Tag Archives: Pandemic

Rethinking Pandemics At Several Levels

Here’s a question for you: Historical records show that another pandemic will occur, but no one knows when. How do we create a mind shift among world leaders and people in general to start planning for the next one now?

This question is being posed in connection with the series premiere of National Geographic’s “Fighting Pandemics” (November 1 at 9 pm ET on National Geographic Channel). The question is about pandemics, but the inspiration for the series, and the question, is the recent ebola pandemic in West Africa. I have a few thoughts, and I’ve been thinking about Ebola for a long time.

My first two encounters with Ebola might not have been encounters with Ebola, but might have been.

I was doing archaeology in a remote part of the Congo, not far from some of the earlier known outbreaks, in a region where later outbreaks occurred as well. In researching abandoned villages, one of which I partially excavated, I found out that there were settlements that had been struck with a terrible disease that killed many of the residents and made many others very ill. These events, of the previous decade or two, were so tragic and traumatic that those village sites were abandoned, and everyone I talked to claimed that they would never use those village sites again, even though re-occupation of villages previously abandoned as part of the swidden agricultural system was common. Ebola? Maybe.

Around the same time I was reading through a 1950s vintage travel guide to Uganda and the Belgian Congo, owned by my then father-in-law, Neil Tappen. Neil and his wife, Ardith, had worked there in the early 1960s, where Neil produced the first comprehensive survey of the rich primate fauna. They had acquired the book used, so they could not explain the marginal notes added by a previous owner, tallying the death rates of some group or another, with a mortality rate of about 60%. Ebola? Maybe.

If I had told those stories to an Ebola expert five years ago, I’d probably be told this was unlikely to have been that particular disease because it wasn’t around then. Now, we might be thinking Ebola has a longer history in the region. That is one of the many ways in which Ebola is being re-conceived in light of both the experience of the Ebola pandemic, and research spurred by that horrible chapter in West African history.

This and other events were enough to spark a long term interest in Ebola, and years ago I was able to contribute a couple of ideas to help in the hunt for a natural non-human reservoir. That was when fruit bats were first being given a hard look, and today, they are still suspect.

So what about the question at hand?

The first thing that comes to my mind is how do we put in place the resources needed to come immediately up to speed when a new pandemic seems to be starting. This would include monitoring in order to get on top of the problem as quickly as possible, infrastructure to transport good and people where they need to be, trained personnel to take on the various on the ground roles needed to isolate and treat patients and stop the spread of the disease.

However, these things are both obvious and outside my area of expertise. I’m pretty sure there are people at the UN’s WHO, the CDC, and other major health related organizations, thinking about these things.

But there is another aspect of preparation that I think is important. This is the way in which we misconceive Ebola or other diseases, because of a combination of incorrect thinking (about diseases), lack of information, and lack of experience. These misconceptions are usually found among the general public, and result from simply not knowing the science. But sometimes they arise among the medical researchers themselves, and result from not having enough research done, and not having enough experience with a disease.

For example, during the Ebola pandemic, many people were on the edge of panic because they somehow knew that it was only a matter of time before Ebola became fully airborne, like horrid diseases seem to do rather quickly in their fictional form, in novels, in movies, or on TV. In fact, Ebola is highly unlikely to become easily transmitted by air for reasons I go in to here.

That is an example of uninformed but concerned non-experts getting it wrong. But, the “airborne” nature of of Ebola, or lack thereof, is actually less than perfectly understood by many in the health business. For example, we often think of Influenza as an airborne disease because it can be spread by coughing and sneezing. However, this common disease is probably almost never spread that way. Rather, it is spread by physical contact, with bodily fluids (which may have been coughed or sneezed at the start) from the nose or mouth going to the hand, then to another person’s hand, then to the recipient’s nose or mouth, possibly with some intervening step such as an object handled by the patient. So, while many may be concerned that Ebola could turn into something like the flu, if it did that, it still would not be especially airborne. If you want to look at an airborne disease, check out measles, which can apparently travel down the hall from one patient examining room to another, through the air, resulting in a new infection.

