Even when it’s not Halloween, Simon Anthony, PhD, spends a lot of time with bats.
When Dr. Anthony isn’t in his office in the School’s Center for Infection and Immunity, he is circling the globe in search of deadly microbes. For the past year, he and a research team have gotten up close and personal with the Amazon rain forest, the most bio-diverse area on the planet. Huge anaconda and other poisonous snakes, jaguars, crocodiles, piranha, and frightening number of bizarre insects are all part of the scene. And there are the bats, great black clouds of them, representing 40 or so species, some carnivorous. Yes, even the blood-sucking vampire bat (see picture).
The real fright isn’t the bats, but what they carry. A single bat can be infected with as many as 50 viruses, some which have the sinister ability to “jump” across species and infect humans. An estimated 75% of emerging infectious diseases in humans come from wildlife, many times from bats. “Bats contain many viruses that infect people,” says Dr. Anthony. “Ebola, SARS, rabies, Nipah virus, Hendra virus: All these came from bats. And it’s a rapidly growing list.”
To learn more about the natural habit of these viruses before they emerge, the research team treks for miles into the dense jungle. Working in the dead of night, they trap bats—which are famously nocturnal—using large nets. Once caught, each animal is carefully brought to a mobile field station (team members all wear gloves and face masks). There, Dr. Anthony finds a vein in the wing and takes a blood sample, which is flash-frozen in liquid nitrogen. The bat is then released, unharmed. From catch to release takes all of 10 minutes.
Of course, much of the important work takes place outside of the jungle. Coordinators bring specimens to the Mailman School, where they are processed by Columbia University technicians such as Isamara Navarrete and Eliza Liang. Dr. Anthony leads this lab work under the guidance of W. Ian Lipkin, MD, director of the School’s Center for Infection and Immunity, and Peter Daszak, PhD, president of EcoHealth Alliance. “Simon is a brilliant young investigator and one of the few in pathogen surveillance and discovery who has expertise in both the field and the laboratory,” says Dr. Lipkin.
The Amazon study is part of a larger USAID-funded PREDICT Project, led by Jonna Mazet, PhD, at the University of California, Davis, but also comprising Global Viral Forecasting, the Wildlife Conservation Society, EcoHealth Alliance, and the Smithsonian Institutes. The mission is to discover pathogens that might jump from other species to humans, develop models to understand how and why those jumps occur, and help countries build capacity to respond.
There are study sites in some 20 countries around the world, in hot spots where humans are encroaching on natural habits, such as the expanding city of Manaus, Brazil. Sites are chosen by PREDICT modeling teams at EcoHealth Alliance and UC Davis, two of the partner organizations under which Dr. Anthony conducts the research. “I am grateful to Drs. Daszak, Lipkin and Mazet for the opportunity to carry out this study,” he says.
In many ways, people are the biggest drivers of infectious disease. Every day the rain forest gets smaller, opening opportunities for wildlife and humans to interface and opportunities for the next pandemic to emerge. “The rate at which new diseases is emerging is probably increasing because we are having an exponentially higher impact on the environment in the globalized world,” says Dr. Anthony.
Many questions remain. Such as what the mechanics are of cross-species infection and what exactly people are doing to the environment that increases this possibility. And while it is known that most diseases emerge from cross-species infection, Dr. Anthony says, “we have no idea how often viruses jump over into people or other animals and never cause any disease.”
Results of the lab work for the Amazon study remain to be seen, but scientists are on the lookout for any unusual viruses, especially if they resemble HIV, SARS, or avian influenza. Should that happen, Dr. Anthony says, “We would immediately know that we need to take a closer look.” In a study of flying fox bats in Bangladesh, Dr. Anthony uncovered a ghoulish mix of microbes, including avian, bovine, and human viruses. Not only are humans infected by bats, but the reverse is true. Human viruses pose significant implications for natural habits. “Our work is not just about protecting human health, it’s about protecting wildlife health too,” he says, adding that field workers wear protective gear for both themselves and the animals.
While the diversity of jungle wildlife can be vast, it is nothing compared with the number of viruses. Scientists estimate that they are aware of only 1% of what’s out there. So far Dr. Anthony and other scientists with PREDICT have identified upward of 150 viruses, but this is a drop in the bucket. “Somewhere in that 99% of undiscovered viruses is the next global pandemic,” he says.
Now that’s a scary thought.
October 31, 2012