COVID-19 is just the latest in a long line of plagues to invade our world and change lives forever.

I was thinking of that the other day as I walked up the lane from getting the mail and looked toward the fenceline at the back of the farm. A row of dead branches showed that emerald ash borer (EAB) had finished its deadly work on the ash trees along the property line.

It hardly seems any time at all since I was doing stories about the first discovery of damage by the EAB. It had been discovered in southern Michigan in May 2002 and by that July had spread into Essex County. I wasn’t even aware how many ash trees we had in the landscape when I did my first stories. Now it’s easy to tell just about wherever you look.

It’s the second major tree species to be devastated by an invader since we moved to our current home. The skeletons of mighty elm trees were still silhouetted across the horizon when we moved here in the 1970s, the victim of Dutch Elm Disease, spread by the elm bark beetle. Holland had nothing to do with the disease, except that two Dutch researchers did early research on the fungus in the 1920s.

Both diseases are thought to have originated in Asia and reached our shores thanks to world trade and travel, just like COVID-19 and many diseases like the Spanish Flu. It’s thought the EAB arrived in packing materials, perhaps skids, with goods from China. Dutch Elm Disease came in 1931 when a furniture company in Cleveland, Ohio unwittingly bought infected logs from France. Not only did we import the killing fungus but also the European elm bark beetle which was much more efficient in spreading the fungus than native bark beetles.

Human “improvements” often have unintended consequences. Development of the Erie Canal in the U.S. and the Welland Canal in Ontario allowed the spread of the sea lamprey eel which has been destroying native lake trout populations for nearly a century.

The recent 2019 State of the Great Lakes report released by the Governments of Canada and the United States stated over 185 non-native aquatic species have become established in the Great Lakes basin. Many are undermining the health of native aquatic life in the lakes and damaging the fishing industry.

Of course deadly invaders are nothing new. Indigenous people could argue the worst plague to invade North America was the Spanish, English and French  explorers, closely followed by their nations’ settlers. Sometimes these aggressors directly attacked the people already living here, sometimes simply bought their land for pennies or cheated them out of it.

If that wasn’t enough, they brought with them new diseases the native population had no resistance for, including smallpox, bubonic plague, chickenpox, cholera, the common cold, diphtheria, influenza, malaria, measles, scarlet fever, sexually transmitted diseases, typhoid, typhus and tuberculosis.

There were relatively few communicable diseases among the Indigenous peoples of North America (the one disease they traded back was syphilis) and spread thinly across two huge continents, they had social distancing down pat and didn’t share diseases often.

The common thread in all this is travel. And the greatest “advance” of the modern world is – travel. Never in the history of the world have so many people travelled so much, and so quickly. Never have so many resources and goods been shipped between continents.

And so, I suspect, my neighbourhood’s ash trees will not likely be the last victims of an imported plague. Neither will COVID-19 be the last pandemic we’ll face. Apparently we’ll accept that cost to enjoy trade and travel.◊