“Previews of Coming Attractions”
People wonder just how bad the Ebola outbreak could get. Well, with a bit of understanding of the relevant mechanisms, knowledge of the math involved, and a spreadsheet, putting together a “quick and dirty” approximate model for the spread of that disease is relatively easy.
What it shows may be somewhat hard to swallow. And it is a simplified model; reality will be somewhat more complex. But for the early stages of an epidemic – and we’re still in the relatively early stages of this one – I think this should be relatively close.
First, a few known facts and/or best estimates for the current outbreak and about Ebola itself.
- Although the first case was reported 6 months ago, the current outbreak has actually been ongoing since Dec 2013. The index case infection(s) occurred in Guinea, in late Dec 2013. It simply wasn’t recognized as Ebola for around 3 months.
- The mortality rate (percentage of those infected with the disease who die) for a disease outbreak cannot be calculated until after the outbreak has run its course. However, an estimate – the current case fatality rate (CFR) – can be calculated. The CFR is a snapshot in time, and tends to rise during the course of an outbreak as more complete information becomes available and some of the patients sick at the time of last calculation die. For the current outbreak, data indicates that the CFR for the current outbreak is approximately 53%.
- The total number of reported Ebola cases during the current outbreak is believed to be only approximately 40% of the actual number of cases. Roughly 60% of the cases (and deaths)in the current outbreak are believed to have never been reported – or in other words, multiply the current reported totals for cases and deaths by 2.5 to get the best guess at the true number.
- Facts and best estimates concerning Ebola virus disease.
- The average Ebola incubation period seems to be about 10 days (min observed is 2 days; max observed is 21).
- During incubation, patients are asymptomatic (without symptoms). Individuals are not in general contagious prior to becoming symptomatic.
- At the onset of symptoms, patients begin shedding the virus in bodily fluids and become contagious.
- Transmission of Ebola appears to be via human-to-human transmission through close contact and/or contact with contaminated fomites/surfaces. Contact with an symptomatic Ebola sufferer’s bodily fluids (sweat, urine, feces, vomit, semen, vaginal secretions, mucous, saliva, or blood) is believed to be the mechanism by which Ebola is transmitted from person to person. For that reason, shaking hands with or standing within 1 meter of an Ebola patient without PPE is considered close contact.
- The virus appears to enter the human body through mucous membranes or open wounds.
- Aerial transmission of Ebola does not appear to be a normal means of transmission from human-to-human. However, the possibility cannot be ruled out. Ebola Reston is believed to have spread between primates in different rooms of the famous Hazelton “monkey house” in Reston, VA, through the facility’s ventilation system. After analysis, aerial transmission through the facility’s ventilation system was determined to have been the most likely mechanism by which that Ebola variant spread.
How epidemics work.
An epidemic in an immunologically naïve population (e.g., one that has no previous exposure, and thus no natural resistance to the disease) works and can be modeled at a somewhat simplistic level as follows.
- A first case – termed the index case – becomes infected. This begins the first generation of the outbreak.
- The index case proceeds through the disease’s incubation period. For Ebola, this is on average 10 days. For Ebola, the individual is not contagious during the incubation period.
- The individual becomes contagious. For Ebola, this occurs with the onset of symptoms. Also for Ebola, the period during which a sufferer is contagious lasts until they either recover (average is approximately 16 days) or die (usually around day 10 after onset of symptoms). (One caveat here: the Ebola virus persists in certain organs of recovered Ebola patients for up to 90 days after clinical recovery. Though the recovered patient’s body does eventually rid itself of the virus, transmission to others after recovery can occur. In particular, sexual transmission of Ebola by a “recovered” Ebola patient several weeks after clinical recovery has been recorded.)
- Transmission to others occurs during the period while an infected person is contagious. During this period, the individual transmits the disease to some number of other individuals. The average number of persons to whom each sufferer transmits the disease is a critically important parameter, called the “reproduction number”. So long as this number is greater than 1, the number of people infected will continue to increase. It’s just a question of how fast. For the current Ebola outbreak, the reproduction number is estimated to be somewhere between 1.5 and 2.
- The transmission to others referenced in step 4 begins the next generation of the virus. Steps 1 through 4 then repeat.
That’s it. Until the numbers of persons with some type of immunity to the disease (either through survival or vaccination) in the affected population becomes significant, the above is a reasonably accurate – though somewhat crude – description of how an infectious disease propagates through a susceptible population. It will hold until something (deaths, developed immunity, behavioral changes, whatever) changes the transmission cycle of the disease – usually by changing the reproduction number.
Those familiar with calculus might be wondering if this is a process exhibiting exponential growth. The answer, unfortunately, is yes. Epidemics in fully susceptible populations are indeed exponential growth scenarios until “herd immunity” (the fraction of the population immune due to prior exposure or vaccination) becomes significant – or until the population dies out, or something else intervenes to reduce the reproduction number below 1.
