The base graph is the WHO/CDC released figures on the Wikipedia page about the outbreak.
Posted on 09/15/2014 2:50:13 PM PDT by scouter
My User Name on Free Republic is Scouter. I have been a member of Free Republic for 14 years. I don't write many vanity posts, but I consider this one to be very important. I had been working on this post for several days, and I was planning to post it tomorrow. But the Drudge Report headline CDC: PREPARE FOR EBOLA has moved up my timeline.
I have developed a model for making future projections of the number of Ebola cases. I have undertaken this project for several reasons. First, out of simple professional curiosity. Second, I believe the time has come to be concerned and to prepare for the possibility that the Ebola epidemic could spread to other countries, including the United States. And third, my daughter will soon begin working as a nurse in a major Pediatric Intensive Care Unit, which will likely see some of the first Ebola cases in the United States, should it make an appearance here.
I am not an epidemiologist, and I have no inside knowledge about the current Ebola epidemic. But I have spent the last 26 years of my career applying computers to the practice of medicine and to medical data. I hold a Master's Degree in Medical Informatics from a major university known for their expertise in that field. I currently work in that field at a large, famous, metropolitan teaching hospital. I am remaining anonymous only because I don't want my employer to be held responsible for this post in any way. It is my work exclusively, and I am responsible for any information or projections it makes.
The numbers produced by this model are "projections", not "predictions". That is to say, I do not predict that there will be x number of Ebola cases on any given future date. Rather, I "project" into the future, assuming a constant Daily Transmission Rate (DTR), based on past data. Any number of factors can influence future DTR, in either a positive (bad) direction, or in a negative (good) direction. There is no way to know how these factors will actually play out. If there were, then we would be able to make actual preditions. As it is, we are left only with the ability to say "If Ebola continues to spread at the same rate it has been spreading for the past x number of days (or months), then this is approximately how many people who will have contracted the disease as of this particular date in the future." Not ideal, for sure, but still quite useful to understand the seriousness of the situation.
I have validated the model based on actual data by calculating the DTR for various periods of time and comparing the model's projections with what actually happened in subsequent periods. This is the same concept that is being used by epidemiologists at CDC and elsewhere. It is a valid method, within the constraints I have mentioned above. My model has been completely in line with projections I have seen quoted in the mainstream news. It works quite well. If anything, my model's projections are a bit more conservative than some projections you may have seen in the mainstream media. I just take them out further than you have seen in other places.
That being said, the following projections are based on the Daily Transmission Rate (DTR) from June 1 through September 10, the last date for which I have data. The DTR has remained relatively stable over that period. To be conservative I assumed that the reported number of cases represent the true size of the epidemic. However, the WHO, CDC, Medicins Sans Frontieres, and Samaritan's Purse all agree that the number of reported cases represents only 25% to 50% of the true number of cases. I have decided to be conservative in the numbers published below, but the model allows you to adjust this percentage.
As you review these projections, remember to pray for all those who are currently affected by this terrible disease, those who have it, those who will die, and their families. Do not forget that these are real people with eternal souls, who will either go to heaven or to hell, depending on whether or not they die in friendship with God. Pray, too, for an end to this epidemic. Do not underestimate the power of prayer!
The following projections assume that the currently reported cases represent 100% of the true epidemic size. In other words, that there are no cases that were missed by the epidemiologists. We know this not to be true, so we know that the "best case" is something worse than this, assuming the Daily Transmission Rate remains stable.
