The Mathematics of Ebola Trigger Stark Warnings - <AUTHOR> http://www.wired.com/2014/09/r0-ebola/ <comment><USER4> Going 'meta' for a moment, this is a tragedy of huge proportions, the question I have been considering is whether or not it is even _possible_ to avoid?

Updates from MSF which highlight the level of mistrust and superstition amongst the infected population, where people hide their sick relatives from isolation wards and take them back to their village. We cannot exactly put a giant fence around the place (and not that this would be a reasonable goal anyway).

Do we invade these countries and force our will on them in order to prevent a humanitarian tragedy? What gives us that right? What gives anyone that right? To someone who is not sick, forcing them from their village, for forcing them to stay in their village violates their basic human rights, and yet it is for their own good, but if they don't believe that, what moral authority allows us to overrule that belief?

As you can see I struggle with the challenge of imposing a solution on these people, knowing that without aggressive actions tens of thousands, perhaps hundreds of thousands of them will die. While explaining to someone who doesn't understand the virus, or the danger, who undergoes forced relocation to a quarantine camp and is never sick during the outbreak, that they were in very real danger from this thing they do not believe in.

<comment><USER5> The American perspective is to solve every problem with the military or money. We believe that violence and more money are the only effective solutions to every single problem the world faces. Original thinking just doesn't happen.

A creative solution would be to temporarily halt all regulations on anti-ebola drug development and let them experiment on any willing person in Liberia who wishes to receive treatment. The example of Banting and Best in the 20s is a great example of the enormous progress that can be accomplished if there is no regulation on medicine. These guys came up with the idea for extracting insulin from animals and injecting it into humans. They tested it out on willing patients, the first being a 14 year old, released the invention for use by the public and won the Nobel prize in the span of 3 years (1921-1923). That speed of drug development and testing is impossible today.

A good analogy of the present situation would be this. Someone is drowning in the river. You can use the military to prevent him from knocking any nearby bathers into the river as he floats down stream but don't you dare throw him something handy like a branch or a quickly improvised flotation device because that might help him float and it may not work and there would be lawsuits or regulatory violations! You can pay someone to swim after him and try and save him, but the stream is really rushing fast and they might drown too, but that's seemingly a-ok.

<comment><USER6> And who pays for the, potentially unbounded fallout from that decision ?

Let's say this happens : [http://en.wikipedia.org/wiki/Thalidomide](http://en.wikipedia.org/wiki/Thalidomide)

(First read about the advantages of the drug, then move to the crises. in particular the birth defects crisis)

And please don't just say that people knowingly took the risk, read the article first to see how that played out.

People won't accept the consequences of decisions made under duress (and this decision would be "death or we experiment on you". Decision to be made in an isolation camp, guarded by soldiers with guns), for obvious reasons, and this has been an accepted legal principle since a millenium before Jesus was born. You're suggesting just canceling it ? Really ?

What you're suggesting is a really, really, really, really bad idea.

<comment><USER7> Why? When you are going to die you should have the choice to go on a treatment which is untested. That's what people with AlS have been asking for YEARS and still cannot get because they have to follow the usual regulatory process.Cancer patients can get drugs as soon as Phase I, I don't see why we don't allow other patients who are in critical condition to try whatever is new out there. What do you have to lose?

<comment><USER8> The death rate from the current ebola is approximately 50%. While that sucks, what patients have to lose is both a 50% chance of living and their right not to be a playground for medical experimentation.

edit: and just who vets the people/companies who get to offer drugs to desperately ill people? Does anybody with $1k to buy needles get to make a sign and advertise curative injections? I'm sure glibertarian idiots will say it was a freely made choice, but choices made while infected with ebola (or even scared of being so infected) aren't freely taken, not to mention the asymmetric information.

<comment><USER9> _glibertarian idiots_

Please avoid making personal attacks like this on HN.

As a mostly libertarian-minded person myself, the height of compassion is to allow dying people to reach out for any hope out there.

Cruelty would be to prevent people from attempting to save their own lives "for their own good"; especially when no alternative cure is being offered by the politicians and bureaucrats making such life-impinging decisions.

Yes, the quacks and charlatans will try to take advantage and they should specifically be combatted. That doesn't mean that people should not be able to make decisions about their own lives.

</comment></comment></comment></comment></comment></comment><comment><USER10> The author of the article kindly submitted here, which I found quite interesting and informative, notes that she used to write for the Center for Infectious Disease Research and Policy (CIDRAP) based at my alma mater university. Sure enough, CIDRAP has its own current write-up on ebola[1] that is a good supplement to the information in the _Wired_ article we are discussing here.

"The possibility of an airborne-transmissible Ebola virus is one 'that virologists are loath to discuss openly but are definitely considering in private,' wrote Osterholm. In its current form, the virus spreads only through contact with bodily fluids, he noted, but with more human transmission in the past few months than probably occurred in the past 500 years, the virus is getting plenty of chances to evolve."

