Archive

Essay

Great News From Liberia

The news from Liberia is wonderful: the last known Ebola patient has been discharged from treatment! [NYT 3/6/15] This doesn’t make Liberia “Ebola free” – that requires 42 days (twice the incubation period) with no new cases. Many contacts are still being monitored, and others may not have been identified, so Liberia may still have to deal with a few more local outbreaks before it can declare victory. Also, so long as Ebola continues in neighboring countries the disease may be brought back to Liberia by travelers (though note this heartening item about an effective Liberian border control operation: [IOM 2/4/15]). And the risk of an unrelated jump to a human from an animal reservoir will continue indefinitely. Nevertheless, this is a moment to be savored!

Update 3/24/15: A new patient has been identified in Liberia, who probably was infected by her boyfriend, an Ebola survivor. [NYT 3/24/15]. This is disappointing, but the fact that only one instance has come to light suggests that this mode of transmission is rare.

Ongoing Transmission in Sierra Leone and Guinea

Sierra Leone initially showed a similar pattern of precipitous decline in patients, but since the end of January weekly cases have stabilized between 60 and 100. [WHO 3/4/15] This is better than exponential growth, but it’s not on track to ending the epidemic. Guinea didn’t have as sharp a peak, but it also hasn’t experienced such a dramatic improvement: about 50 cases are continuing to arise each week. In both countries the steady rate of new cases implies an Effective Reproduction Rate of about 1. Pushing this down just a little would eventually end the epidemic, while letting it rise would allow exponential growth to resume. Liberia has shown that it’s possible to snuff out the epidemic, but Sierra Leone and Guinea are not yet following in Liberia’s footsteps.

I don’t claim to know how Liberia did it, but somehow the Effective Reproduction Rate dropped to about 1 in September, then fell much lower from October on. Sierra Leone’s peak and fall were similar, but occurred about two months later, and the decline has now leveled out. While the opening of new treatment centers certainly helped in recent months, my own best guess is that the main factor in both countries is that people simply “got religion.” That is, a large enough fraction of Liberians came to accept that Ebola is caused by a virus, not a curse; that people who fall ill need to be cared for in safe settings, rather than at home; and that corpses need to be handled with extreme care. I suppose that a comparable fraction of Sierra Leone’s population reached similar conclusions, but the epidemic is now continuing there and in Guinea within sub groups that haven’t fully accepted the message.

Devilish Details

The last Ebola patient in Liberia, Beatrice Yardolo, came from a worrisome cluster of cases “in a community called St. Paul’s Bridge, located in what was one of the biggest Ebola hot spots in Monrovia, New Kru Town.” [NYT 3/6] The New York Times reported that, “[t]he outbreak was unusually violent and far-reaching, in part because it involved criminal gangs that did not cooperate with the authorities and fears that it could be spread through a knife fight with one member nicknamed Time Bomb.” Even more troubling was the fact that known contacts on several occasions left Monrovia for other parts of the country. [FrontPageAfrica 2/3/15] One of the escaped contacts died in Margibi County, and required the tracking of 256 contacts there. [GNN Liberia 2/4/15]

Ebola came into the Yardolo family from Beatrice’s cousin Steve, who probably became infected at an Ebola treatment center where he worked. [AllAfrica 3/6/15]  Steve infected several other members of the family, eventually including his daughter Amanda. Beatrice took responsibility for Amanda’s care, but again and again Amanda was mis-diagnosed and rejected from Ebola treatment centers. Beatrice was left responsible for bathing and otherwise caring for her. After Amanda died Beatrice went immediately to a treatment center started showing symptoms, which probably saved her life.

Ebola didn’t end in Liberia because people behaved well, but because the strategies of isolation and contact tracing worked despite much bad behavior and many mistakes.

Sierra Leone’s experience is vividly described in another New York Times piece. [NYT 2/18/15] The epidemic was re-ignited by three sick fishermen who landed in a poor area of Freetown in early February. Two dozen people in the area ended up contracting Ebola from this initial group before transmission was brought under control. A quarantine was imposed but was frequently broken. One shopkeeper fell ill but was afraid to go to a hospital in Freetown. Instead he broke quarantine and traveled three hours to his home village, where he visited a traditional healer, then died. He caused the infection of some 42 people in the district.

Endemic Ebola?

Ebola is still being actively transmitted in Sierra Leone and Guinea, and may yet recur in Liberia, or spread to other countries. But the Liberian experience gives every reason to hope that the techniques that worked there can eventually end this epidemic altogether. The possibility must be acknowledged, however, that the epidemic will continue indefinitely, neither growing exponentially nor definitively ending. In this case Ebola would become “endemic” to West Africa — just one of the typical diseases that people get there. I can’t disprove this — indeed it seems to be happening now in Guinea — but I have several reasons for doubting that this will happen with the current strain of Ebola:

  • It’s too deadly. A cluster of a less lethal disease might go relatively unnoticed, but this can’t happen with Ebola. The deaths of family and friends, one after another, cannot be ignored. The presence of Ebola in a community will not be tolerated for long.
  • Its incubation period is too short. A disease that takes months or years to emerge (e.g. AIDS, leprosy, tuberculosis) can hide in a human population, but Ebola emerges quickly, or not at all.
  • It’s only transmitted from person to person. Aside from the wild animal reservoir (discussed below) Ebola appears to be transmitted only from person to person. A disease that could also infect some more familiar animal, like fleas or rats, could hide in the animal reservoir and reemerge unpredictably. Fortunately, Ebola shows no sign of doing this.
  • It’s only transmitted by direct contact. Fortunately, Ebola isn’t airborne; it’s transmitted only by direct contact with bodily fluids or contaminated surfaces. This makes contact tracing and isolation so effective. It’s much more difficult to contain a disease like the flu that spreads through the air.
  • People are infectious only when they are ill.  Update 3/24/15: (except for the semen of male survivors). There is no indication that there are “Typhoid Marys” who can transmit Ebola without themselves falling ill, except for one instance in which a male survivor appears to have infected his partner, presumably through semen, which is known to contain Ebola virus for several months after recovery. [NYT 3/24/15] This will make the disease a bit more difficult to eradicate, but is not cause for panic. As noted above, the fact that just one infection of this type has come to light suggests that this mode of transmission is infrequent. Additionally, now that an example exists one might expect many “discordant couples” (in which the male is a survivor and the female is not) to use condoms, which should further reduce the risk. One question that calls for further research is how long the virus can persist in the semen of a male survivor, and whether a negative semen test is sufficient to make unprotected intercourse safe for the survivor’s partners.

For these reasons I think it’s highly unlikely that Ebola will become endemic based on human-to-human transmission (absent mutation). So long as we don’t lose focus I expect that Sierra Leone, and eventually Guinea, will be able to end this epidemic using the standard techniques of contact tracing, isolation, funeral management and education.

The Wild Animal Reservoir

In one important respect Ebola already is endemic to East Africa: For forty years it has jumped every few years from its wild animal reservoir (probably fruit bats) into a human population. Just this year an unrelated Ebola outbreak in a rural area of Uganda flared briefly and was extinguished. [CDC]  There is every reason to expect this pattern to continue, since:

  1. even when we have a vaccine it will never be feasible to vaccinate the entire relevant population,
  2. contact with infected animals such as bush meat may be reduced through education but can’t be prevented altogether, and
  3. there is no conceivable way to eliminate Ebola from the animal reservoir.

