October 16th, 2014
by Fabius Maximus, FabiusMaximus.com
Summary: The hysteria about Ebola grows apace, fed mostly by those who profit from it (through status, publicity, clicks, or sales). Information is the antidote. Here we have experts telling us the key facts about Ebola, and debunking some of the most incendiary myths.
A follow-up to An epidemic afflicting America: fear about Ebola. Avoid the carriers. Facts are the antidote. Much of the hysteria results from our loss of confidence in experts; see posts about this problem here.
- Status report: good news and bad
- Debunking the Ebola myths
- A far greater threat than Ebola
- Sources of reliable information about Ebola
- A history of pandemics
(1) Status report: good news and bad
(a) Good & bad news from the Ebola situation assessment, WHO, 14 October 2014:
If the active surveillance for new cases that is currently in place continues, and no new cases are detected, WHO will declare the end of the outbreak of Ebola virus disease in Senegal on Friday 17 October. Likewise, Nigeria is expected to have passed through the requisite 42 days, with active surveillance for new cases in place and none detected, on Monday 20 October.
... In Guinea, Liberia, and Sierra Leone, new cases continue to explode in areas that looked like they were coming under control. An unusual characteristic of this epidemic is a persistent cyclical pattern of gradual dips in the number of new cases, followed by sudden flare-ups. WHO epidemiologists see no signs that the outbreaks in any of these 3 countries are coming under control.
... For WHO to declare an Ebola outbreak over, a country must pass through 42 days, with active surveillance demonstrably in place, supported by good diagnostic capacity, and with no new cases detected. Active surveillance is essential to detect chains of transmission that might otherwise remain hidden.
The period of 42 days, with active case-finding in place, is twice the maximum incubation period for Ebola virus disease and is considered by WHO as sufficient to generate confidence in a declaration that an Ebola outbreak has ended.
(b) Counting the toll, from the Ebola Response Roadmap Update, WHO, 10 October 2014:
A total of 8,399 confirmed, probable, and suspected cases of Ebola virus disease (EVD) have been reported in seven affected countries up to the end of 8 October. 8,376 (99.%) were in Guinea, Liberia, & Sierra Leone. Four other nations have cases imported from them. Twenty in Nigeria, One each in Senegal, Spain, & USA.
There have been 4,033 deaths. 4,024 (99.7%) were in Guinea, Liberia, & Sierra Leone. Eight in Nigeria; one in USA.
(2) Debunking the Ebola myths
(a) "Ebola is highly contagious - plus seven other myths about the virus", James Ball, The Guardian, 9 October 2014 - Excerpt:
Don your tin foil hat & click here to watch! It's not by the WHO.
1. Ebola is highly contagious
Compared with most common diseases, Ebola is not particularly infectious. The primary risk of catching Ebola comes from the bodily fluids of people who are visibly infected - primarily their blood, saliva, vomit and (possibly) sweat. These can transmit the disease if they make contact with the mucus membranes (lining of your nose, mouth, and similar areas).
Each patient in the current Ebola outbreak is infecting on average two healthy people (this figure, known as the R0 value, can be reduced with appropriate precautions). The Sars outbreak of 2002-03 had an R0 of five, mumps 10 and measles a huge 18. ...
3. If you catch Ebola you'll almost certainly die
At present, about 8,000 people have been confirmed as diagnosed with Ebola, and of those 3,865 have, sadly, died. This is a fatality rate of 48% (though it could increase as some of those still ill die) - tragically high, but not nearly as bad as it could be.
Given the rudimentary and overloaded conditions in many of the hospitals in affected areas, it is likely this rate could be lower still for patients with access to top-tier medical care.
(b) "What we know about transmission of the Ebola virus among humans", Ebola situation assessment, WHO, 6 October 2014 - Excerpt:
The Ebola virus is transmitted among humans through close and direct physical contact with infected bodily fluids, the most infectious being blood, faeces and vomit. ...
Ebola virus disease is not an airborne infection. Airborne spread among humans implies inhalation of an infectious dose of virus from a suspended cloud of small dried droplets. This mode of transmission has not been observed during extensive studies of the Ebola virus over several decades. ... Epidemiological data emerging from the outbreak are not consistent with the pattern of spread seen with airborne viruses, like those that cause measles and chickenpox, or the airborne bacterium that causes tuberculosis.
Theoretically, wet and bigger droplets from a heavily infected individual, who has respiratory symptoms caused by other conditions or who vomits violently, could transmit the virus - over a short distance - to another nearby person. This could happen when virus-laden heavy droplets are directly propelled, by coughing or sneezing (which does not mean airborne transmission) onto the mucus membranes or skin with cuts or abrasions of another person.
WHO is not aware of any studies that actually document this mode of transmission. On the contrary, good quality studies from previous Ebola outbreaks show that all cases were infected by direct close contact with symptomatic patients.
Moreover, scientists are unaware of any virus that has dramatically changed its mode of transmission. For example, the H5N1 avian influenza virus, which has caused sporadic human cases since 1997, is now endemic in chickens and ducks in large parts of Asia. That virus has probably circulated through many billions of birds for at least two decades. Its mode of transmission remains basically unchanged.
