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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.

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Ebola is obviously much less contagious than airborne viruses like influenza, and much more contagious than some other viruses, such as HIV, the virus which causes AIDS. What can we say at this point about how contagious Ebola really is?

The Official Statements

Through mid-September the WHO’s web page included this unfortunate paragraph, which is still widely quoted:

The risk of Ebola transmission is low. Becoming infected requires direct, physical contact with the bodily fluids (vomit, faeces, urine, blood, semen, etc.) of people who have been infected with or died from Ebola virus disease (EVD). [WHO 9/16/14]

As of September 20 this language had disappeared, and WHO’s current fact sheet has a more detailed and sobering description of how Ebola is transmitted between people:

Ebola … spreads through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.

Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD. This has occurred through close contact with patients when infection control precautions are not strictly practiced.

Burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola.

People remain infectious as long as their blood and body fluids, including semen and breast milk, contain the virus. Men who have recovered from the disease can still transmit the virus through their semen for up to 7 weeks after recovery from illness. [WHO 9/19/14]

The U.S. Centers for Disease Control (CDC) Transmission web page roughly parallels WHO’s fact sheet:

When an infection does occur in humans, the virus can be spread in several ways to others. Ebola is spread through direct contact (through broken skin or mucous membranes) with

  • blood or body fluids (including but not limited to urine, saliva, feces, vomit, and semen) of a person who is sick with Ebola
  • objects (like needles and syringes) that have been contaminated with the virus
  • infected animals
  • Ebola is not spread through the air or by water, or in general, food. However, in Africa, Ebola may be spread as a result of handling bushmeat (wild animals hunted for food) and contact with infected bats.

Healthcare providers caring for Ebola patients and the family and friends in close contact with Ebola patients are at the highest risk of getting sick because they may come in contact with infected blood or body fluids of sick patients.

During outbreaks of Ebola, the disease can spread quickly within healthcare settings (such as a clinic or hospital). Exposure to Ebola can occur in healthcare settings where hospital staff are not wearing appropriate protective equipment, including masks, gowns, and gloves and eye protection. …

Once someone recovers from Ebola, they can no longer spread the virus. However, Ebola virus has been found in semen for up to 3 months. People who recover from Ebola are advised to abstain from sex or use condoms for 3 months. [CDC 9/20/14]

This post will try to tease out what these texts mean, and how well they square with the way in which the West African epidemic has developed. Public information needs to be clear, simple and not dangerously misleading. But it also tries to avert panic; it isn’t always the “whole truth.”

Reading Between the Lines

Both WHO and CDC state that contact with bodily fluids, etc. must be “(through broken skin or mucous membranes).” Apart from a cut this refers to the mouth, nose, eyes and anal and genital openings. What neither statement emphasizes is the importance of the hands as a means for the virus to get to a mucous membrane. A touch to the lips or the eye with a contaminated hand could do the trick, as could also a stray droplet of any sort of bodily fluid.

The examples given of contaminated surfaces differ oddly between the two descriptions. WHO mentions “bedding and clothing” while CDC mentions “needles and syringes.” Both obviously have the potential for transmission. Possibly the WHO fact sheet is directed to individuals while the CDC was thinking more about healthcare providers.

The CDC fact sheet says that “Ebola is not spread through the air.”

  1. It is obviously possible for someone to be infected by a droplet that passes “through the air” onto a mucous membrane. Various experiments have shown such transmission between animals in a laboratory setting. CDC acknowledged this in an earlier fact sheet, but explained, “While all Ebola virus species have displayed the ability to be spread through airborne particles (aerosols) under research conditions, this type of spread has not been documented among humans in a real world setting, such as a hospital or household.” [CDC 4/9/10]
  2. Ebola is obviously not spreading through the air anywhere near as easily as flu. This is the current phrasing of the CDC guidance for managing ill airplane passengers that originally was cited as evidence that the CDC believed in airborne transmission: “Ebola does NOT spread through the air like flu.” [CDC 9/20/14]
  3. The key question is whether Ebola is in fact being transmitted during the current epidemic through the air, and if so how significant this mode of transmission is, and how much it is affected by the condition of the patient. We’ll consider this further below.
  4. Mutation could in principle affect contagiousness by air, and we must remain vigilant about this possibility.