This is too bad, but it’s a bearable situation, since most outbreaks start in remote rural areas, where they can be quickly snuffed out so long as they are detected early and the response is competent and decisive.

So far as we know the West African epidemic arose from a single jump between a wild animal reservoir and a human. There might be some reason why this was an isolated incident that won’t recur. But it seems much more likely that Ebola is now established in a West African animal reservoir, from which it will now jump periodically into humans, the same way it has for decades in East Africa. After the current epidemic is brought under control it will be essential for all West African countries to establish systems for early detection of new Ebola outbreaks, as has long been the case in East Africa.

We’re lucky that infective contacts between humans and the wild animal reservoir are so rare. If Ebola became established in an animal population that lived in closer contact with humans — rats, pigs, or even dogs — animal-human transmissions could be much more frequent. There is no evidence, however, that this is happening. Genetic evidence continues to indicate that the entire West African epidemic was sparked by a single animal-human transmission in Guinea, from a bat to a 2-year-old boy.

There are still great challenges and great dangers — more on that later — but the big news is the abatement of the epidemic in Liberia.

Miracle in Liberia

Here is WHO’s chart of new cases in the country as a whole, and in the Montserrado district (which includes the capital, Monrovia). [WHO Current Ebola Situation Report]

Liberia_New_Cases_20141203

The drop, starting in mid-September, is breathtaking, even when figures from the patient database are adjusted by more realistic situation reports. There is now a big oversupply of isolation beds in Monrovia, and in some other parts of the country. The ready availability of beds certainly contributed to the drop in new cases, but other factors must also be at work since the fall began while all available beds were still occupied. I speculated on the reasons for the apparent drop in my previous post: Too Good to be True? I don’t have much to add, except that behavior must have dramatically changed in Liberia. Changing people’s behavior is very hard, especially when it relates to deeply-rooted cultural norms such as caring for loved ones and religiously-mandated burial practices. The message from Liberia is that behavior change is possible, and it can stop Ebola (in its current form) in its tracks.

The magnitude of the change is dramatic. The Reproduction Rate (defined in The Ebola Chain Reaction) for Liberia had been estimated in September at 1.51 [NEJM 9/23/14] , which is consistent with the left half of the charts shown above — exponential growth. The right half of these curves implies a Reproduction Rate far below the steady state of 1.0, which means that the rate dropped by at least a factor of two in a period of just a few weeks. It’s marvelous that such a large change was possible in such a short time frame. This affords a solid basis to hope that the same can be accomplished in the other affected countries.

The epidemic is by no means over in Liberia! We must not let down our guard, or infection rates could jump up again. But we can certainly take heart. It might also be reasonable to mothball the construction of new isolation facilities in Monrovia, keeping open the option of finishing them if they are ever needed. To the extent possible, new facilities should be constructed in Sierra Leone and Guinea, or perhaps under-served parts of Liberia,  rather than in Monrovia.

Steady Rate in Guinea

The rate of new cases jumped dramatically around the end of August and has continued at more or less the same level. This is a continuing severe epidemic, with Reproduction Rate around 1, but it is growing slowly if at all.

Guinea_New_Cases_20141203

WHO’s helpful situation report breaks the results down by region and points out a particular vulnerability in the northern area adjacent to Mali, which may lead to further spread to that country.  [WHO Current Ebola Situation Report] This is still a desperate crisis, but the slow rate of growth gives us time to get ahead of the situation. And the example of Liberia shows that control is possible.

Exponential Growth in Sierra Leone

The big worry now is Sierra Leone, where the rate of new cases is continuing to grow exponentially.
Sierra_Leone_New_Cases_20141203

Growth in Sierra Leone is country-wide, but the capital of Freetown presents the most acute problem because it is running out of beds. Once again, the WHO situation report describes what’s happening and the management plan: [WHO Current Ebola Situation Report]  We just have to hope that the miracle in Liberia can be replicated in Sierra Leone.

Concluding Observations

Just a few weeks back Liberia was the greatest worry, and the focus was on building isolation facilities there, especially in Monrovia. Now many of those facilities stand empty. Like a wily prize fighter Ebola ducked the roundhouse punch we had planned for it there, and is continuing to fight in other parts of the ring. This doesn’t mean that our plans were mistaken, or even unnecessary, since nobody could have foreseen the dramatic drop in transmission in Liberia. But it does mean that we need to be nimble in responding to where the greatest need currently is — Sierra Leone and the northern districts of Guinea. The need to redeploy resources is problematic, since it takes time and effort to design, build and staff a new facility. We have no choice, however: we must follow the epidemic wherever it goes.

So long as there is active transmission we are still exposed to two big risk factors:

  • spread to another country with crowded slums, traditional practices and a weak healthcare system, and
  • mutation to become more contagious.

I’m optimistic at this point that we can control the epidemic before either of these disasters occurs, but the need to end Ebola is still urgent.

 

 

 

 

For months treatment centers in Monrovia have been turning away patients, who are then cared for at home, which places household members at high risk of infection. New treatment facilities have been filled as soon as they become available. Projections showed the need for ever increasing numbers of beds, for at least the next several months.

But suddenly, around the middle of October, reported cases and burials in Monrovia have started to drop. Some Ebola clinics are less than half full! [NYT 10/31/14]  [Economist 11/1/14] Can it be that the epidemic is waning? Or are appearances deceiving? On the same day Yale researchers warn that deaths could skyrocket, consistent with the earlier models of exponential growth. [Yale Daily News 10/31/14]

I don’t have a crystal ball, but I will just throw out a few ideas:

  • Home treatment kits started being distributed around the middle of October. [Reuters 10/20/14] This is a desperate stopgap, since patients become so highly contagious in the last stage of illness that caregivers and others in a household are likely to be infected. But is it possible that many people are using home treatment kits instead of taking patients to clinics? If so, the epidemic could be roaring ahead unnoticed. Except for this: where are the burials? To make sense of this hypothesis you would have to also assume that families were secretly burying their dead members (thus creating more opportunities for infection). While this has been reported it seems implausible that it would occur widely enough to impact statistics, especially in an urban context.
  • More hopefully, the worst Reproduction Rate seen for Ebola in this epidemic was 2.2, which, though ample to fuel exponential growth, is not that much above the steady-state level of 1.0. (See my earlier post for details). Also, transmission of Ebola is a function of human behavior: primarily incautious care-giving and the handling of dead bodies. It’s difficult to change people’s behavior but the crisis in Liberia may just have been sufficiently acute for this to happen. Many individual decisions just may have added up to success: not to touch someone who seems ill; to use a barrier when touch is necessary; to sterilize objects with chlorine bleach; to allow a body to be taken away without traditional cleaning and funeral rites.
  • This report is from Monrovia, the capital of Liberia. We must not lose sight of what’s happening in other parts of Liberia, and in the other countries with active transmission: Guinea, Sierra Leone, and now quite possibly Mali.

Meanwhile, a new 200-bed treatment unit opened on October 31 in Monrovia. This is a big addition to the 500 beds previously available. “The daily management of the treatment centre will be taken care of by the Liberian Ministry of Health and Social Welfare, with support from African Union and Cuban foreign medical teams.” [WHO 10/31/14] I hope it is never needed, and that unused Ebola facilities may perhaps become the nucleus of an improved ongoing healthcare system in these desperately poor countries.

