Ebola Transmission: Health Care Worker Practice Most Important Consideration

Not long after we learned that a health care worker treating Thomas Duncan has tested positive for Ebola, I ran across this terse tweet from Mackey Dunn, the pen name of Don Weiss, who is “a medical epidemiologist with the New York City Department of Health and Mental Hygiene”. The tweet linked to this short but incredibly important blog post. In the post, Weiss notes the baffling development that a health care worker, who wore full personal protective equipment (PPE), contracted Ebola from Duncan even though at this point, none of his family or other close contacts, who did not have full PPE, have developed symptoms of the disease.

That set of facts prompts Weiss to pose the question “So, what does this tell us about Ebola and how we can attain control?” His answer begins:

One, that Ebola patients become more infectious as the illness progresses. The newly reported case in a healthcare worker had onset on October 10th. If we take 9 days as the mean incubation period for Ebola this means the healthcare worker’s exposure was sometime around October 1, which was day 8 of Mr. Duncan’s illness. This is similar to what was seen with SARS, that patients become more infectious (and dangerous) with time.

In setting up the circumstances for his question, Weiss had noted that Duncan was hospitalized, ending exposure to family members, on day 5 of his disease.

Although he doesn’t mention it, this aspect of Ebola, where patients produce more virus and become more infectious during the course of a fatal infection, also accounts for why burial practices are so important to containing the spread of Ebola. Patients produce the most virus and are thus at their most infectious at death.

The converse also appears to be true. Duncan was symptom-free when he flew from Liberia to Dallas on September 19 to 20. At 24 days since the end of that trip, we have now passed the incubation period, commonly given as 2-21 days, for Ebola to develop in anyone who could have been exposed during the flights. No infections among those airline passengers have been reported. I have yet to see a major media outlet mention this point, though.

We are now at 16 days since Duncan was hospitalized, ending his family’s direct exposure, so we have passed the two-thirds point of the incubation period for them (and well past the 9 days that Weiss gives as the average incubation period for Ebola).

The second part of Weiss’ musings on the infection of the nurse is extremely important:

Second, that only hospitals that are well prepared to care for highly infectious patients should be allowed to do so. Standard practice is to have a staff person dedicated to observing the donning (putting on) and doffing (taking off) of PPE. This observation should continue throughout the period of clinical care (from an ante-room with a window). Perhaps gentle reminders during the doffing can avoid the presumed situation in Spain where the nurse may have touched her face with a gloved hand.

When a patient presents to a hospital early in the illness there is time to transfer to such a facility. That’s the plan here in NYC. Bellevue hospital has a specially equipped ward to care for Ebola patients. Their staff are well trained. The number of healthcare workers entering the room should be kept to a minimum, especially after day 7 of the illness.

Weiss was prescient in his push for an observer for workers putting on and taking off PPE. In today’s New York Times, we have this on the CDC’s thoughts regarding improving practices for health care workers treating Ebola patients:

“We have to rethink the way we address Ebola infection control, because even a single infection is unacceptable,” Dr. Thomas R. Frieden, director of the C.D.C., told reporters.


A team of C.D.C. officials — reinforcements sent to Dallas in the aftermath of the second Ebola case diagnosed in the United States — worked through the night at the hospital to identify what was described as a “large group” of health care workers who might be at risk of infection because they treated the original Ebola victim, Thomas Eric Duncan, 42, at the hospital from the time he was admitted on Sept. 28 until he died last Wednesday.

And they are now watching hospital personnel as they put on and take off their protective garb, retraining the staff and evaluating the type of protective equipment being used. They were considering using cleaning products that kill the virus to spray down workers who come out of the isolation unit where the nurse is being treated.

I still hope that the other part of Weiss’ comments, though, are implemented. At least for patients who are diagnosed with Ebola early enough, they should be transferred to facilities that already are trained in the handling of highly infectious diseases.

While the current effort by CDC to improve practices at Texas Health Presbyterian Hospital Dallas has now been described as CDC looking to tune up its own guidelines for treating Ebola patients, and that is laudable, I find it unfortunate the Frieden was forced to apologize and back off his original comment that the infection of the nurse had to have been caused by a breach of protocol. The sad truth of the situation is that it is almost entirely certain that a simple breach of safe practices is how the nurse became infected. And that is why relying on only a few specialized treatment centers is best.

Note also that Weiss mentions that best practices at these facilities means that they minimize the number of workers who are at risk of exposure. Despite that, it appears that there may be a group of as many as a hundred workers in Dallas at risk of infection. That suggests to me that the Dallas hospital is entirely out of its element in treating Ebola patients.

For all the wailing in the press that this outbreak of Ebola, and especially the infection of a nurse wearing PPE has occurred, means that the virus has suddenly changed in character to become much more dangerous, known biology of the virus can account for everything that has happened to this point. One mistake is all that it takes for a health care worker to become infected, and in the end it comes down proper technique being observed at all times to prevent infection spreading.