The Model.
Here is a simplified spreadsheet model I’ve come up with for the current West Africa Ebola outbreak. As noted, it’s a rather crude, “quick and dirty” model. But it gives a reasonable idea of what may be in store; I don’t think it’s grossly in error. Format is Excel 97-2003. If anyone with more knowledge of the subject or the parameters in question has criticism or comment, I’m all ears. Getting it right is what’s important.
Fair warning: I would suggest you (a) sit down, and (b) get a cup of coffee (or something stronger) before you look at the model. And I wouldn’t recommend do so immediately after or while eating.
Assumptions used were the following.
- Single index case in late Dec 2013.
- 53% mortality rate.
- Reproduction number of 1.57
- Average incubation period of 10 days.
- Transmission on average occurs (and thus begins the next generation of the epidemic) on day 5 after each infected individual’s symptoms begin.
- Reported cases and deaths are each 40% of actual.
- Estimates based on averages are reasonably representative of physical reality and will not be grossly in error.
For 9 October – the start date of the model’s generation 20 of the outbreak – this model predicted a reported number of cases of 7,724 and a reported number of deaths of 4,090.
Per the CDC website, on 8 October 2014, the reported number of cases was 8,011; the reported number of deaths was 3,857.
On the “bright side” – if you can call it that – the model I developed doesn’t predict 1.4 million cases until late Feb/early Mar 2015. Without changes in the outbreak, CDC predicts that number of cases by late January.
I guess I could say “Happy Halloween” at this point; the above is certainly scary enough. But I don’t see much to be happy about above.
THIS is why we need to do everything possible to keep this sh!t out of the United States. Period.
Are you listening, Mr. President?
Category: "The Floggings Will Continue Until Morale Improves", Barack Obama/Joe Biden, Foreign Policy, Military issues, Reality Check
Thought you were being alarmist until I got the that Dec 2015 total of cumulative cases WW of 5.9 BILLION. That’s 14 months… and effectively the entire planet.
The last few generations in the model are quite suspect, as human behavior would doubtless have changed dramatically by that time due to fear and/or societal collapse.
But IMO a death toll approaching or exceeding 100M worldwide is not outside the realm of possibility if this “goes really bad”. Neither is the complete disruption of regional economies and/or major portions of the world economy.
If that crap gets established in a major city or two anywhere, things could get incredibly nasty. The world owes Nigeria one helluva debt for clamping down in Lagos and Port Harcourt as quickly as it did.
I fear Sierra Leone and Liberia may be beyond help at this point.
Would not the model begin to fail too, as the number of survivors could potentailly be used as hosts for antidotes/antibodies to assist the sick? Or was that covered or possible?
JBS. Not considered, actually. But also very likely impractical because of the following.
1. The effectiveness of the procedure (transfusion of plasma or whole-blood from a survivor) has not been rigorously tested. It may or may not be particularly effective, anecdotal case evidence to the contrary notwithstanding. We just don’t know at present. It’s an experimental treatment, just like ZMapp and the other experimental drugs. It may or may not help (but if you’re dying anyway, it’s worth a shot).
2. One survivor can only likely give only enough blood/serum to help maybe one other person.
3. For transfusions, blood types must match.
4. Blood has a fixed lifetime in storage.
5. Survivor must be willing and healthy enough to give blood. Neither can be assumed – many Ebola survivors have medical issues afterwards.
6. Medical system will likely be overwhelmed long before enough donors are available to make a difference, even if the therapy proves effective (each sick individual requires intensive care for around 1 to 2 weeks).
Bottom line: workable on a small-scale (a few cases) – maybe. Probably not workable for a large and widespread outbreak involving tens or hundreds of thousands of cases.
Folks, although this sh!t spreads differently, in some respects it’s like smallpox. You catch it, you’re gonna be sick as hell and require intensive care to survive. At present, there aren’t any drugs that will “cure” you after you catch it. And you’ve got a damn good (25% or better – probably much better, actually) chance of dying. You catch it, you are screwed. Period.
Understood. However, Dr. Brantly has given his blood to assist already: Ashoka Mukpo, 33, who was working in Liberia as a freelance photographer for NBC News, is scheduled to receive a blood transfusion Wednesday from Dr. Kent Brantly.
Brantly, who contracted Ebola while working with Samaritan’s Purse in Liberia, had previously donated blood to Dr. Richard Sacra, a Massachusetts doctor who has since recovered from the virus.
Mukpo is being treated at the Nebraska Medical Center in a biocontainment unit, the same isolation center where Sacra was treated.”
It goes on to say that his blood “may” have been a factor in the survival. And not-with-standing proper blood types, perhaps there could be light at the end of the tunnel. And yea, we will loose many to get to this point.