Ebola Resources

Ebola’s mortality rate may depend on several factors:

  • The particular strain of Ebola.
  • The age and underlying health of the patient.
  • How ill the patient is when s/he begins receiving care.
  • The quality of the care the patient receives.
  • The availability of antibody treatments such as ZMAPP or serum taken from survivors.

Prior Outbreaks

Before this year most Ebola outbreaks have been confined to rural areas, and treatment has been what was feasible in a tent. The West African epidemic is of the Ebola Zaire strain, for which WHO reports mortality rates from prior epidemics ranging from 44% to 90%. [WHO 9/14]

West Africa

It was initially thought that the mortality rate for the West African epidemic was around 55%. [Reuters 8/5/14]  In September, however, a scholarly article in the New England Journal of Medicine calculated the mortality rate in Guinea, Liberia and Sierra Leone at around 70%. [NEJM 9/23/14]  A Sierra Leone study of 44 patients [Reuters 10/29/14] showed 74% overall mortality, but broke the figure down in illuminating ways:

  • 57% of people under age 21 died, compared to 94% of those over the age of 45. Older patients have greater mortality risk.
  • 33% of patients with less than 100,000 copies of the virus per milliliter of blood at diagnosis ultimately died, compared with 94% of those whose had more than 10 million copies per milliliter. As we’ve previously suspected, mortality is highly dependent on how sick a patient is when treatment starts.

A thrilling anecdote from Liberia is also suggestive: A student nurse named Fatu Kekula cared for four household members, and managed to save three of them, achieving a 25% mortality rate. [LA Times 10/6/14]  She avoided infection herself using a resourceful combination of surgical gloves, plastic bags, raincoats and copious amounts of chlorinated water. Critically, she was able to give them IV drips, and she was on call essentially 24/7. What happened to any four patients has no statistical significance, but the demonstration that such a good outcome is even possible is heartening.

Nigeria

Nigeria had an outbreak sparked by a single air traveler from Liberia. Despite many high-risk contacts — and many incidents of quarantine-breaking and other misconduct — in the end there were only 19 cases, of which 7 died, for a mortality rate of just 37%. [WHO c.10/15/14] The number of cases is small, so this figure isn’t too statistically significant. One may speculate, however, that the lower mortality rate in Nigeria reflects two main factors: (1) better quality of health care, and (2) the fact that many patients were being monitored daily, so were presumably given care as soon as they began showing symptoms. The single patient who traveled to Senegal survived, and the child who traveled to Mali died, but neither case tells us anything about overall mortality rates.

The U.S. and Europe

The number of cases treated in western countries is also small, so even less statistically meaningful than the figure for Nigeria. As in Nigeria, most of these patients received treatment as soon as symptoms were noticed, which may be a significant benefit. Disregarding patients still in treatment, the figures, from the excellent New York Times Ebola Facts page, are as follows:

  • United States: 8 patients, of which 1 died and 7 recovered, for a mortality rate of 13%.
  • Europe: 8 patients, of which 3 died and 5 recovered, for a mortality rate of 38%.

Since the figures are so small the difference between Europe and the U.S. could easily be random. But it’s interesting to note that Thomas Eric Duncan, the patient who died in Dallas, had initially been turned away by the hospital, and only started receiving care after he had become so ill that he had to be transported by ambulance. His two nurses, in contrast, began receiving care soon after they first developed fevers, and both have recovered fully. CNN’s discussion of the factors that affect survival in western countries is a bit dated but still worth a look: [CNN 10/20/14]

Dr. Paul Farmer, a Harvard professor and co-founder of the charity Partners in Health, has expressed the hope that with top-notch care the mortality rate for Ebola could be as low as 10%. [London Review of Books 10/23/14] This isn’t inconsistent with the U.S. experience, keeping in mind the low sample number. It will be wonderful if it proves possible to substantially reduce the mortality rate in the African setting. An improved standard of care would not directly help stop the epidemic, but it would indirectly contribute to stopping transmission if it encouraged more people to enter clinics rather than staying at home, which increases the risk of infecting other household members.

Added 10/31/14: Paul Farmer’s emphasis on quality of care implicitly criticizes the way some twenty Ebola outbreaks have been handled since 1976, most notably by Médecins Sans Frontières / Doctors Without Borders (“MSF”). I would characterize the MSF approach as embodying three priorities:

1. Stop the Outbreak, by Isolating Patients.
2. Protect Staff from Getting Infected.
3. Cure as Many Patients as Possible.

For nearly 40 years MSF has been stunningly successful at achieving these goals, often in remote rural settings with extremely limited infrastructure. I’m sure Dr. Farmer would hasten to agree that we owe MSF and its peers an enormous debt of gratitude for their extraordinary service to humanity.

My own view is that MSF’s priorities are correct. Stopping the outbreak must always be job #1. One wants also to minimize risk to staff, but some risk is inevitable and must be accepted in order to end an Ebola outbreak. Curing patients is every doctor’s objective, but if a choice must be made stopping the epidemic is more important. Similarly, if staff start becoming infected at excessive rates we would lose the ability to either stop the outbreak or cure patients.

Saying that these priorities are correct does not, however, answer the question of how much can and should be done to cure patients.

My understanding, for example, is that MSF typically does no blood work apart from an initial test to confirm the diagnosis and final tests to confirm a cure. Often there would be no lab available to do additional testing anyway; it’s difficult and risky for a staff member wearing goggles and three layers of gloves to take a blood sample; puncturing the skin of an Ebola patient can lead to infection and/or uncontrolled bleeding; getting a blood sample takes precious time away from other patients; blood tests would cost money that might be better spent elsewhere; etc. etc. When regular blood tests are available, as in western hospitals, care can be customized to the patient’s individual needs. Infections can be identified and halted; imbalances in electrolytes identified and corrected, etc.

I presume that MSF would agree that a higher standard of care would be desirable, wherever it is feasible. The real question in each situation is where do you strike the balance between an aspiration for the best standard of care and the need to quickly isolate patients to stop the outbreak, as well as constraints of money and infrastructure. It may be that the MSF approach should be implemented quickly as soon as an outbreak is identified, then upgraded as time and resources permit.

Dr. Farmer’s push for a higher standard of care is directly opposed to a recent WHO proposal for “clinics” that would isolate patients but offer little or no medical care. [AP 10/2/14] This is a desperate response to the situation in Monrovia several weeks back where patients were being cared for at home — often infecting many household members — because there were no beds available. Since there now appear to be open beds it may be hoped that we don’t have to do in this inhumane direction, which explicitly sacrifices patient care to the overriding goal of stopping the epidemic.  [Economist 11/1/14]

Antibody Treatments

A handful of U.S. and African patients received the few available doses of ZMAPP, an artificial antibody treatment that has been successfully tested in monkeys. The U.S. patients survived and several of the African patients died, but the numbers are too small to reach any conclusions about its effectiveness. Similarly, several U.S. patients received antibodies in serum taken from survivors. The fact that they survived is encouraging, but again the numbers are too small at this point to support conclusions.

Yet again, Ebola has infected a caregiver: a nurse who gave extensive care to Thomas Duncan in Dallas. She wore full protective gear and is not aware of any breach of anti-infection protocol. [NYT 10/13/14] This is worrisome, but consistent with the pattern we have previously noted: How Contagious is Ebola?

