Spillover: From bats to humans
Posted on 14 September 2017
Researchers study how human behavior impacts spread of infectious diseases
By Skip Anderson/MSU News Service
BOZEMAN — Two Montana researchers are studying how bats bring disease to humans.
Montana State University faculty Elizabeth Shanahan, left, associate professor of political science and Raina Plowright, assistant professor of microbiology, received $1.65 million from the National Science Foundation to research the ways human activity contributes to the spread of infectious diseases. MSU Photo by Adrian Sanchez-Gonzalez
“Periodic food shortages, combined with the deforestation of winter habitat of fruit bats, has sent the flying mammals — each with a massive wingspan that can rival that of the American bald eagle — into towns and cities looking for food,” Raina Plowright, an assistant professor in the Department of Microbiology and Immunology in MSU’s College of Agriculture and College of Letters and Science, said.
The National Science Foundation has awarded a $1.65 million grant to a pair of Montana State University professors that will enable them, and an international team of researchers, to study The collaborators come from three continents, involving 10 academic institutions and a nonprofit agency. The grant will also enable MSU political scientist Liz Shanahan to study how scientific information is communicated to people at risk of disease spillover, and how people talk about this risk.
The grant will help fund Raina Plowright’s research on pathogen spillover from bats to domestic animals and people. The grant focuses on urban bats in eastern Australia, where there has been an influx of fruit bats into towns and cities and, at the same time, Hendra virus has been spilling over from fruit bats into horses and people.
The urbanization of the bats is a nuisance for residents, Plowright said, as the colonies are annoyingly loud, especially in pre-dawn hours. But it’s also a health concern, as the bats often carry Hendra virus.
“The bats are living next to people’s houses and feeding off fig trees and palm trees that people have planted,” she said. “If they feed on trees in horse paddocks, horses can become infected with Hendra virus and then pass it on to people.”
Hendra virus can cause death in horses within days to weeks of initial contact, and bring about flu-like or neurological symptoms in humans that are usually fatal, she added.
“There is a Hendra virus vaccine for horses that is highly effective, yet it’s not being widely used,” Plowright said. “There is very poor uptake of vaccinating horses. For some horse owners this is due to lack of awareness about the risks of Hendra virus, and for others it is because of an anti-vaccination movement.”
The NSF grant will enable this international team of researchers, as well as a team of MSU graduate students who are already on the ground in Australia, to study how the loss of habitat is affecting human-wildlife interaction and the spread of diseases.
Shanahan said that the scientific community is now realizing that lawmakers and the public better understand and respond to scientific information when it is presented in a narrative way, taking a cue from the literary world, which uses characters and a plot to tell a story.
“My part in the project is to understand how horse owners, community members and the media narrate the risks of Hendra virus outbreaks, paying close attention to who is ‘cast’ as the hero, villain and victim,” said Shanahan, an associate professor in the Department of Political Science in MSU’s College of Letters and Science.
Shanahan will also consider how the information is framed to support each point, such as whether the issue is presented as an economic risk or as a health risk.
She will then compare the different narratives to the information disseminated by the science community to see where the gaps are and in what specific ways future communications can be improved to potentially reduce the risk of Hendra virus spillovers.
Plowright said the team approach to understand and address Hendra virus spillover in Australia is driven by a “one-health” philosophy.
“This whole cascade of events — from the deforestation of the bats’ winter habitat, to the bats taking up urban residence, to the transfer of Hendra virus to horses and humans — could potentially be solved if we can restore their winter habitat and draw the bats out of the cities,” Plowright said.
Using a one-health approach would be a win-win situation, potentially providing solutions that benefit the health of the forests, bats, livestock and humans, she said. And, she added, it would restore a vital ecological function that the fruit bats play in maintaining healthy forests.
“When these bats move across the landscape, they move pollen with them, and now they’re staying put (in the urban areas) and not performing their pollination function in the forests that do remain,” she said.
The research may also lead to larger, more comprehensive, solutions for other continents that are seeing the emergence of more and more infectious disease from bats, such as SARS in Asia and Ebola in Africa, where it is difficult to do detailed multidisciplinary studies, Plowright said.
“We often assume there’s some environmental driver of disease emergence, but rarely can we scientifically identify the cause and effect,” she said. “We find ourselves responding to outbreaks after the pathogen has gotten away from us rather than preventing emergence in the first place.
“If we could identify the underlying environmental driver, as we are trying to do for the fruit bats in Australia, we can potentially reverse and eventually prevent it by getting to the root cause of this public health problem.”
Collaborators on the project also include: Nita Bharti, Penn State University; Liam McGuire, Texas Tech University; Olivier Restif, Cambridge University; Alison Peel, Griffith University; Peggy Eby, University of New South Wales; Wayne Bryden, University of Queensland; Peter Hudson, Penn State University; James Lloyd-Smith, University of California, Los Angeles; Hamish McCallum, Griffith University; Vincent Munster, Rocky Mountain Laboratories; Melanie Taylor, Macquarie University; Lillian Lin, Montana State University