Attack of the killer amoebae

In another case of TV shows being prescient, abuzz here at other Scienceblogs is this story, which sounds like a bad B movie: ” 6 die from brain-eating amoeba in lakes.” The amoeba in question is a species of naegleria, which was featured on the medical drama House last year. According to the article:

Beach said people become infected when they wade through shallow water and stir up the bottom. If someone allows water to shoot up the nose — say, by doing a somersault in chest-deep water — the amoeba can latch onto the olfactory nerve.

The amoeba destroys tissue as it makes its way up into the brain, where it continues the damage, “basically feeding on the brain cells,” Beach said.

People who are infected tend to complain of a stiff neck, headaches and fevers. In the later stages, they’ll show signs of brain damage such as hallucinations and behavioral changes, he said.

Once infected, most people have little chance of survival. Some drugs have stopped the amoeba in lab experiments, but people who have been attacked rarely survive, Beach said.

“Usually, from initial exposure it’s fatal within two weeks,” he said.

More after the jump…

On House, he co-infected the patient with Legionella pneumophila, the bacterium that causes Legionairre’s disease. Legionella is an environmental bacterium, and in nature it frequently infects amoebae and lives within these protozoa–so on TV, this worked to end the amoeba infection and cure the patient slow down the infection. Real life, unfortunately, isn’t nearly as pretty, and there have been a spike in Naegleria infections this year (6 deaths in the U.S. so far, compared to 23 total in the period from 1995 to 2004). And unlike on TV dramas, there’s no known cure.

Though an increase has been noted, this doesn’t necessarily mean there’s anything to fear. However, the unknown is often scary, and a problem with this organism is that we don’t currently test for it. In areas where cases have been identified, they’ve cautioned locals to avoid “warm, standing water and areas with algae blooms,” since these are conditions in which the heat-loving amoebae thrive. Officials also suggest using nose clips, to prevent the organism from entering the nose while swimming and splashing around.

Or, it could just be that vaccines cause these infections as well –scientific evidence be damned.

Comments

  1. #1 Dennis
    September 29, 2007

    Tara,

    I’m sorry, I’m just not buying into your nonsense. If it’s REALLY magic little bugs causing disease, and not your cherished vaccines, then explain polio – and smallpox! These diseases used to be positively common, and now… er…

    Okay. Try this on: only dummies think that disease is anything but a curse from God. Are you a dummy?

  2. #2 Paul Orwin
    September 29, 2007

    Tara,
    I read that article this morning, but I had forgotten the legionella angle. One thing I wonder about is whether or not the bacteria are actually pathogenic to the amoeba? I know that some of these intracellular pathogen/protozoan interactions are stable, and have been suggested as potential environmental reservoirs. Although the process of entering the cell is similar, and the same genes are involved in amoeba invasion, I wonder what the true relationship between amoeba and bacterium is. Still, neat stuff, as usual.

  3. #3 Jane
    September 29, 2007

    Just a nit-picky point, but on House, the Legionella slowed down the infection but did not cure it.

  4. #4 noreen
    September 30, 2007

    Tara, Anthony Fauci on the new this morning stated that in 2007, only 6 cases have occured around the world. Should we hit the panic button again as we have done for the swine flu, the bird flu, etc. Once again, the news media is largely to blame for all of this hype, overall much to do about nothing. Heck, one would have better odds to win the lottery than to be in contact with this amobea.

  5. #5 Dale
    September 30, 2007

    noreen writes Should we hit the panic button again as we have done for the swine flu, the bird flu, etc. Once again, the news media is largely to blame for all of this hype, overall much to do about nothing. Heck, one would have better odds to win the lottery than to be in contact with this amobea.

    Of course no one should hit the panic button. But hype makes people aware of ways of avoiding evan a potential problem with some pretty simple solutions i.e. avoid warm standing water and large algae blooms (who would want to swim in a large algae bloom anyway?) and wear nose plugs while swimming.

  6. #6 Tara C. Smith
    September 30, 2007

    noreen,

    I think you mean 6 cases in the US? As stated in the article, there have been three in Florida, two in Texas and one in Arizona this year alone, and worldwide, it’s caused several hundred deaths since its discovery. You can call it “hype” if you want, but besides the B-movie-sounding headline, as Dale notes, it’s a problem that has a simple solution for prevention, so why not make parents aware of it? I’m sure the parents of the 6 kids who died wish they knew then what they know now regarding swimming in these types of waters.

