The Amoeba That Eats Human Intestines, Cell By Cell

sciencehabit (1205606) writes "Entamoeba histolytica is a tiny pathogen that takes a terrible toll. The single-celled parasite—an amoeba about a tenth the size of a dust mite—infects 50 million people worldwide and kills as many as 100,000 each year. Now, a new report reveals how the microbe does its deadly damage: by eating cells alive, piece by piece. The finding offers a potential target for new drugs to treat E. histolytica infections, and it transforms researchers' understanding of how the parasite works."

Comments

infects 50 million, eh?

[Cthefuture]

Infects 50 million and kills 100000... I'll take those odds. Better than driving to work for a year.

Re:infects 50 million, eh?

[fuzzyfuzzyfungus]

The major nuisance with those odds (even if the nonkilled are all aymptomatic, rather than variously sickened) is that it means the organism can remain in the population basically forever, with an ample supply of carriers, barring develpment of some persistent eradication mechanism so effective and safe that it can ethically be mass-applied as a largely preventative measure(as, for instance, with the polio vaccine, where the safety and efficacy are good enough, and the duration of effect long enough, that you can just blanket entire areas with vaccination campaigns until the organism disappears from the population).

Re:infects 50 million, eh?

[hawkeyeMI]

I'm guessing you haven't had amoebic dysentery. It saps all your energy and makes you poop blood. I'll take driving to work, thank you.

Re:infects 50 million, eh?

[Anonymous Coward]

Kills 100,000 *per year.* So, each year it kills 1 in 500 people that have it. That's very roughly a mortality rate of over 10% (rough math: of 500 people that have it now, approximately 50 of them will be dead from this after 50 years, and approximately 400 of them will be dead from other causes (with about 50 still alive)).

Much less than 10% of the people who decide to drive to work during the course of their lifetimes are killed by driving to work.

In the US in 1972, there were about 200 million people, and about 50 thousand of them died in traffic fatalities (about 2.5% of all US deaths that year). This was the worst year for traffic fatalities by volume and the eighth worst by percent. Let's say that roughly one quarter of the people in the US at the time displayed the symptoms of "driving to work" that year. Even if we presume that all of the traffic fatalities that occurred that year were due to driving to work, that's still a mortality of half of this mortality rate. We would need to suggest that only 1/8 of the population of the US drove to work that year to get to the same mortality rate as this pathogen.

And that's the worst year for traffic fatalities in US history. Since then, our population has increased 50%, and traffic fatalities have decreased 40%. And once again, this is all using a worst case scenario of every traffic fatality being caused by driving to work, rather than driving for any other reason.

So no, having this pathogen is *not* better than driving to work...these are not odds you would take.

Re:infects 50 million, eh?

[Anonymous Coward]

I had this (stayed in some slums in tropical areas where the water supply comes from a deep-well 5 meters down, meanwhile the toilet buries the shit in sand 2 meters down. . . so shit has 3 meters to turn back into water. . . usually this works surprisingly well!).

Anyway, treated it goes away fairly quickly, even with the current non-specific medicines (though these are powerful antibiotics and will wipe out *all* of the good stuff with the bad. . . this can have serious consequences for some).

Untreated, you're in for a year of fever and shitting blood before you'll eventually clear it (maybe staying a carrier) and develop immunity.

Re:treatment

[fuzzyfuzzyfungus]

I'm not a tropical medicine expert or anything (and even if I claimed to be, would you trust a guy who impersonates an opinionated fungus on the internet recreationally?); but according to Our Wiki Overlords, corroborated by assorted googling, the current treatements of choice appear to be a number of antiprotozoal drugs found to work against this organism; but nothing particularly specific to it, and definitely nothing that targets the specific genetic and chemical pathways the ameoba exploits to achieve the 'nibbling' attack. Again, nonexpert here; but the use of a grab-bag of nonspecifics suggest that it hasn't (yet) done anything brutally clever in terms of drug resistance; but that existing understanding of the organism probably hadn't provided any really elegant attacks against this organism in particular, leaving 'probably best to use stuff that works on protozoa, since it is one.' as the standard.

