There’s a disturbing reality that’s clear to experts in infectious disease — but the rest of us ignore it on a regular basis.

The next pandemic is coming.

New diseases are always on the rise. Viruses and bacteria can mutate and become more infectious or deadly (or both), and there’s a constant risk that new illnesses could find ways to jump from their hosts to humans. As Bill Gates wrote in a recent op-ed for Business Insider, a terrorist attack could involve the creation of a particularly contagious and deadly flu strain.

“Whether it occurs by a quirk of nature or at the hand of a terrorist, epidemiologists say a fast-moving airborne pathogen could kill more than 30 million people in less than a year,” Gates wrote. “And they say there is a reasonable probability the world will experience such an outbreak in the next 10-15 years.”

Five disease experts recently convened at the American Museum of Natural History (AMNH) to discuss the threat of pandemics.

“A pandemic is something that stretches like a colossus around the world; an epidemic that affects many parts of the world,” Tom Frieden, former director of the Centres for Disease Control and Prevention, explained at the event.

In many ways, the experts’ thoughts about pandemics were reassuring — over time, they said, we’ve improved how we respond to disease outbreaks by acting quickly to isolate and care for sick patients. But regions of the world that struggle with poverty or war still struggle to contain disease outbreaks.

“The pandemic of greatest concern is the pandemic of poverty,” said Don Weiss, a medical epidemiologist with the New York City Department of Health and Mental Hygiene, during the discussion.

Each expert also explained their biggest worry about the next pandemic. Here are their concerns (with responses lightly edited for clarity):

Lack of trust in scientists and experts: Wafaa El-Sadr, professor of epidemiology and medicine at Columbia University, said that given the recent disregard for scientific facts (like human-caused climate change, for instance), she’s concerned that people won’t heed experts’ warnings.

“I think my biggest worry is mistrust, mistrust of experts in general,” she said. “That’s worrisome because that has implications for what we’re talking about today; and that has implications for everything else.”

Learning lessons from the past: Tom Frieden said he’s concerned that people won’t study responses to recent pandemics enough to improve responses to future ones.

“The world has a unique opportunity following Ebola to close gaps, to address blind spots around the world and to become much safer. If we don’t take action very quickly to close the gaps that are being identified, we will lose that opportunity,” he said.

Antibiotic resistance: Laurie Garrett, Pulitzer Prize-winning science journalist and author of several books on disease and public health, points to a related problem as her primary concern.

“I’m increasingly very worried about broad spectrum drug resistant plasmids emerging in a huge range of bacterial populations and the high probability that we’ll lose the efficacy of much of our antibiotic armamentarium,” she said.

In other words, bacteria around the world are adapting and becoming resistant to our existing antibiotics. As this continues, we could return to an era where a simple scratch becomes deadly — unless we find new types of antibiotics to stay ahead. (Garrett also says that a particularly bad strain of influenza is a very real pandemic threat.)

Destruction of species and environments that might hold the keys to future medical breakthroughs: Mark Siddall, an AMNH curator and principal investigator at the SICG Genomics Lab, said the natural diversity humans are destroying might hold solutions to many of our problems.

“As a biodiversity specialist here at the Museum of Natural History, my concern is that the next artemisinin, which is a drug for malaria; or the next cephalosporin, which was discovered in a soil fungus; or the next avermectin, which was found in a soil bacterium, is going to be wiped out from somebody burning a forest down before somebody figures out what it is,” he said.

Funding for public health workers: Don Weiss said he hopes the people on the front lines when a new disease pops up will have the resources they need.

“I would like to shout out to all the students out there who want to go into public health and who want to get a job in public health … I’m hoping that there will be funding so that we can hire you and that when I hang up my calculator that I will be able to hand the mantle off to a new crop that will be funded and well supplied with whatever they need to do the job,” he said.

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