Update 10/15/14: Another nurse has been diagnosed. This is tragic, and unnecessary, but completely predictable given the criminally shambolic conditions under which Duncan was treated. [AP / Mashable 10/15/14]  Obviously, America has to do a lot better. But there’s every reason to think that we will rise to the occasion. What cannot continue is for Ebola patients — especially in the last stage of the illness — to be treated casually or on an ad hoc basis. Ebola will bite you if you don’t respect it! But MSF knows how to handle Ebola patients with minimal risk to caregivers. CDC simply needs to take the lessons of Africa and Spain and Dallas to heart. The solution is simple:

  1. All healthcare providers must be trained to identify and isolate potential Ebola patients, with minimal risk to themselves and others, and
  2. Confirmed Ebola patients must be treated by fully-trained professionals, with top-notch equipment, in well-designed facilities, following clear and prudent protocols.  At the moment there are plenty of beds in the four bio-containment hospitals but at least one hospital should gear up in each major city to be able to safely treat Ebola patients. Full bio-containment isn’t necessary for Ebola.

Some facts about Ebola are becoming clear:

  • Those at greatest risk are caregivers — either healthcare providers or those who care for a seriously ill patient in the home. Intense focus and attention to detail are needed to protect a caregiver, especially when a patient is in the last stage of the illness.
    • The African protocol developed by Médecins Sans Frontières / Doctors Without Borders (“MSF”) has been extraordinarily successful, although some members of their staff have nevertheless been infected.
    • The protocols used in Spain and in the U.S., as implemented so far, have not given caregivers complete protection.
  • Patients are most infectious in the last stage of the disease. There is no evidence of transmission before a person becomes symptomatic, and even after symptoms begin patients seem to be remarkably non-contagious until the final stage. The main focus should be on where patients are, and who has contact with them, in the final stage of the illness.
  • Corpses are also highly infectious. African customs of washing and touching corpses present a second important channel of infection, that needs to be discouraged. Developed countries should not encounter this issue, however, so long as suitable precautions are taken.

These lead to a few specific conclusions:

  • In the developed world the main risk presented by Ebola is to healthcare providers. There are plenty of beds, and nobody is going to try to care for an extremely ill patient in their home. CDC needs to refine its anti-infection protocol and to provide better training and support to hospitals and staff who treat Ebola patients, and similar steps need to be taken in other developed countries. There’s every reason to think that this will happen, and indeed is already happening. Ebola will teach us, as I’m sure it taught MSF in the early outbreaks, what we need to do to stop it. I still see no reason — apart from possible mutation — why the developed world should have any problem snuffing out little Ebola outbreaks as they inevitably occur.  (I’m still quite concerned about the ability of other poor countries, with crowded slums, to do the same.)

    • Healthcare providers need to be monitored for 21 days after their last contact with an Ebola patient. Duh!
  • West African healthcare providers also need to be better protected, ideally with identical gear and an identical protocol to those in the developed world.
  • In West Africa the key to stopping Ebola is isolation beds for patients in the last stage of illness. The best feasible standard of care should be provided for humanitarian reasons, but from the perspective of stopping the epidemic the critical element is isolation. The only way to bring the Effective Reproduction Number down below one is to break the cycle of transmission to home caregivers, by isolating patients and caring for them under the anti-infection protocol. Again, this issue has been identified and is being dealt with. The big question is whether beds can be provided fast enough to get ahead of the epidemic.
  • West African funeral practices also need to be addressed, and of course corpses must continue to be buried or cremated, which may prove problematic if the numbers of deaths mount as currently predicted. [NYT 10/14/14]

There are really only three things you need to know about Ebola. Each of them is a serious problem, of a distinct type. But the only solution to all three issues is to end the epidemic in West Africa as soon as possible.

1. Humanitarian Crisis in West Africa

In case you’ve been distracted by the news from Dallas, the real issue is in Liberia, Sierra Leone and Guinea, where the epidemic is continuing to grow exponentially. In case you aren’t aware how bad it is my last blog post will better inform you. These countries urgently need our help to moderate and eventually end this terrible situation.

2. Risk of Spread to Other Poor Countries

There will continue to be isolated cases of Ebola in the Western world: A traveler will occasionally fall ill, as in Dallas. A healthcare worker will occasionally be infected, as in Spain. Each patient may possibly infect a few more people, but with care and attention any little outbreak should be readily brought under control. Hard though it is to believe, Ebola really isn’t very contagious, relative to common diseases like measles and the flu. The total number of people affected in developed countries will probably be on the order of how many people are struck by lightning. Accidents, suicides, and many other diseases present far greater risks in our world.

In a poor country, however, with weak healthcare infrastructure, and crowded slums, Ebola might gain a foothold. It is hard to imagine that the world would ever again allow an epidemic to get as far out of hand as the one in West Africa, but it’s possible. And that has the potential to multiply the disruption, sickness and death of the current epidemic many fold.

3. Risk of Mutation

The last worry is the possibility that Ebola could mutate to become more infectious. The Ebola Reston strain seemed to pass between monkeys through the air, so this anxiety isn’t entirely fanciful. [CNN 10/6/14] The best way to prevent such a mutation is to stop the cycle of human-to-human infection in West Africa. The more rolls of the dice Ebola gets the greater the risk that a mutation will increase its ability to infect. Which could obviously be a big problem.

Conclusion: We Must Stop the Epidemic

The brouhaha about Dallas, and most recently about the Spanish nurse’s puppy, is predictable, but we need to return our attention to the main point. For all three of the reasons mentioned above job #1 is ending the epidemic in West Africa. Cutting off travel and the like may seem to make us safer, but in fact they make us less safe, by exacerbating all three of these primary issues. We’ve got to stop the epidemic!

(I’ve oversimplified a bit: If you’re a healthcare worker you need to know more, precisely in order to avoid as many as possible of the blunders which have characterized the responses in Dallas and in Spain. And if you’re in West Africa of course you need to think about a lot of additional issues.)

The main purpose of this blog is to analyze Ebola as rationally and dispassionately as possible. In this post, however, I’m going to collect some of the most moving and stirring items I’ve encountered in connection with the West African epidemic. I’ll start with the most ghastly images I’ve seen, then mention some pieces that are harrowing but less horrible, and end with stories that are inspiring and even hopeful. I plan to add to each category as the epidemic develops, with the hope that eventually everything will be added to the final group.

Horror

These are the most dreadful items I’ve read. I don’t recommend reading more than one or two at a time, and if you are at all squeamish just skip to the next section.

Disorder

Cultural Damage

Survival

Inspiration

Hope

Note: Thanks to the EbolaReport blog for collecting several of these items.

Like sparks from a burning building, travelers are carrying Ebola around the world. What’s been happening? What will happen? What can we do?

The Ebola Diaspora

People travel for lots of reasons, some related to the epidemic, some not.