It turns out that the categorization of modes of spread has been revised now and then and some feel that further revision would be appropriate, or at least, that everyone should be using a more nuanced and detailed method of describing how diseases can spread. A disease can spread through the air, in a sense, but not be truly airborne. But the distinction is critically important in dealing with a pandemic situation, or even a minor outbreak.

Dr. Ian Crozier
From the New York Times (May 7, 2015):
When Dr. Ian Crozier was released from Emory University Hospital in October after a long, brutal fight with Ebola that nearly ended his life, his medical team thought he was cured. But less than two months later, he was back at the hospital with fading sight, intense pain and soaring pressure in his left eye.
Test results were chilling: The inside of Dr. Crozier’s eye was teeming with Ebola.
The accepted belief at the start of the Ebola pandemic was that Ebola would not persist in a survivor beyond a certain number of days, so post-infection quarantine periods needed to be just so long. Even then, however, it was known that Ebola could persist in the sperm of infected males for a much longer period. This should have been a clue. By the end of the pandemic, it was understood that Ebola could actually persist in an infected individual for a much longer time. Long enough, perhaps, to attribute an outbreak to a person who had harbored the disease rather than a novel infection from its wild reservoir. This is a significant finding that not only changes how we address quarantine, but also, how we ask questions about the wild reservoir.

A third area in which individuals making wrong assumptions can negatively impact an effort to address a new pandemic is in the locally variable beliefs about where infections come from, along side various mortuary practices that may be important to someone’s religion or belief system, but that enhance spread of the disease. I can not honestly characterize this set of local beliefs because, as an anthropologist who has worked in the Ebola region, I can tell you that belief systems are extremely variable there, with many different systems overlapping in space, within individual villages, and that even within the context of households or families, there is a great deal of individual variation.

I have known families where five or six people living together had three or four entirely different sets of beliefs about important (and unimportant) things. You know this too. Does everyone at a major family gathering, or a get together at work or in your community, share all their basic beliefs? That is highly unlikely. Yet we tend to see people living in other lands, more often than not in developing regions, as being far more homogeneous than they really are. Then, when someone points out a belief system interfering with a scientifically based endeavor (such as a major public health disaster), the assumption is that this is a widespread, intractable, universal problem. There is, though, more diversity than that around your Thanksgiving table and in a typical West or Central African village.

Sometimes these diverse beliefs emerge simply because different “tribal” groups all live near each other and traditional beliefs get thrown together when people, and this is very common, marry across those relatively artificial boundaries. But the most dramatic divergences in beliefs have to do with local reaction to systems, technologies, and practices, that come from the outside. This can be something simple like the best way to restore life to a nearly dead battery you were hoping to use in a radio, something more important like the best way to catch fish or wild game given the availability of key western goods like fishhooks and wire, to somewhat more bizarre arguments (in more remote areas) about what really is in those cans of foodstuffs that sometimes trickle in from Western sources.

When a “traditional” population sticks firmly to their beliefs even though it harms them, that’s a story and it may get reported in the New York Times. We saw reports like that during the Ebola pandemic, reports about people refusing to go to clinics because they believed something about Ebola that simply wasn’t true. But, it is also possible for people to put aside their traditional beliefs and accept new knowledge, and change their minds. In my experience, this is the much more common result of interaction between traditional indigenous thinking and intrusive Western thinking. But those stories, where people learn new stuff, change their minds, and change their practices, usually don’t make news. So, our Western conception of the West African peoples who were afflicted with this pandemic is that a huge problem arises from folks sticking to their old and incorrect folklore. Maybe that is true at times, but I strongly suspect that this aspect of the problem was way overplayed by the press.

So, here is what we have to do, aside from all that logistical planning (and fund raising) noted above.

More research. After many smaller outbreaks of Ebola over many years, the scientific and medical community was left with a number of important misconceptions about Ebola that might have been better known had there been more prior research. This must be assumed to be true of any disease that has pandemic potential but that has not developed to such a level so far. There needs to be a well funded, ongoing, international research program addressing emerging diseases that is proactive, addresses whatever research questions come along in good scientific tradition, as pure research rather than as a reaction to untoward events.