WHO advises that men use condoms for 7 weeks after recovery, while CDC recommends 3 months. That’s a pretty big difference! The Public Health Agency of Canada states that, “Ebolavirus has been isolated from semen 61 to 82 days after the onset of illness, and transmission through semen has occurred 7 weeks after clinical recovery.” [PHAC 9/20/14] This would seem to be a situation in which WHO is minimizing a risk that might exist for more than 7 weeks. At the moment sexual transmission by survivors is the least of our worries, but it may become important in the final phase of ending the epidemic.

The West African Experience

The current epidemic has provided a treasure trove of information about how Ebola does — and doesn’t — spread. Hopefully someone is collecting as much of this information as possible for scientific analysis. Only a few specific cases have been well enough described in the press for any conclusions to be drawn by outsiders, however. While anecdotal, they are nevertheless highly suggestive. For this purpose we are as interested in who didn’t get infected as in who did.

The Super-Spreader Funeral

All cases of Ebola in Sierra Leone have been traced to 14 women who were infected at the funeral of a traditional healer in Guinea. [NYT 8/28/14] It is customary at traditional funerals for people to wash, touch and even kiss the body, so it’s not surprising that they were infected. What’s interesting is that dozens of people attended the funeral — presumably quite a few more than the 40 who agreed to give blood samples — and it’s reasonable to suppose that many of them also had contact with the body. The corpse was clearly quite infectious, but even so it infected only perhaps 1/4 of those who attended the funeral.

The Nigerian Outbreak

Patrick Sawyer was a sociopath who caused the death of a dozen people, and very nearly unleashed Ebola on the most populous country in Africa. [EbolaStrategy 8/31/14] He was also a naturalized American citizen, and the Coordinator of the Economic Community Of West African States (ECOWAS) Unit of the Liberian Finance Ministry. [Note: Nigeria reported a total of 19 Ebola cases. I’ve been able to identify only 14 from the press. The others may be secondary infections plus a handful of additional primary infections, but they don’t much change the picture painted below. I’ll update this post if I’m able to sort out this discrepancy.]

Princess

The story begins with Sawyer’s sister, known as Princess, who was bleeding uncontrollably when her fiancé brought her to St. Joseph Catholic hospital in Monrovia. Her symptoms were recognized and hospital staff initially refused to touch her, but the Chief Administrator of the hospital, Brother Patrick Nshamdze, decided to treat her as if she presented a simple case of a miscarriage. [NationalChronicle 7/29/14] [FrontPageAfrica 8/13/14] Princess continued to bleed, however, and she was about to be moved to an isolation ward when Sawyer arrived. “He insisted that she be given a private room and plunked down $500 to secure it. He proceeded to personally change her gown and placed her in a wheelchair for the move. He was seen to get her blood on his own clothes as well as his shoes in the process.” [DailyBeast 8/14/14] Princess died on July 7. Understandably, Sawyer, Nshamdze and other healthcare staff who treated her without precautions became infected. Then the same thing happened when Nshamdze himself fell ill – doctors, nurses, a social worker and a lab technician fell ill. There’s no special information about contagiousness here, however, since there was lots of blood and few precautions.

Patrick Sawyer

Because of close contact with his sister, Sawyer was monitored daily and told not to leave Liberia. On July 20, after he began showing serious Ebola symptoms, including fever and vomiting, he got on a plane to Lagos, Nigeria, with a layover in Togo, as part of a nine-member ECOWAS delegation to a conference. He vomited repeatedly during the flight, then collapsed in Lagos airport. He was helped into a taxi and taken to First Consultant Hospital, where he initially told the medical staff that he had malaria and denied contact with any Ebola cases. Only two days later was he tested and found tentatively positive for Ebola, at which point he was quarantined.