For further proof that actual practices by health care workers are even more important that the type of PPE used, we need only read this fascinating CNN article from September 26 (h/t @Pedinska) about a student in her final year of nursing school in Liberia who treated (at home!) four family members who were infected with Ebola, with three of them surviving. Her inventive technique is now being taught elsewhere in areas of West Africa where the hospitals are overwhelmed:

Every day, several times a day for about two weeks, Fatu put trash bags over her socks and tied them in a knot over her calves. Then she put on a pair of rubber boots and then another set of trash bags over the boots.

She wrapped her hair in a pair of stockings and over that a trash bag. Next she donned a raincoat and four pairs of gloves on each hand, followed by a mask.

It was an arduous and time-consuming process, but Fatu was religious about it, never cutting corners.

All the proof we need that Fatu did not cut corners is in the remarkable fact that she cared for these four patients in a home setting without catching the disease herself. As long as health care workers display Fatu’s level of vigilance, Ebola can be prevented from spreading in health care facilities.

25 replies
  1. Saltinwound says:

    My interpretation of the breach of protocol comment was that it was blaming the nurse for her practices not being safe. But protocols are changing. It is possible that she followed the protocol she was told to follow but the protocol itself needed adjusting.

    • Lefty665 says:

      Looks like the answer may both flawed protocols and individuals. Plus, facilities and people that are just figuring out how to consistently ensure that protocols are followed.
      Not much of a surprise that Presbyterian Hospital in Dallas that failed to communicate Duncan’s travel history also failed to ensure staff safety, or that Duncan died there.
      If none of the folks Duncan stayed with contract Ebola after being confined in that contaminated environment, in contrast with the nurse when he was sicker and who took precautions, it will put a fine point on the proliferation of virus over the course of illness. That will not prove you cannot get infected by someone in earlier stages of illness, but confirms advice that the spread is much less likely.


  2. orionATL says:

    truly an excellent series of posts on ebola – factual, analytical, and without a hint of the novel-writing or hyperbole available in mainstream media.

  3. TarheelDem says:

    Most of the US commentary focuses on high-cost solutions that will cause US health care to spend more money to guard against an high-impact, low-risk event. Where have we seen that sort of thinking before (along with demands to close the borders)?

    No one is asking what will it take to eliminate the possibility of an ebola outbreak almost entirely? Fifty years ago, American scientific optimism and attitudes toward global charity were such that that question would be the first to be asked.

    But to ask that, USians have to get beyond a couple of items of bigotry and an acknowlegement in their complicity in creating this outbreak.

    First, the origin of this outbreak is traced to “bushmeat”, most likely fruit bats or monkeys. The use of the colonial term “bushmeat” is an exoticism that hides the growing food insecurity of that part of Africa. Bushmeat season starts most places in the US next month; USian preference in bushmeat is venison, but there are some bushmeats that should food insecurity come to the US might be capable of carrying highly lethal viruses. So far, in the US, food insecurity has led mostly to killing of squirrels and opossums. So a very critical strategy to stopping the generation of future outbreaks is food security for Guinea, Sierra Leone, and Liberia.

    Second, the US media have not proportionally reported the scale of the outbreak, serious as it is, because it is in Africa. The WHO report for last week was of 8400 cases worldwide, all but 23 of which are in Guinea, Sierra Leone, and Liberia. The combined population of those three countries together is about that of the state of Florida. Providing a health care infrastructure in those three countries is not an insurmountable task. And since Florida spends (like most of the US) two to three times the cost of best-of-class health care systems but gets poorer results, providing basic public health infrastructure to the three countries would likely cost less and provide better results over the long term that repeating panicked ad hoc measures to close borders and up US hospital’s procedures on a intermittent basis. This does not happen because Congress has no clue what actual US “interests” are and have used foreign aid as a political foil for fifty years.

    Democracy Now interviewed Paul Farmer, who has made a career of working to improve health care infrastructure in the most difficult places. The most striking part of his interview was in discussing how basic nursing care even in the poorest hospital facilities increased the survival rate and reduced hospital-created cases.

    What West Africa could use most right now is 10,000 individual (as opposed to ward) care units and sufficient trained staff to provide the intensity of nursing care that can notice critical changes in a patient. If the US military does not have the disaster assistance capacity to handle 10,000 cases of one epidemic or another, we are in very serious trouble of having wasted money on military baubles instead or real national security. What President Obama has done, although it has not be widely reported, is send military medical units to West Africa (which the braindead media reported as “troops”–technically correct but grossly misleading). There has been no reporting as to the scale of this action, but it was tucked into the $750 million appropriation for fighting ISIL/ISIS.