  7. #7 Tara C. Smith
    September 30, 2007

    Oh, and thanks, Jane. I’ll change that.

  8. #8 cooler
    September 30, 2007

    fauci caused genocide when he ignored the army’s scientist shyh ching lo’s md phd mycoplasma incogitus, found in many aids/cfs cases by pcr (monkeys inoculated died with only a weak antibody response when near death, cant test for it that way), a microbe that killed every animal injected, lo determined it to be the cause of death in 6 hiv negative patients who died of mysterious a flu like illness. Who cares about 6 ameoba deaths? Fauci is a murdering fraud that cant be trusted to protect the nations health.

    For all the peer reveiwed refrences on this, check the end of the other thread “lonliness causes AIDS” I just blew franklin away, hes a
    bonafide scientist and I rocked his world lol in our debate.

    Project day lily google it to find out how it was part of the bioweapons program, its a true story slightly fictionilized to stay out of court. And I have all the peer reviewed referneces on the other thread, sad how Fauci unleashed an epidemic of mycoplasma incgonitus/penetrans and you guys get all worked up over 6 ameoba deaths, not that we shouldnt, but Fauci is a hack,put things in the proper persective.

  9. #9 noreen
    September 30, 2007

    Cooler is right, where is the outcry about mycoplasma, especially the manmade ones, some of which are stored away at the biological center in Maryland? Mycoplasma have been linked to chronic fatiuge, Gulf War Syndrome, AIDS and fibromyalgia to name a few. It would certainly seem to have more detrimental health effects to the individual than HIV.

  10. #10 Torbjörn Larsson, OM
    September 30, 2007

    Infectious diseases is an area where ignorance thrives. I first heard about such amoebas from Australia, IIRC they have 3-4 species making cases in the southern areas. Then it was cases in fresh water in Thailand you should take care around. Finally, when I check, these buggers are most everywhere. :-(

    Sigh. I guess you get comfortable when you grow up in a cold climate without too many pests or poisonous animals or plants. The worst I had was an unidentified little parasite that never made it below the skin but died after leaving a few cm long air filled white strip, quickly grown away. The hospital blamed the immigrated Canada goose population around the lake where I picked it up – I wasn’t the only case with an uninvited guest that summer.

  11. #11 Torbjörn Larsson, OM
    September 30, 2007

    “an unidentified little parasite” – um, technically the hospital thought it was a parasite on the birds. On me, it was a nuisance.

  12. #12 Kausik Datta
    September 30, 2007

    Amoebas are not just innocuous unicellular organisms. They have been implicated in dysentry and liver abscess (Entamoeba), meningo-encephalitis (Naegleria), keratitis and uveitis (Acanthamoeba), and various diseases of aquatic animals. Beyond the tropical countries like India, Mexico, Central and South America, where these are endemic, much of the developed world remains largely unaware of the potential risks of amoebic diseases. Therefore, by spreading word about them, health-bodies like CDC and the NIH can help clinicians maintain a high index of suspicion, to specifically look for an amoebic etiology.

    Acanthamoeba castellani, on the other hand, has a valuable research function. Organisms which invade macrophages and replicate intracellularly can also invade A. Castellani using same mechanisms, and therefore, can be studied mechanistically.

  13. #13 Justin Moretti
    September 30, 2007

    “Don’t get water up your nose” was a slogan when I was a kid, well over twenty five years ago and pushing thirty years ago. The reason then was given as amoebic meningitis. This sounds more like necrotizing amoebic encephalitis, but the end result is much the same.

    The media campaign simply stated that some kids had caught something godawful and died, and this was how to take reasonable steps to avoid it. A model for today, if only people could remember!

  14. #14 Jorge Gajardo Rojas
    October 1, 2007

    Kausik Datta posted that ameba of this kind is endemnic also in South America.My question is if naegleria is include and in what countries?

  15. #15 AK
    October 1, 2007

    Swimming Amoeba and genetic diversity.

    I suspect the reason this species can infect the CNS in ways other infectious amoebae can’t is that it has a swimming phase. This allow much more mobility in the open areas than the purely amoebic forms of the immune cells fighting it.

    As for the rarity of infection, could it be that successful infection requires enough diversity that it can out-evolve the immune system?

  16. #16 sex shop
    December 22, 2007

    Mycoplasma have been linked to chronic fatiuge, Gulf War Syndrome, AIDS and fibromyalgia to name a few. It would certainly seem to have more detrimental health effects to the individual than HIV.