One of the nurses who treated him, Obi Justina Ejelonu, became infected even though: “I never contacted his fluids. I checked his vitals, helped him with his food (he was too weak). … I basically touched where his hands touched and that’s the only contact. Not directly with his fluids. At a stage, he yanked off his infusion and we had blood everywhere on his bed … But the ward maids took care of that and changed his linens with great precaution.” Another hospital source “told [Front Page Africa] that in addition to yanking the infusion tubes, Sawyer took off his pants and urinated on the floor as nurses fled from his presence.” [FrontPageAfrica 8/11/14] He died five days later, on July 25.

A doctor who treated him, Dr. Ada Igonoh, also became infected. She gives an extremely detailed account of Sawyer’s stay at her hospital (and of her own illness and recovery) in a moving Front Page Africa article. [FPA 9/18/14] She felt that, “my contact with Sawyer was minimal. I only touched his I.V. fluid bag just that once without gloves. The only time I actually touched him was when I checked his pulse and confirmed him dead, and I wore double gloves and felt adequately protected.” The first several days in which Sawyer was treated for malaria without full precautions could explain her infection, however, as well as that of Dr. A.S. Adadeveoh, who treated Sawyer during the same period. [FPA 8/25/14]

“In total, Sawyer reportedly came in direct contact with 59 persons, 44 of whom were at the hospital… Sawyer came in contact with three ECOWAS officials – a driver, a liaison officer and a protocol officer. Also in the list are two nursing staff and five airport handlers.” [FrontPageAfrica 7/31/14]

Out of all his 59 contacts Sawyer appears to have directly infected just 5 people: The nurse and two doctors already mentioned, an ECOWAS official who picked Sawyer up at the airport and took him to the hospital, and an ECOWAS diplomat who was part of the group who greeted him on his arrival. All his other contacts did not get infected. That includes both passengers and crew on two flights, during which he was repeatedly vomiting, and everyone else in the Monrovia, Togo and Lagos airports. He was capable of infecting others, obviously, but on balance Sawyer was not very contagious.

The ECOWAS Diplomat

The ECOWAS diplomat escaped from quarantine in Lagos on July 26, traveled to Port Harcourt, and arranged to receive secret treatment in a hotel room by a local doctor, Iyke Enemuo. The diplomat recovered but the doctor was infected. There’s no indication that any other contacts of the diplomat were infected, however, so once again the healthcare providers bear the brunt of transmission. Apart from infecting Enemuo, the ECOWAS Diplomat was not very contagious.

Dr. Iyke Enemuo

Dr. Enemuo was yet another sociopath, following in Patrick Sawyer’s footsteps. He kept his contact with the infected ECOWAS diplomat secret and continued to pursue an active medical practice and social life, even after falling ill. WHO recounted the shocking details (apologies for the duplication from my first post):

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.
[WHO 9/3/14]

Nigeria had to track some 255 contacts, 60 of whom had high-risk or very high-risk exposure!

Of all those many contacts, Dr. Enemuo actually infected only 5 people: his wife (also a doctor), his younger sister, a doctor who treated him at the hospital, a pharmacy technician, and an older woman who shared his hospital room. [NigeriaTimes 9/19/14]  [Reuters 9/1/14]  He was certainly capable of infecting people, but considering the number of people he was in contact with after falling ill, Dr. Enemuo was not very contagious. Once again, caregivers and immediate family members were at greatest risk.

The Senegal Student

A 21-year-old college student was under observation in Guinea because he had helped care for several family members who had fallen ill with Ebola. Nevertheless, he traveled in a six-passenger vehicle to Dakar, Senegal, arriving on August 20. He stayed with his uncle in a crowded household for three days, then went to a local hospital, but did not mention his exposure to Ebola. He was initially sent home, but the following day “the Guinean health services reported ‘the disappearance of a person infected with Ebola who reportedly traveled to Senegal,’ according to Senegal’s health minister,” and the student was quarantined. [BBC 8/29/14] [Bloomberg 8/31/14] 67 close contacts were placed under observation: people he was in contact with during his journey, members of his uncle’s extended household, healthcare providers at the hospital, etc. [WHO 9/12/14]

The striking feature of this case is that none of the student’s 67 close contacts became infected! This is very different from other situations. My best guess is as follows: The student was never terribly sick, and has fully recovered. Consequently, he may not have had the same viral load as other patients, and may not have been throwing off bodily fluids as prolifically. It’s also possible that the main hospital in Dakar follows more rigorous universal precautions than those in the other affected countries. Whatever the reason, this is a striking instance of how non-contagious Ebola can sometimes be.

