kaigou: this is what I do, darling (5 bookstack)
[personal profile] kaigou
Watching Jin and there's talk of a cholera epidemic four years before the show (a time-travelling history work) takes place -- that would be the massive cholera outbreak of 1858, apparently. In the show, there's word that cholera has returned and naturally the population of Edo (and the few doctors, especially those trained in Western/Dutch medicine) are panicked about it.

Naturally this prompted another foray into wiki and beyond, into pdfs and google-books history analyses and texts, because hell if I know jack about cholera. It's just not an illness I've run into, or that has ever been a threat, in the part of the world where I live (though it does continue to be a threat in many other parts of the world). I had thought it was a virus, but it's not; it's a bacterium.

Doesn't that mean that if you were exposed to cholera and managed to be one of the one-in-two to one-in-twenty who survived (honestly, a 50% death rate is just unfathomable)... that your body would have developed the antibodies? Wouldn't that mean that epidemics would be separated by generations, because it'd take time before a large enough percentage of the population existed that had not been exposed? So you might have an outbreak four years later, but wouldn't it be substantially smaller due to a large part of the (surviving) population having developed antibodies -- in other words, city-newcomers and young children would be struck, but anyone who'd been around four years earlier might not be affected?

Or do bacteria mutate, such that a return of cholera could actually be a different strain? I know viruses mutate (and that's why they're so difficult to treat and/or inoculate, something to do with having to inoculate against the specific virus and if you're exposed to a different strain, the inoculation does little to nothing)... but I thought the life-cycle of bacteria changes was much slower, comparatively. At least, that's my uneducated reasoning, given how long it's taken bacteria to develop antibiotic-resistance. (I thought viruses develop a resistance much faster, because they change/mutate faster.)

Just curious; hoping someone might know because I'm failing at the google to find any article that answers that specific question.

Incidentally, wiki also notes that in terms of treatment: "Rice-based solutions are preferred to glucose-based ones due to greater efficiency." I wonder who first realized that, and was able to compare the two. I presume someone in Asia, since I doubt a rice-based anything would've been first on the list in Europe, rice not being a major staple of diet for most of European history. At least, that's my guess. Hell if I know, really.

Man, watching historical dramas (from any country) always ends up with me running to wiki to look stuff up, even moreso when it's not my own country's history. Get into time-travel stories and it's even worse, because characters will know or reference something and I'm lost. Although this time, at least, I got that one reference -- when the from-the-now doctor asks a young woman of Edo, "what year is it?" She replies, "the second year of Buncho" (something like that). He draws a complete blank -- he's a doctor, after all, not a historian. He waffles about, trying to figure it out, then lands on a definitive historical landmark: "have the black ships arrived?" Ah, she answers, that was ten years ago. Ahaha, do the math, it's 1862.

The show's full of nice little touches like that, like when the young lady offers to run back and get the medicines she'd missed. The doctor -- with patient at hand, needing attention -- asks how long that'll take. She replies, "a moment." How long, he asks, is a moment? She says, indignant, "a moment is a moment." Frustrated, he finally asks, "how much of the day will pass?" We take "hours" and "minutes" for granted now. It's almost incomprehensible to think of a time in which there's no knowledge of the passage of time, even when we don't have a clock right there on our wrist.

Well, incomprehensible... but not nearly as much as trying to fathom a disease that took out one person in every twenty.

(Incidentally, some of the epidemiology articles I've found suggest that Japan's deathrate was lower due to the Japanese habit of boiling water prior to drinking.)

Date: 3 Apr 2011 03:05 am (UTC)
From: [identity profile] haya5h1.livejournal.com
It's because cholera is a bacteria that the body cannot build up defenses against it. (Antibodies work against viruses, not bacteria.) There might be a factor of mutation involved but as I understand it, the white blood cells simply can't keep up as the bacteria multiply very fast once they take hold in the body. Victims generally die of dehydration due to diarrhea and vomiting. (Lately there've been reports of antibiotic-resistant cholera strains due to rampant misuse of antibiotics here, but that's a whole other story.)