As I said above: in a small, isolated outbreak that type of emergency, experimental therapy may be feasible – as well as treatment of last resort. But it’s not IMO suited to industrial-scale application as would be required during a major epidemic.
Isolating the antibodies and figuring out how to produce them synthetically in a reliable, industrial-scale process is a decent start.
Developing an effective vaccine is even better. That’s what it took to take out smallpox – which is believed to have killed over 500M prior to its eradication.
Nice job, Hondo.
Whoa. Holy. Sh!t.
For you old folks.
Time to declare a Code 2319 at all points of entry to the US.
What would have to happen here in the US to cause an uncontrolled outbreak like the one in Africa? And how would our government respond to it?
Well, here’s one possible response. This ought to do it. No more bugs–viral or crawling.
Only within maybe a 10-mile radius, 2/17 Air Cav. While 3rd degree burns at 100km were thought possible from something like that, that would only be on the side towards the blast. The “dark” sides would escape irradiation – and thus remain unsanitized.
Moral considerations aside, Liberia and Sierra Leone are each far larger than 314 sq mi.
Well, who said only one would be used?
Well, 2/17 Air Cav – aside from the fact that only 1 was ever built (smile): Liberia, Sierra Leone, and Guinea total somewhere around 166,000 sq mi. At 314 sq mi each, that means you’d need somewhere around 530 of them.
The 100MT version of the Tsar Bomba would have derived half of it’s power from fast fission of its U238 tamper (the version detonated only generated 50MT because it used an inert tamper – lead, I believe). That means it would have been dirty as hell – e.g., lots and lots of radioactive fallout.
Don’t think we want to see 530 of those detonated anywhere on earth, for any reason. Bad juju, indeed. (Yes, the pun was intentional.)
Well, Pinto Nag, let’s see. How long do some poor people in big-city slums push themselves while sick before going to a clinic or hospital emergency room to get checked out? How do they get there? Do they ever take public transportation – including Greyhound or Trailways – to visit people or run errands?
How often do people in big cities ride elevators with someone coughing and hacking, or bump into one another? Or shake hands?
The only saving grace is that this one is not normally spread via air transmission. So I think we could contain a small outbreak. But it would be expensive and disruptive.
And if there were multiple simultaneous outbreaks in different areas, well . . . .
It was a serious question, so your sarcasm is not appreciated, Hondo.
Our government has taken no effective steps to stop the disease from coming here, so we must assume we’ll have to deal with it. You did answer the first part of my question, but the second is important, also. What will the government do if it becomes uncontrolled here? Will they implement martial law? Containment camps and facilities? Drop a nuke?
What is the government plan in the event of (what could turn out to be) a biological weapon on American soil? That’s what the “B” in “NBC” warefare stands for, right? We’re supposed to have plans in place to fight an “NBC” attack, right? Or has the government ignored the “B” part of that acronym for the last 60 years?
Under this administration? Seriously?
Wasn’t being sarcastic, Pinto Nag. I was illustrating how an outbreak could possibly occur – albeit indirectly. I thought I made that clear at the end of the comment.
To answer directly: a few infected individuals in a major city IMO could – under the right conditions – cause a small-ish local outbreak (10-100 cases). My guess is that such an outbreak could be contained if confined to a single city.
The problem is that the US population by and large is highly mobile. That’s true even of those living in “poverty” (some of whom have substantial incomes from “off the books” or lawfully exempt sources). Should a number of those individuals travel while incubating and cause multiple outbreaks – or travel in different economic circles for a while for whatever reason – a number of simultaneous outbreaks isn’t outside of the realm of possibility IMO.
That scenario does worry me, because I don’t believe we have enough surge capability to handle multiple serious outbreaks if the “multiple” is big enough.
To answer your last question above: yeah, from my perspective bio has indeed been the “neglected red-headed bastard stepchild” of NBC for my entire professional life. Best I can tell, that pretty much started when we took the UN BW Convention at face value back in the early 1970s. IMO we may well regret that in the future.
I just answered my own question, and here’s the link:
http://www.fema.gov/pdf/emergency/nrf/nrf_BiologicalIncidentAnnex.pdf
I missed (and thus didn’t address) the second part of your question above. Yes, that’s probably how the Federal government would respond to a natural outbreak of a serious disease also.
The question is how well we could execute. Under this Administration, I have to say I’m not exactly optimistic. Providing adult leadership doesn’t seem to be their strong suit.
I think that, in countries with highly superstitious and uneducated large rural populations like India, Pakistan, Afghanistan, and many parts of SEAsia and Asia proper, the rate of infection and the rate of mortality would rise quickly.
Lower caste and extremely poor people in India have little to no access to medical care. I truly would expect to see entire villages wiped out, as happened in Europe during the Plague years.
It’s also reasonable to speculate that, as happened with the Plague, there might be small population groups, like the village of Eyman in England, that had the mutated CCR5 delta32 immune variation, which not only prevented their contracting the disease and surviving it, but was passed on to their descendants.