More education of the general public. Part of the problem in addressing a pandemic is the inappropriate response, often time and resource wasting, of the press and the public. This happens because the basic, and often rather simple, science needs to be taught fresh to reporters and those who consume the news each time something like this happens. After a decade and a half of major news agencies removing science bureaus, and the spread of anti-science sentiment largely for political reasons, we are paying a cost. If you watched any of the CDD or state health department press conferences at the time Ebola cases were popping up in the US, you will remember the difficulty officials and medical experts had in explaining the science to the reporters, and the often breathless and, frankly, foolish way many reporters were acting at those events. Those events were hardly remarked upon at the time, but the need to explain basic stuff to the reporters, and their poor level of preparation to understand these things, was shameful. But it is also fixable.

More education on the ground in areas that may be affected. Pandemics of this type may be thought of as more likely to emerge in tropical areas, but in fact, they can emerge elsewhere as well. Part of public health education should be to address proper public, community, family, and personal response to an infectious disease crisis, balancing between urgency and sensibility, to avoid undue panic or inappropriate responses when something does happen.

It is especially important that populations in regions that may be affected by pandemics can prepare by laying a groundwork of education and new new thinking about what these diseases are and how to spot them and cope with them.

Finally, Ebola is not the only pandemic causing horrid disease in the tropics, so the question at hand needs to be addressed generally. Moist equatorial Africa is not the only region where this sort of pandemic can develop. And, with climate change, the warmer regions of the world, where certain kinds of diseases seem to do better, are getting larger.

MERS-CoV, The Haj, and the remote chance of a killer global pandemic

It seems to me that the science of epidemiology is a lot like being in shoe sales in a country on the pacific rim. You never know when the other shoe is going to drop, but you know it will. Our species (humans) is numerous, contiguous, and dense (in more ways than one). This means that a highly virulent pathogen could spread across the globe and kill a gazillion people before we could do anything to stop it. Yet, such a thing has not happened in modern times, meaning, since the widespread and easy flux of population provided by the airline industry at several scales of space.

At the present time we (humans) are faced with yet another threat of pandemic disease, this time from the coronavirus MERS-CoV. Spoiler: It is very unlikely that MERS-CoV is going to be a major pandemic because it does not seem to be all that virulent, in the sense that it does not seem to spread easily from one person to another. When it shows up in a population, it does not seem to spread around quickly. On the other hand, it is human-spreadable, similar coronaviruses are virulent so maybe this one could evolve to be so, and the mortality rate is so far an alarming ~50%. And, there is another complication. MERS-CoV is very likely to be carried from its homeland in the Middle East to several other countries by the mass movement of pilgrims returning from The Haj.

A recent study in PLoS Currents Outbreaks (yes, that’s a clumsy phrase, not a typo) looks at the situation. Researchers use reasonably good (but limited) data on air travel to estimate the number of people who will return-travel form the major Middle Eastern pilgrimage sites between June and November. They look at relative rates of return-travel to each area, and at health care expenditures per capita as a way of estimating the ability to address an influx of deadly disease-carrying return visitors, in each country.

16.8 million travelers on commercial flights departed Saudi Arabia, Jordan, Qatar and UAE for an international destination between June and November 2012. 7.5% had final destinations in countries that were low income, 47.4% lower-middle income, 17.3% upper-middle income and 27.8% high income. 51.6% had final destinations in just eight countries: India (16.3%), Egypt (10.4%), Pakistan (7.8%), the United Kingdom (4.3%), Kuwait (3.6%), Bangladesh (3.1%), Iran (3.1%) and Bahrain (2.9%; see Table). Individual cities with the highest travel volumes include Cairo, Kuwait City, London, Bahrain, Beirut, Mumbai, Dhaka, Karachi, Manila, Kozhikode, Istanbul and Jakarta, each of which received more than 350,000 commercial air travelers from MERS-CoV source countries between June and November 2012. Furthermore, an estimated 8.7% of foreign Hajj pilgrims in 2012 originated from countries that were low income, 56.4% lower-middle income, 27.3% upper-middle income, and 7.6% high income. 60.7% of foreign pilgrims originated from just eight countries – Indonesia (12.4%), India (10.1%), Pakistan (9.9%), Turkey (7.8%), Iran (6.5%), Nigeria (5.7%), Egypt (5.5%) and Bangladesh (2.9%). A bubble plot depicting the volume of international travelers departing Saudi Arabia, Jordan, Qatar and UAE from June to November 2012, the estimated number of foreign pilgrims performing the Hajj in 2012 and estimated healthcare expenditures per capita in 2011 is shown in Figure 1.