    The most important consideration in my opionion is rebuilding the deteriorating global public health action prevention and response infrastructure, which involves subsidizing US epidemiological research but cannot be reduced to that research.

    In searching for where the breach in protocol occurred in Dallas, I would focus on the specifications of the equipment the nurse was using, not the procedures. And I would look for where the hospital was not purchasing equipment and supplies that could provide protection for something like ebola. Low expectation-higher cost is the most likely fixable culprit. Another round of employee-blaming or writing off the procedural incident as an unpreventable oops of procedure gives no guarantee of changing a future outcome and through increasing employee anxiety might actually guarantee more oopses.

  4. Don Bacon says:

    news report:
    THE NUMBER OF CASES in the Ebola outbreak has risen to nearly 9,000, with the number of dead climbing to nearly 4,500 — nearly all of them in West Africa — as the World Health Organization warns that there could be up to 10,000 new cases a week in two months.
    I checked the airline departures at Monrovia (Liberia) and Freetown (Sierra Leone): One flight from each one to the other one today, plus a flight from Freetown to Casablanca, Morocco.

    • Ben Franklin says:

      Freeport on the Liberian coast sends a lot of freighters out of that port. Airlines are just the tip of the spear. Recognizing that the time to destination is longer, and likely is favorable wrt incubation and infection period it could result in a ghost ship as ebola survives in the body long after death, it still should be looked at. I don’t hear anyone discussing Nigeria in that regard either. We are always behind the curve.

  5. Lefty665 says:

    Any bets on how high the pressure will be to escape the charnel houses of nations when the infection rates go to 10k per week as is now forecast. And that’s just for starters, it accelerates from there. With each infection generating 1.5-2 more and average 9 days incubation, that’s 20k per week in about 2 weeks, 40k in a month…

  6. TarheelDem says:

    USians of all political persuasions seem to be enjoying the apocalyptic sang-froid of the ebola outbreak. As long as it doesn’t threaten them personally.

    • Lefty665 says:

      Expect with the numbers going up it’ll be here in volume soon. We’re not looking all that great at stopping the spread either.

      • P J Evans says:

        No direct airline flights, and freighters (if any) tend to take longer to get here than the disease takes to develop.

        • lefty665 says:

          Fortress America. Are the Teabaggers right? Seal the borders?
          Those numbers are scary. If we’re at 10k per week by the end of the year, it’s out of control, and the curve starts to look increasingly vertical. There hasn’t been a pandemic in my lifetime, but Ebola’s looking like a good opportunity.
          On the bright side, as most bugs (used loosely to include virus) spread they mutate and lose lethality as they pick up transmissibility. That might make all them fundamentalists pray for evolution.
          Guess the laugh’s on the morons who brought us the sequester and stupid budget cuts for places like NIH and CDC. Unfortunately, the rest of us are caught in the backwash.

          • TarheelDem says:

            The end of the year is 11 weeks away. That is a very long time and given the level of hype, there are likely additional measures being taken to stop this epidemic.

            Out of 7 billion people in the world, there are now 8500 or so cases of ebola in treatment and no one knows how many who have contracted it. Of those cases all but less than 100 are in three countries. The total population of those three countries is 17 million, about the population of the state of Florida. Nigeria appears to have its cases under control as does the United States. So the disease for now is being successfully contained to those three countries.

            The austerian bankers and free agricultural trade folks have a lot to answer for in creating the economic conditions that allowed this outbreak to occur. And the failure to extend the public health infrastructure to the poorest countries.

  7. orionATL says:

    commenting here but with reference to the ew post above on dod and climate change as well as ebola,

    i’ve heard that dod had a lab/epidemiology program in the last few years aimed at helping underdeveloped countries develop a sort of forward warning system for deadly diseases. not surprisingly for dod they set these programs up in border countries formerly part of the soviet union – georgia, for example – just in case some anthrax blew across borders from russia. i don’t know that dod gave africa a thought, though they may have.

  8. pdaly says:

    I haven’t heard much comment about the fact that Duncan was on dialysis and was ventilated, two potential sources of spreading the virus beyond just physically touching Duncan’s body.

    “Oct 7 (Reuters) – The Ebola patient fighting for his life in a Dallas hospital is on a ventilator and a kidney dialysis machine to help stabilize his health, the hospital said on Tuesday.”

  9. qweryous says:

    Another report concerning what might have gone wrong in Dallas.

    Dallas nurses complain Ebola patient left in open area; hospital staff given flimsy protection

    Unconfirmed of course, but not at all sure how one can successfully mix and match when it comes to the protocols which both protect caregivers and prevent the spread of infection.

    In the face of constantly shifting guidelines, nurses were allowed to follow whichever ones they chose.

    “There was no advance preparedness on what to do with the patient, there was no protocol, there was no system,” Burger said.

