Animals in cities are getting bolder. The increasing encroachment of humans into wild nature significantly increases the risk of pandemics such as the current Covid-19 outbreak, an international team of researchers claims.
The task of scientists was to try to understand where new infectious diseases came from and to predict the sources of new epidemics that posed the greatest risk to humans. A new method based on detecting patterns of infection spread has been used by scientists at the University of Liverpool as part of an international effort to find more effective ways to combat future epidemics.
British biologists have studied where and under what circumstances dangerous diseases previously unknown to medicine have arisen. Primarily, humans were infected by wild animals, and then, due to lack of immunity and means to fight the new infection, it spread like wildfire. Using analogies, experts tried to calculate the most serious threats.
Camels can carry one of the new coronaviruses – MERS. Professor Baylis and his colleagues have developed a predictive detection system that can identify the most dangerous bacteria, parasites and viruses in terms of their impact on humans from among the thousands known to affect wildlife. The system is based on the number of species that act as vectors for a particular pathogen and their potential for contact with humans. If the pathogen is included in the “black list”, scientists recommend to start developing protection against it without waiting for the beginning of the epidemic.
Bats are natural reservoirs of coronaviruses. (The number of offers remains the same) “In the next stage, we will try to identify which specific pathogens are capable of causing an epidemic,” says Professor Bailey. Many experts point out that our actions, especially deforestation and invasion of wildlife habitats, are contributing to the increase and acceleration of animal-to-human disease transmission. “There is a lot of evidence that human-altered landscapes with low biodiversity, such as fields and plantations, are more often associated with a higher risk of people contracting various infections,” says Professor Kate Jones of University College London.
Diseases can be transmitted from humans to animals: volunteers who rescue exotic animals from dealers often need to protect them from respiratory infections. “Of course, this is not the only cause of disease,” she says. “However, it is often the animal species that coexist more easily with humans, such as some rodents, that also turn out to be more efficient carriers and spreaders of pathogens.” The dangers of direct or indirect contact between humans and wildlife are well documented.
For example, the 1999 outbreak of Nipah virus in Malaysia began at a pig farm on the edge of a forest. The pigs were eating fallen wild fruit that had been bitten by flying bats and contaminated with their saliva. As a result, more than 250 people who had contact with infected pigs have been infected and more than a hundred have died. The Nipah virus kills 45% to 75% of those infected, while the fatality rate of the Covid-19 coronavirus is currently estimated to be around 6%.
Covid was transmitted from bats to humans through an as yet unidentified intermediate link. High-risk areas where the boundaries between the human and natural worlds are blurred, such as forest edges and markets where wild animals are sold, should be under special and constant surveillance, says Professor Eric Fevre, who works with the University of Liverpool and the International Livestock Institute in Nairobi, Kenya. “It is necessary to have pre-planned action algorithms in case there is an outbreak of a disease or something unusual in such a place,” he says.
Areas of human economic activity adjacent to wilderness, such as farms, become hotspots for the emergence of new diseases. Matthew Baylis agrees that continuous monitoring of new diseases is extremely important. “The conditions are almost perfect for pandemics to break out,” he says. “I’m afraid this will happen again,” says Professor Feb. “Things like this have happened all the time that humans have interacted with wild nature. The question is, what do we understand and how do we react?
The paved road through the jungle. The current crisis, says Eric Fevra, should make the world think. “Everything we use and take for granted – the food we consume, the materials in our smartphones; the more we consume, the more someone makes money by extracting all this from nature and transporting it around the world. We need to think about how many resources we use and how that affects nature.