Healthcare Providers

More than 240 healthcare providers have been infected during the West African epidemic, half of whom have died. [WHO 8/25/14] The great majority were local doctors and nurses who did not wear full protective gear, often because they were not yet aware that a patient had Ebola and sometimes because of a shortage of supplies. In a few cases, however, healthcare providers who were apparently following standard procedure nevertheless became infected. These cases raise concerns about the mode of transmission.

Dr. Kent Brantly

Brantly became infected working with patients at a Monrovia hospital operated by evangelical Christian organization Samantha’s Purse. He asserts that he followed all CDC recommended procedures, including wearing a standard N-95 face mask, the type also used by Médecins Sans Frontières/Doctors Without Borders (“MSF”).  [MSF 7/28/14]  This raises a question of whether Brantly was infected by airborne droplets that passed through his mask. This point is pressed in a tendentious but interesting article, written by a doctor who argues that Ebola healthcare providers should use the more expensive and uncomfortable P-100 (HEPA) face masks to fully protect against airborne droplets. [AmericanThinker 8/24/14]

The N-95 mask is designed to block 95% of “solid and water-based particulates (i.e., non-oil aerosols)”. The P-100 (HEPA) face mask blocks 99.97% of particulates and aerosols, whether or not oil-based. [CDC Jan, 1996]

  • Maybe Brantly made some other mistake, of which he wasn’t aware. This seems frighteningly possible, with the odds of an error — small though they may be — relentlessly adding up as he worked day after day in close contact with Ebola patients.
  • Maybe airborne transmission is indeed very rare, but Brantly got unlucky.
  • Maybe airborne transmission is easier than we have thought, and MSF has been very, very lucky.
  • Maybe the virus has mutated to become more easily transmitted by air — though obviously still vastly less easily than the flu.

The French MSF Volunteer

MSF announced on Sept. 17 that a French volunteer at one of its treatment centers in Monrovia had become infected, despite their strict infection-prevention protocol. She is the first international MSF staff member to be infected in the West African epidemic, although 7 local staff members had previously fallen ill, out of more than 2,000 MSF staff members in the region. The treatment center is turning away new patients pending an investigation into how the volunteer became infected. [Reuters 9/17/14]

From one perspective eight people out of 2,000 is less than half of one percent. But, as MSF President Joanne Liu had previously pointed out, the entire control effort can fall apart if healthcare providers feel personally unsafe.

We have no further information about how this volunteer may have been infected, but the announcement of the MSF investigation implies that it wasn’t due to anything obvious. Airborne transmission is a possibility.

The American Journalist

Added 10/6/14: An American journalist, Ashoka Mukpo, tested positive for Ebola on Oct. 2. He believes that he may have become infected when he was splashed while spray-washing a car in which an Ebola patient had died. [ABC 10/6/14]  This seems credible and consistent. He is, by the way, being treated in the high-level biocontainment unit at the University of Nebraska Medical Center. This unit is the largest of four U.S. biocontainment units, and has 10 beds, which means that the U.S. has a total of less than 40 bio-containment beds in the entire country. Hmm…  [NPR 10/6/14]

Ebola Transmission in the Developed World

At this writing there have been only two instances of transmission of Ebola outside of Africa, both involving nurses who cared for Ebola patients in the last stages of the illness. Both wore full anti-infection gear; this is not like the West African cases in which healthcare providers were infected before precautions started being taken, or because proper gear wasn’t available. Both nurses — at least initially — said they were not aware of any breach of the anti-infection protocol.

