Future pandemic: COVID-19 can happen again if we don’t learn lessons
Many viruses and bacteria are amplified by human activity and we need to change our behaviour to stop future pandemics. Experts say we can expect more pandemics unless China gets serious about food hygiene and rethinks its stance on wet markets.
NSW
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We will beat COVID-19 but this will not be the end of new coronaviruses — especially if the “wet markets” in Asia are allowed to continue.
And, while science will help us fight off these super bugs, good hygiene is actually our best defence against their spread.
This is the warning — and message of hope — from medical experts.
Virologist Associate Professor Ian Mackay said we are witnessing the birth of “a new common cold” but one that was predictable due to unhygienic practices in the wet markets of China.
“It is a random event … it is bad luck that sees it take hold but it is habits that see it propagate,” Prof Mackay said.
“We have this issue with live animals market and fresh butchered animal markets that are really a risk for the spread and mixing of viruses from different species.”
SARS-CoV-2, the virus that causes COVID-19, is a new coronavirus. Coronavirus in its many forms has been around for millennia and several versions cause colds and croup.
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In every case, the virus jumped from animal to human, just like this new one that is believed to have been born in the wet, bloody, crowded mess of a variety of live animals being butchered in Wuhan’s Huanan market.
“There are four coronas in humans that we get mostly in winter called HCoV and there is 229E or OC43 or NL63 and HKU1,” Prof Mackay said.
“These mostly cause common colds but also pneumonia and NL63 is associated with croup. “So plenty of precedent and sometime in the past they would all have jumped from something to us.
“It is the beginning of a new common cold virus — but infecting people that have no immunity, so you see a portion who get a pretty bad outcome, including death.”
After Severe Acute Respiratory Syndrome broke out in 2002, after jumping from bats to civet cats to humans, killing more than 700 people, the Chinese government vowed to clamp down on wet markets.
But after a token effort they were soon back and thriving.
Prof Mackay is adamant wet markets must be closed down.
“They need to not exist, they increase risk and these things transmit due to lapses in hygiene,” he said.
“We know when you bring animals in contact with humans there is a risk because every living creature has its own library of viruses and sometimes they can cross species.
“You’d like to not be chopping up animals and killing them in among people who are not having the right levels of hygiene.”
Years ago the virus may have stayed and died out in China but modern travel delivered it to the doors of just about every country.
The wet markets are just the latest in a long line of incidents throughout history where a toxic mix of animals, people and a lack of hygiene and clean water has been fatal to humans.
The Black Death, or bubonic plague 1347-51 killed over 200 million.
The Spanish flu killed 40 to 50 million in just one year between 1918-19. It was thought to have crossed from pigs to humans in Kansas in the USA mid-west but was not reported until it arrived in Spain.
HIV/AIDS came from chimpanzees in Africa; bird flu or avian influenza from birds, swine flu from pigs on the Mexican/USA border, ebola from wild animals to humans in Africa, SARS from bats and civet cats and MERS from bats and camels to humans.
“Influenza is a classic one because of the various animals that can act as mixing pots, us being the end of the chain,” Prof Mackay said.
“Ducks is where influenza A plays around but where you have ducks close to pigs, pigs can take those viruses and adapt them to be better forward transmission to humans.
“As we are seeing now with this coronavirus, other viruses can do that as well.”
By overusing antibiotics, humans are creating their own superbugs in the form of drug-resistant bacteria that could, at any moment, produce another pandemic.
A decade ago, Professor Peter Collignon, an Infectious Diseases physician and microbiologist at the Canberra Hospital tried an experiment.
He swabbed his backside and that of his wife’s, before a trip to China, then repeated the exercise on his return. He then recruited his hospital colleagues, 110 of them, to do the same before they travelled to various Asian destinations.
He was keen to see how many drug-resistant bugs they would pick up.
“When they came back, 50 per cent carried superbugs — and they had not been to hospital, they had just been travelling, eating the food and mixing with people,” he said.
The bugs were colonised in the gastrointestinal tract and did not make them sick but Collignon saw other cases of patients with antibiotic-resistant urinary tract infections they had picked up in travels to China.
Of his healthy research subjects, most lost their bugs after six months.
“Two-thirds lost these superbugs within six months of being back in Australia with clean water, better quality food and tighter rules,” he said.
“My wife and I did not get it because we would not eat anything except hot food. No salads, only cooked food, cooked food is where all the bacteria and viruses should be dead.”
“Places with poor water supplies have more superbugs because you spread it more easily because water is such a good vehicle,” he said.
“That is the same for lots of other things including a lot of viruses. Influenza viruses come from ducks and it’s in their guts and they poop into water and then other animals drink it and get it that way.
“You can predict where these things are more likely to happen where you have more pigs, more ducks, more chickens, more animals and more people and guess where that is?
“Anything you do to increase interaction of people with live animals or animals that are not cooked, the bigger the chance you might pick up something.
“Wet markets are a big factor for two reasons, there are more animals there and more people crowded together and, particularly if the water is unsanitary and you are using that water to hose the place down.
“This will happen again. What we have to do is do everything we can to stop bugs spreading from person to person, no going to work when sick, basically the things we should do every winter but never do.”
Professor Brian Oliver from the Woolcock Institute of Medical Research is a respiratory virologist who has expertise in transmission. He said future pandemics can be predicted.
“You could make a list of the next 10 pandemics if you wanted to and sooner or later they will all come true,” he said.
“If you look back through history, there is a big viral pandemic about every hundred years.
“If you think about the things that drive the viral pandemics, there are more people on the earth, we are living closer together, we live closer to animals, so we might only have to wait 50 years for the next one.
“We will certainly have more viral pandemics but whether they will be new viruses as in this one or a pre-existing virus mutates and becomes nasty, for example, the flu.
“But if something like the common cold virus (rhinovirus) for which we don’t have any drugs … if it mutates into a particularly nasty version, then we’d have a pandemic like this one where there is no treatment.
“It is likely both scenarios will occur in time. From a big risk point of view it is antimicrobial resistance. All we need is for one of those bacteria (like tuberculosis) to become untreatable and we will have a bacterial pandemic.”
Prof Mackay said there are lessons here and a small upside. The virus that causes COVID-19 just waits for anyone with a hand, a nose and a mouth and, without that, it can’t survive.
“If there is any good side to this, it is the knowledge generated around health and hygiene, how viruses spread and how we can avoid that spread,” he said.
“The only way to stop a virus is starve it of hosts. It can’t do anything if it does not have live human cells to replicate in. It is primitive.”
Originally published as Future pandemic: COVID-19 can happen again if we don’t learn lessons
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