However, I don’t see this just yet as a doomsday scenarios as long as we are kept informed with accurate information from reliable sources.
And by that, I do not mean the government.
The U of MN has found recent changes in the virus’s symptomatic display. This means it mutates. It may find humans to be a better host than fruit bats, where it seems to have originated.
What does it take for some common sense to be used and ban all flights from the affected countries, as well as separating incoming passengers from those countries? The UK is doing high-end screening NOW.
What the hell is wrong that jackass in Washington? What does it take to make him deal with the real world? Does he think this has nothing to do with him?
Hondo…
With enough transmission it could become an airborne vector because of mutations. No telling how long it would be, either.
Dried secretions such as spit can also be a vector…
We are in big trouble!!
DefendUSA…The question of airborne transmission seems obvious to me. If I am in close proximity to an infected person and they cough or especially sneeze, uncovered, as a reflex, in my general direction, I think I’ll get it. I’ve seen slow motion videos of a person coughing and especially having an uncontrollable sneeze. The airborne, wet contaminates they put out and I perhaps inhale through my nose and mouth seem pretty sure to me an easy way to transmit it. Perhaps by airborne they are speaking strictly about normal breathing near an infected person, not a full blown sneeze or cough in my direction. So I am NOT assured at all it could not be transmitted this way.
Coughing or sneezing isn’t usually what’s meant by airborne transmission, Sparks. There, you’re getting sprayed with small droplets of saliva. Those droplets are generally too large to remain suspended in the air, and settle out of the air rather quickly.
However, some diseases (influenza, smallpox, I believe measles) cause the body of an infected individual to produce tiny droplets that are actually small enough (generally approx 1 micron or smaller) to stay suspended in air for a protracted period of time. Those droplets are typically large enough to carry a virus or ten, and often do so – very effectively and efficiently. This is generally what is referred to by airborne transmission.
To date, there is no evidence that Ebola Zaire (what we’re dealing with in the current outbreak) can spread that way from human to human. However, there is evidence that Ebola Reston (the one of Hot Zone/Reston “monkey house” fame) did indeed spread that way between the monkeys in the facility. So IMO it’s not outside the realm of possibility, even though it doesn’t appear to be happening at present.
Hondo…Thanks for the correction brother. Good information to know. I’ll “breath” a lot easier now when the wife and I travel through Dallas before long. 😀 (Though I am debating that trip and watching the news from the area.)
I would watch the news. And if there does end up being an active outbreak there, I think I’d avoid DFW – simply to avoid the hassle, if nothing else. An outbreak could conceivably foul road and air travel pretty badly, even if safely contained, due to checkpoints, additional first responders, etc . . .
Hondo…No worries my friend. If there is even a hint of the word outbreak, the trip is off. Our place is an hour and a half east of Dallas in the piney woods. We’d just put it off.
Pinto Nag…”What would have to happen here in the US to cause an uncontrolled outbreak like the one in Africa?” Great questions. I fear what would have to happen here, has happened. Mr. Duncan lied to get into the country for treatment he thought would be better for the Ebola he knew he had. After his symptoms appeared, he was around many family and community members. Hospital waiting room patients, nurses and doctors before he was diagnosed with Ebola. The number of close contacts he possibly made prior to his quarantine could be quite large. The community in his families area of Dallas is close quartered, concentrated and relatively poor. Public transportation is the preferred means of travel. My comment here is to simply say, we have the potential for this is Texas right now. I do not know how his symptoms were progressing when he transitioned through the airports to get to Dallas. If he had even “flu like symptoms”, he could have been contagious and thus transmitted the virus. This is all just my speculation based on current news. About what our government will do? I think what they have NOT done thus far is a pretty good indicator of what they WILL do or not do in the future. This Administration, once again, is putting their heads in the sand on this one and having the CDC and other agencies, (Agencies which know nothing about this but are saying what Obama is telling them to say.) release the, “Don’t Worry, Be Happy” press releases. I think it is called quelling the masses. I hope we as a nation do more than debate this on the floors of Congress, until some Senator or Congressman collapses due to Ebola. I hope they will stand up to Obama and DEMAND strict and harsh measures be taken now. Cut off all travel to even close areas to those infected in Africa. Cut off ALL incoming travel from regions even close to those infected. Inspect every travel visa to be sure someone has not gone from Liberia to Germany to Australia to… Read more »
Hondo…Thank you for all the work on this.
I’m with you Sparks, yet again.
Thank you Hondo. You are right on the money.
It would appear that if this does turn to epidemic proportions gathering places for treatment would NOT be a good place to go.
Stay out of the hospitals if at all possible and stay away from large crowds of people.
Obala is really dangerous and I prefer to watch it from my RV here at the Thunder Ranch !!!
