Preventing Future Pandemics: Lessons from Experts on COVID-19
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Chapter 1: Understanding the Roots of Pandemics
In January 2009, Jonathan Epstein found himself on the rooftop of an abandoned storage facility in Khulna, Bangladesh, alongside journalist David Quammen and a dedicated team of veterinarians. Their unusual mission? To capture bats. This task was a direct response to the lingering specter of the Nipah virus, which had first emerged in Malaysia over a decade earlier. Nipah, named after the village of one of its earliest victims, leads to severe respiratory issues, brain inflammation, and seizures, with a mortality rate ranging from 40% to 75%. Notably, the virus served as the inspiration for the 2011 film "Contagion."
The original Nipah outbreak in Malaysia during 1998 affected 283 individuals, resulting in 109 fatalities. Scientists ultimately traced the virus’s transmission from bats to local pig farms, prompting the government to cull over a million pigs to control its spread. However, Nipah has resurfaced sporadically across the globe, claiming numerous lives. Epstein and his team were investigating whether the bats in Bangladesh harbored the virus and posed a risk of transmission to humans.
Epstein, a veterinarian and disease ecologist at EcoHealth Alliance, has travelled extensively to trace viruses that could potentially jump from animals to humans, particularly as human activities encroach upon natural habitats. His work includes identifying the origins of outbreaks like SARS in 2003 and MERS in 2013, with bats often implicated as primary carriers.
"There are always two critical inquiries," Epstein shared during a phone call from his home in Queens. "What caused this? And could it happen again?"
Section 1.1: The Zoonotic Threat
Approximately 60% of newly emerging infectious diseases, akin to COVID-19, originate from domesticated animals and wildlife, frequently involving bats, rodents, or non-human primates. Scientists estimate that around 800,000 zoonotic viruses exist in nature that could potentially infect humans. The species carrying these viruses often remain asymptomatic, acting as "reservoirs," which allows pathogens to accumulate while awaiting the opportunity for a cross-species jump.
The increasing frequency of these dangerous transmissions is alarming. Human population growth and environmental degradation are placing people in closer contact with virus-carrying species. "Every potential viral threat already exists and circulates among these animals," stated Dennis Carroll, an authority on zoonotic diseases and former head of the emerging threats division at USAID. "Now, we are encountering them with a frequency that permits spillover."
As COVID-19 rapidly spread across the globe, affecting nearly 3 million individuals and resulting in over 200,000 deaths, public health officials, policymakers, and journalists began scrutinizing the missteps that led to such an unprepared response. Should nations stockpile more ventilators, masks, and ICU beds? Were stay-at-home orders issued too late?
These considerations arise only after an epidemic has taken hold, following the moment when a virus leaps from animal to human—a phenomenon known as "spillover." However, a small cadre of ecologists, epidemiologists, and veterinarians has dedicated the past decade to preempting pandemics by cataloging viruses before they can infect humans. By understanding and mitigating potential spillover events, the aim is to prevent outbreaks entirely.
The first video, "Why do we keep blowing it? Covid, monkeypox and the next pandemic," discusses the ongoing challenges in pandemic preparedness and the lessons learned from recent outbreaks.
Section 1.2: The PREDICT Initiative
In 2005, the emergence of the H5N1 avian influenza virus raised alarms as it spread from Southeast Asia to Eastern Europe. Although the disease was rare, it boasted a mortality rate of about 60%. Carroll, then at USAID, focused on the response to this potential crisis and recognized the growing risks associated with increasing poultry production in China. This realization spurred Carroll to consider the numerous viruses waiting for the chance to infect humans.
To address these concerns, Carroll initiated the PREDICT program in 2009, a project aimed at discovering new viruses before they could spill over into human populations. The program enlisted scientists from institutions like the University of California, Davis, and EcoHealth Alliance, focusing on identifying viral hotspots worldwide.
The ambitious PREDICT project operated with an annual budget of $20 million, training local populations in over 30 countries, including Sierra Leone, Uganda, and Bangladesh, to capture animals, obtain blood samples for viral testing, and safely release them back into their environments.
Subsection 1.2.1: The Scale of Viral Diversity
Researchers estimated that approximately 1.67 million undiscovered viruses circulate among mammals and birds, with between 631,000 and 827,000 having the potential to infect humans. Fortunately, only a small fraction of these viruses could cause severe illness. "Most microbial infections in humans are inconsequential," Carroll noted, suggesting that researchers should focus primarily on the lethal threats.
Jonna Mazet, who directed PREDICT until last year, reported that the initiative collected 168,000 samples from various species, identifying over 900 new viruses, including 160 coronaviruses related to SARS-CoV-2.
But simply cataloging potential diseases was not enough. The team also sought to uncover patterns of transmission and risky behaviors that could facilitate spillover events. Notably, the first case of the 2013 Ebola outbreak in Guinea was traced to a child who had played under a tree where bats roosted, underscoring the connection between environmental disruption and disease transmission.
Chapter 2: Addressing Human Behavior and Environmental Impact
While some spillover events are predictable and avoidable, certain human behaviors exacerbate the risk. For example, live animal markets continue to pose significant threats, as they bring wild animals, including bats and rodents, into urban environments where they can interact with each other and humans. The SARS outbreak in 2003 is believed to have originated from a wildlife market in Guangdong, China.
To mitigate these risks, Epstein advocates for interventions such as improving hygiene at wildlife markets or banning the sale of wild animals altogether. He emphasizes the importance of culturally sensitive approaches to ensure community cooperation.
The second video, "Preparing for future pandemics: Learning from Covid-19," emphasizes the need for comprehensive strategies to reduce the risk of zoonotic diseases and improve global health systems.
In Bangladesh, Epstein and his team investigated another Nipah outbreak linked to the consumption of sap from date palm trees, which had been contaminated by bat droppings. This incident illustrated the broader issue: human activity—such as deforestation and agricultural expansion—forces wildlife into closer proximity to human populations. "It’s not the animals' fault for carrying these diseases," Epstein remarked. "These are consequences of our environmental choices."
In the last century, the global population has surged, creating conditions ripe for pandemics. The lessons learned from COVID-19 highlight the urgent need for sustainable practices and increased awareness to prevent future outbreaks.
Despite the setback of the PREDICT program, which ceased operations due to funding issues, the scientists involved have initiated the Global Virome Project. This ambitious endeavor aims to identify and assess major viral threats over the next decade, with an estimated budget of $1.6 billion.
Though the future remains uncertain, the insights gathered from years of research may provide crucial knowledge to avert the next global health crisis. As Epstein succinctly put it, "These pandemics are preventable."