The current rather high rate of transmission of the disease from one patient to another is alarming, and is perhaps preventable by better public-health practices aided by significant overseas funding, but if the virus haphazardly mutates into a form that spreads though more modes of transmission while still being as lethal, the world is in for a very severe challenge. As it is, the predicted number of cases by the end of the year will overwhelm several countries in the region where ebola is now spreading.

[1] [http://www.cidrap.umn.edu/news- perspective/2014/09/experts-r...](http://www.cidrap.umn.edu/news- perspective/2014/09/experts-raise-specter-more-contagious-ebola-virus)

<comment><USER11> How hard is it to predict (if possible at all) the mutation based on the virus type and particular strain (maybe somehow computationally simulate or mutate it) ?

In general do mutations follow probability distributions that are known?

And then let's say someone wanted to cause mutations that would make it airborne. Could they do it?

<comment><USER12> >In general do mutations follow probability distributions that are known?

In some ways, yes. Substitution matrices[0] describe how likely it is for an amino acid to mutate into another amino acid. However, they are generalized descriptors. At the same time, PWMs[1] describe how the probability of any given variant (mutation) is in a specific sequence, and are created by analyzing all known homologs (similar sequences) of that sequence.

However, the number of mutations required for a virus which is incapable of becoming airborne is probably large and definitely unknown. I'm not an expert in virology, but I believe that there are two requirements for a pathogen to become airborne:

A. It must infect and replicate in an area of the body capable of generating aerosols (generally, the respiratory system, like Influenza and Tuberculosis).

B. It must be good at surviving in aerosols- I believe this requires specific environmental adaptations and the right surface proteins and sugars.

I believe that Ebola meets neither requirement (especially the first), and you could see how meeting both would require not just large physical adaptation, but also a complete change in the virus' life cycle in the host.

>And then let's say someone wanted to cause mutations that would make it airborne. Could they do it?

I think in general it would be easier to start with an airborne virus, and make it deadlier. I'm not an expert but this BBC article[2] quotes that a deadly virus has never been observed to change their vector of infection.

0\. [http://en.wikipedia.org/wiki/Substitution_matrix](http://en.wikipedia.org/wiki/Substitution_matrix)

1\. [http://en.wikipedia.org/wiki/Position_weight_matrix](http://en.wikipedia.org/wiki/Position_weight_matrix)

2\. [http://www.bbc.com/news/blogs- echochambers-29168905](http://www.bbc.com/news/blogs-echochambers-29168905)

<comment><USER11> That made sense. Thank you for explaining.

</comment></comment></comment></comment><comment><USER13> Doctors Without Borders/Médecins Sans Frontières (MSF) is on the ground and is one of the most effective ways to directly support efforts to aid Ebola victims and stop the spread (disclosure: I just donated):

[https://donate.doctorswithoutborders.org](https://donate.doctorswithoutborders.org)

The health systems in these countries were already overwhelmed and under- resourced long before Ebola broke out, and the international governmental response has so far been alarmingly tepid.

Recent AmA with an MSF doctor:

[http://www.reddit.com/r/IAmA/comments/2g79ip/i_work_for_doct...](http://www.reddit.com/r/IAmA/comments/2g79ip/i_work_for_doctors_without_borders_ask_me/)

Note that MSF has an excellent efficiency rating (~87% of revenue goes to program expenses, 11% to fundraising):

[http://www.charitynavigator.org/index.cfm?bay=search.summary...](http://www.charitynavigator.org/index.cfm?bay=search.summary&orgid=3628#.VBZqlHWx3UY)

</comment><comment><USER14> I hate to be the cynical one here, but the countries with the power to stop this outbreak aren't going to start taking it seriously until more people from western nations start dying. It is true, it will be really bad if it is not stopped soon. Containing an outbreak of >5000 is out of the reach of most of the states affected by the disease and quite honestly very expensive for any nation. Once this spreads closer to Europe, watch people start to take more action. I hope it won't be too late

<comment><USER15> There are massive global political ramifications that restrict the ability of those countries that do want to make a difference. As the article refers to, it is ultimately the UN that has the powers to essentially trample on a country's sovereignty (that is what you need to do to make a difference). The UN has been called a toothless tiger in many respects - this is another example where they can and should take a more proactive and aggressive stance. Only then can we comment on the actions of other Western nations.

The way that South Africa dealt with their AIDs epidemic (from a western perspective, true head in sand activity) is a case in point: despite many aggressive offers of help from western governments, the South African's continued their denial. To make a change would have required going against the government policy of the time. This is viewed legally as an invasion by an outside force.

<comment><USER16> I am not sure what relation your (or the article's) talk of trampling sovereignty has to do with the present situation on the ground.

The articles I read describe the problematic issues being; a lack of running water in existing clinics, a lack of medical supplies, a lack of clinics and notably a lack of food everywhere - patients are escaping isolation in efforts to find food.