    Hopefully we are not about to be billed in full for putting MBAs and professional managers in charge of our so called health care system for the past 40 years.

    • Jim White says:

      The combination of that report, which is damning, and the news I just heard on the radio that a second health care worker at Presbyterian has tested positive tells me that the folks at that hospital had-and have-no business treating Ebola patients. Those two who are now alive and being treated need to be transferred to either of the two facilities in Atlanta or Nebraska that have successfully treated Ebola patients without their own workers being infected.
      I’d think Presbyterian may face difficulty surviving as a hospital after more details emerge.

      • lefty665 says:

        Begins to look like nobody at Presby even bothered to do as much as ask the Google if there were precautions they should take:
        “Duncan, was left in an open area of the emergency room for hours. National Nurses United, citing unidentified nurses, said staff treated Duncan for days without the correct protective gear, that hazardous waste was allowed to pile up to the ceiling and safety protocols constantly changed.”
        The count of cases among people who were in that ER will give us an indication of just how transmissible acute Ebola is.
        Is there a reason that hospital should survive?

  10. Tinky says:

    I wonder how long serious commentators are going to continue to dismiss the likelihood that it is aerosolized? In 1995, a test on rhesus monkeys was summarized in this way:

    The potential of aerogenic infection by Ebola virus was established by using a head-only exposure aerosol system. Virus-containing droplets of 0.8-1.2 microns were generated and administered into the respiratory tract of rhesus monkeys via inhalation. Inhalation of viral doses as low as 400 plaque-forming units of virus caused a rapidly fatal disease in 4-5 days.

    That was 20 years ago! Here’s the link to the study:


    In other words, wearing an ordinary mask is probably not sufficient.

    • Jim White says:

      Uh. The experiment you cite intentionally made aerosols of the virus. It is already known the virus enters through mucous membrane, so creating aerosol droplets of virus for the monkeys to inhale would indeed be fatal to them.
      But that says nothing about what happens in the real world when a patient has the disease. Nothing, not one bit of evidence, suggests that the virus spreads through anything other that shit and barf. Got it?
      No, you will just keep spouting your bullshit. In a situation like this, relying on actual science instead of sensational bullshit psuedo-interpretation of publications over your reading level is what will save lives. Your bullshit will cost them.
      Just fuck off.

      • Tinky says:

        Penetrating analysis, Jim. I suppose it hasn’t occurred to you that droplets of varying sizes are emitted when patients sneeze, including micro-droplets.

        Oh, and while you’re at it, why don’t you tell the Center for Infectious Disease Research and Policy – University of Minnesota to “fuck off”. Here’s what they have to say:

        Health workers need optimal respiratory protection for Ebola. We believe there is scientific and epidemiologic evidence that Ebola virus has the potential to be transmitted via infectious aerosol particles both near and at a distance from infected patients, which means that healthcare workers should be wearing respirators, not face masks.

        The minimum level of protection in high-risk settings should be a respirator with an assigned protection factor greater than 10. A powered air-purifying respirator (PAPR) with a hood or helmet offers many advantages over an N95 filtering facepiece or similar respirator, being more protective, comfortable, and cost-effective in the long run.

        • Ben Franklin says:

          Ebola, in a laboratory situation is handled at Level 4. Trash bags over your head don’t make the grade. I shudder when I see or hear or read people proclaim confidence in CDC. Bureaucracies are inherently stupid and incompetent.

          “explosive diarrhea and projection vomiting” makes a poorly trained and poorly administered policy the most dangerous element of ebola.

          • lefty665 says:

            There is no doubt that Ebola can be transmitted via aerosols, thus the Level 4 handling in the lab. The experience we can see in the current epidemic is that it is not easily transmissible via aerosols. If it was easily transmitted by aerosols there would be no health care workers left and the spread would have been much, much faster.
            While I share your opinion about general bureaucratic behavior, stupid and incompetent is not mandated. CDC/NIH have bright and knowledgeable folks. They are our best reservoirs of expertise, certainly hugely more aware and skilled than the morons at Dallas Presby. They are our opportunity for raising the performance of health care facilities nationwide. We will get a measure in the coming months of how well they do. You express my fears, I’ve just expressed my hopes.

            • Ben Franklin says:

              “CDC/NIH have bright and knowledgeable folks”

              Undoubtedly. But if you examine the politics of bureaucracies, you’ll find the dross metals rise to the top of the cauldron, and this is where the system breaks down.

              Same with the Dallas hospital.

              • lefty665 says:

                Generally maybe so, and apparently absolutely in Dallas, but not always. Your cynicism ill becomes you Ben.
                As an example to the contrary, while the dross has indeed risen to the top, NSA has been disgustingly, awesomely, and terrifyingly technically competent. We can only hope the virologists and epidemiologists at CDC/NIH do half as well as the techies at Ft. Meade.

Comments are closed.