Thursday, March 26, 2020

The Human Outbreak, and the Pandemic We Should Have Expected


As we sit sheltering in our homes and worrying about ourselves and friends and relatives, it is a good time to recall a warning that David Quammen issued to us in 2012 with his book Spillover: Animal Infections and the Next Human Pandemic.  He pointed out that the rate at which zoonosis, the transfer of pathogens from non-human animals to humans, seemed to be increasing, with new strains of viruses appearing every several years.  He provided this list.

“If you assembled a short list of the highlights and high anxieties of that saga within recent decades, it could include....Machupo [1959]....Marburg (1967), Lassa (1969), Ebola (1976)....HIV-1 (inferred in 1981, first isolated in 1983), HIV-2 (1986), Sin Nombre (1993), Hendra (1994), avian flu (1997), Nipah (1998), West Nile (1999), SARS (2003), and the much feared but anticlimactic swine flu of 2009.”

Timing forced him to miss MERS (2012) which was identified in the year of his publication.  And now we have another deadly coronavirus, COVID-19 (2019).

Quammen’s thesis was that this parade of threats is something we are responsible for and something we should expect to continue, and that someday our luck will run out and a truly deadly pandemic is inevitable.  We are responsible because as we increase in number on the planet, we make epidemics more likely, and we move ourselves into new regions with unfamiliar ecologies where new pathogens are likely to exist.  We also come in closer contact with animals who might be harboring unfamiliar pathogens.  In fact, our mass breeding and raising of animals for food sources greatly increases the likelihood that those animals will develop new diseases and spread them to us. 

“Make no mistake, they are connected, these disease outbreaks coming one after another.  And they are not simply happening to us; they represent the unintended results of things we are doing.  They reflect the convergence of two forms of crisis on our planet.  The first is ecological, the second is medical.  As the two intersect, their joint consequences appear as a pattern of weird and terrible new diseases, emerging from unexpected sources and raising deep concern, deep foreboding, among the scientists who study them.”

Quammen refers to us as “the human outbreak.”

“Outbreak in the broader sense applies to any vast, sudden population increase by a single species.”

“....we are hungry.  We are prodigious, we are unprecedented.  We are phenomenal.  No other primate has ever weighed upon the planet to anything like this degree.  In ecological terms, we are almost paradoxical: large-bodied and long-lived but grotesquely abundant.  We are an outbreak.”

“And here’s the thing about outbreaks: they end.  In some cases they end after many years, in other cases they end rather soon.  In some cases they end gradually, in other cases they end with a crash.”

“We have increased our population to the level of 7 billion and beyond....We live at high densities in many cities.  We have penetrated, and we continue to penetrate, the last great forests and other wild ecosystems of the planet, disrupting the physical structures and ecological communities of such places.  We cut our way through the Congo.  We cut our way through the Amazon.  We cut our way through Borneo.  We cut our way through Madagascar.  We cut our way through New Guinea and northeastern Australia.  We shake the trees, figuratively and literally, and things fall out.  We kill and butcher and eat many of the wild animals found there.”

“We multiply our livestock as we’ve multiplied ourselves, operating huge factory-scale operations involving thousands of cattle, pigs, chickens, ducks, sheep, and goats, not to mention hundreds of bamboo rats and palm civets, all confined en masse within pens and corrals, under conditions that allow these domestics and semidomestics to acquire infectious pathogens from external sources (such as bats roosting over pig pens), to share those infections with one another, and to provide abundant opportunities for the pathogens to evolve new forms, some of which are capable of infecting a human as well as a cow or a duck.”

Quammen indicated that SARS had the potential to do serious damage to the global population, but we got lucky and were able to contain it because it showed symptoms before it could be spread widely.  His suggestion was that the greatest danger to us on the horizon was from H5N1, the bird flu.  This version of influenza is extremely lethal, but thus far is only transmitted to humans from animals—ducks in this case.  Quammen quotes one scientist, Robert Webster.

“’As long as H5N1 is out there in the world,’ Webster said, ‘there is the possibility of disaster.  That’s really the bottom line with H5N1.  So long as it’s out there in the human population, there is the theoretical possibility that it can acquire the ability to transmit human-to-human.’  He paused.  ‘And then God help us’.”

The lesson to be learned is that while the current coronavirus is not an existential threat, it is going to knock humanity on its butt for a significant amount of time.  And once it has been dealt with, we must expect that another will emerge in a year perhaps, or ten or more years, and they will continue to come.  And each time the next one could be much worse than what we are experiencing now.


The interested reader might find the following article informative:




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