Liberian officials have pleaded for help in fairly abject terms (one official mentioned the possibly of nation ceasing to exist - I think that means they're worried). The details of what Western nations have done so far is fuzzy but it seems like there not been a sufficient rush to deliver these acutely needed supplies.

Sure, once the existing clinics have food, supplies and running water, parachuted in field clinics sound grand. There's no evidence I've seen that the Liberians would refuse these.

<comment><USER15> The article references having burial specialists. This would require certain people having the right to take deceased corpses and burying without regard for the family/tribal/religious requests/requirements etc. This would at the very least be seen as impinging on the rights of the family, it would likely need armed support. If these burial specialists were say American, they would NOT be deployed without American armed support. Having American armed support (most likely the army) on the ground supporting people who are likely to be impinging on perceived rights will be viewed as trampling sovereignty.

Australia and the Netherlands had a similar issue with the downing of the Malaysian Airliner in Ukraine. In this case, the Ukrainian government had to pass legislation to allow armed Australian and Dutch military to support inspectors. They were just 'inspecting', not creating forced closures of specific areas, forcing burials, witholding care, etc all under significant armed guards.

The present situation on the ground (and the lack of 3rd party government level interaction) is largely a result of weak leadership by the UN. The better question is why the UN hasn't taken ownership of the outbreak?

<comment><USER16> Well,

Liberia does have Liberian burial specialists now, who do what you describe and it indeed is probably the most awful job in the world. Indeed, the Liberian government, with varying levels of competence, has attempted to do most of what you describe. Essentially, there's no evidence, _no indication_ that the Liberian state would resist UN or US aid but also very little evidence of such aid. If anything, the Liberian government has done some stupid impingements on rights itself (quarantining the entire poor sector of Monrovia for example).

Yes, the Liberian state is already taking desperate and extreme measures but when most clinics _without running water_ , their options are limited. I'm sorry, this stuff make me so angry I could ask what it says about you and your ilk when you're so eager solve things with guns that you don't notice that _lack of food and water_ is the primary problem?

Obama some announcements about military assistance but I've read not article about anything materializing.

Seriously, we're talking pretty well unprecedented disaster - the response has been much than even the response to "typical" third world disasters, much less than the response to the Haitian earthquake for example.

<comment><USER17> > no evidence, no indication that the Liberian state would resist UN or US aid

It is not official action that the parent commenter is referring to. Individuals themselves could treat actions they see as counter to their religion and belief as very hostile.

</comment></comment></comment></comment></comment></comment><comment><USER18> I recommend anyone proposing solutions to the crisis first read this explanation of events to date: [http://www.vanityfair.com/politics/2014/10/ebola-virus- epide...](http://www.vanityfair.com/politics/2014/10/ebola-virus-epidemic- containment)

In particular, the history of events to date makes it clear it is _not_ a case of the world doing nothing. Back in the spring, when there was reasonable hope that sending a bunch of foreign doctors could stop the outbreak, that was done - for a little while, it even looked as though it had worked.

Unfortunately, it didn't, by a long shot. Now WHO and MSF want to repeat that strategy on a much larger scale.

My opinion is that this is a very bad idea. The epidemic in West Africa not going to be stopped. That window of opportunity closed months ago, if it was ever open. If we send in thousands of doctors now, a large percentage of them will end up dead, and the epidemic still won't be stopped. It will be a waste of life, and at that, of the lives of trained doctors and nurses who will be all too soon and badly needed if the epidemic does start hitting other regions where the outcome would still be in doubt.

And no, sending in the military is not the answer. Not only does "it's for your own good" not morally justify aggression, but by further eroding the trust of the local population for authority in general and foreigners in particular, it would make matters worse, not better.

The affected area needs to be sealed off so the disease can't spread to the rest of Africa and the rest of the world. By all means airdrop medical supplies to Liberia, but _don 't_ for heaven's sake start sending hordes of doctors, soldiers and camp followers there to create more fodder for the virus.

<comment><USER19> Your recommendations are exactly contrary to the guidance from those who have spent their entire careers studying the best way of responding to these types of epidemics.

Attempting use "force" to seal off the area, is perhaps the single most effective way to lose all control of this disease, and see it spread to hundreds of thousands, if not millions of people who (quite reasonably) decide to fight back against such an activity.

Careful Training, use of locals who have developed immunity, _massive_ injections of beds, medicine, and supplies, can have a huge impact, and keep this current epidemic under control

<comment><USER18> Your argument is from authority, but authority is trumped by empirical fact. The kind of strategy you advocate was, yes, the right thing to try back in spring, when there was reasonable hope that it could work. It conclusively failed, at a time when the outbreak was far smaller and more tractable than it is now. It cannot possibly _keep the current epidemic under control_ , because the current epidemic is _already not under control_ , hasn't been for months. Meanwhile, hundreds of healthcare workers have, despite training, been among the dead. No amount of training can compensate for the fact that with a caseload of this magnitude you get overworked to the point of exhaustion and start making mistakes.

By contrast, the strategy I advocate has thus far been working.