  • Now as always people will want to travel for business, tourism, or to spend time with family or friends. With Ebola increasingly out of control more and more of the people traveling from West Africa will turn out to be infected. I’ll address later in this post the idea of stopping travel altogether, but in short it wouldn’t work, except perhaps to delay the inevitable.
  • As life becomes more difficult in the affected countries people will have an additional reason to travel, seeking either a temporary respite or an extended or permanent refuge. If things get really bad this could change from a trickle to a panicky exodus.
  • People who have been exposed to Ebola, but are not yet symptomatic, may have a special incentive to travel to a country with a modern healthcare system. Such passengers also have a strong incentive to lie about their Ebola exposure, as the traveler from Liberia to Texas apparently did. [CNN 10/3/14] This could be a particular problem for developed Western countries, but also for more prosperous African countries such as Nigeria and South Africa.
  • Fever monitors in airports should prove to be an effective method of barring symptomatic patients from air travel. Update 10/6/14: It has been suggested that ibuprofen could be used to hide a person’s fever in order to get a symptomatic patient through airport screening. [Reuters 10/3/14]  I don’t know whether this is true, but if so it would be a weakness in the screening process.
  • Symptomatic patients may still slip across porous borders on the ground, but airport controls somewhat reduce the spread of Ebola and nearly eliminate the already-low risk to the airplane’s crew and passengers. Port authorities in the affected countries and their neighbors are attempting to do the same type of screening of ship’s crews. [AFP 9/29/14]

The bottom line is that people infected with Ebola will travel to other countries, on the ground and by air and by sea. Wherever they go they will fall ill, and potentially infect others, setting off local Ebola outbreaks. Everything will depend on the location and the response. Stable countries with capable healthcare systems and effective governments should be able to snuff out their Ebola outbreaks fairly easily, depending on the the level of noncompliance they encounter. Poor countries with crowded slums and limited healthcare may not be so lucky.

What’s Been Happening?

Apart from medical evacuations we know of just three cases in which someone infected with Ebola traveled outside of Guinea, Liberia and Sierra Leone.

Nigeria – Patrick Sawyer

Patrick Sawyer, a Liberian-American diplomat, traveled on July 20 from Monrovia to Lagos via Togo despite having severe Ebola symptoms, including vomiting repeatedly during his flights. He collapsed in the airport and was taken to a hospital where he died a few days later, but not before infecting half a dozen people who themselves went on to infect a dozen more. Nigeria identified and tracked 894 contacts of Sawyer and other infected people, of which 20 came down with Ebola and 8 died. [Washington Post 9/30/14] Details are in my earlier posts: Arrogance and Privilege Imperil Nigeria’s Attempt to Contain Ebola and How Contagious is Ebola?

This story involves multiple instances of noncompliance with quarantine orders and lying, as well as many cases in which hospital staff were unnecessarily infected. Nevertheless, Nigeria’s persistent contact tracing and isolation measures, and capable healthcare system, eventually brought the outbreak (apparently) to a close.

Senegal – A Guinean Student

A 21-year-old student named Mamadou Alimuo Diallo was under surveillance in Guinea because several relatives had fallen ill with Ebola. He nevertheless traveled by car to Dakar, Senegal, despite the fact that the border between Guinea and Senegal was supposed to be closed. He arrived in Dakar on August 20, and stayed in the large household of his uncle. He began feeling ill on the 23rd and went to a medical facility seeking treatment for fever, diarrhea and vomiting, but concealed his contact with Ebola patients, and was sent back to his uncle’s home. He was eventually admitted to a hospital for Ebola treatment on the 26th. [USNews 9/1/14]  Some 67 people with whom the student had been in contact were monitored, but none came down with the disease. The student recovered and returned to Guinea. [Modern Ghana 9/10/14]

Senegal apparently did a good job of contact tracing but really just got lucky, since this situation illustrated a lot of problems:

  • The student broke quarantine in Guinea.
  • The student was able to get into Senegal despite the fact that the border was supposedly closed.
  • The student lied about contact with Ebola patients on the 23rd, putting medical staff and family members at risk by going back to his uncle’s home.

It may be that Senegal’s medical facilities used better precautions than those in other countries, or it may be that the student was for some reason just not very infectious. But you couldn’t even call this an outbreak since there was no transmission of the virus in Senegal.

Dallas – Thomas E. Duncan

Thomas Duncan is a Liberian who traveled by plane from Monrovia to Dallas, Texas, arriving on Sept. 20. He lied on an exit form which asked whether he had had any contact with Ebola patients, since on Sept. 15 he had helped carry a stricken neighbor back into her apartment (after she had been turned away from a hospital). His temperature was taken at the Monrovia airport but was not elevated. [NYT 10/2/14]  On the 24th he developed symptoms and on the 26th went to the Texas Health Presbyterian Hospital Dallas. Although he told hospital staff that he had recently traveled from Liberia this information didn’t reach the diagnostic team and they sent him home. Update 10/4/14: The hospital has changed its story and admitted that in fact the entire diagnostic team had access to the fact that Duncan came from Liberia. [NYT 10/3/14] Reportedly, however, on his first hospital visit Duncan falsely denied having contact in Liberia with anyone who was ill. [AP 10/2/14]  On the 28th Duncan was taken to the hospital by ambulance and placed in isolation, with laboratory confirmation of Ebola on the 30th. [NYT 9/30/14]

The people at greatest risk were the four people in the apartment where he stayed in Dallas. They were initially told to stay at home, but were “noncompliant,” including sending at least one of their children to school! [Dallas Business Journal 10/2/14] Formal quarantine orders were then issued requiring them to stay home and not to receive visitors, and a police guard was posted. [Yahoo 10/3/14] Bureaucratic snags delayed cleaning of the contaminated apartment for several days after Duncan went into hospital. They subsequently have been moved to a lovely isolated home donated by a member of “a Dallas faith community.” [NYT 10/3/14]

A total of 12 to 18 people are believed to have had direct contact with Duncan, and they may in turn have had contact with around 100 other people. Those with direct contact are being monitored. This includes 5 school-age children. [Dallas Business Journal 10/1/14Updated 10/4/14: About 50 people are being monitored daily, of which 10 had direct contact with Duncan. [CDC 10/4/14]

Lots of mistakes have been made already, and it’s reasonable to guess that several people will pay for them with their lives:

  • Duncan shouldn’t have traveled or stayed with his relatives so soon after his contact with an Ebola patient, and he shouldn’t have lied about it on the exit form.
  • It’s incredibly stupid that the hospital sent Duncan home after he presented with a fever and told them he had come from Liberia.
    • Very possibly inadequate infection prevention procedures were taken while he was in the hospital, which presents a risk that healthcare workers were infected. Patrick Sawyer infected several doctors and nurses and the entire hospital had to be closed for a month-long decontamination! [Africa Independent Television 9/9/14]
    • This also of course increased the risk to the family where he was staying and any other people he contacted over the next couple of days.
  • It’s mind-boggling that students who had direct contact with Duncan might have been sent to school! And the other unstated “noncompliance” by the household where Duncan had been staying is worrisome.
    • Nigeria closed all schools in the entire country at the height of its Ebola outbreak to protect its children!  [BBC 8/27/14]
  • The delay in cleaning the apartment is inept but in point of fact those people are all so thoroughly exposed that it may not make a difference.

Since the mean incubation period is 11 days and Duncan’s symptoms started on Sept. 24 we can expect the first wave of infections in a few days, with hospital staff following a few days later. That’s if he’s as infectious as Patrick Sawyer; if instead he’s like the Senegal student nobody will be infected!

