In 1999, the New York State Department of Health asked me to test brain samples from people in Queens experiencing encephalitis, or brain inflammation. Surprisingly, we found they were infected with West Nile virus, a mosquito-borne virus that had never been reported before in North America. How did a virus endemic in Africa and the Middle East end up in Queens?
At the time, scientists posited that there were stowaway mosquitoes on a flight from Tel Aviv. It seemed plausible that these stowaways fed on infected geese in Israel before infecting birds in New York. Local mosquitoes that fed on the New York birds then fed on people, and now we had an outbreak.
Like today with the origins of Covid-19, there were other, often polarizing, theories. Back in 1999 there were claims that the virus had been bioengineered by Saddam Hussein.
Although the global community never officially pinned down the provenance of the West Nile virus, the outbreak was brought under control by reducing the mosquito population in Queens — West Nile nonetheless remains the leading cause of mosquito-borne disease in the continental United States. Since 1999 it has infected at least seven million people, resulting in more than 51,000 cases of encephalitis and more than 2,300 deaths.
Similarly, in 2008 my team investigated a hemorrhagic fever outbreak with an 80 percent case fatality rate in Zambia and South Africa. Viral sequencing led to identification of a new virus named Lujo (for the location of the first case in Lusaka, Zambia, and the subsequent outbreak in Johannesburg, South Africa). We predicted it would be sensitive to an existing antiviral drug, and thankfully it was. Although four people died, we saved the last person infected and interrupted further transmission. But 15 years later we still don’t know how the first person became infected, although we suspect that the reservoir was a wild rodent.
Finding the origin of a viral outbreak can be incredibly difficult, even with full government cooperation and the best available technologies. It’s important to try, because the insights into how a virus emerged may be useful in reducing the risk of future outbreaks. But these efforts and debates over uncertainties cannot come at the expense of action. We cannot wait for answers that may never come before doing what must be done to prevent the next pandemic.
There have been several news cycles dedicated to theories about the origin of Covid-19 that focus on the roles of wild animal markets versus research-related incidents. The latest revelations have gotten us no closer to resolution and agreement than when I visited China in January 2020 at the outset of the pandemic to try to investigate the cause and contain it. To the contrary, rancor has increased and the relentless focus on the origins of the virus has obscured the primary objective: preventing future pandemics.
Even if scientists could confirm the link of SARS-CoV-2 to a laboratory or to a raccoon dog, that wouldn’t mean that wild animal markets in cities can safely continue or that regulations concerning scientific experimentation with infectious agents are less important. And yet very little has been done in the wake of this pandemic to better either source of risk.
What must improve is our ability to track viruses. We estimate that a minimum of 300,000 viruses are lurking in wildlife. It’s unlikely that all of them can infect humans or domestic animals. However, the risk is substantial even if only 1 percent of them can do so. More than 70 percent of emerging infectious diseases, including H.I.V., influenza, West Nile, Ebola, chikungunya, Zika, mpox (formerly monkeypox) and SARS, can be traced to human exposure to wildlife.
More than a decade before the Covid-19 pandemic, scientists and policymakers called for stronger efforts to detect infectious threats to human health. A 2011 report from the National Biosurveillance Advisory Subcommittee to the Centers for Disease Control and Prevention and the White House recommended steps to reduce the risks of a pandemic, including a call for global investments in people and the science needed to provide an efficient and effective early warning system for potential threats. This includes sampling humans, domestic animals and wildlife with unexplained illnesses for the presence of known and unknown viruses and developing methods for monitoring social media for clues to outbreaks. Having such a system would be helpful whether an outbreak is due to wildlife contact or results from a research-related event.
Wildlife markets should be banned, as well as all trade in wildlife as food or pets, to reduce the frequency of human exposures to infectious pathogens. But such bans would be difficult to enforce, and accidental exposures would still occur. It is important, therefore, to continue the research needed to rapidly identify potential threats to human health and domestic animals that threaten food security.
Public health authorities should monitor humans at risk for exposure to infectious diseases through proximity to wildlife, travel, residency in densely populated areas, or participation in mass gatherings. As we learned from the recent mpox outbreak, infectious agents can rapidly go global after festivals where people from many geographic regions converge and then disperse again. By comparing test results obtained with animal and human samples we will have the ability to detect and respond to early evidence of cross-species transmission through containment and development of diagnostic tests, drugs and vaccines. These investments will promote economic as well as public health. A conservative cost of $100 million per year for surveillance is a small fraction of the more than $10 trillion in the global gross domestic product estimated to be lost from the pandemic in 2020 and 2021.
Laboratory-based infectious disease research is essential, but it must be better regulated. At present we have a patchwork of regulations that varies from country to country, and in some instances within countries. The World Health Organization should convene an international panel of experts to define best practices for research with wildlife and infectious agents. With the rise of synthetic genomics it has become possible to create new viruses and recreate old ones like smallpox. Manufacturers should be required to monitor orders for gene sequences that could be assembled to create potential pathogens.
A global surveillance system must truly be global. Risks of exposure are frequently higher in low- and middle-income countries than in better-resourced ones. Countries with robust surveillance systems historically have been able to detect and contain outbreaks quickly, while those without have struggled to respond effectively. Equal access to science and medicine is a fundamental human right. Given that infectious diseases don’t respect borders, it is also in our self-interest to contain them before they hit closer to home.
We must not get stuck endlessly rehashing the origins of Covid-19 without action; we must move to implement necessary programs and policies to stop the wildlife trade, as well as international regulations and oversight over research that may carry risks, and build a truly global surveillance system with data sharing between scientists and public health officials to stop the next pandemic in its tracks.
W. Ian Lipkin is the John Snow Professor and director of the Center for Infection and Immunity and the Global Alliance for Preventing Pandemics at Columbia University, and was scientific adviser for the film “Contagion.” This article originally appeared in The New York Times.