Cholera is common in rural areas (where people get their water from rivers and wells) here, and there are occasional outbreaks in city and town areas especially when there's flooding. Better access to medical services and the increased availability of piped treated water has cut the death rate, but cholera-related deaths do happen in the more inaccessible areas or when people leave it too long without treatment.

Date: 3 Apr 2011 03:12 am (UTC)
nagasvoice: lj default (Default)
From: [personal profile] nagasvoice
Our white blood cells do attack and destroy bacteria, but my impression has been that cholera bacterial divide so quickly (and the initial dosage of them in water may be so high in the first place) that they overwhelm the unresistant body. They also generate a toxin that damages the system independently.

Date: 3 Apr 2011 03:26 am (UTC)
nagasvoice: lj default (Default)
From: [personal profile] nagasvoice
It is. Very much like food poisoning, where the botulinum bacteria is not so much the problem as the chemical toxin it excretes

Date: 3 Apr 2011 03:27 am (UTC)
nagasvoice: lj default (Default)
From: [personal profile] nagasvoice
Yes, there's an editorial in SciAm this month pointing out that stopping the antibiotics there did not reduce productivity. The better management they had to use improved productivity--which says to me we could do a lot better on the management end over here, too.

some cholera info

Date: 3 Apr 2011 03:05 am (UTC)
nagasvoice: lj default (Default)
From: [personal profile] nagasvoice
Bacteria can mutate very rapidly.
I've never heard of anybody developing a resistance to cholera, either--but it has to be if they have a vaccine for it, as noted below.


Just read an article in SciAm discussing how bacteria conjugate and exchange genetic material so they can mutate faster. Something resistant can pass it along to things that aren't even in the same family of germs. This is particular fast and dangerous in the gram negatives, which have a lot of the nasties (due to a second bacterial cell wall granting increased resistance to drugs or one.)
You can d a search on their site for "cholera" and pick up a lot of info.
Here's one.
It has three problems: It does have mutating strains, it creates a very bad chemical toxin in the body, and it hides out in reserves in the environment. It has zero fatalities if you know how to treat it right away, however.

...What are the best ways to keep the disease from spreading to more people? Is it mostly an issue of clean water?
There are different ways of making your water clean. One thing I haven't seen out there so far is consideration of the vaccine, which is available now. It has only been since March this year that the World Health Organization has recommended the use of the cholera vaccine on a wide scale. I think this is a situation where it might be considered.

From the numbers that have come out so far, it seems that there's been a mortality rate of roughly eight percent. Is that a pretty standard number of expected deaths?
Standard mortality should be zero. I've worked in Bangladesh for many years, and in our hospital, we treated thousands of patients, and nobody died of cholera. So no deaths are inevitable if you provide the right treatment.

Nobody's had much experience with it in Haiti, so case mortality rates become very high at first, but as facilities become more experienced and people learn where to get treatment, the case mortality rates should come down very quickly.

Cholera seems like a disease of the past—will it ever be eradicated?
No, because of its environmental reservoir. I don't see any way we could eradicate it like eradicating polio or smallpox. As long as you have an environment, you will have cholera. ..

Edited Date: 3 Apr 2011 03:06 am (UTC)

Re: some cholera info

Date: 3 Apr 2011 03:28 am (UTC)
nagasvoice: lj default (Default)
From: [personal profile] nagasvoice
Yes, that was one of the first and most famous case histories justifying public health epidemiology. Unfortunately I'm blanking on the name of the gentleman who had the bright thought about mapping the outbreaks to pinpoint the source.

Re: some cholera info

Date: 3 Apr 2011 04:06 am (UTC)
nagasvoice: lj default (Default)
From: [personal profile] nagasvoice
Woot!! Awesome, thank you!

Re: some cholera info

Date: 3 Apr 2011 04:29 am (UTC)
mishalak: Mishalak reading a colorful book. (Reading Now)
From: [personal profile] mishalak
The story is fairly cool and was made into a fantastic book called The Ghost Map by Steven Johnson.

Re: some cholera info

Date: 3 Apr 2011 04:37 am (UTC)
tesserae: white poppies in the sun (Default)
From: [personal profile] tesserae
Which is a really excellent book, if you enjoy that sort of thing - really fascinating.