Scouter Ebola Projection Model Version 1.0 - Ebola Case Projections
*********************************************************
Projection Parameters
*********************************************************
Start Date: 6/1/2014
End Date: 9/10/2014
Reported cases represent 100% of the true epidemic size
Daily Transmission Rate (DTR): 1.00422415489918
*********************************************************
Weekly for the Next 8 Weeks
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/10/2014 4,845 2,376 171 84
09/17/2014 6,227 3,054 219 108
09/24/2014 8,003 3,925 282 138
10/01/2014 10,285 5,044 362 178
10/08/2014 13,218 6,482 465 228
10/15/2014 16,988 8,331 598 293
10/22/2014 21,833 10,707 769 377
10/29/2014 28,060 13,761 988 485
End of Month for the Next Year from the End Date
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/30/2014 9,923 4,866 349 171
10/31/2014 30,146 14,783 1,061 521
11/30/2014 88,357 43,331 3,111 1,526
12/31/2014 268,427 131,637 9,451 4,635
01/31/2015 815,475 399,911 28,713 14,081
02/28/2015 2,224,815 1,091,055 78,336 38,416
03/31/2015 6,758,941 3,314,601 237,983 116,707
04/30/2015 19,810,535 9,715,135 697,531 342,071
05/31/2015 60,183,993 29,514,379 2,119,084 1,039,204
06/30/2015 176,399,989 86,506,991 6,211,061 3,045,920
07/31/2015 535,899,508 262,806,446 18,869,075 9,253,441
08/31/2015 1,628,051,594 798,400,534 57,323,860 28,111,763
09/10/2015 2,329,918,242 1,142,597,677 82,036,655 40,230,979
The following projections assume that the currently reported cases represent 75% of the true epidemic size. Remember that Medicins Sans Frontieres, Samaritan's Purse, the CDC, and WHO all agree that the number of reported cases already vastly underestimates the true size of the epidemic. They say by a factor of 2 to 4.
Scouter Ebola Projection Model Version 1.0 - Ebola Case Projections
*********************************************************
Projection Parameters
*********************************************************
Start Date: 6/1/2014
End Date: 9/10/2014
Reported cases represent 75% of the true epidemic size
Daily Transmission Rate (DTR): 1.00422415489918
*********************************************************
Weekly for the Next 8 Weeks
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/10/2014 6,460 2,376 235 115
09/17/2014 8,373 4,106 305 149
09/24/2014 10,853 5,322 395 194
10/01/2014 14,068 6,899 512 251
10/08/2014 18,234 8,942 663 325
10/15/2014 23,635 11,591 860 422
10/22/2014 30,635 15,024 1,115 547
10/29/2014 39,709 19,473 1,445 708
End of Month for the Next Year from the End Date
Date Cases Deaths Daily New Cases Daily New Deaths
========== ==================== ==================== ==================== ====================
09/30/2014 13,556 6,648 493 242
10/31/2014 42,764 20,972 1,556 763
11/30/2014 129,996 63,750 4,729 2,319
12/31/2014 410,085 201,107 14,920 7,317
01/31/2015 1,293,657 634,413 47,066 23,081
02/28/2015 3,651,570 1,790,739 132,851 65,150
03/31/2015 11,519,271 5,649,079 419,092 205,524
04/30/2015 35,016,714 17,172,283 1,273,972 624,759
05/31/2015 110,464,001 54,171,820 4,018,881 1,970,869
06/30/2015 335,792,614 164,673,529 12,216,744 5,991,122
07/31/2015 1,059,294,023 519,480,413 38,539,038 18,899,640
08/31/2015 3,341,657,268 1,638,757,001 121,575,553 59,620,953
09/10/2015 4,840,743,028 2,373,912,370 176,115,013 86,367,239
Obviously, there are many factors that will affect these projections. Rather, this model simply projects the number of cases and fatalities based on the current Daily Transmission Rate (DTR), which has been stable for about 3 months. Consider the following other factors that are likely to change the DTR (either for good or for bad) as we move forward from today:
While the numbers quoted above are grim, they do not yet represent fact. Do not panic, but do not be complacent, either. Any preparations you make to "shelter in place" will serve you well for other contingencies, too.
On the other hand, epidemiologists are already saying that the number of cases is already doubling every two weeks. That means that the numbers I've posted above are actually quite conservative.