Fig. 1: Country-Level Destinations of Air Travelers Departing MERS-CoV Source Countries*, Origins of Hajj Pilgrims†, and Healthcare Expenditures per Capita‡ * Final Destinations of Air Travelers Departing Saudi Arabia, Jordan, Qatar and the United Arab Emirates via Commercial Flights between June and November 2012† Estimated for 2012 ‡ Sizes of the circles are proportionate with healthcare expenditures per capita as estimated by the World Bank, 2011
Fig. 1: Country-Level Destinations of Air Travelers Departing MERS-CoV Source Countries*, Origins of Hajj Pilgrims†, and Healthcare Expenditures per Capita‡
* Final Destinations of Air Travelers Departing Saudi Arabia, Jordan, Qatar and the United Arab Emirates via Commercial Flights between June and November 2012† Estimated for 2012 ‡ Sizes of the circles are proportionate with healthcare expenditures per capita as estimated by the World Bank, 2011

The researchers note that MRS-CoV has the potential of being a pandemic disease, and that understating population movements that could underly its spread is essential. The key points here seems to be that there is an intersection between countries that have a lot of pilgrims returning from MERS-CoV source areas and a low probability of detecting and containing cases of international spread because of inadequate health care systems. Related to this, they also identify possible blind spots in the global health care industry. For example:

The four countries with confirmed cases in returning travelers…the United Kingdom, France, Italy and Tunisia…account for an estimated 7.1% of the final destinations of all international travelers departing the MERS-CoV source countries since September 2012 (each of which are high or upper-middle income countries). By comparison, India, Pakistan and Bangladesh represent the final destinations of an estimated 27.7% of all international travelers over the same time period (each of which are low or lower-middle income countries), but have not reported cases of MERS-Co. Although not definitive, these findings could indicate the presence of epidemiological “blind spots” to MERS-CoV as a result of limited infectious disease diagnostic and surveillance capacity.

So, we’ll see how this goes.

Above I note that despite the obvious risk of a global pandemic of something spreading across the human population there really hasn’t been one, but I think this should be put in context. We have had widespread and multi-layered (in terms of economic and other strata) air flight for less than fifty years, but that air travel has probably not penetrated all regions of the world until the last 25 years or so. Pandemics with really large death tolls, however, are very rare. The HIV/AIDS pandemic is a slower moving but very deadly one, and is the largest in modern times, and it started in 1981 and was certainly facilitated by the ability of humans to travel. The previous large pandemics that could possibly have been facilitated by air traffic in a major way were two flue pandemics, in 1968 and 1957, each very small compared to HIV/AIDS but effective at a much higher temporal rate. The previous pandemics that were very large, but prior to major air travel effects, most likely spread internationally with boat traffic, were the famous 1918 flu pandemic and the less famous 1889 flu pandemic, and a handful of near-million death level cholera pandemics, in 1899, 1881, and the 1850s.