The Spanish Nurse

Added 10/6/14: A nurse (more precisely, a volunteer auxiliary nurse) contracted Ebola while treating a Spanish missionary in Madrid’s Carlos III hospital, where he died on Sept. 25. She is the first person known to have contracted Ebola outside of Africa. Reportedly she only entered the patient’s room twice, once after his death. [NYT 10/6/14] We have no information about what precautions the nurse used, and whether a mistake may have been made. Update 10/8/14: The nurse initially said that she had followed the anti-infection protocol to the letter, which would have undermined confidence in the protocol and increased the anxiety of healthcare personnel. She then said that she “might have” touched her face with a contaminated glove as she was taking the protective suit off. [NYT 10/8/14]  It’s reassuring — if also a bit too convenient — to have an explanation for how the nurse was contaminated.

The infection of the Spanish nurse is worrisome but not inconsistent with the experience in Africa, where hundreds of healthcare workers have contracted Ebola, and several Western medical personnel have been infected without noticing a failure of protocol. We do need to figure out why this is happening, but the extreme infectiousness of corpses and people in the last phase of the disease is known, and there’s nothing about this case which changes the picture.

The real issue in her case has nothing to do with contagion: it’s the fact that Spain took nearly a week to test her for Ebola after she reported that she was running a fever. This casual attitude will have to stop! Western countries have ample resources to contain Ebola, but it will bite anyone who treats it with laziness or contempt.

The Dallas Nurses

Added 10/14/14: Nina Pham, a Dallas nurse who gave extensive care to Thomas Eric Duncan throughout his hospitalization is the first person known to have contracted Ebola in the U.S. As noted above, she was not aware of any breach of protocol. This is of course worrisome, and affords further evidence that the CDC needs to focus more closely on the protocol, and the way in which training is given. But it isn’t a new issue. [NYT 10/13/14]

Again, the important issue isn’t contagion, but the fact that Ms. Pham wasn’t monitored as a contact. Fortunately, she self-monitored, detected a low-grade fever, and had herself admitted to the hospital. She tested positive for Ebola on the evening of 10/11.

Added 10/20/14: A second nurse who treated Duncan, Amber Joy Vinson, was confirmed as having contracted Ebola on Oct. 15. She had been self-monitoring and had reported a low grade fever, but was nevertheless allowed to fly to Cleveland on Oct. 10 and back to Dallas on Oct. 13. That was obviously stupid, and put at minor risk a large number of people in both cities and on both flights. But once again, the fact that an inadequately trained and protected nurse got infected from a later-stage Ebola patient is nothing new. [NYT 10/20/14]

Added 10/29/14: Both nurses have now been declared Ebola-free and discharged from hospital.

The Other Contacts of Thomas Eric Duncan

Added 10/8/14: It’s too early to say, but the fact that none of Duncan’s other contacts have yet shown symptoms is notable. He was very ill before being taken to the hospital the second time, and lived in close quarters with his girlfriend, her son, and her two nephews. He wasn’t as sick the first time he went to the hospital, but it seem clear that several doctors and nurses were in contact with him without taking exceptional precautions. It would be a remarkable confirmation of how infectious Ebola isn’t if all of these folks escape infection.

Added 10/20/14: Happily, nearly all of the 50 contacts with Duncan before his second hospitalization have now completed their 21-day quarantine period, with no Ebola symptoms! As well as being great news for them and for Dallas it confirms once again that Ebola is remarkably noncontagious until the final stage of the illness. Dozens Declared Free of Ebola Risk in Texas [NYT 10/20/14].

One nuance doesn’t change this conclusion, but could lead to a further little outbreak: As noted below, 5% of people infected with Ebola don’t show symptoms until more than 21 days from exposure. [NEJM 9/23/14]  If someone released from quarantine turns up with symptoms after the 21-day period CDC might end up with egg on its face, and public confidence could be seriously eroded. I understand why 21 days has been chosen as a way of sending a simple message to the public but taking this approach is a somewhat risky strategy.

The Contacts of the Dallas Nurses

Added 10/29/14: Nina Pham apparently had only a few contacts, chief among them being her boyfriend. Amber Joy Vinson, however, flew to Cleveland and — after reporting a low-grade fever — back to Dallas. Vinson accordingly placed at theoretical risk a large number of people. It will be interesting to see whether any of these contacts became infected. My own guess — based on the other cases described above — that nobody else will come down with the disease based on contact with either of the nurses. If so, that should alleviate the public’s anxieties, but probably won’t.