Nigeria? Cut travel to the affected area. One idiot had slipped through, causing an outbreak. Because it was only one small outbreak, it was possible to contain it.

Senegal? Same. Tougher problem because it has a land border with the affected area. In response, citizen groups have been supplementing the security forces, patrolling the border and turning back people trying to enter the country, thus far successfully.

Ivory Coast? Cut off travel from the affected area. Thus far, no Ebola detected.

Do you believe in results? I advocate abandoning the strategy that has been proven not to work and focusing on the strategy that has been proven to work.

</comment></comment></comment><comment><USER20> I had a discussion with a friend, and he pointed out that Malaria infects something like 200 million people a year in Africa, and kills around half a million. It's brutal.

So this new paper is projecting that Ebola deaths in Africa will be about as common as Malaria deaths.

I guess I'm trying to draw any conclusions or imply anything here other than life in Africa is pretty freakin' tough.

<comment><USER21> The two main differences I see are: 1) The Ebola death rate is still increasing, which makes it scarier that Malaria, which has a relativly stable death rate. 2) Malaria (being tied to mosquitoes) is inherently a regional disease. Ebola has much more potential to spread to other regions.

</comment></comment><comment><USER22> Time to face some brutal facts here.

1) We are due for another pandemic. If this one isn't it, there will be another.

2) Democracies run on public opinion. Right now everybody is riled up about some homicidal idiots in Iraq. This is off their radar. Hundreds of thousands of people die from some natural cause or another all of the time. It's not a huge spectacle on YouTube.

3) The enemy really isn't Ebola. Ebola is just the opportunistic pathogen that came along. The enemy is really weak governments with little or no public health systems, combined with very poor local sanitation practices.

4) There was a time when air-dropping in a thousand healthworkers with tent hospitals _might_ have stopped this. That time is over. Now it's in the big city, and trying to control or service a population of several hundred thousand is beyond most any country's ability to project intervention.

5) If it doesn't go airborne and stay lethal, which is where the safe money currently is, we'll end up with hundreds of thousands or millions dead and it should burn itself out over the next year or two. That's the optimistic scenario. We have no reason not to believe that's the way it's going to play out.

6) If it goes airborne and stays lethal, we're in for a major shitstorm. But I really don't think second-guessing how we responded will be useful. There are different countries in the world. They have different governments. We do not have one world government, nor do most of us want one. That means that there are always going to be large pockets of humanity where something like this can take off. Structurally humanity is huge. Disease is going to be an issue for us for a long time.

<comment><USER23> Saying that we're due for another pandemic is quite simply the gambler's fallacy: [http://en.wikipedia.org/wiki/Gambler's_fallacy](http://en.wikipedia.org/wiki/Gambler's_fallacy) . The odds of a pandemic may well be higher than recent experience would indicate, but pandemics still occur randomly.

</comment></comment><comment><USER24> The article this Wired post is mostly reblogging is quite a bit better imo, at least in having a higher ratio of facts to commentary: [http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=2...](http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20894)

<comment><USER25> Seriously, what utter crap: [http://www.wired.com/wp- content/uploads/2014/09/Nishiura-cur...](http://www.wired.com/wp- content/uploads/2014/09/Nishiura-curves.jpg)

Did they seriously screenshot that image with a tooltip up?

</comment></comment><comment><USER26> This should be obvious to anybody who knows about geometric growth. The only time you can really stop Ebola without a cheap and easily-available _cure_ is now while it's small. As it grows, its rate of growth will increase, and it will quickly spread to every vulnerable area.

<comment><USER27> < As it grows, its rate of growth will increase

No, R will stay the same. Or decrease as the population becomes more exposed.

<comment><USER28> He's taking about the number of people infected per unit of time, which will indeed increase over time if the reproductive number stays larger than 1.

<comment><USER29> Growth is number of people per unit time. Rate of growth is number of people per unit time squared. Just as with speed vs. acceleration, there certainly is a distinction.

<comment><USER28> I'm not a native speaker so I could be wrong. But in the wikipedia article about exponential growth, "growth rate" is defined as the first derivative with respect to time, which contradicts what you are saying: [https://en.wikipedia.org/wiki/Exponential_growth#Differentia...](https://en.wikipedia.org/wiki/Exponential_growth#Differential_equation)

I understand the distinction you are trying to make, but I think what you call "growth rate" would actually be "growth acceleration".

</comment></comment></comment></comment></comment><comment><USER30> This seems to be the usual knee jerk military can solve everything response you would expect from Americans, and also African governments who are always eager for handouts from Western governments.

So you want to send the military in? Do you have any idea of the size of the area in which you would have to deploy them, coupled with the panic their presence might cause, together with the issues which would be caused by militia factions which would inevitably arise to tackle what they would rightfully see as an invasion of their countries?

What did the UN manage to do after the Haitian earthquake that the Haitians couldn't have done themselves, besides introducing cholera to the region and nearby countries?

