Seven global epidemics of human diseases have occurred since 2000, an alarming acceleration that makes another one almost inevitable. But what will cause it?
That was the question for three Duke infectious diseases experts during DGHI’s first Think Global event of the 2023-24 academic year. At the Sept. 12 event, cosponsored by the Triangle Center for Evolutionary Medicine, the professors made the case for lesser-known viral, bacterial and fungal pathogens that could pose global threats.
Moderated by TriCEM's Johnny Uelmen, Ph.D., the event was presented as a debate, with attendees voting at the end to judge which researcher made the best case.
Chris Woods, M.D., DGHI’s Wolfgang Joklik Distinguished Professor of Global Health and executive director of the Hubert-Yeargan Center for Global Health, made the case for viruses as the most likely cause of the next pandemic. He cited the regularity with which viruses pass from animals to humans, just as it is suspected the coronavirus that caused COVID-19 did.
Woods singled out a class of viruses known as Paramyxoviruses. He noted that 66 unidentified Paramyxoviruses were found in studies of bats, according to a 2012 research study.
“There is potential for severe diseases from this, and there are no proven therapies yet for these [viruses],” Woods said. “It’s something to think about when [it comes to] pandemic potential.”
Asiya Gusa, Ph.D., an assistant professor in the molecular genetics & microbiology department in Duke’s School of Medicine, made the case for fungi as a pandemic threat. That may sound familiar to fans of the HBO show, “The Last of Us,” which imagines a future world in which a fungus causes a pandemic that wipes out most of civilization and infects the brains of those left alive.
While Gusa said there’s no evidence fungi can cause a zombie apocalypse, she said the show’s fantastical premise is based on some real science.
Typically, fungal infections are rare in humans because the body acts as a thermal barrier. But global changes such as warnming temperatures, heat stress and natural disasters are causing fungi to grow in foreign areas and mutate at faster rates, Gusa explained.
Gusa cited the fungus Candida auris, which has been emerging primarily in healthcare facilities, according to the Centers for Disease Control and Prevention.
“[Researchers] are behind on diagnostics, surveillance and treatment of new fungal diseases,” Gusa said. “We can’t ignore unknown threats we haven’t seen before because that’s what we want to safeguard against. Don’t discount fungi.”
But Thuy Le, M.D., Ph.D., an associate professor of medicine, molecular genetics and microbiology, argued for a threat that is already causing problems for many patients with bacterial infections: antimicrobial resistance. Le, an DGHI affiliate, said antimicrobial resistance can make the smallest injuries – for example, a cut – dangerous.
“Before penicillin, people would die from a sore throat,” she said. “The antimicrobial resistance is already here. It’s not coming. If we don’t do something about it, we are going to move back into a pre-antibiotic era. Modern medicine won’t be modern medicine anymore.”
Le and Woods both addressed the factors that are making it more likely for novel pathogens to emerge and spread in human populations.
“There’s deforestation, human migration and pathogens that jump between species,” said Le. “And with urbanization, people live closer together, which means diseases spread more rapidly. These are the major drivers.”
At the end of the event, attendees voted for which professor made the most compelling case for a pandemic threat. While many of the questions during the discussion revolved around the crisis of antimicrobial resistance, Gusa’s argument for fungi received the most instant votes.
But Woods reminded attendees that the best protection against any emerging public health threat is a well-prepared health system.
“There’s a lot of energy going into where we need to be surveilling for the next [pandemic],” Woods said. “The best thing we can do to combat potential causes of pandemics is to have solid public health and [sound] medical infrastructure around the globe.”