fowleri).
Photo Credit FDA
The bottom line is that after introduction of this Free Living Amoeba (FLA) into the nasal passages, it makes a direct bee line to the brain, usually with tragic results. Yesterday, the State of Kansas announced the death of a 9 year-old girl (see local media report) from PAM, although the exact route of exposure is uncertain.
July 11, 2014
KDHE Office of Communications
Fatal Primary Amoebic Meningoencephalitis (PAM) Case Reported
TOPEKA, Kan. - Kansas Department of Health and Environment has been notified of a fatal case of primary amoebic meningoencephalitis (PAM) caused by Naegleria fowleri, a free-living amoeba found in freshwater, in a resident of Johnson County. The investigation indicates there were several potential fresh water exposures in Kansas, so the actual source of the infection cannot be determined.
Initial laboratory examination has identified the presence of Naegleria fowleri in a specimen from the patient, and additional laboratory testing by the U.S. Centers for Disease Control and Prevention is pending. This is the second known case of PAM caused by Naegleria fowleri in Kansas. The first case occurred in 2011.
Naegleri fowleri can be found in freshwater environments around the world, but infection causing PAM is extremely rare. From 1962 to 2013, there have been 132 cases reported in the United States, with 34 of those cases occurring from 2004 to 2013. Most cases have occurred in southern-tier states. The risk of infection is very low, but increases during the summer months when water temperatures rise and more people participate in water-related activities. The infection typically occurs when the amoeba enters the body through the nose while the person is swimming underwater or diving and travels to the brain.
“We are very saddened to learn of this unfortunate circumstance, and our thoughts and prayers are with the family and friends during this difficult time,” said Robert Moser, MD, KDHE Secretary and State Health Officer, “It is important for the public to know that infections like these are extremely rare and there are precautions one can take to lower their risk – such as nose plugs.”
Symptoms usually appear about five days after infection, but can range between one and seven days, and include headache, fever, nausea and vomiting, stiff neck, confusion, lack of attention to people and surroundings, loss of balance and bodily control, seizures, and hallucinations. This infection cannot be spread from person to person or contracted from a properly maintained swimming pool.
Though the risk of infection is extremely low, the following precautions might decrease the possibility of infection:
- Hold your nose shut, use nose clips, or keep your head above water when taking part in water-related activities in bodies of warm freshwater.
- Avoid putting your head under the water in hot springs and other untreated thermal waters.
- Avoid water-related activities in warm freshwater during periods of high water temperature.
- Avoid digging in, or stirring up, the sediment while taking part in water-related activities in shallow, warm freshwater areas.
There is no known way to control the occurrence of Naeglaria fowleri in freshwater lakes and rivers.
For more information on healthy swimming visit the CDC website at http://www.cdc.gov/healthyswimming/.
Naegleria infection happen almost anywhere, but in the United States is most common in the warmer southern states. Every year the State of Florida issues warnings to people on how to avoid this rare, but deadly, parasite. Here the Florida Department of Health offers some additional common sense safety advice on how to avoid this parasite.
Photo Credit – Florida DOH