Re: some cholera info

Date: 3 Apr 2011 08:57 am (UTC)
pensnest: bright-eyed baby me (Default)
From: [personal profile] pensnest
It wasn't that the pump handle was the source—the cholera was in the water at that well, but when the handle was removed, people could not draw water out of that well and had to go elsewhere. (I went to a museum last summer which had a display on the London sewage system—quite fascinating—and this was of course the big story there.) Here's a link. As I remember, there were two or three weird outlying cases, one of which turned out to be the mother of someone who worked in the Broad Street area. She thought the water from that pump was better than from elsewhere, so her son used to take her a bottle of it regularly.

Date: 3 Apr 2011 04:36 am (UTC)
tesserae: white poppies in the sun (Default)
From: [personal profile] tesserae
Bacteria mutate rapidly because their lifecycles are so short. This book, Microsm, by Carl Zimmer, is perhaps the best explanation of bacterial genetics in reference to disease I've run across lately (it was widely recced on a variety of well-regarded science blogs, too).

Date: 3 Apr 2011 07:58 am (UTC)
cyphomandra: boats in Auckland Harbour. Blue, blocky, cheerful (boats)
From: [personal profile] cyphomandra
There are at least 150 strains of Vibrio cholerae, and protection against one strain may not carry over to another. In addition, protection can be lost over time. There's a bit of confusion in your comments above - antibodies can be formed to both bacteria and viruses, but may or may not be useful depending on the particular disease. Antibodies against measles stop people getting reinfected. Antibodies against HIV (like measles, a virus) do no good at all against the disease, but can be useful as a marker to tell if someone's infected. Antibodies against bacteria are useful for stopping certain types of pneumonia.

With cholera, people have tried to induce artificial immunity by vaccination for at least 100 years, which is usually a good indication that it's a bad disease. Oral live vaccines probably work best (closest to natural infection), but in early trials about 50% of people got diarrhoea on these. Currently they use killed oral vaccines as the next best, and protection from cholera due to that is about 85% at 6 months in large studies, dropping to 50% at 3 years (this was in Bangladesh). If you take those efficacy figures as a reasonable approximation of what might happen with natural infection, and add in people who escaped infection the first time round, epidemics are going to be a fairly close and present danger.

Date: 3 Apr 2011 09:53 am (UTC)
cyphomandra: boats in Auckland Harbour. Blue, blocky, cheerful (boats)
From: [personal profile] cyphomandra
So basically antibodies can be created by dealing with either virus or bacteria, but in some cases the illness is just so virulent (or adapts/mutates so fast) that existing antibodies do nothing against the next round? Or just in some cases the body's immune system only keeps the record (so to speak) for a certain length of time before expiration? In a very non-scientific way of putting it, granted.

Very basically - the immune system has two main parts to it, innate and adaptive. Innate gets you the same response every time, whereas adaptive learns from what it encounters. Antibodies are part of the adaptive immune system, along with T cells and a bunch of other stuff, all designed to help get rid of that specific infection this time and remember it for next time, so if you do get exposed again the adaptive system kicks in that much faster and more effectively.

Antibodies are the easiest thing to measure after infection/immunisation, but there are a lot of other things going on and, depending on the infection, antibodies may be very important, moderately important, or completely useless. Because it's not the only part, though, you can still be immune. Flu vaccine protection doesn't correlate all that well with antibody levels, for example, and where I live no one checks flu antibody levels after vaccination. Location is important, too - for cholera you really want antibodies that get into the gut wall, not just those in the blood.

There's a Japanese doctor with Western medical training in Kaze Hikaru, actually, and it's fascinating seeing his take on things (and the complete ignorance of the locals about medicine also comes in handy for plot developments...)

Date: 8 Apr 2011 09:09 am (UTC)
cyphomandra: boats in Auckland Harbour. Blue, blocky, cheerful (boats)
From: [personal profile] cyphomandra
Kaze Hikaru - manga (as far as I know!). Tokugawa era Japan, with the tension between the Shogun and the Emperor over opening up Japan. Sei disguises herself as a boy to join the Shinsengumi and seek revenge for her family's deaths. Great characters, interesting and mostly not predictable plot (she does have a crush on the only guy in the troop who knows her real identity; on the other hand, her alibi for having her period is having her own prostitute who she visits monthly), fascinating historical detail, and I am doing all this from memory, so apologies if details inaccurate, but the mangaka does these brilliant research notes about her work, which has obviously become one of those overwhelming passions, and what exactly some small object was in the side of a particular panel. Very good.

