COVID-19 Through An Ecological Lens.

Posted on | February 2, 2022 | Comments Off on COVID-19 Through An Ecological Lens.

Mike Magee

It is fair to say that the vast majority of Americans know more about viruses today than they did 24 months ago. The death and destruction in the wake of COVID-19 and its progeny has been a powerful motivator. Fear and worry tend to focus one’s attention.

Our collective learning’s are evolving. We have already seen historic comparisons to other epidemics . Just search “The 10 worst epidemics” for confirmation. But one critical area which has been skimmed over, and only delicately probed (if at all) is the ecology or “the ecological point of view.”

For those interested, let me recommend “Natural History of Infectious Disease” published in 1972 by Nobel laureate and Australian biologist Sir Macfarlane Burnet and his colleague David O. White.

Chapter 1 begins: “In the final third of the twentieth century, we of the affluent West are confronted with no lack of environmental, social, and political problems, but one of the immemorial hazards of human existence is gone. Young people today have had almost no experience of serious infectious disease…For the first time in history deaths in infancy and childhood are not predominantly from infection.” But a few sentences on, they add this addendum, “Infectious diseases may be almost invisible, but it is still potentially as important as ever it was.”

Americans are all too familiar with the living biologic organism named COVID-19. By now, they know what it looks like, the role of its outer spikes, its nuclear makeup, and genetic alterations that allow creation of derivative variants and vaccines. But in addition to its biological science, it also has an ecological life as well.

As the authors say, ecology “deals with the interaction of organisms with their environment and especially with other organisms, whether of their own or different species in the environment.” When ecology is applied to the natural history of infectious diseases, we encounter the discipline of epidemiology – the study of the incidence, distribution, and possible control of disease.

In the eyes of an ecologist, all living entities are survivalists, and there is little difference (except in size) between a parasitic microorganism and a large predatory carnivore. They all need nourishment. As our experts write, whether the bite comes from inside or out, “It is just another method of obtaining food from the tissues of living animals.” COVID-19 is an organism that is “smaller and less highly differentiated than its host…and gains its nourishment at the expense of the host’s living substances.”

Checks and balances rule in the world of ecology absent human intervention. The authors illustrate this with an example. In the late 19th century, orange growers in California reached industrial scale. In 1888, little white cushions began to appear on their trees. Within them were tiny, sap-sucking insects, and the damaged trees production of fruit plummeted. The responsible “scale insect”, it was found, was a foreign invader from Australia.

In Australia, its primary nutrition came from the native acacia tree. Orange trees were infested as well, but rarely damaged. This was because the insects numbers were naturally controlled by a local ladybird beetle. As the ecologists explained, “If the scale insect is particularly plentiful, the ladybird larvae find an abundant food supply, and the beetles in turn become more plentiful. An excessive number of ladybirds will so diminish the population of scale insects that there will be insufficient food for the next generation, and therefore fewer ladybirds.”

But in California, there were no ladybird beetles. And so the agricultural leaders in 1889 imported the beetles, and once they reached adequate numbers in the orchards, the scale beetle “was reduced in importance to a relatively trivial pest.”

Simple,right? Well not exactly. As our experts write, “The mutual adjustment is an immensely complicated process, for all the food chains concerned are naturally interwoven, and for every species there will be fluctuations in numbers from time to time, but on the whole, in a constant environment a reasonable approach to a stable balance will be maintained.”

For predators of any shape or size (and that includes a virus) , “there is less opportunity for enemies…of restricted prey to thrive at their expense.” Vaccination, masking, and distancing, in effect, restrict us as potential prey to COVID-19.

Another point. Our ecologists remind us that “Most parasites are restricted to one host species (for their nutrition)…and the main problem that a parasitic species has to solve, if it is to survive, is to manage the transfer of its offspring from one individual host to another.” That often requires intermediate hosts “whose movement or activities will help the transfer to fresh, final hosts…an increased density of the susceptible population will facilitate its spread.”

To site a modern example, a certain percentage of fully boosted and immunized are able to be infected by the Omicron variant and remain asymptomatic carriers and spreaders, especially if they enter dense gatherings where they and unvaccinated and unmasked persons are present in crowds.

One last caution as we continue to investigate the origins of this pandemic (whether a zoonotic host or laboratory creation): The authors warn that “disastrous disturbances of natural ecosystems” are often the result of “irresistible pressure of technological advance…short term human benefit will sooner or later bring long-term ecological or social problems which demand unacceptable effort and expense for their solution.”

As we corner our biologic adversary, it might be useful to examine this unfortunate disaster closely and thoughtfully, through an ecological lens.