Hondo, this is freaky and scary
Pinto, if you’ld like to see an example of how bad governmental response could be to a bio disaster, try reading ‘The Last Centurion’ by John Ringo.
Hondo,
This information is pretty alarming and sufficiently frightening. But it leads me to ask the question:
If this data accurate, realistic and legitimate, why don’t you do something with it beyond just another blog post? I mean, it’s fantastic that you can throw together a spreadsheet, but I’m guessing that the CDC has run some slightly more sophisticated analysis than =+TRUNC. There aren’t any factors in your spreadsheet that represent the fight against the virus. It just calculates it’s unchecked spread. I’m not sure how that’s helpful beyond making it look like you’re the smartest guy in the room…and scaring the bejezus out of people.
Everyone here seems to always be rooting for total economic/societal collapse so they can be the first to say “look I told you so!”. Whether it’s Ebola killing us all or Obama being Obama, it all leads to the same place: America in shambles. This place is an echo chamber.
The spreadsheet calculates an unchecked spread because that is what we have seen to date. It’s also a simple model based on spare-time effort. I do have a “day job” – which, unfortunately, doesn’t involve making policy concerning US response to the Ebola outbreak. Lord knows the naive fools calling the shots for that need some adult leadership. I assume that above you actually mean “measures taken to limit the spread of the virus” vice “measures to fight the virus”. With the possible exception of some unproven experimental drugs we have nothing at present that effectively “fights the virus”. In any event, such measures are accounted for by the model’s reproduction rate. Such measures would reduce it – when they begin, but so far they really haven’t happened. Feel free to modify it to take those changes into account (e.g., lower the reproduction rate beginning at some future date) and play whatever “what if” games you like from there. However, since you were apparently unable to figure out that the “TRUNC” and “ROUND” functions were used solely so that the results would be integers vice fractional people (I never have been able to figure out precisely what a fraction means with respect to a fatality or a survivor; people either survive or they don’t), should you choose to modify the model you might want to have someone who actually understands what they’re doing with both spreadsheets and math help you out there. I didn’t do that for two reasons. First: as I said previously, my time is limited. And second: I don’t have any data on what those changes would be over the next month. My crystal ball is dirty today, I can’t find my Ouija board, and my Tarot deck was lost in the last move. I think everyone’s in the same boat there, actually. You also might want to have someone help out by explaining the relatively simple English in this article to you – for someone now claiming a doctoral degree your reading comprehension seems a bit suspect. You apparently missed the fact, clearly stated above, that… Read more »
Nice smack down Hondo !!!!!
That’s gonna leave a mark……
OC
DrKnowPHD,MD…Here you are again. I tell you sir, I for one appreciate the work Hondo put into his analysis and shared. Am I an end of the world alarmist, NO. Not by any means. Do I believe that much more could be done by our government to protect its citizens before this does become a national problem, absolutely. If you have a better spreadsheet to share by all means post it. Until then, attacking and belittling Hondo for his efforts is childish for a man who is a PHD and MD. If you believe this blog to be “an echo chamber”, then please feel free to reduce the reverberations here by absenting yourself. Yes it is a free blog for all to participate but as a rule of courtesy and common decency, we don’t attack one another for their posts or efforts. In my mind, you are the one coming here to point out that YOU are the smartest guy in the room. First by adding your credentials to “show us dumb folk just who we’re dealing with” and second to belittle someone else instead of adding your own pertinent information. So get off the high horse DrKnow. You’ll get a nose bleed from the lofty heights from which you impart to us wee folk you superior intellect.
This is for Dr.Know:
There is also this factor, which should be taken into account but usually is not: there is such a thing as a shifting antigen virus, which is one that mutates rapidly for its own survival.
That was the basis for the flu disease in ‘The Stand’. Despite efforts to contain it, it spread rapidly and killed its host (mostly horses, dogs and humans), and altered its structure to allow it to jump to other hosts, just to survive.
If you think this does not happen in nature, think again. A few years ago, the common measles virus (rubieola) infected a horse racing stable near the Sydney, Australia airport. It had mutated into a lethal strain, infected many of the horses in the stable, the exercise riders and the owner. The owner, several horses and several of the exercise riders died from the effects of this mutant virus.
The H5N1 flu virus, which caused such a panic a few years ago, was a natural recombinant strain of flu in which avian, human and swine flu viruses bonded together to create a new strain, which, as was found later, was genetically nearly identical to the flu strain known as the Spanish flu, and just as deadly, with the same pulmonary impact and age range.
Those are two examples of natural occurrences in viruses, which have no other purpose than to survive and find new hosts. This strain of ebola is not the ebola Reston monkey virus, and frankly, there is nothing to say that it can NOT alter its structure to remain dormant in a carrier while it finds new hosts to infect.