Speculation that Ebola virus disease might mutate into a form that could easily spread among humans through the air is just that: speculation, unsubstantiated by any evidence.
(c) Ebola will mutate into a super-bug
"Scientists Rein In Fears of Ebola, a Virus Whose Mysteries Tend to Invite Speculation", New York Times, 13 October 2014 - Excerpt:
News that a nurse in full protective gear had become infected with the Ebola virus raised some disturbing questions on Monday. Has the virus evolved into some kind of super-pathogen? Might it mutate into something even more terrifying in the months to come? Evolutionary biologists who study viruses generally agree on the answers to those two questions: no, and probably not.
The Ebola viruses buffeting West Africa today are not fundamentally different from those in previous outbreaks, they say. And it is highly unlikely that natural selection will give the viruses the ability to spread more easily, particularly by becoming airborne. "I've been dismayed by some of the nonsense speculation out there," said Edward Holmes, a biologist at the University of Sydney in Australia. "I understand why people get nervous about this, but as scientists we need to be very careful we don't scaremonger."
... Evolutionary biologists see no evidence that new mutations in the Ebola virus are responsible for the huge size of the current outbreak. "It's far more plausible that the difference is that it's gotten into a different human population," Dr. Rambaut said. Instead of being limited to remote villages, the virus ended up in cities like Freetown, Sierra Leone, and Conakry, Guinea. The combination of a big population of hosts and a medical system unable to control the infection has led to an epidemic. "You've got a fairly standard Ebola virus," Dr. Holmes said. "It's just in the worst possible place."
... Over the course of millions of years, viruses do sometimes switch their route of infection. "It does happen in an evolutionary context," Dr. Holmes said. But it would be a mistake, he warned, to imagine that with a single mutation Ebola might become an airborne pathogen. The change would require many mutations in many genes, and it might be nearly impossible for so many mutations to emerge during a single outbreak. The mutated viruses would survive only if they were superior to the ones spread by bodily fluids. "The virus is doing pretty well right now," Dr. Holmes said. "So it would need to be beneficial for the virus to make this quite big jump."
Dr. Rambaut agreed that the odds were exceedingly low. "Viruses generally don't change to that radical degree," he said.
Dr. Sabeti said, "It is biologically plausible, but very unlikely."
(3) About a far greater threat than Ebola
"The Worst Pandemic in History", Mark Joseph Stern, Slate, 26 December 2012 - Excerpt:
A flu virus isn't particularly complex; it's just a stretch of RNA transmitted between animals, human and nonhuman, that has evolved to mutate quickly enough to outpace any long-term immunity. But one stretch of RNA can wreak a lot of havoc. Spanish influenza killed about 50 million people (estimates vary), including 675,000 in the United States, and up to 40% of the world's population was stricken with the flu.
... Spanish flu was a pandemic of a different magnitude compared to swine flu, bird flu, or any other recent outbreaks. And perhaps because of its worldwide prevalence, it became the foundational flu of modern times. Before 1918, another influenza virus was surely being passed from human to human. When Spanish flu emerged, it out-competed this virus, mutating with greater celerity and spreading with ease. And though it has since mutated further, Spanish flu remains the basic strain of influenza being spread today. If you had swine flu, or even a standard-grade seasonal flu, you almost certainly contracted a mutation of Spanish flu.
... The problem comes along when a completely new influenza virus emerges, one that knocks Spanish flu off its throne. ... "You can say with almost complete certainty that humans will face future pandemics of influenza," Taubenberger said. "And at the moment, we can't predict them in advance."
(4) Reliable information about Ebola
(a) Debunking the hysteria:
- "Why you're not going to get Ebola in the U.S.", Washington Post, 1 August 2014
- "How calm can counter Ebola", editorial in the Christian Science Monitor, 3 August 2014 - "Health officials say they must act as much to calm fears of Ebola as to contain the outbreak. Media-driven hysteria about Ebola doesn't help."
- "Containing Hysteria About Infectious Disease", Dr. Eugene Beresin, Psychoogy Today, 2 October 2014
- "Out of control: How the world's health organizations failed to stop the Ebola disaster", Washington Post, 4 October 2014
- "In the Face of Ebola, Stay Calm", Anna Altman, op-ed in the New York Times, 7 October 2014
- "The Ebola alarmists: Stoking panic will not help America fight Ebola", The Economist, 11 October 2014
(b) About Ebola, the disease:
- Ebola fact sheet, WHO, September 2014
- "Ebola virus and U.S. preparedness: Review of research perspectives", John Wihbey, Journalist's Resource, 3 October 2014
- "'In 1976 I discovered Ebola - now I fear an unimaginable tragedy'", The Guardian, 4 October 2014 - A history of Ebola, by its discoverer.
- "Controlling Ebola: next steps", Ranu S Dhillon, Devabhaktuni Srikrishna, and Jeffrey Sachs, The Lancet, 8 October 2014
(5) A history of pandemics
With Africa reeling from the recent Ebola outbreak, global attention is focused squarely on the danger of an uncontrollable outbreak of disease. In this interactive piece, we look at the world's deadlist outbreaks, as well as history's most dangerous diseases.
Click on the title to see the interactive graphic. Use the scroll bar at the top to view the history of outbreaks, or click any of the diseases at the bottom for more info.