What African countries need to do is what they would have to do if there was no possibility of outside support. In this case it is not even a question of central government intervention when it is more a question of dealing with Ebola at the local level or county / village level.

Moving infected people to centralized locations for treatment means more travel and the possibly infected relatives and carers for the ill spreading the disease more, unless they are transported by specialist units. The process of travelling to report an infection and calling for a specialist unit itself carries the risk of the traveller spreading the disease let alone the person with the symptoms.

The only way to contain Ebola is to give the families or communities of infected people the knowledge, the drugs, the equipment and the protective clothing to they need to treat themselves and the economic support they will need when they are isolated, which needs to be done at a local level. That means sustained public education via television and video, protective clothing for carers and disease detection kits.

</comment><comment><USER31> I'm no expert and I'm just as frightened by the spread of this disease as everyone else, but I think people in this thread, and the media in general, are being a tad "end-of-the-world"-y about this without looking at some of the important facts. Namely:

1) The article mentions the R0 of Ebola and claims it is between 1-2 in the current outbreak. Previous outbreaks of Ebola have been as high as 2.7. But this is relatively low compared to other diseases... the R0 of the Measles for instance is 12-18 (and nobody is really talking about the recent outbreaks in the US due to parents not vaccinating their children). Chances are, this rate would even be lower in the West because conditions in African slums and even hospitals are downright deplorable. Doctors aren't using suits or even gloves to examine patients, medical staff are reusing disposable needles, hospitals rely on family members to wash soiled linens because they don't have in-house cleaning services like western hospitals, etc. And don't forget that cultural norms are feeding the spread of the disease: well family members are observed to be sharing beds with sick loved ones in hospitals, people are practicing cultural burial routines of washing and in some cases kissing deceased loved ones, people are still eating the meat of things like bats and gorillas that are sick with the virus (and even found dead), etc. These are all things that just wouldn't happen in the West. People also do much better here at heeding the advice of the medical professionals - for instance, bodies of people who had died of Ebola would like be burned without concern for any regular traditions, without much complaint.

2) Part of the reason Ebola is so scary is the high fatality rate cited in articles: 50-90%. If you extrapolate to the entire planet, this sounds like it would be devastating to the human race. But is this the actual fatality rate? Western hospitals do a much better job of carefully monitoring patients and tending to every minor development. The main problem with Ebola isn't that the body can't fight it, it's that it kills you before your body can recover - <USER2> drastic difference in care between the West and Africa would likely make a huge difference in mortality. Make no mistake, this is a deadly disease, but probably not quite as bad as 50-90% in the West.

3) This article and others like it have shared the concern that Ebola could mutate into something transmissible by air. This would make the R0 of the disease skyrocket up into something that could quickly overwhelm Western medicine and very rapidly turn into something perhaps even more devastating than the plague. It's possible of course the virus could mutate in this way, of course, it's already believed that it can spread like this in pigs. One important thing to recognize is that Ebola in humans affects the liver not the lungs, which poses a barrier to being airborne. In addition, to become truly airborne, the virus would have to mutate it's outer coating to resist the drying effect of the air. So in order to become transmissible by air, it would have to mutate 2 different major adaptations and completely change everything about itself. The example I've read is that we don't worry about HIV becoming transmissible by air, and it is thought to mutate more quickly than Ebola. We've never observed any deadly virus change it's method of delivery, although of course airborne diseases evolved that adaptation in the first place.

None of these points mean we should sit back and do nothing. We need to help at minimum because of the following reasons:

1) People are dying and we can help them. With effective medical care, the mortality rate as mentioned in point 2 above should go down.

2) Ebola is destabilizing the region. This is already a region prone to state failure, corrupt and ruthless governments, etc. This disease could well cause wars in Africa, which in turn would make conditions worse and likely increase the fatality rate and the infection rate.

3) While there is a reasonable scientific case to be made against the unlikelihood of the mutation of the virus into airborne transmissible, it's possible and very scary. When considering the risks, we need to multiply the rather small chance against the rather large negative effect of such a change. We need to stop this to avoid this thing from becoming more deadly.

<comment><USER32> A basic reproductive number of two can be really really bad, provided it stays that high. If exponential growth holds long enough, it doesn't matter too much what the rate is, so long as it's above one.

With that being said it varies a LOT between different countries for exactly the reasons you mention. My initial work shows a lot of heterogeneity:

[http://grantbrown.github.io/Ebola-2014-Analysis- Archive/Sep_...](http://grantbrown.github.io/Ebola-2014-Analysis- Archive/Sep_08_2014/Ebola2014/figure/unnamed-chunk-11.png)

I agree wholeheartedly with your last three points. Also, from the looks of things the cheapest and most effective time to tackle the disease was months ago. The second cheapest and most effective time to try to stamp it out is as soon as possible.

P.S. The ProMed daily digests are some of the best and most comprehensive updates on this situation I've seen:

[http://www.promedmail.org/](http://www.promedmail.org/)

<comment><USER31> Thanks for the links!