And yes, diseases can do that. Mary Mallon was better known as Typhoid Mary, an asymptomatic carrier of the pathogen that causes typhoid fever. She herself was never sick with the disease, but wherever she worked, people became ill with typhoid and died of it. She herself died of pneumonia in November, 1938.
I believe your model fails because it over simplifies the basic reproduction number. The latest research I could find says that the effective reproduction number in Sierra Leon and Guinea has dropped to unity (endemic rather than epidemic), while still remaining 1.57 – 1.60 in Liberia.
Assuming that failure to implement adequate control measures in Liberia and slow impelementation in Sierra Leaon and Guinea would be replicated in the U.S. and the rest of the world is not realistic and contradicted by the examples in this current outbreak where the reproduction number has reached unity and below.
Please provide a citation to that research. I’d be interested to see it. What I found leads me to believe that both nations still have a reproduction number greater than one, though they may be lower than that in Liberia.
Senegal and Nigeria indeed have contained their outbreaks (though Senegal’s was tiny – precisely one case, in an individual who came there after being infected in Guinea). So those nation’s reproduction numbers for the Ebola outbreak are indeed now less than one. (smile)
Addendum: assuming these charts are accurate (and are based on best estimates for the reproduction number in each nation) – all three countries (1) still have a reproduction number greater than 1, and (2) will for at least the next month. Otherwise, the charts would show a peak, then stabilization to steady state (horizontal) or a decline (downward slope, left to right).
http://www.huffingtonpost.com/2014/09/26/ebola-forecast-graphs_n_5889520.html
Variously from these studies.
http://currents.plos.org/outbreaks/
Some of them disagree of course. The one from September 2nd is the first one I saw that the authors believe shows SL and G at unity. Other studies actually disagree with the idea of even using the k variable.
I scanned the abstracts. The R0 estimates are between 1.5 and 2.0. Using Hondo’s little model, I plugged in various reproduction numbers.
For an reproduction number of 1.5, there will be 1,000,000 cumulative dead by April 22, 2015:
1.5 = 22/apr/15
1.6 = 8/mar/15
1.7 = 22/jan/15
1.8 = 8/dec/14
1.9 = 23/nov/14
2.0 = 24/oct/14
I think that it is fair to point out that all of these number assume that the reproduction number does not change. The abstracts indicate that the reproduction rate in Guinea and Sierra Leone have dropped to about 1.
There are things that humanity can and will certainly do to change the reproduction number – like staying home and isolating ourselves from each other. When there is enough horror, we will do that without waiting for the government to tell us. Seems to me that at some point the medical profession will stay home – after all it is a job not a suicide pact. It is October, does everyone have enough firewood or propane or oil for a month?
On NPR today I heard an interview; the lady said we need a way to quickly determine if someone is infected. In my opinion, that would help a lot. It is research worth doing.
Lots of people have speculated about this kind of thing, Tom Clancy wrote a novel about an ebola epidemic. Seems to me that he gave the problem a lot of thought and I for one think that he was fairly close to the mark. FWIW I think that he may have received some professional advice. He had a lot of high drama but the math is the right and I think that he got the psychology right.
Fortunately for us, we don’t have multiple index cases.
Unfortunately Mr. Obama bears no resemblance to the fictional Jack Ryan. More’s the pity.
Thanks. I’ll take a look at them as time permits.
Here is the raw report data for the countries with infection, data up through about 3 days ago.
Select country_timeseries.csv for daily reports by country up through October 8th.
The person maintaining that data is CM Rivers. She is one of the authors of this powerpoint. It showed a crude reproduction rate of 2.16.
I built a model based on
this paper.
I am not trained in this so I am just playing with numbers.
I wondered if anyone had taken into account the possibility how this virus might react to cold winter weather, and found this bit of info from September:
http://pissinontheroses.blogspot.com/2014/09/us-army-says-ebola-flu-in-airborne.html
I remember some years back when Nightline was still respectable. They had a week about a pandemic viral attack against the US. I think it was when Anthrax and Smallpox were the monsters of the week. It ended with the questions about blowing the bridges and nuking the infected area to make sure. That ethical question and no one who wore a government badge at the time was comfortable answers without trying to find wiggle room.
Suddenly being in a college in the middle of nowhere isn’t looking like such a bad thing after all.
I wonder how this is all going to play out. If we can manage it, maybe even find a way to stop it.
“but I’m guessing that the CDC has run some slightly more sophisticated analysis than =+TRUNC”
The CDC advises against travel to West Africa but its director sees no problem with West Africans coming here. I don’t need a spreadsheet, or a satin one for that matter, to see which way the political wind blows for the CDC. (Roll tape, Chip.)
We are still a week out from seeing if the dallas incident becomes an outbreak. With the recent news of the botched response to our patient Zero, I’m very afraid that we may see several more cases there. I am heartened that the increased scrutiny of the potential new victims may be enough to stall this from becoming a full scale epidemic. If the virus has jumped out of the initial group of family members we may see a much worse scenario.