Date: 3 Apr 2011 09:28 am (UTC)
From: (Anonymous)
Cholera is an interesting beastie: lives and reproduces in the human gut, secretes a toxin. As I recall, the toxin buggers up the sodium/potassium exchange protein pump in the cells lining the gut wall (I've forgotten the exact mechanism) causing osmotic pressure to drag lots of water into the gut, which gives rise to the characteristic diarrhoea. Death results from dehydration; meanwhile the cholera bacteria have been flushed into the water supply outside the body and may infect other people.

If a cholera patient is systematically rehydrated with isotonic fluid (basically boiled water with the correct proportion of salt and sugar dissolved in it) the infection is self-limiting -- the guts flush themselves clean within 48 hours, and the hydrated patient can recover.

Antibodies, though, imply the bacteria got into the body and the immune system got a chance to recognize it. Which doesn't happen. So you don't develop immunity to cholera.

Date: 4 Apr 2011 06:50 am (UTC)
From: [personal profile] taithe
One aspect that hasn't been mentioned is that the cholera toxin causes the actual diarrhea. The toxicity of cholera bacteria evolved out of horizontal gene transfer -- meaning cholera bacteria evolved to have toxicity genes due to viruses infecting cholera bacteria and leaving behind specific genetic material. (This process of viruses infecting bacteria and accidentally leaving behind genes that become incorporated into bacteria DNA is a common way for bacteria to mutate.)

Whoever said antibodies work against only viruses and not bacteria is dead wrong. Antibodies recognize anything that's foreign to them -- antibodies are adept at recognizing bacteria and killing them through multiple methods. Look up opsonization and complement cascade system if you're interested in the details.

There are cholera vaccines out there -- the one mentioned in my microbio lecture had inactivated (killed) cholera bacteria that would trigger the immune system so that it would remember that bacteria if it encountered it again. This can prevent someone from getting the disease by allowing the immune system to react quickly and effectively against cholera. Antibiotics also help, but the issue of resistance is always in the air.

Doesn't that mean that if you were exposed to cholera and managed to be one of the one-in-two to one-in-twenty who survived (honestly, a 50% death rate is just unfathomable)... that your body would have developed the antibodies?

I'd say yes.

Wouldn't that mean that epidemics would be separated by generations, because it'd take time before a large enough percentage of the population existed that had not been exposed?

No, because I don't think cholera antibodies would be heritable. There are certain antibodies you inherit from your mother (innate immunity), but others you have to develop on your own (adaptive immunity). This would explain why you wouldn't have generational gaps. Even if you're not exposed, your children are still susceptible to cholera. Also someone else mentioned there are numerous cholera strains -- just because your body has antibodies for one doesn't mean you won't get cholera from a different strain.

If I'm repeating anything, I apologize. It's been a long night and I skimmed through the comments before replying.

Date: 4 Apr 2011 08:03 am (UTC)
From: [personal profile] taithe
*smacks forehead* Ah sorry, my bad. You're right, it would be a smaller epidemic if it was the same strain of cholera focused in one region. Frequency of outbreaks in a region would depend on sanitation/water quality among other factors. Here's something interesting I came across just now:

After sifting through historical records of cholera deaths in Bengal, a team of scientists in the United States and Europe proposes a new explanation for these repeated outbreaks, suggesting that immunity to cholera wanes more rapidly than thought and that many more people than believed become infected without exhibiting symptoms.


This means people who survive can still be infected and co-infect others. Even so this hypothesis would only explain why severe outbreaks would become epidemic/pandemic. Like you said, having another severe outbreak in a place that has just recently been already devastated with cholera doesn't really add up. Without intervention, cholera disappears once it doesn't have enough hosts.

(Another article suggests parasitic infections, which are common in poorer nations, would lower your immunity to cholera somehow. If I can use my university's database to find out more information, I'll let you know.)