</comment></comment></comment><comment><USER33> I searched for R_0 data on flu pandemics and found this:

[http://www.ecdc.europa.eu/en/healthtopics/documents/0905_pan...](http://www.ecdc.europa.eu/en/healthtopics/documents/0905_pandemic_influenza_pandemics_of_influenza.pdf)

Note the sharp jump as R_0 goes from sub-2 to over-2, which should not be surprising (hand wave about branch processes, light of a thousand suns, etc).

Over to someone better qualified to comment - is the present situation with Ebola taking us into a pandemic territory similar to 1918 H1N1?

</comment><comment><USER34> > in particular by bringing in local residents who have survived Ebola, and > are no longer at risk of infection.

I have seen this several places over the past week or two – is it actually true that people who survive Ebola are not at risk of re-infection? I can see where that might be true shortly after recovery (i.e., due to there still being antibodies in one's system), but how long would the immunity last?

<comment><USER35> Antibodies generally last a very long time [citation needed], but would they be useful against such a rapidly-changing pathogen ?

<comment><USER34> > but would they be useful against such a rapidly-changing pathogen ?

Does that explain why people are not immune from the flu after having it once – the version they have antibodies to is not the same as the mutated version which circulates later?

<comment><USER36> >Does that explain why people are not immune from the flu after having it once

Yes. There are many strains of Influenza, immunity to one strain doesn't necessarily confer any immunity to another strain.

However, Ebola mutates much less rapidly that Influenza.

</comment></comment></comment></comment><comment> chestnut-tree If you're in the UK, there's an informative BBC documentary on Ebola broadcast just last week. The programme talks to survivors of the virus, to the staff of Médecins Sans Frontières (MSF) treating victims, to Peter Piot, the Belgian doctor who discovered the virus (and established that the disease was not airborne) and the medical staff seeking a cure. There are some harrowing scenes.

It's available on iPlayer until Friday 19 Sept. 2014 [http://www.bbc.co.uk/iplayer/episode/b04hcthj/](http://www.bbc.co.uk/iplayer/episode/b04hcthj/)

Someone's uploaded it to YouTube, although the last 10 minutes are missing [https://www.youtube.com/watch?v=bjuQofIleOg](https://www.youtube.com/watch?v=bjuQofIleOg)

</comment><comment><USER37> > In a worst-case hypothetical scenario, should the outbreak continue with > recent trends, the case burden could gain an additional 77,181 to 277,124 > cases by the end of 2014.

What I wonder is: why do they think it will _stop_? What's going to put a brake on the epidemic's explosion? This is not a world where a disease can burn itself out on the local level by simply killing everyone susceptible.

</comment><comment><USER38> Just for those of you wondering somewhat about the risks of Ebola becoming airborne - it has been shown to be transferred without contact before: [http://healthmap.org/site/diseasedaily/article/pigs- monkeys-...](http://healthmap.org/site/diseasedaily/article/pigs-monkeys- ebola-goes-airborne-112112)

</comment><comment><USER39> My fear is that we're not able to stop a simple stomach flu which is spread almost the same way, through bodily liquids, so I don't think it will be easy to stop once it hits first world countries like most people currently assume...

<comment><USER40> Wait a minute, when was the last time that the stomach flu was an epidemic?

<comment><USER41> The last flu epidemic with a major death toll was the pandemic of 1918, which is estimated to have killed more people than World War I. A less deadly version of the same strain was officially listed as an epidemic in 2009.

<comment><USER26> Stomache flu, which is the symptom gastroenteritis, is unrelated to influenza. It's a misnomer. So the Spanish Flu is not a good example here.

And to the point, we've never successfully "beat" GI because the stakes were never this high.

</comment></comment></comment></comment><comment><USER42> How does the world's response to Indonesia, Haiti compare to this? Do we need some celebrities to put on a telethon to get more nations acting AND acting immediately on this?

</comment><comment><USER43> Informative graph:

[http://en.wikipedia.org/wiki/File:Diseased_Ebola_2014.png](http://en.wikipedia.org/wiki/File:Diseased_Ebola_2014.png)

<comment><USER44> The log graph is scarier: [https://upload.wikimedia.org/wikipedia/commons/2/2d/Evolutio...](https://upload.wikimedia.org/wikipedia/commons/2/2d/Evolution_of_the_2014_Ebola_outbreak_in_semiLog_plot..png)

(It's easier to recognize a straight line on a log scale, than to distinguish an exponential line on a linear scale from a line that's "merely" quadratic, say.)

<comment><USER45> What do similar charts for prior outbreaks like?

<comment><USER46> Here's one of the previous largest outbreak, 2000-2001 in Uganda. (Note unlike the Wikipedia one, it's not cumulative). Looks like a sudden decline in new cases right after a CDC intervention -- very sharp inflection point. The cumulative version would be roughly a sigmoid.

