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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