Bats and humans are closer than ever, and the risks have never been clearer: ScienceAlert

Bats and humans are closer than ever, and the risks have never been clearer: ScienceAlert

The link between habitat destruction, climate changesand the emergence of new ones viruses was never more evident than during pandemic.

Arrival from SARS-CoV-2 and expansion COVID-19 brought into sharp focus how human activities such as deforestation can bring wild animals carrying viruses closer to humans.

In a new study, researchers sought to provide more precise data collected over 25 years in Australia to illustrate the links between habitat loss, animal behavior and the spread of the virus.

Specifically, scientists observed Hendra carried by a bat virus, which mainly infects fruit bats (also known as flying foxes); the virus can jump to humans via horses.

“Interactions between land-use change and climate are now leading bats to permanently reside in agricultural areas, where intermittent food shortages lead to overflow clusters,” behavioral ecologist Peggy Eby of the University of New South Wales in Australia and colleagues piss in his published work.

Zoonotic transmission describes how viruses and other pathogens found in animals can jump into humans, sometimes with fatal consequences. Hendra virus is one example; HIV, Ebolarabies and plague make up a dismal short list of other zoonotic diseases.

Hendra virus – named after a suburb of Brisbane where it was discovered 1994 – can cause severe or even fatal disease in humans and horses. The virus is most commonly transmitted by infected bats that feed on flocks of horses, and since 2006 the frequency and extent of Hendra virus spread in Australia has increased increased.

In this study, Eby and colleagues mined decades of data to examine the rapid changes in bat behavior that coincided with Hendra virus spillover events in south-west Queensland between 1996 and 2020. The timing and location of these events were mapped against site data for bat resting, foraging areas, local climate, food supply and habitat loss.

“From about 2003 to 2020, bat behavior and the frequency of overflows changed rapidly: the number of roosts tripled, and 40 overflows were detected,” Eby and colleagues report.

By fitting the data to a statistical model, the researchers showed how climate change and changes in land use are forcing bats to live in agricultural and urban areas, increasing the risk of Hendra virus spreading to horses.

By 2018, nearly a third of the fruit bat’s natural habitat from 1996 had been cleared, causing the bats to flock to urban areas for roost, although most spillovers (86 percent) occurred in agricultural areas where horses roam.

Drought-inducing El Niño events have also caused winter food shortages for bats, heralding an increase in roosts closer to human-populated areas where bats are likely to find food.

Not only are food shortages and habitat loss pushing bats into areas where people and horses live—increasing human-animal encounters—but past research suggests nutritional stress can lead to increased virus shedding in bats.

“The timing of Hendra virus shedding in winter, months after food shortages in the previous year, may be due to the cumulative effects of nutritional stress overlaying high energy demands in winter (thermoregulation and pregnancy) and scarce resources within suboptimal habitats,” researchers piss.

When nearby native forests bloomed profusely in winter—something that is becoming increasingly rare—the bats returned to their usual nomadic lifestyle, abandoning urban and agricultural areas in favor of their natural habitat, and during these periods no spillovers occurred.

Protecting remnants of native forests, particularly winter-blooming forests that provide food when food is scarce, “could be a sustainable, long-term strategy to reduce overflow and protect livestock and human health,” the researchers say. conclude.

Replication of a study such as this in other areas where zoonotic diseases are common could reveal the dynamics that contribute to these outbreaks and inform strategies to mitigate the risk of infection.

But long-term data spanning decades on viral reservoir hosts, especially bats, are scarce. Even with our data, we keep coming back to the same problem: humans are constantly destroying habitats and destroying biodiversity.

AND Analysis 2020 about 6,800 ecological communities on 6 continents found that as biodiversity declines, animals that survive and thrive, such as bats and rats, are also more likely to host potentially dangerous pathogens, concentrating the risk of zoonotic disease outbreaks.

“We’ve been warning about this for decades,” Kate Jones, an environmental modeler at the University of London who co-authored the study. told Nature when it was published in August 2020.

– No one was paying attention.

The latest study was also published in Nature.

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