Mali – The Little Girl With a Nosebleed

Added 10/29/14. On October 19 a two-year-old girl was taken by her grandmother on public transport from a funeral in Guinea to Kayes in western Mali, including a two-hour stopover in Bamako, Mali’s capital and largest city. The child had developed a nosebleed in Guinea, so was symptomatic for the entire trip. The child was examined by a healthcare worker on Oct. 20, admitted to a hospital on Oct. 21, tested positive for Ebola on Oct. 23, and died the next day. Initially, some 43 close contacts were monitored, including 10 healthcare providers. [WHO 10/24/14]  This unfortunately has the potential for several to many infections, especially including the healthcare workers. The silver lining is the fact that the initial case was — eventually — identified, so her contacts could be traced. “If you have one case very early on and you catch it, you’re actually lucky,” says [Dr. Samba Sow from the National Center for Disease Control, CNAM, in Bamako] “If you don’t detect that first case you run the risk of people who are contagious staying in the community without being reported and that’s when you run the risk of an epidemic.” [VoA 10/29/14] At last report 82 contacts were being monitored. [Reuters 10/28/14]

Update 10/31/14: It now appears that the little girl traveled on buses and taxis or otherwise had contact with 141 people, of whom 57 have not yet been identified and found. [Reuters 10/31/14] This could be a disaster for Mali, or wherever those people were going. Or the day could be saved once again by the limited contagiousness of the Ebola virus.

What Will Happen?

Travelers infected with Ebola will continue to pop up from time to time, all over the world. The outcome in each case will depend on intelligence, resources, compliance with quarantines and luck.

  • One assumes that the resources available will enable developed countries to stop Ebola fairly quickly. The classic technique of isolation, contact tracing and monitoring has worked in dozens of rural outbreaks as well as in Nigeria, despite serious noncompliance. 
  • This should be true in Dallas, despite stupidity at the hospital and noncompliance by the family which have increased risk, and may cause unnecessary deaths.
  • The real problem is when Ebola pops up in a poor country with a weak healthcare system, especially in a crowded slum, and especially when there are endemic diseases like malaria that can cause similar symptoms. If Ebola gets established in such a situation it could become another Liberia.

Update 10/6/14: Northeastern University researcher Alessandro Vespignani has developed a computer model which predicted, as of Oct. 1, the likelihood of an infected person traveling to particular countries over the first three weeks of October. [Boston Globe 10/1/14] The ten countries with the highest probabilities are, in order: Ghana (46%), France, Senegal, U.S. (25%), Ivory Coast, U.K., Nigeria, Mali, Belgium and Morocco (about 10%). Of course the U.S. has already identified one such traveler, but it would seem that we still have about a one in four chance of encountering another by the end of the month. One question which isn’t clear from the article is whether the investigators took into account the possibility of a travel bias towards countries with good healthcare systems by people who are concerned about the possibility of having been exposed to the virus. The investigators are posting updating predictions at this link: Ebola – MoBS.

As noted above, the big concern is when one of these people arrives in a poor country with a weak healthcare system. The biggest worry is Ghana, followed by Senegal, Ivory Coast, Mali and Morocco. Nigeria is also high on the list but they showed considerable skill in quashing the Patrick Sawyer outbreak so may be somewhat less at risk (unless the virus gets loose in the ungovernable northern region). The slums of India or South America would also be quite vulnerable but the likelihood of travel there is much less.

What Can We Do?

There are just a few things we can — and must — do.

Limit Travel From Affected Countries?

There will no doubt be a move in America to bar travelers from the three affected countries (Guinea, Liberia and Sierra Leone). This has a superficial appeal, on the same reasoning as the cordon sanitaire around an epidemic ravaged city. (This is discussed in an earlier post: Ebola Quarantines) WHO takes the view, however, that travel bans are counter-productive. [AlJazeera 9/22/14] Not only do travel bans have detrimental economic consequences, but they can worsen the epidemic itself by hindering relief efforts. 
This article makes the case rather persuasively:

It’s also questionable how effective a travel ban would be. The Guinean student demonstrated how porous African land borders are, even when theoretically “closed.” Someone who really wanted to leave the affected countries could get out. Rich and privileged people may have multiple passports, that could be used to conceal their nationalities and/or their itineraries. And there would always have to be exceptions, of one sort or another. A ban might slow the process of seeding Ebola all around the world, but it wouldn’t altogether stop it. Update 10/6/14: The Northeastern University computer model mentioned above elegantly quantifies this. Even with an 80% reduction in flights from the affected countries the probability of an infected person arriving in a given country is only delayed by 3 to 4 weeks. [MoBS Lab 10/1/14]

Update 10/6/14: Despite the arguments against it, I see two possible reasons why a travel ban may nevertheless happen: (1) it may be forced on politicians by a panicky electorate, and/or (2) the numbers of infected travelers may become excessive, due either to a general exodus or medical tourism by people who suspect (or know) that they are infected.

The five-day Hajj (Muslim pilgrimage to Mecca) started on Oct. 2. Saudi Arabia denied visas to residents of the three West African countries, and asked travelers to fill out a medical screening form that details their travels for the previous three weeks. [BBC 10/2/14] Of course people may lie, but it certainly is to be hoped that this year’s Hajj at least will be Ebola-free.

Quarantine Arriving Travelers

Travelers from suspect countries could be quarantined for 21 days before being allowed into the country. This is a tried and true Medieval technique but it’s a really poor fit with our fast-paced globalized world. A non-starter.

Continue to Screen Travelers

Thomas Duncan’s temperature was taken at the Monrovia airport as part of the screening system put in place following the Patrick Sawyer debacle. This part of the process worked as intended, to keep symptomatic travelers off planes. He was asked all the right questions; though unfortunately he lied. This sort of screening is the best you can do, and it’s helpful, even though it can’t prevent pre-symptomatic people like Duncan from traveling.

It would be helpful to add arrival screening of people who have been in affected countries (or U.S. states!) but it’s difficult to identify those people and it would be a huge project to screen everyone on arrival.

Be Prepared

Healthcare providers all over the world must be alert to the possibility of Ebola. In this case Duncan didn’t lie about coming from Liberia (although there’s no indication he told anyone about his contact with an Ebola patient) but there was a lapse in communication within the hospital. This sort of mistake can be fatal! Both to healthcare providers and others who may be needlessly exposed when an Ebola patient is sent home.

Poor countries with weak healthcare systems must be especially vigilant to spot any unusual patterns of disease or death before Ebola has a chance to get intrenched.

There’s not much we can do as individuals, except perhaps to practice good general hygiene, including frequent hand washing. Oh, and if someone is visiting from West Africa feel free to ask whether they’ve had close contact with Ebola patients in the last three weeks…

End the Epidemic

The only definitive solution is to end the West African epidemic. In addition to compelling humanitarian reasons we need to wipe out Ebola everywhere (in humans, anyway) in order to feel fully safe in our own lives.

In April, early in the West African epidemic, the New York Times published an Op-Ed piece entitled “Ebola Virus: A Grim, African Reality.” It closed with this paragraph:

Ebola in Guinea is not the Next Big One, an incipient pandemic destined to circle the world, as some anxious observers might imagine. It’s a very grim and local misery, visited upon a small group of unfortunate West Africans, toward whom we should bow in sympathy and continue sending help. It’s not about our fears and dreads. It’s about them.

I felt then as I feel now: Ebola is not just an African problem, it’s a human problem.

