Dr. Farley Cleghorn | Palladium - Feb 28 2020
Coronavirus: Context and Perspective from a Global Health Expert

Photo Credit: Macau Photo Agency

As the death toll rises and financial markets plunge, Bill Gates has gone as far as to speculate whether COVID-19 – more commonly referred to as coronavirus – could be “the once-in-a-century pathogen we’ve been worried about.”

The novel coronavirus SARS CoV-2, causing a disease syndrome called COVID-19, emerged in Hubei Province, China in late 2019 and is causing growing disruption around the world. Let’s try to bring the economic, social, medical and epidemiologic data together.

Like climate change preparation, response, and mitigation, global health security truths mandate that we prepare and respond to the diminishing distance between the microbiomes of the world’s animals and the world’s humans. The primary reasons for this diminishing distance include man’s exploitation and control of the natural environment, the enhanced opportunities for interaction in dense human cities, and the “shrinking” of the world through travel.

Why does it seem that this is becoming more frequent and more devastating?

This process is continual and intricately linked to human genetic history and evolution. The human genome is littered with the junk DNA of past viral incursions into humans. In the remote past, some of these infections may have significantly reduced human genetic diversity; (we are only now fleshing out the human family tree with all our extinct relatives). Countless cross-over events in the past, which we call zoonoses, have plagued mankind. A partial recent virus list with pandemic implications demonstrates a variety of natural hosts:

  • Ebola – Zaire and Sudan, 1976; West Africa, 2014 (bats)
  • HTLV I and II – 1900’s, recognised in 1980 (primates)
  • HIV I & II – 1900’s, recognised in New York and California, 1981 (primates)
  • Bird Flu – Hong Kong, 1997 (birds)
  • Nipah – Malaysia, 1998; India 2019 (fruit bats)
  • West Nile – New York, 1999 (birds)
  • SARS – China, 2002-3 (bats and via secondary species)
  • MERS – Saudi Arabia, 2012 (camels)

"Countless cross-over events in the past have plagued mankind." 

Given how many times we’ve been here before, why the global disruption today by COVID-19?

In 2004, the last time we had a novel coronavirus (SARS CoV 1) emerge in China, it caused almost 8,000 cases and over 700 deaths worldwide. But China then accounted for only 5% of global economic output.

Today China accounts for over 22% of the global economy and is a critical part of just-in-time supply chains for most sectors all over the world. It also boasts more than 10 megacities with over 10 million people. So, while the case fatality rate appears lower than SARS (although more than twenty times that of influenza), the transmissibility and pandemic potential for COVID-19 appears much greater.

Think of the billions of trips by airplane around the world today for business and pleasure, amounting to almost 1.5 billion tourist trips in 2018 alone – almost triple what it was in 2004. The potential for global spread of any infectious disease is thereby amplified. This is the case every year for influenza, where existing and novel flu viruses recombine and evolve in the incubator of south east Asia because of the confluence of humans, pigs and birds, both wild and domestic. The new flus, then, sweep around the world during winter. (In fact, they are called cold viruses for this reason, but this has more to do with how humans densely associate with each other during winter.)

Therefore, we have every reason to treat this threat with the seriousness it deserves, and to undertake planning and mitigation for the significant disruption it is already causing.


Dr. Farley Cleghorn is Group Health Director at Palladium.