The researchers did experimentally disrupt this process(once with a drug, in a second case with a genetically crippled ameoba strain) as part of demonstrating that the 'nibbling' was the mechanism behind human cell death(which can apparently cause some ghastly intestinal trouble), so presumably there is some hope that we'll be able to weaponize the mode of attack they used, and get an elegant, selective, unlikely-to-interfere-with-other-eukaryotes-like-the-patient, drug that will prevent the horrible-death-by-intestinal-nibbling; but nothing in pill form just yet, certainly not that you could just go shoving into patients without killing some little fuzzy animals first.

(Also, if Malaria is anything to go by, the statistical answer to 'how do you treat it?' is 'On average, you don't. Protozoa are tough motherfuckers and it mostly just kills poor people in ghastly countries anyway. Let's go find a cure for hair loss and midlife limp-dick syndrome...')

Re:treatment

[Anonymous Coward]

They had a show on tv called 'Monsters Inside Me' the show is about parasites that invade the human body. They also show how doctors seem to fail, or use their educated minds keep the diagnosis simple. They also show or describe the treatment.. And it is what you'd expect just use antibiotics, or antiprotozoal drugs.
Sarcasm, what could possible go wrong with that? History tells us something but we continue to go ahead with using those drugs.

Something that should be universal in health care are running tests for parasites, I really wonder how many people are being forced to go thru terrible treatments for something like cancer, or pick another illness, when it was a parasite, another failure of the medical system. Parasites have been around as long if not longer then the flu, and yet there isn't a mandatory test. Whether it is a check up or an emergency.

Re:treatment

[Luckyo]

The normal approach to parasitic treatment is to give patient drugs that are highly toxic to the parasite and much less so to the host.

Re:treatment

[gregor-e]

We should develop a drug that gives them a liking for the taste of their own kind while disliking the taste of humans. Maybe call it ouroborosin?

What's eating you?

[MindPrison]

Ah, perfect - now I have an answer for that annoying question people sometimes ask me:

What's eating you?

E. histolytica!

Re:treatment

[khallow]

(Also, if Malaria is anything to go by, the statistical answer to 'how do you treat it?' is 'On average, you don't.

The statistical answer is drain the swamps, kill the mosquitoes, and malaria goes away. There's a reason malaria no longer has a presence in the developed world and it's not because nobody cared about it.

Re:treatment

[treeves]

But isn't "draining the swamps" now called "wetlands destruction", so people don't want to do it?

not anymore

[dutchwhizzman]

Malaria and dengue are on the rise again. Humans have created so many opportunities in their own landfills and housing (a single old car tire is enough) that these mosquitoes dont go away if you drain a swamp. We are also rather good at helping these animals spread, since every continent not Antarctica now has both species carrying the disease roaming in the wild because we let them ride along with our goods. As far as killing them goes, they have proven to be able to mutate such that common `environmentally friendly pesticides no longer work and we have to resort to really nasty stuff to sufficiently kill an outbreak. So, statistically, you dont treat malaria or dengue but you try to avoid it, contain the spread and fight the symptoms if you happen to get ill from it.

Eating fat

[Tekoneiric]

Why is there never a parasite that eats unwanted fat and sugars then poops useful enzymes and vitamins into it's host's body?

Re:treatment

[Opportunist]

Well, parasites have become the zebras of today's medical zoo. While it was very common in the good ol' days of yore when it was pretty much a given that you'd have some sort of parasites in you (quite literally to the point where it was a surefire way to tell that something's wrong with you if you did NOT have the "normal" collection of parasites in you), parasites have become something rather rare in our highly sterilized world with through screening of food and other stuff that we put on or into us. Hell, even eating sushi in areas that are days away from any coast is not the food equivalent of playing Russian Roulette.

It is simply far more likely that you have some kind of bacterial disease or even cancer rather than some odd parasite.

Re:Wonder what's worse?

[Opportunist]

That's like asking what's worse, Parkinson or Alzheimer. Does it really matter whether you spill your beer or whether you forgot where you put it?