So, during the 163 years from 1850, worldwide pandemics that killed 6 figures and above happened about 8 times. That’s about every 20 years. So, when we look back at the history of air travel, which has allowed the ready movement of large numbers of people across a wide range of social and economic categories living in most populated areas, we should not be surprised at the number of pandemics. It is hard to put a year on when humans became as internationally mobile as they are today, but the east-west divide was a major factor dampening movement until the 1990s. One could say that the current highly mobile situation dates to about 1990, and is thus, just over 20 years long. In other words, the rough time scale of the emergence of diseases with the ability to spread widely and quickly, using cholera and flu as a proxy for “disease” is once every 20 years, and the situation in which the Giant Killer Pandemic in which human population is measurably reduced because of a disease we can’t control for several years could occur is recent. I quickly add that Cholera is a lousy proxy for such disease because it is readily treated these days and its initiation and spread is only partly related to human movements. It may well be that the frequency of the evolution of a spreadable pandemic disease is much longer than 20 years.

There are shoes. They can drop. They seem to drop slowly, infrequently, but as time has passed over the last few decades the potential severity of such an event has clearly gone up in some ways while our ability to control disease through treatment and vaccination has probably stabilized or even gone down.

MERS-CoV is probably not the next pandemic. But the idea of there being such a pandemic, and even a pandemic with previously not seen qualities because of our denser than ever, larger than ever, and more connected than ever population is nothing to sneeze at.

Khan, Kamran, Jennifer Sears, Vivian Wei Hu, John S Brownstein, Simon Hay, David Kossowsky, Rose Eckhardt, Tina Chim, Isha Berry, Isaac Bogoch, Martin Cetron. 2013. Potential for the International Spread of Middle East Respiratory Syndrome in Association with Mass Gatherings in Saudi Arabia. PLoS Curents Outbreaks. July 17, 2013. Full Text here.

Innate Immune Response Defines Pathology and death in Those Infected by Highly Pathogenic Influenza

ResearchBlogging.orgFor the last couple of decades, perhaps beginning around the time of the publication of Laurie Garret’s excellent thesis (The Coming Plague: Newly Emerging Diseases in a World Out of Balance) on disease and politics and continuting through Gina Kolata’s “Flu: The Story Of The Great Influenza Pandemic” there has been increased attention on the 1918 flu virus and pandemic, as well as subsequent outbreaks. This interest has probably been fueled by increased knowledge of (or incidence of?) tragic and highly newsworthy outbreaks of Ebola, SARS, and so on. More recently, the perception has grown that the Bird Flu is a’comin’ any time now to ultimately replace the Great Pandemic of 1918 as well as the mud shark in our mythology.

If you read the better done public-oriented literature of this period, you will learn that the nature, cause or origin, and pattern of the 1918 epidemic has been very mysterious. The same level of mystery (but with only a few victims) arose in connection with the Swine Flu threat of the 1970s (see expecially Garret’s book for how this event links to current attitudes as well as public policy regarding vaccines).

This brings us to some time last year or so, when key papers were published (and I presume presented at conferences) regarding what may ultimately be seen as the most important single step in the history of understanding the way the flu vaccine works, and thus, how to combat it. (See this to explore one of those key moments in research history.)

The new knowledge is essentially an improved evolutionarily and developmental understanding of how influenza virus strains change over time. To put it very simply, these viruses are made of chunks that come apart in the host and then recombine. If there are multiple ‘strains’ (think species, more or less) of influenza in an individual, these genetic chinks, each representing a huge percentage of the influenza genome, can and do re-combine to form entirely new strains.

That is in a sense macro-evolution of a pathogen in situ, in the host. What is an immune system to do!?!!?!?? Not much, really. This can be very fatal.

It is now understood that these epidemic or pandemic influenza outbreaks arise from these recombination events. If you now look back at the quirky data, the odd logic influenza seemed to be patterned by, the epidemiological dead ends that seemed to confound everyone through the lens of knowledge of these genetic chunks, called “reassortants,” things suddenly become much much clearer.

A paper has just come out in PNAS reporting research using a primate model to explore immune response and associated pathology under the influence of a recombinant influenza virus, and this research is a direct outcome of this new way of looking at the flu. I offer it here without comment largely because you can get the article yourself, since this one is an OpenAccess piece from the normally not OpenAccess PNAS. Here.

Continue reading Innate Immune Response Defines Pathology and death in Those Infected by Highly Pathogenic Influenza