This reminds me of something I was thinking about the other day…. So you know that police officer that they tested because he went into the apartment, he was cleared, they say he does not have it. Why did they not give that test to the family in the apartment, instead they have to do the full 21 day quarantine? Seems fishy to me, if they can just give them the test too and find out in one day whether they have it or not. Any theories on that?
Thanks, Hondo. You explanation helps me understand how the CDC put together its calculations. I sincerely hope I don’t have to learn any of this in full detail.
For those interested in the Operation Dark Winter reference above from Hondo, here ya go.
http://www.upmchealthsecurity.org/our-work/events/2001_dark-winter/
Jacobite: thanks. Found that some time back, but managed to lose the link. Got it bookmarked now.
Smallpox is the true nightmare scenario – even worse IMO than Ebola. Very deadly (30% fatality rate vice 50%-80%), and much more transmissible.
Yes, it’s been eradicated. Maybe. If you believe Ken Alibek, maybe not. The Soviets allegedly weaponized smallpox by the ton before the Soviet Union disintegrated. And all it would take is a few grams of weaponized agent to touch off a wildfire – because unlike Ebola, smallpox DOES spread via airborne transmission (during the prodrome and early symptomatic phases, if I recall correctly).
Yes, we have a vaccine, and yes there is a stockpile of same. But we quit vaccinating the general public in the early 1970s – so unless you’ve received a vaccination as a deploying member of the military or as some other special case, you have no immunity. That’s the case with the majority of the world’s population today.
As I recall, the vaccine takes a couple of weeks to confer immunity. We’d thus see a race between vaccination and the spread of the disease with the stakes literally being millions or tens of millions of lives.
That’s not something I want to ever see in my lifetime. IMO, Ebola – while I don’t think it would be as bad as a renewed outbreak of smallpox – would be bad in its own right if it got completely out of control. And it might well come close to being as bad as a worldwide smallpox pandemic if unlikely things were to happen and things “went south” badly enough.
Ah, smallpox. Yeah, I have TWO smallpox vaccination scars, one from early childhood and one from RTC(W) 1967, when we went for all those shots you get for things you’ll never run into, like yellow fever, typhus, etc.
They both ‘took’. That either means that neither of them was effective, or there is no such thing as lifetime immunity.
Ex-PH2…You posed a good point. I also received the smallpox vaccine as a kid as well as the military. However, my son born in 1980 did not receive it in school like I did. I wonder if you or anyone knows if the smallpox vaccine is available from a doctor if someone wants to have it to “be sure”. Not trying to be an alarmist but my son having Crohn’s, an autoimmune disease, already has a compromised immune system and has to be very careful if he even gets a cold or the flu. Many Crohn’s patients die, not directly from the disease but they get a cold or the flu which quickly becomes bronchitis and then very quickly turns to pneumonia. By the time they are in the hospital, they can’t get enough antibiotics in their system soon enough and they succumb to the rampant pneumonia. I am just thinking about him is what prompted my question. Thanks for any info you or anyone else has.
I was inoculated as a kid, and again before heading to Iraq.
It’s still scares me more than ebola.
However, I’m WAY more afraid of the flu, or more specifically what happens when our infrastructure breaks down the way it would if we were to experience another true flu pandemic.
The flu it’s self wouldn’t be what ultimately took us down as a nation.
Scientists have not been sitting on their butts since the previous Ebola outbreaks. There were a number of solutions developed, but not manufactured for one reason or another. Those are being resurrected now.
http://reason.com/archives/2014/10/10/how-cutting-edge-medicine-might-have-spa
Finally found links to this, about Duncan having a 103F temp at the hospital before he was sent home.
http://www.nydailynews.com/life-style/health/dallas-ebola-patient-103-degree-fever-er-visit-records-article-1.1970141
Now, in most circumstances, if you have that high a temperature, you should be in bed getting lots of fluids, if nothing else. But he lied about whether or not he’d had contact with anyone with ebola in Liberia, and we now see the result of that lie.
On another note, Jesse Jackasson is still thrusting himself into the spotlight, moving Duncan’s family up to Chicago to Rainbow PUSH for another one of his grandstanding displays of self-absorption.
Ex-PH2…Wow. Just wow. While Jesse is busy playing the “poor pitiful, disenfranchised black folks card”, I wonder how many of Duncan’s family being moved to Chicago could possibly be infected? I only hope he flies them on the same plane with him and for public safety, that it is a private jet. But knowing how genuinely concerned Jesse truly is, he’ll probably fly first class commercial and put the Duncan family on Greyhound or Amtrac. Ex-PH2, have you heard any news about whether his family has safely made it through and past the incubation period for this disease yet? I understand they have been followed for symptoms, if that news is correct. But I have lost track of the time from Duncan’s possibly exposing them until now. I will do some digging but if you hear anything before me, please share it. Thank you.