The Bottom Line

Here are a few concluding observations:

  • Even though the epidemic is growing exponentially, the individual cases we’ve been able to review support the official position that Ebola is not very contagious, and generally requires contact with bodily fluids or contaminated surfaces. Even a corpse only infected about a quarter of the attendees at a traditional funeral in which touching the body was customary.
  • Caregivers and immediate family members are at highest risk, and others are at relatively low risk.
  • Infectiousness depends on how ill the patient is, both from the perspective of viral load and the amount and character of emitted bodily fluids. There is no evidence of transmission before the patient becomes symptomatic; very little evidence of transmission before the last stage of the illness; but a high risk of transmission to caregivers and others who have direct contact with a patient during the last stage of illness.
  • It isn’t clear to what extent the virus can be transmitted through the air, but:
    • Casual contact such as sharing an airplane or even mingling in a social setting rarely or never seems to be enough to infect. Added 10/20/14: As noted above it’s astonishing that Duncan’s girlfriend and the three boys who also shared the apartment where Duncan stayed avoided infection.
    • Something is infecting healthcare providers, even when they believe that they are following CDC guidelines. It is urgently necessary to determine why so many healthcare personnel who claim to be following CDC procedures are getting infected. We have to figure out what’s happening with that and fix it, whether or not it involves airborne transmission.

Update 10/3/14: A survey article by the WHO Ebola Response Team in the New England Journal of Medicine provides a lot more information, although it doesn’t greatly change our understanding of the situation. [NEJM 9/23/14]  Here are a few key points:

  • The mean incubation period is 11 days, and 95% had symptoms within 21 days of exposure, the recommended period for follow-up of contacts. Accordingly, 5% of infected contacts will first present symptoms after follow-up ends.
  • The article estimates the current effective reproduction numbers at 1.81 in Guinea, 1.51 in Liberia and 1.38 in Sierra Leone. This basically means that each infected person is infecting on average between one and two more people, thus causing the epidemic to grow exponentially. See my earlier post, The Ebola Chain Reaction, for a more detailed explanation. The article rather cheerfully comments that : “This means that transmission has to be a little more than halved to achieve control of the epidemic and eventually to eliminate the virus from the human population. Considering the prospects for a novel Ebola vaccine, an immunization coverage exceeding 50% would have the same effect.”
  • Without changes in control measures, their estimated doubling times range between 15 days for Guinea and 30 days for Sierra Leone.
  • Case fatality has been 70% in Guinea, Liberia and Sierra Leone, in contrast with earlier reports closer to 55%. It was lower in Nigeria but the number of patients was so small that this might be a fluke.

Also, here’s a very clear statement, in the Oct. 2 New York Times, of what is considered “direct contact” with the bodily fluids of an Ebola patient: Understanding the Risks of Ebola, and What ‘Direct Contact’ Means

Update 10/8/14: An article in the LA Times collects questions about whether Ebola might be more contagious than is currently believed: [LA Times 10/7/14]

  • Mutation is of course a wild card, which could make the virus somewhat or much more contagious. This is one of several good reasons for devoting resources to stopping the epidemic as soon as possible. But I don’t see any evidence of significant change in contagiousness, and nobody is claiming specific evidence of relevant mutations.
  • What we do see is a pattern of poorly-explained infections of healthcare providers, especially when patients are in the last stage of illness. This might involve small highly-infections droplets passing through the air, and conceivably might lead to further tightening of the anti-infection protocol. Added 10/14/14: In any case one must welcome CDC’s plan to improve training and to send a team to any hospital treating an Ebola patient. [NYT 10/13/14]
  • What we do not see is large numbers of infections of people who have casual contact with patients, or who have contact with patients before they have become symptomatic. So long as that pattern holds Western nations should have little difficulty keeping Ebola under control, so long as they treat it with the great respect and vigilance that it deserves.

Update 3/24/15: Liberia has identified a single Ebola patient who appears to have been infected by her partner, a male survivor. [NYT 3/24/15]  This presumably came through his semen, which is known to contain Ebola virus for several months after recovery. This will make the disease a bit more difficult to eradicate, but is not cause for panic. 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.

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.