This model is contained within a macro-enabled Microsoft Excel 2010 spreadsheet (i.e., a .xlsm file). I would be willing to share it with other Freepers if someone can provide a place to post it for download and can tell me how to sanitize my name from it (again, I don't want my employer to be in any way held accountable for this).
While this article isn’t the one I had recalled, it does talk a bit about pre-symptomatic contagiousness.
http://scienceblogs.com/gregladen/2014/07/27/ebola-outbreak-in-west-africa-some-basic-information/
I’ll keep looking.
Aha. The place that the pre-symptomatic contagiousness was noted has been removed from the website, but was originally found at
While that page no longer exists, it was, while it was up, cited by many other websites. If you google this phrase:
cdc-changes-criteria-for-ebola-transmission-admits-being-within-3-feet-or-in-same-room-can-cause-infection
which was basically the name of the page, you will find a host of reputable sites pointing to this page. So what happened? Was the original posting in error, and removed? Or was I removed for other (politically correct) reasons?
Very good question. Almost worthy of its own thread.
Your math is not making sense to me.
First a DTR (Daily Transmission Rate) of 1.004 is way too low.
And I’m not sure what you are doing putting both the DTR and the DaysOut in the exponent. That might work in your formula, but I don’t think the formula makes logical sense.
Work it through one day at a time and see if you get the same result.
Start with 100 cases and let’s do just 3 days.
If you have 100 cases on day 0 and the DTR is 1.004 then you would have 100*1.004 = 100.4 on day 1, and 100.4x 1.004 = 100.8 on day 2, and 101.2 on day 3.
But if you plug it into your formula for 3 days, then you get:
100^(((1.004-1)*3)+1=
100^(.004*3)+1 =
100^(.012+1) =
100^1.012 = 105.6, but it should equal the same result that we walked through day by day. So either your formula is wrong, or I don’t understand exactly what you are doing.
http://www.cdc.gov/vhf/ebola/transmission/index.html
http://www.cdc.gov/vhf/ebola/hcp/clinician-information-us-healthcare-settings.html
http://www.cdc.gov/vhf/ebola/hcp/infection-prevention-and-control-recommendations.html
If it were to spread in the U.S.A., it would likely be carried to all points in the country quickly by travelers then stay in the communities for several years. Unlike flus, it’s an extremely tough virus that lives a long time on dry surfaces in a great range of temperatures, leaves survivors contagious for about six months and spreads very slowly but surely. Generally, nearly all people would be resigned to trying to live as they have.
‘Don’t Touch the Walls’: Ebola Fears Infect an African Hospital
http://www.freerepublic.com/focus/f-news/3190930/posts
Patrick Sawyer became infected in Liberia, traveled to Nigeria, denied to medical folks that he had it and urinated on nurses in defiance. Medical personnel contracted the disease from him. So he used a weapon that was more dangerous than firearms.
The disease is transferable to dogs that might then infect their owners.
Ebola Virus: From Wildlife To Dogs
ScienceDaily
http://www.sciencedaily.com/releases/2005/06/050608065550.htm
Date:
June 9, 2005
Source:
Institut De Recherche Pour Le Développement
“Ebola virus antibodies were detected in dogs exposed to the virus during the latest epidemics, which suggests that these animals may well have been infected and can therefore be a new source of transmission to humans.”
How is Ebola spread?
The virus is spread through direct contact (through broken skin or mucous membranes) with blood and body fluids (urine, feces, saliva, vomit, and semen) of a person who is sick with Ebola, or with objects (like needles) that have been contaminated with the virus. Ebola is not spread through the air or by water or, in general, by food; however, in Africa, Ebola may be spread as a result of handling bushmeat (wild animals hunted for food) and contact with infected bats.
Can I get Ebola from a person who is infected but doesn’t have fever or any symptoms?
No. A person infected with Ebola is not contagious until symptoms appear.
http://www.cdc.gov/vhf/ebola/outbreaks/guinea/qa.html
We’ve seen many articles with headlines about cures (as with the false reports about AIDS cures for decades), but there’s no cure and no vaccine. Blood serums might help as a treatment (not known), but most of those who recover will be very messed up—mind and body—for the remainder of their short lives.
