More than 40 Jamaican flying foxes will be transported to a laboratory in Bozeman, Montana, USA, to be part of an experiment with the ambitious goal of predicting the next pandemic.
Worldwide, bats are the primary vectors for virus transmission from animals to humans.
These viruses are often harmless to bats but can be deadly to humans.
For example, Chinese horseshoe crabs have been cited as a possible cause of the Covid-19 outbreak.
Researchers also believe that the pressure on bats from climate change and encroachment from human development has increased the frequency at which viruses are transmitted from bats to humans, causing diseases known as zoonotic diseases. .
“The spillover phenomenon is the result of a series of stressors: bat habitats are being wiped out, climates are becoming more extreme, and bats are migrating into human settlements in search of food,” said Raina Plowright.
She is a disease ecologist and co-author of a recent paper in the journal Nature and another ecology letter On the role of ecological change in disease.
So Agnieszka Rynda-Apple, an immunologist at Montana State University (MSU), brought Jamaican flying foxes to Bozeman this winter to start a breeding colony, as part of a team of 70 researchers in seven countries. We are planning to accelerate our lab work.
Called BatOneHealth and founded by Plowright, the group wants to find a way to predict where the next deadly virus might make the leap from bats to humans.
“We’re trying to understand what makes their immune system retain the virus and under what circumstances it sheds it.”
To study the role of nutritional stress, the researchers created a variety of diets for them and asked “how much virus she sheds after being infected with influenza virus, how long viral shedding We will study the reaction,” she said.
She and her colleagues are already doing this kind of experiment, but breeding bats could expand their research.
Fully understanding how environmental changes contribute to nutritional stress and predicting spillovers more accurately is a painstaking effort.
“If you really understand all the pieces of the puzzle, you have the tools to think about the environmental measures you can put in place to break the cycle of spillovers,” says Associate Professor Andrew Hogue. His MSU stats modeling possible spillover scenarios.
A small team of researchers at MSU is collaborating with researchers at the National Institutes of Health’s Rocky Mountain Laboratory in Hamilton, Montana.
Recent papers published in Nature and ecology letter It focuses on the Australian Hendra virus from which Plowright originated.
Hendra is a respiratory virus that causes flu-like symptoms, is transmitted from bats to horses, and can then be transmitted to people who treat horses.
It is highly lethal, with a mortality rate of 75% in horses.
Of the seven confirmed cases, four have died.
The question that drove Plowright’s research was why Hendra began appearing in horses and humans in the 1990s, even though bats have likely hosted the virus for a long time.
Studies show that the reason is environmental change.
Plowright began working with bats in 2006.
In samples taken from Australian bats called flying foxes, she and her colleagues rarely detected the virus.
In 2005-2006, hundreds of thousands of bats disappeared after Cyclone Rally off Australia’s Northern Territory wiped out their food sources.
However, they found a small population of weak and starving bats carrying the Hendra virus.
This has led Plowright to focus on nutritional stress as a major player in spillovers.
She and her collaborators reviewed 25 years of data on habitat loss, spillovers, and climate and found an association between loss of food sources due to environmental change and high viral loads in food-stressed bats. I found gender.
In the years following an El Niño weather pattern, with warmer temperatures every few years, many eucalyptus trees are unable to produce the nectar-laden flowers needed by bats.
Alternate food sources are also being lost due to human encroachment on other habitats, from farms to urban development.
As such, bats tend to migrate to wooded urban areas such as substandard figs and mangoes, where they shed the virus when stressed.
When bats excrete virus-laden urine and feces, horses smell the ground and inhale it.
Researchers say studies using Hendra-infected bats illustrate universal principles of how the destruction and alteration of nature increases the chances of deadly pathogens escaping from wild animals to humans. I hope to
The most likely sources of spillovers are bats, mammals, arthropods, especially ticks.
About 60% of emerging infectious diseases that infect humans originate in animals, and about two-thirds of them originate in wildlife.
The idea that deforestation and human encroachment on wild lands contribute to pandemics is not new.
For example, experts believe that HIV (Human Immunodeficiency Virus), which causes AIDS (Acquired Immune Deficiency Syndrome), first infected humans in Central Africa when people ate chimpanzees.
The bat-borne Nipah virus, which emerged in Malaysia in late 1998 and early 1999, spread from bats to pigs.
Pigs amplified it and it spread to humans, infecting 276 people and killing 106 in the outbreak.
Currently, links to stress induced by environmental changes are emerging.
recovery of nature
One of the key pieces to this complex puzzle is the bat’s immune system.
Jamaican fruit bats housed at the MSU will help researchers learn more about the effects of nutritional stress on viral load.
Vincent Munster, Chief of the Virus Ecology Unit at Rocky Mountain Laboratories and member of BatOneHealth, is also looking to different species of bats to better understand the ecology of spillovers.
“There are 1,400 different species of bats, and there is a very big difference between bats that carry the coronavirus and bats that carry the Ebola virus,” he said.
“And the comparison between bats that live in groups of hundreds of thousands of[other bats]and bats that live relatively alone.”
Meanwhile, Plowright’s husband, Gary Tabor, is president of the Center for Massive Landscape Conservation, a non-profit organization that applies the ecology of disease research to protect wildlife habitat. Spillover.
“Habitat fragmentation is a poorly addressed planetary health issue given that the world continues to experience unprecedented levels of land clearing,” he said.
As our ability to predict outbreaks improves, other strategies become possible.
Models that can predict where Hendra virus will flow could lead to vaccination of horses in those areas.
Another possible solution is the set of “environmental measures” mentioned by Hoegh. For example, large-scale planting of flowering eucalyptus trees to discourage fruit bats from seeking nectar in developed areas.
“Right now, the world is focused on how we can stop the next pandemic,” said Plowright.
“Unfortunately, preserving or restoring nature is rarely discussed.” – By Jim Robbins/Kaiser Health News/Tribune News Service
Kaiser Health News (KHN) is a US national newsroom that produces in-depth journalism on health issues. KHN is one of the three main operating programs of the Kaiser Family Foundation (KFF), along with Policy Analysis and Opinion Research. KFF is a non-profit organization that provides information on health issues in the United States.