Daniel Streicker, Infectious Disease Ecologist
Seeking Answers That Could Help Us Prevent the Next Pandemic
Daniel Streicker's work on cross-species transmission of disease may help us anticipate and prevent the next pandemic. Armed with a headlamp and a net, Streicker—who was awarded the Science and SciLifeLab Prize for Young Scientists in 2013 for his work on the transmission of the vampire bat rabies virus in Peru—spends much of his time in the Amazon, negotiating mudslides or political instability.
Talking from his lab in Glasgow, Scotland, he describes how early fieldwork in Virginia set him on a path to studying bats, why deforestation can bring humans into contact with emerging pathogens, and how data gathered in the field can influence health policymakers. —Simon Worrall
I just watched a video of you feeding blood to a baby vampire bat. It's pretty creepy. How did you get interested in vampire bats?
[Laughs.] To clarify: I was just a narrator on that video. It wasn't actually me feeding blood to the bat. But I got interested in vampire bats by first getting interested in bats generally. As an undergraduate at the University of Virginia, I studied intestinal parasites that infected small mammals in the wild. I was spending summers in the mountains of Virginia doing rodent captures, looking at the things found in their feces. I found bats interesting because there's so much ecological variation between species. I was really interested in how all that variation would influence patterns of disease transmission. Rabies stood out as an interesting pathogen because each bat species has its own genetically and epidemiologically distinct rabies virus.
Your specialty is the cross-species transmission of disease from bats and other animals. Explain, please.
We know that a lot of pathogens in humans and in domestic animals and wildlife come from other animal species. The current Ebola outbreak in West Africa likely originated from bats. HIV is originally a virus from non-human primates. Cross-species transmission means trying to understand the frequency of transmission of a pathogen from one species to another. What interests me is which species that's likely to happen between and which viruses will be transmitted. And if they are transmitted, what are going to be the consequences? Is it just going to be a one-off infection? Or will that pathogen continue to transmit within a new host species?
Ebola caught everyone's attention. How did the connection with bats occur?
We don't know exactly how the current outbreak was started. But generally for Ebola and other pathogens associated with bats, we know they have to be maintained within the bat population. Often what we see is some sort of anthropogenic change associated with the emergence of those pathogens in people. That could be something like hunting bats or wildlife markets, as was likely the case with the emergence of SARS [severe acute respiratory syndrome] in China, which is another bat virus. Or it could be things like deforestation, which puts bats and people into greater contact with each other. When systems get perturbed it can create the ecological opportunity for transmission to happen from bats to people.
You frequently go to Peru for your research. What dangers and logistical obstacles do you face?
We have a number of projects. Probably the most long-term and intensive of those is our work on the ecology and transmission dynamics of rabies and vampire bats. We've established a network of field sites and spend a lot of time trying to negotiate logistics because it's a big project spanning about 30 sites. In the field, it's all about capture, sampling, preserving the samples, and making sure they get where they need to go.
Peru is a beautiful country, but, of course, there are dangers. We're often in the Amazon, so there are risks of getting bitten by snakes or falling on a trail. We also work in the Andes, where we have to deal with steep mountainsides, which are begging for somebody to fall down them, or roads closed because of mudslides. There is currently an El Niño event in Peru, so roads often get washed out or impassable. Political instability can hold us back as well.
How does habitat loss impact the transmission of disease?
Habitat loss can change what's going on within animal populations. That might mean preferentially promoting the growth of one species versus another. If that species also happens to be important for a particular disease it could increase the prevalence of that disease and therefore the risk to people. The other way land-use change or deforestation can influence disease transmission is by putting certain species into more contact with humans than previously. You might not change the incidence within the animal population. But you increase the amount of interaction between that wild animal and either humans or livestock.
How can fieldwork data be integrated into the decisions of health policymakers working in rigid bureaucracies thousands of miles away?
This is always a challenge. We try to maximize the visibility of the work that we're doing through things like websites and blog posts. We also try to work directly with governments by trying to translate the results we get from the field into models that might be useful for policymakers.
How likely are we to suffer a deadly new epidemic like Ebola in the next few years?
That's the $100,000 question! We know there are many viruses and other pathogens lingering in wild animals, so it might just be a matter of time before they make that jump. Unfortunately, at the moment, we cannot say with a whole lot of certainly when that event is going to happen—and how severe it will be.
What inspires you in your work?
What inspires me is the ability to answer some fundamental questions that can potentially make an impact on the world. When I say an impact, it might mean improving arguments for conservation or improving the prospects for controlling a disease like rabies, which still deeply affects people in developing countries.
In Their Words
What inspires me is the ability to answer some fundamental questions that can potentially make an impact on the world.
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