Given your qualifications for creating these projections, as to the qualifiers effecting the data as it unfolds in the real world, in your work with statistics are their not certain logarithmic formulae that can be applied, particularly with the data when the available pool becomes larger and perhaps more accurate, that might tighten your projections around probabilities?
Wouldn't it be more accurate to hash out columns rated against their range of probabilities, e.g., 10-20 % 10 to 20 millions; 20-30 % 10 to 5 millions, etc?
Thanks for the ping!
Ebola is transmitted exclusively by bodily fluids and not by air, like colds and the flu. In developed countries, Ebola would be less transmissible because of less crowding, much greater sanitation as a matter of routine, and the availability of modern medical care. Finally, in the developed countries, isolation measures would prevent the hospitals from being centers of Ebola infection as they commonly are in Africa.
Sir,
I have an advanced degree in mathematics, and unfortunately I confirmed your findings last week when the death total was near 1500. When the WHO reported that the number of cases was doubling every three weeks, I quickly realized that there would be over a billion people with Ebola in 12 months unless something changes. Therefore, I concur with your projection. We are facing an apocalyptic scenario unless something fundamentally changes. May God help us.
Thanks,
M.F.
I Googled that phrase, and all that comes up are a bunch of conspiracy sites (which really don’t interest me). I did go to one, and it had a screenshot from the CDC, which supposedly showed something that the CDC later “hid” by removing that particular page. Since that one site had screenshotted the CDC web page, I looked at it and compared to what is currently posted on the CDC. The page was edited and rearranged, but the information there is identical.
Despite the supposed conspiracy and “admission” that Ebola is suspected to transmit through droplets—which has been suspected for decades, and so hardly is a new “admission”—I do not see anything on any page that contradicts anything I know about Ebola.
Every single medical journal article I have read says that Ebola is only transmissible when symptoms appear, and that it becomes more transmissible as symptoms worsen. It can remain infectious in certain compartmentalized fluids for weeks after infection, but will eventually clear.
Quite true. In Africa, theft and corruption undermine virtually every hospital and medical clinic. Travelers who venture outside of major African cities are sometimes urged to bring along emergency medical kits since antibiotics, bandages, and hypodermic needles are often unavailable or local examples are unsafe to use.
The base graph is the WHO/CDC released figures on the Wikipedia page about the outbreak.
Ebola would spread even faster in developed countries.
* Travel, eating out, shopping, public entertainment, etc., are much more common.
* Customers are forbidden from wearing masks in many public places.
* There’s a popular aversion to hand-washing, where even medical professionals are hastily using hand sanitizer instead of scrubbing.
* Although the floors are shiny, many hospitals and clinics even smell filthy compared to such places forty years ago.
* There’s also the trend toward socio-political spite between groups (balkanization).
* The aversion to hygiene is most apparent in public places around tourist centers in western states.
* Our country has far too few medical employees and hospital beds relative to the population.
* There will not be enough quarantine facilities for more than a very few.
* The economy would completely seize, so fearful market interests (sponsors, most influential political constituents,...) are motivated to prevent any measures that could alarm the population and decrease revenues. They would lose all that they have during an epidemic and will take all that they can get in advance.
* Drug abuse is very common and has been legitimized in some states by legalization.
* The few highest bidders for questionable treatments in very short supply would do anything to get them, exacerbating the situation.
Every body fluid you can think of. Sweat. Spit. Urine. Feces. All of these exit the bodies of the victims in copious amounts and all of these have copious amounts of the virus. Cough or spray aerosols the virus over a relatively large area. Being in a car with someone who is sick has already spread the disease and killed others.
In developed countries, Ebola would be less transmissible because of less crowding, much greater sanitation as a matter of routine, and the availability of modern medical care.