[http://web.stanford.edu/group/parasites/ParaSites2012/Lassa%...](http://web.stanford.edu/group/parasites/ParaSites2012/Lassa%20Libby%20Burch/images/LassaEbolaMarburg_LibbyBurch_3-8-2012_img_19.png)

[http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5005a1.htm](http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5005a1.htm)

Looks like there were about 10 new cases/day at its peak; the current outbreak is at 150/day.

A couple things stood out to me:

        Fourteen (64%) of 22 health-care workers in Gulu were
        infected after establishing the isolation wards; these
        incidenses led to the reinforcement of infection-control
        measures.

So that's not novel to the current outbreak at all!

        During the 4-month outbreak and response period,
        approximately 5600 contacts in Gulu District were under
        surveillance for 21 days by approximately 150 trained
        volunteers.

</comment></comment></comment></comment><comment><USER27> I find it interesting that people worry about Ebola going airborne but not something like AIDS.

I guess there's a biological reason....

<comment><USER47> Because Ebola has already been shown to be transmissible via the air, but only in other species.

[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498927/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498927/)

> Piglets [with Ebola] were transferred to the room housing macaques in an > open inaccessible cage system. All macaques became infected.

<comment><USER48> Dont overstate this particular study, the team did nothing to eliminate the possibility that there was transmission via droplets flung off the animal, and did not fully eliminate the possibility of particulate cross contamination which could have lead to transmission via infectious fluids piggybacking to the macaques on the particulate cross contamination.

Yes there is a risk of mutation to transmit via air, but we have not yet seen it. We have merely proven that 'shit happens' and 'ebola is dangerous'.

</comment></comment></comment><comment><USER49> [http://www.telegraph.co.uk/news/worldnews/europe/france/1084...](http://www.telegraph.co.uk/news/worldnews/europe/france/10847344/Jean- Marie-Le-Pen-Ebola-epidemic-would-solve-immigration-problems.html)

I'm afraid some people either think this is a game, or just an opportunity - since most of the worlds problems today stem from overpopulation.

<comment><USER50> >since most of the worlds problems today stem from overpopulation

Why do you think that most of the world's problems today stem from overpopulation? What problems?

If you're talking about hunger, that's demonstrably false. There is plenty of food produced to feed the entire population. Even African produces plenty of food to feed itself. Famine occurs in times of war and natural disaster, or other great upheavals. Most of the causes are man-made and have nothing to do with overpopulation.

<comment><USER49> I would argue that war can be a result of overpopulation. Famine is also - <USER3> occurs in the places least able to deal with ebola. "Global warming" \- we could reduce emissions by reducing population without changing the per capita energy consumption. Unemployment - not enough jobs is the same thing as too many people. Strife in the middle east? Too many people in that area of the world with not enough resource (or governments that squander what they have).

I'm not saying all of these are correct in an absolute sense, just that population certainly plays a role.

<comment><USER50> > Famine is also - it occurs in the places least able to deal with ebola

The areas currently buckling under Ebola have _not_ been the regions of Africa most affected by famine in the last few decades, most of which are in the Sahel and Horn of Africa. And which were caused by political problems. Other than that, I'm not sure what this means.

>"Global warming" \- we could reduce emissions by reducing population without changing the per capita energy consumption.

This would be true if you reduced population _in the West and in Asia_ but the energy and food consumption of Africa is absolutely minuscule compared to the rest of the world.

See the references in my other post:

[https://news.ycombinator.com/item?id=8320473](https://news.ycombinator.com/item?id=8320473)

>Strife in the middle east?

Israel has a relatively low birth rate.</comment></comment></comment></comment>


Hackers, Disconnect From Your Computer and Go For a Walk - <AUTHOR> http://www.discusr.com/post/451/hackers-disconnect-from-your-computer-and-go-for-a-walk

<comment><USER2> The sunlight! My eyes! The goggles do nothing!</comment>


Nginx and Memcached, an easy 400% boost in req/s - <AUTHOR> http://www.igvita.com/2008/02/11/nginx-and-memcached-a-400-boost/ <comment><USER3> Sloppy thinking. Sloppy measurements.

If you have almost 1000 reqs/sec initially, that's 1ms per request. By bringing this down by the amazing 400% (!!) percent you've shaved off 3/4th of a milisecond per request. Congratulations - you have no idea what you've been measuring. Just the way in which the request is logged can make a 5ms difference. Insignificant and completely uninteresting.

Back when 3d game programming was cool, people would get a rotating cube and show off their 1200 fps frame rate. Of course they would get upset that by adding a texture to the cube the framerate dropped by 400 frames to 800 fps. "Textures are slow!", they'd say. Yeah, right...

<comment><AUTHOR> Fair enough, but this is / was a controlled experiment. The codebase did not change, the method through which the cached content was served did. Hence the textured cube argument is not the best analogy here, I think. :)

Having said that, I agree -- there is a lot of other variables out there, and they should not be swept under the rug.

<comment><USER3> The point of the textured cube analogy was that if you don't consider the context of the benchmark, the numbers aren't useful.