Reproduction Rate

The way Ebola spreads is simple: from one person to another. There’s an African animal reservoir — probably fruit bats — from which the virus finds its way into a human being once or twice a year. But from then on the virus is transmitted only through bodily fluids, not via an animal vector such as mosquitoes or fleas. Ebola spreads by a simple chain reaction: each person it infects may infect one or more additional people, and so on. The key is how many susceptible people, on average, each infected person passes the virus on to. This is called the “Effective Reproduction Rate,” or “Re”. (Almost everyone* is initially susceptible to Ebola, but Re will drop proportionately if a substantial portion of the relevant population becomes immune, either by surviving or by receiving some future vaccine. The rate at which the virus would be transmitted in a completely susceptible population, with no immunity, is called the “Basic Reproduction Rate,” or “Ro”.)

  • If, on average, each infected person passes the virus on to just one other susceptible person (Re is one) the epidemic will continue at a steady rate, neither growing nor dying out. This is called an “endemic” disease. The total number of cases grows, but the rate at which new cases occur stays the same.
  • If Re is less than one the epidemic will die out, slowly or rapidly depending on where the number falls between one and zero.
  • If Re is more than one the epidemic will mushroom until some factor pushes that number back down below one. The rate of growth will depend on how big this number is, but the epidemic will relentlessly accelerate so long as Re is greater than one. This is “exponential” or “explosive” growth.

The only way to stop an epidemic is to push Re down below one. Of course it’s also best to get as close to zero as possible as rapidly as possible, but so long as Re is less than one the disease will eventually die out.

Forty Years of Rural Outbreaks

Ebola outbreaks have so far always started in rural areas, with the likely suspect usually being some sort of bush meat, typically bats or monkeys.

Home caregivers are very likely to be infected, so at the outset an Re of at least one is almost assured. Other family members and visitors are also at risk. This mode of transmission can be greatly reduced by caring for patients, as soon as they become infectious, in a facility that follows rigorous infection-control procedures. This approach has worked for Médecins Sans Frontières (“MSF”) in all prior outbreaks. (Lugubriously, this form of transmission may also be reduced when patients aren’t cared for by anyone, either because they are the last member of a family or because they are put out of the house when they fall ill.)

Healthcare providers are especially vulnerable, particularly in the early stage of the outbreak. The initial symptoms of Ebola are similar to those of many other less-infectious diseases, so the first wave of sufferers typically walk in to clinics or hospitals and are examined and cared for like other patients. Not only are doctors and nurses likely to become infected, but before the outbreak is recognized they may pass infection on to other patients. This is tragic, and definitely helped the current outbreak get a foothold, but it may ultimately not be an important element of Re. For one thing, MSF has shown that rigorous procedures and high-quality anti-infection suits can essentially eliminate this risk. As of a recent report, no MSF employees had become infected in the West African outbreak, though many other healthcare providers have been. For another, hospitals and clinics may be closed when they have become contaminated, and patients may stop going there for any illnesses once the risk of Ebola infection becomes known. The collapse of the health care system has many adverse effects, but the silver lining is the fact that people who don’t go to a hospital at all can’t either transmit or acquire Ebola there.

African funeral practices have played a big role in amplifying Re.

  • The body of someone who dies is traditionally hand-washed by members of the family. This almost guarantees that the washers will be infected.
  • Mourners at a traditional funeral may touch and even kiss the body. This can infect many people, who bring the virus with them when they return home. The entire outbreak in Sierra Leone, for example, has been traced to fourteen women who attended a single traditional healer’s funeral in Guinea. [NYT]
  • Finally, those who bury the body are at high risk unless infection-control procedures are used.

It is obviously essential to stop these funeral practices, since one victim can infect a huge number of other people this way. Again, MSF has been able to do this in the villages affected by previous Ebola outbreaks by working with local chiefs and explaining the situation to the villagers.

The impact of funeral practices on Re is affected by the mortality rate. In prior outbreaks up to 90% of those infected died, so almost all had the potential to infect many others through their funerals. In West Africa only about half seem to be dying, so the impact of funerals is somewhat reduced. This effect is swamped, however, by the large number of potential infections from one traditional funeral. Even though the reduced mortality rate makes funerals somewhat less important it is still essential to bring traditional funeral practices to a stop if Re is to be reduced below one.

In more than a dozen rural outbreaks over nearly forty years Re has been decisively driven below one, and the outbreak stopped, by rigorous infection control, contact-tracing and quarantine. The support of local communities was obtained by personal contact and education.

New Complications in West Africa

The West African outbreak, however, presents a very different picture. The health care systems in the affected countries had been damaged by years of civil war as well as profound poverty. This is the first time Ebola has appeared in any of these countries, so they were slow to recognize it and unfamiliar with the steps needed to contain it. Whatever the reasons, the virus was able to spread for several months before being recognized, and the consequences have been tragic.

Several new elements have complicated the relatively simple pattern of previous outbreaks:

  1. Ignorance, superstition and rumor have frustrated efforts to apply the established protocol, both in certain rural villages and in poor urban neighborhoods, notably the West Point district of Monrovia. Health care personnel have had to withdraw completely from a dozen “red villages” in Guinea where residents fear that MSF and Red Cross are causing Ebola rather than seeking to control it.[NYT] People have been hiding Ebola victims instead of letting them go into isolation wards.
  2. The uncontrolled spread of Ebola into several big cities raises the risk of additional modes of transmission, such as physical contact in taxis, buses and crowds, and contamination of shared surfaces.
  3. The number of patients has overwhelmed available isolation facilities.
  4. In several cases people who had been exposed to Ebola, or were already ill, have nevertheless chosen to travel, thus putting many others at risk. [Ebola Strategy 2014-08-31]  Some people have also lied about potential exposure to gain admission to hospitals, thus risking infection to doctors, nurses, staff and other patients.

The consequence has been that Re appears to be at least one in Guinea and Sierra Leone, and more like 1.5 in Liberia. An excellent article in Science projects a tripling to around 10,000 cases by September 24, and hundreds of thousands in subsequent months, with no end in sight so long as Re stays so high. [Science 2014-08-31].

The only way to stop the outbreak is to identify and implement a suite of feasible measures that together push and hold the Effective Reproduction Rate (Re) below one. It is of course also important as a humanitarian concern to provide the best possible care for those who fall ill, but care has no effect on the rate at which the virus spreads except to the extent that it implies reduction of potentially infective contacts.

The outbreak has naturally segmented itself to some degree, into rural and urban areas, and by country. A couple of attempts at quarantine barriers, called cordons sanitaire, have attempted to segment it further, with mixed success. (I plan to discuss this in a future post.) To the extent that segmentation works it may be possible to stop the outbreak using different suites of infection-reduction measures in different segments. In particular, relatively well-organized countries such as Nigeria and Senegal may well be able to bring their own smaller outbreaks under control using the standard protocol of contact tracing, monitoring and quarantine, even if the epidemic continues to grow uncontrollably in, say, Liberia.

Wild Cards

The current situation is bad enough without worrying about how it could get worse, but there are a few uncertainties that it’s useful to keep in mind.

Ebola is mutating rapidly,[Washington Post 2014-08-28] and it’s possible that the virus could change in ways that increase its infectiousness, especially through the air. That would be very problematic, to put it mildly.

An animal transmission vector might emerge, particularly in places where bodies are not promptly disposed of.