You would think. Except for subways, Walmarts, restaurants, malls, trains, airplanes, schools, immigrants living stacked on one another to save money, etc. etc. If anything it's just as crowded in most of our major cities as it is in Africa.
Finally, in the developed countries, isolation measures would prevent the hospitals from being centers of Ebola infection as they commonly are in Africa.
People routinely get "hospital" diseases such as mrsa. That can't even be eradicated. Unless ALL medical personnel are willing to suit up every time they see a patient with the sniffles, runny nose, fever or diarrhea this disease will spread just as surely as it is in Africa.
We have a better health care system, and are able to keep patients quarantined while tests are run to determine if they do have Ebola (if they have the travel history to suggest such testing is worthwhile). In the hospital, we practice good infection control measures.
An even more important factor is that we do not have the customs that they have in Africa.
That's right. The USA has 128 Million people who commute to work every day. Only 75% of these people drive alone. The rest really "commute", sharing the ride by carpooling, bus, train, subway, plane. Lots of filthy people contact all along the way.
Most of those people interact with others a couple of times each day at fast food joints, convenience stores, gas stations, dry cleaners, grocery stores, big box stores, etc., exchanging money, credit cards, products, etc., hand to hand.
Probably half of these working people have at least one meeting each day, crammed into little meeting rooms.
There are also 200 Million people who don't go to work, but interact with other people daily at schools, daycares, stores, bars, on the street, sporting events, etc.
People in the USA are just as filthy and stupid as people in the worst cultural conditions in Africa, just in different ways.
When ebola starts spreading in the USA, it will travel faster and farther than in Africa. Aiding in its spread will be the people saying, "there's nothing to worry about here," to their last gurgling gasp.
In the US and other developed countries, there are well-established public health measures to identify, isolate, and treat dangerous infectious disease cases and contacts. This would probably suffice for even Ebola, but, if not, the menace of a general outbreak would swiftly lead to stronger measures such as the cancellation of public events and suspension of non-essential work, shopping, and travel.
An outbreak of Ebola in a developed country would lead to face masks, gloves, and the general spraying of disinfectant becoming routine in public places. In contrast, in Africa, poverty, corruption, theft, and the shambolic nature of its societies commonly make it impossible for even medical personnel who treat Ebola to have the benefit of containment garments and disinfectants.
In a developed country that suffered an Ebola outbreak, medical care for the disease would improve rapidly, with new treatments and vaccines fast tracked into use. The result would almost certainly be the rapid and permanent containment of any such Ebola outbreak, just as bird flu and SARS were contained despite the dire predictions that attached to them.
In sum, Ebola is cause for concern and excitement in the US and other developed countries but is extremely unlikely to generate more than a relatively small number of cases.
There are many ways in which our culture is not conducive to the spread of a disease like Ebola.
The most important way is in the way we treat the dead. We don't wash the bodies, we don't give them enemas. Instead, we ship them off to a mortuary to prepare for burial or cremation. During the funeral, most people do not touch the body. This is very different than the African burial customs which are completely responsible for the early spread of Ebola. Later on, nocosomial infection became important.
For another thing, even in the most crowded situations, we avoid touching each other. I noticed this at Disneyworld over the summer: no matter how crowded an area was, every American had a no-touch zone around him or herself. This was not true of some of the foreigners, who did not seem to mind bumping or being bumped.
Ebola requires direct contact to spread. While other potential means of spread have been mentioned--droplet transmission, fomites--there is no real evidence supporting those means. People who are sick enough with Ebola to be shedding virus in fluids aren't going to be out riding buses and so forth--they are really, really sick. I could see such a person hunkering down in their home until they die, but not being out and about contaminating public restrooms with their diarrhea and vomit.
If Ebola were easy to catch, this thing would have already gone around the world. Compare to influenza--it is about to sweep the northern hemisphere again, and it will essentially hit every continent at once, because it spreads easily and it spreads through aerosols. Ebola, on the other hand, is still confined to three countries--the imported outbreak in Nigeria is controlled, and I don't think there are new cases.
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