Ebola virus outbreak

ProfessorPlum wrote: »

Epidemiologists like to talk about R numbers. Generally they are people who are pretty good at statistics. Of course it's not meaningless. Put it this way: Measles has an R number somewhere approaching 18. It also would have about the same timeline of being infectious as Ebola. Also, as a downside for bystanders, people with measles tend to be in contact with more people while they're ill (owning to the fact that they're not lying down dying in their bed). Measles is highly contagious. 18 is 9 times 2. Ebola is contagious, but not highly contagious in the grand scheme of things.


As for isolating West Africa from the rest of the world - do any of you realise how big a land mass you're talking about. I'm guessing you don't. (The maps we use massively underrepresent the size of Africa)
As URL says, how are we going to do it? How about Guinea - there's only a (relatively) tiny portion of the country affected - do 'we' lock the whole place down? How about Nigeria and Senegal. Spain and the USA for that matter. I think we need to be a little more nuanced here with our approach.
Oh, and those epidemiologists I was talking about earlier - the majority feel closing borders would be the wrong thing to do.





I'm sure the bordering Nations will be delighted with that plan.



Your analogy translates more like - if you have a gangrenous little toe, you should cut off both the lower limbs to save the patient.

In fairness, I agree about West Africa. I mean Liberia and Sierra Leone should in a worst case scenario be isolated as much as possible. I agree it wouldn't be possible to full isolate by land. But as much as possible flights out should be restricted. The reason for this has nothing to do with racism or the like. The reason is I don't trust the testing proceedures. There are reports of people being tested, coming up negative, only for them to become sick with ebola days later. In other words, testing has failed in some cases.

What testing can they do at an airport? Blood tests? Nope. Urine tests? Nope, and probably pointless in the case of ebola. They are doing temperature checks. My understanding is ebola has an encupation period of about 21 days. Someone could pass a test in the early days of infection, and appear perfectly normal. Its risky in the extreme.

ProfessorPlum wrote: »

It is ridiculously easy to get past fever screening. A couple of paracetamol will do it. And so far (as of earlier today at least) of all those stopped at borders in affected countries with a fever, none had Ebola. So I'm not sure how well the strategy is working.

Which supports my argument, in a worst case scenario. The tests could be next to useless for all we know. Of course people will display fever symptoms in a late stage infection. But early stage?

ProfessorPlum wrote: »

Epidemiologists like to talk about R numbers. Generally they are people who are pretty good at statistics. Of course it's not meaningless. Put it this way: Measles has an R number somewhere approaching 18. It also would have about the same timeline of being infectious as Ebola. Also, as a downside for bystanders, people with measles tend to be in contact with more people while they're ill (owning to the fact that they're not lying down dying in their bed). Measles is highly contagious. 18 is 9 times 2. Ebola is contagious, but not highly contagious in the grand scheme of things.

My own experience is that most people - even those who use them a lot - have poor intuition for statistics. Most people who use stats a lot will tell you that even though you can learn how to use the really in-depth stuff, the really "difficult" statistical methods, if you don't get the basics, you probably never actually will get it. Like I saw an article laughing about the fact that just about half of parents considered their child to be of above average intelligence...

Statistics are really only valid if you're comparing like with like. Something that kills rapidly is not like something that kills over the course of decades. The implications are also different, one might leave you with pock marks (measles!), whereas the other is more likely to kill you (Ebola). When assessing risk, you have to assess the probability of occurrence AND the consequence of occurrence. Therefore the R number alone is simply NOT adequate to conclude that Ebola is not a high risk highly contagious disease. One also has to look at the precautions taken around the disease - gloves at best for measles; full on level 4 protection for Ebola -- and we've since seen that even level 2 protection appears not to be adequate as that poor Spanish nurse who appears to have followed protocol got infected anyway.

R numbers can be a useful starting point. An epidemiologist will talk about the R number because they're concerned about how a disease can spread, however, the timeframe simply CANNOT be ignored. If each Ebola victim passes it on to 2 people within the space of 3 weeks, and each of those pass it on to 2 people and so forth, this is what happens:

T0: 1 person infected
T3 (weeks): 3 (1+2)
T6: 7 (1+2+4)
T9: 15 (1+2+4+8)
T12: 31 (1+2+4+8+16)

So within 3 months, ONE infection has caused 30 others. Here's how it would look for a HIV infection:

T0: 1
T3: 1
T6: 1
T9: 1
T12: 1

So if you're going to look to R numbers in any sort of useful way for containing a disease, you MUST put them in the context of the time-frame in which they occur. The ONLY reason that Ebola doesn't have a higher R number is that people simply don't live long enough to pass it on to more people. Hence my comment about the most dangerous mutation that could occur being a reduction in the mortality rate.

the_monkey wrote: »

What Ebola hangs around the toilets does it ???

have you any idea how the disease is actually spread or are you just in here spouting mindless scaremongering crap ?

Most ebola victims suffer from severe diarrhoea. Would you use a toilet seat after an ebola victim?

Thought not!

ProfessorPlum wrote: »

Can't find where I read it - it was a WHO or CDC document. They've been isolating those with a temperature, refusing travel, and testing them for ebola. They've all come up negative. Most have had malaria.
It seems fairly pointless. Closing borders is impossible.

Stopping flights is not impossible. You are making my argument by the way. And I am not really referring to late stage ebola infection. People in late stages are usually very sick, high fever, severe pain and diarrhoea. It's unlikely they would be getting on a flight and if they did, would be spotted right away. It's the early stage victims that are far more dangerous, who present no visible symptoms. I'd imagine the guy from Texas had early stage infection when he flew home.

ProfessorPlum wrote: »

Agghhhh. By the time they have sever diarrhoea, they won't be on your plane. And as you rightly pointed out, everyone will know to stay well clear.

I agree they won't. I was responding to a poster however who said it can't be spread via toilet seats. In theory it probably can be.

I'm sorry I ever watched Contagion!!

the_monkey wrote: »

Yeah im stupid, I'm not gonna worry about my son in Spain getting Ebola - in a country with ONE case !!!!

I guess he's no where near Madrid either ... makes the stats even more interesting ...

The sarcasm is a bit unnecessary. It's her son and it's natural she's going to worry. I was very worried myself to the point of a few tears on Wednesday and I've met plenty of people here who are ****ting themselves (most people I've met are calm though). People don't think rationally when their loved ones are involved and with the media hype, it's easy to get sucked in by it all.


Edit: And as Fullblownrose says above, we don't know everything there is to know about the virus at this stage.