We heard of the second death of a 9-year-old Virginia boy after contracting an infection linked to a water-borne "brain-eating amoeba" (although not a true amoeba, the organism is often referred to as an amoeba for convenience). According to the Centres for Disease Control and Prevention (CDC) a 16-year-old Floridan also died not long after swimming in St. John's River a month ago.
Autopsy results confirmed the cause of death as an inflammation of the brain and its lining. The CDC reports of 32 infections, known as Naegleria fowleri between 2001 and 2010 and several hundred cases worldwide since its discovery in Australia in 19651. The Science Discovery Channel2 identifies Naegleria fowleri as the fifth in the top-ten infectious diseases – amongst Rabies, Ebola, and Polio.
The microscopic organism that's found in freshwater lakes, rivers, and hot springs enters the human body via the nose. From there it travels a short distance of a few inches to the brain where it attacks brain tissue.
Whilst the Naegleria fowleri infection has been reported around the world, most of the cases in the United States have been linked to freshwater sources in the southern states. The amoeba proliferates in stagnant freshwater lakes and ponds during hot weather. Because this is a heat-loving amoeba some have even connected this to global warming – claiming reasonably that as water temperatures go up, we may see an increase of these cases.
Onset symptoms of infection start within 2 weeks after exposure. The initial symptoms include, but are not limited to changes in taste and smell, also headache, fever, nausea, vomiting, and stiff neck. Secondary symptoms include confusion, hallucinations, lack of attention, ataxia, and seizures. After the start of symptoms, the disease progresses rapidly 3 to 7 days, with death occurring from 7 to 14 days.3
1. Fowler M, Carter RF (September 1965). "Acute pyogenic meningitis probably due to Acanthamoeba sp.: a preliminary report". Br Med J 2 (5464): 740–2. PMC 1846173. PMID 5825411.
2. http://science.discovery.com/top-ten/2009/infectious-diseases/infectious-diseases-05.html
3. www.cdc.gov