The kid doesn't realize that if texturing a cube brings a framerate down from 1200 to 800 fps, is as significant as going down from 62 fps down to 60. Even though that is only a 2 fps difference.

A 400% performance gain is a constant performance improvement. I don't think a system like nginx + memcached have linear performance benefits in the first place.

</comment></comment></comment><comment><USER4> Many dynamic sites can't just cache entire pages and bypass the appserver completely. It would require a lot of changes to the application code.

<comment><AUTHOR> Yup, definitely true. Having said that, we tend to overuse this thinking even when we don't really have to. This is arguably a scheme that's better adapted to new codebases. :)

</comment></comment><comment><USER5> I refuse to believe in memcached. Apache, along with other web servers, has a built-in in-memory cache for static content. Decent SQL-servers have _several_ caches on different levels, in fact those caches in theory should be far more effective than a simple remote hashtable that memcached is. And all that - <USER2> top of OS level disk I/O caching.

I suspect that memcached was born as a result of sloppy SQL querying multiplied by inefficient SQL schema and lack of RDBMS tuning skills. Moreover, anyone can have memcached with zero programming by either hosting DB on a RAM disk with replication, or using in-memory tables.

<comment><USER6> My hunch is that it's down to cache invalidation logic. It's easier for the app to know when a single memcached entry needs to be invalidated than for the SQL engine, which perhaps tends to be conservative in what it can cache.

(e.g. MySQL query cache is flushed if a single write happens to the table, so _all_ your users will be dumped out of that cache whenever any row is updated.)

Hence you get a better hit-rate with memcached. Perhaps it is also simply easier to tune memcached than most db memory caches.

I benched "retrieve data and instantiate object" on a couple of different, unloaded, systems and a simple select-and-instantiate-from-mysql was a bit faster than the memcached equivalent. I didn't measure CPU usage server-side though, so under load things might be different.

<comment><USER5> I agree, in-memory hash table controlled manually by the application has a million ways to beat any SQL-server caching.

What I am saying is that _I suspect that memcached is way overused by people who don't know much about SQL_. I am not posing like a DB snob, in fact my skills are fairly modest, but even I know that query caching is just one of the many caches SQL servers employ, and well designed servers easily service thousand+ of requests per second. And that's just one instnace.

Very very very few web sites ever reach such loads. In theory memcached should be more like a very niche product for such rare sites, yet it appears that everybody is using it.

I am against it because it increases the complexity. Memcached deployment and cache control become two more things to get right.

That's all.

</comment></comment></comment><comment><USER7> I'm going to blog it in detail soon, but I thought I'd mention that tipjoy's front page is entirely static. The content is refreshed very often, and a new file is saved. Right now lighttpd is setup to serve the static page when / is requested. Soon, it will be nginx because of the ease of using it as a load balancer.

</comment><comment><USER8> It's amazing to me that caching still isn't on by default in Web servers.

<comment><USER9> what kind of caching? why would you want a web server cache that would eat up memory? what you need is an independent distributed dumb cache in memcached terms.</comment></comment>


Ask HN: Does anyone want an HN for music? - <AUTHOR>

I'd quite like a site that lets me discover interesting new music HN-style, with new songs of the day voted up by the community.
The songs would be straight mp3 files or youtube videos, in embedded players, with links to the originals.
None of the cruft and nonsense that last.fm / pandora have in abundance.
Is anyone else interested? <comment><USER2> I think the problem is that "music" is too broad of a category to operate in a similar manner to HN. You'd need to do a reddit-style sub-category system, which not only increases the complexity but also diverges from a HN-like setup.

What's the cruft and nonsense that Pandora has? I'm pretty happy with it -- even upgraded to the pro version to get higher quality audio.

</comment><comment><USER3> It could work if you weighted the votes by those who had also selected favourite genres that you like - from say your last.fm history or manually selected.

I'm always extremely motivated by music related ideas. Have you been involved in a financed startup before?

<comment><USER3> Actually a colleague just pointed out that the reddit code is available:

<http://github.com/reddit/reddit>

Could use that and the last.fm API or MusicBrainz do have a stab at getting the genres?

</comment></comment><comment><USER4> Not interested in actual songs. I would much rather see a music news version of Hacker News. I've actually thought about this a lot. Users would filter noisy articles, pushing relevant news to the top.

</comment><comment><USER5> We used to have that, it was called TheSixtyOne.

But now it's just a hollow shell of it's former self.

<comment><USER6> _But now it's just a hollow shell of it's former self._

Exactly. I liked their older UI. Allowed me to explore music better. Right now it seems like they've cut down on features heavily. This approach seems to give new music a chance.

But I think they should offer an option to switch to the old UI for those who have time to wade thru music and choose what they want to listen to.

<comment><USER5> You can still use it here: <http://old.thesixtyone.com/> But they ripped out the comment system and the group system so there is no way to communicate with other users or artists.

</comment></comment></comment><comment><USER7> hypem.com</comment>