No, I haven’t seen anything on that, Sparks. Keep looking for it. It’s buried somewhere.
I’m just appalled at the sheer stupidity that JJ displays on his rampage through the center of attention.
Meantime, stock up on disposable gloves and rubbing alcohol, and antibacterial household cleaners like Lysol and 409. They actually do work.
Also, 409 kills cockroaches, flies, ants, and other hard-shelled insects that can carry disease. They all have a waxy exoskeleton that softens quickly with a degreaser spray like 409 and they suffocate. And cockroaches are known to carry several nasty diseases.
Ex-PH2, plain vinegar is also an effective bactericide because of how it lowers the pH of where you use it. I’m also a fan of using bleach which is a base vs vinegar which is a mild acid. I didn’t know that 409 will kill roaches, I’ll have to remember that!
Thank you, HONDO, for making this critical information available.
I e-mailed it to all of my contacts, while urging them to also read the responses to your article.
About a zillion years ago, I was employed by the Department of Defense Police in a VERY isolated and remote area where various top secret research, including a biological warfare laboratory, was located and conducted.
When on patrol, if we found that facility unsecure, we were under strict orders to NOT, under ANY circumstances, to ever walk through those doors!
That particular building no longer exists, having been long since torn down and replaced by a newer facility, which I’m certain our government also denies any existence of, or its actual purpose.
I haven’t been back there in MANY years, and everything changes.
Hondo (or anyone familiar with the Reston strain) I know that the specialists duing the Reston outbreak had good cause to believe the Reston strain had gone airborne.
But I also seem to recall some paper criticizing their methodology/assumptions. Not sure if that was propaganda to squelch panic or a serious criticism of those claims.
Can you explain why some are saying the Reston assumptions (studies?) are flawed? Even if you think they are wrong – whats a fair analysis of their argument that the Reston strain did NOT go airborne?
Thanks.
I also don’t understand current preventative measures. My understanding is that Ebola once you develop systems you are passing the virus.
But there is a lag time between when you are infectous and when some authority *determines* you are infectous.
So it would appear there is a significant window of time where you are infectous but don’t realize it because your symptoms are developing.
Think of the lag time between when you start feeling fevorish and letharic VS when you realize you’ve caught the flu.
Fen: the precise point in time at which a typical Ebola sufferer begins to shed the virus is a good question. All I’ve been able to find is that it’s believed to start when the patient begins to show symptoms – and fever, malaise, and muscle aches are among the early symptoms.
But I’m guessing most people don’t recognize or ignore the early symptoms for a day or two, to see if they’ll go away on their own. So IMO, you’re correct – I’d guess most Ebola patients are contagious a day or two before they seek medical care or are otherwise recognized as having the disease.
Some updates on our current Plague:
Re: the health care worker fatality rate:
http://news.nurse.com/article/20141010/NATIONAL06/141010003
The rapid spread and death being underestimated:
http://www.naturalnews.com/047115_Ebola_fatality_rate_disease_transmission.html
I’m trying to find the story that now has the infected total at ++8,000 and the fatality rate at ++4,300. I’ll keep looking.
The infected people are going to die because there is no treatment for this disease. Health care workers can only give sufferers relief.
I’m not giving up hope, but the carelessness and stupidity by this (lack of) administration, and some of what appear to be outright lies, are all appalling.
This is becoming a nightmare.
Ex-PH2…Thank you for the articles. We are singing from the same sheet of music on this.
I found several sources for the infected v. fatality rates. Here’s the latest update:
http://www.telesurtv.net/english/news/WHO-Reports-Over-4000-Ebola-Deaths-20141010-0036.html
Infected reported: 8339
Deaths reported: 4033
This is since Thurday, if I’m not mistaken.
And then that braindead zombie bodaprez goes on TV and says it’s nothing to really worry about because it won’t really affect us here, or something like that. I could not listen to the psychobabble dripping out of his lying mouth.
Me quai gordo! Que lo desprecio!
It’s bad enough that the disease has made it onto US soil, what makes it so much worse is having a POTUS that only cares about his next tee time, fundraiser, or vacation and an incompetent administration that puts political correctness above everything else. I haven’t even contemplated what Jesse and the race pimps are wanting to do with this, I think he and his ilk would protest about movies like “Twister” because no black people got hurt or killed in them!
Buckle your seatbelt, Proud. It’s gonna be a bumpy ride.
The PC crap will start flying out the window before too long. Mark my words. The distance between that and reality is vast, and reality will look a lot more attractive to the zombie suckups than it used to before long.
Phew, just checked the spreadsheet. I’m feeling pretty lucky that I am not one of the 1.1 Million cases of Ebola right now. Good thing we closed the borders and prevented that awful massive global pandemic.