Sexual transmission might become significant in a promiscuous segment of the population, such as a subset of gay men. Not only could an infected person pass the virus on to multiple sexual partners, but this could also happen after recovery, since Ebola is found in the semen of recovered patients for up to seven weeks. [Who Fact Sheet]

Secondary effects of the outbreak could disrupt infection-reduction measures or even destabilize affected regions. The most immediate risk is a breakdown in food supplies, but one could also imagine breakdowns in other public services. Public disorder has broken out in several places, and this could continue or worsen. In the middle term the weak economies of the affected countries will be further damaged by disruption of internal and foreign trade. Also, the breakdown of the health care systems in these countries may facilitate epidemics of other diseases.

At the bottom of Pandora’s Box there is hope:

A safe and effective vaccine could bring the outbreaks to a fairly quick end. Indeed, this may be the only real hope of doing so.

Possible Preexisting Immunity A subsequent New York Times article raises the possibility that some portion of East Africans are already immune to Ebola. [NYT 9/5/14] The article cites a 2010 study in Gabon, which had had four Ebola outbreaks from 1994 to 2002. The study found Ebola antibodies in 15% of the population, ranging from 34% in some remote villages to 3% on the coast. The investigator speculated that many of the antibodies resulted from low-level exposures that weren’t sufficient to cause illness. This is interesting because it might afford a large pool of people who are already immune, who might be able to take on hazardous jobs with less personal risk, and who might be able to donate curative antibodies. There are several cautions, however:

  1. Immunity is to a particular strain.
  2. It’s not clear what level of antibodies is protective in humans.
  3. While an injection of antibodies might help an infected person fight off the disease it would not function like a vaccine to generate long-term immunity.
  4. Levels of exposure in Gabon, which had a long history of Ebola outbreaks, might be higher than in the countries currently affected.
  5. The epidemic is currently most worrisome in coastal cities, where antibodies would probably be lowest.
  6. Whatever preexisting immunity existed in remote villages wasn’t sufficient to keep Ebola from getting a foothold there.
  7. Sophisticated techniques are needed to test for antibodies.

More Information:
[Measuring Disease Dynamics in Populations: Characterizing the Likelihood of Control, Johns Hopkins]

[Exponential Growth and the Legend of Paal Paysam]

I still expect that Nigeria will succeed in snuffing out the outbreak of Ebola sparked by a seriously ill man who flew from Monrovia to Lagos. The Nigerian authorities have been doing it by the book: identifying and monitoring contacts, then isolating everyone who shows symptoms. This protocol has been used successfully in rural areas more than a dozen times over the past forty years. Nigeria has also taken other drastic steps to reduce risk, such as closing schools.

Update 10/2/14: It’s looking very good for Nigeria, although the definitive all-clear won’t come until October 12, after 42 days with no new cases. School is back in session and President Goodluck Jonathan gave a victory speech. [PBS 10/2/14] But it was a close-run thing, principally due to the pattern of quarantine violations described in this post. Nigeria — like everywhere else — will have to deal with a string of similar situations as infected people travel there from West Africa. The U.S. in particular would be wise to heed this story, since there has already been a quarantine violation in the Texas outbreak. [Dallas Business Journal 10/2/14]

My confidence has been shaken, however, by a pattern of quarantine violations which has repeatedly undercut Nigeria’s containment efforts. The culprit is not ignorance, superstition and mistrust, as in rural Guinea and in the urban slums of Monrovia. The problem in Nigeria has so far been arrogance and privilege. I now see that the wealthy and educated, if they are sufficiently arrogant and privileged, can undercut an Ebola prevention program as fatally as the irrationality of the poor.

    • The story begins with Patrick Sawyer, a Liberian who had become a naturalized American citizen.[Daily Beast 2014-08-14] Leaving his wife and young children in Minnesota, he had returned to Liberia to take a high position in its Finance Ministry. When his sister fell ill with uncontrolled bleeding Sawyer took her to a hospital in Monrovia. Her symptoms were recognized and the hospital personnel tried to put her into an isolation ward. But Sawyer paid $500 to have her given a private room, where he personally undressed her. Ultimately about a dozen hospital staff — nurses, a doctor and an administrator — fell ill due to their exposure to Sawyer’s sister. [FrontPageAfrica 8/13/14] Update 10/2/14: The story of Sawyer and his sister and the hospital administrator turns out to be more complicated than first appeared, though the conclusions are the same. For details see EbolaStrategy: How Contagious is Ebola?
    • After his sister died, on July 7, Sawyer was put under surveillance due to his exposure, and told not to leave Monrovia. After showing serious Ebola symptoms he nevertheless flew to Lagos on July 20, nominally to attend a conference. He vomited several times on the plane and collapsed on arrival in Lagos. He was helped into a taxi and taken to a hospital, where he initially denied being exposed to Ebola, and at one point pulled the IV’s from his arms. He infected around a dozen contacts, including doctors and nurses as well as the person who helped him into his taxi. He died on July 25.
    • All of Sawyer’s contacts were put under surveillance, and those with symptoms were isolated. One of his nurses, however, violated restrictions and fled to her home in Enugu State. She had no symptoms when she fled, but showed symptoms in Enugu and was returned to Lagos by special ambulance to Lagos. Six contacts in Enugu were still under surveillance as of August 14.[Premium Times 2014-08-14]
    • On August 26 the Nigerian Minister of Health declared that “Ebola has been curtailed.” [Premium Times 2014-08-28], but it turns out that a Nigerian diplomat who had met with Sawyer had escaped from an isolation ward in Lagos and fled to the oil center of Port Harcourt, where he was secretly been treated by a local doctor, Iyke Enemuo, in a local hotel. The diplomat survived but the doctor became infected, and died on August 22. Subsequently, WHO reported the troubling details [WHO 9/3/14]:

After onset of symptoms, on 11 August, and until 13 August, the physician continued to treat patients at his private clinic, and operated on at least two. On 13 August, his symptoms worsened; he stayed at home and was hospitalized on 16 August. Prior to hospitalization, the physician had numerous contacts with the community, as relatives and friends visited his home to celebrate the birth of a baby.
Once hospitalized, he again had numerous contacts with the community, as members of his church visited to perform a healing ritual said to involve the laying on of hands. During his 6 day period of hospitalization, he was attended by the majority of the hospital’s health care staff.
On 21 August, he was taken to an ultrasound clinic, where 2 physicians performed an abdominal scan. He died the next day.
The additional 2 confirmed cases are his wife, also a doctor, and a patient at the same hospital where he was treated. Additional staff at the hospital are undergoing tests.
Given these multiple high-risk exposure opportunities, the outbreak of Ebola virus disease in Port Harcourt has the potential to grow larger and spread faster than the one in Lagos.

Nigerian health workers and WHO epidemiologists are monitoring more than 200 contacts. Of these, around 60 are considered to have had high-risk or very high-risk exposure.

  • Yesterday, we learned that the doctor’s wife has fallen ill, and his sister had fled to Abia State to avoid being quarantined. [Modern Ghana 2014-08-30] She was returned to quarantine in Port Harcourt, but of course now her contacts also need to be tracked.

Again and again people who were relatively well-off and presumably well-informed chose to break quarantine and place untold numbers of others at risk. Nigeria’s outbreak is spinning out of control not through ignorance and superstition but through the arrogance and recklessness of the privileged few. One still assumes that people will get a grip and start behaving themselves. But it may also be that the culture of wealthy privilege is so deeply ingrained in Nigeria that this will continue until the virus gets into a slum — or the ungovernable north — and Nigeria follows the disastrous trajectory of Liberia.