Diseases: More and More Pandemics?

Diseases originally occurring in animals could increasingly jump to humans in the future – much as very likely happened with the new coronavirus.

This is the warning issued by the UN Environment Programme (UNEP) and the International Livestock Research Institute (ILRI) in a report published on Monday.

“If we continue to exploit wildlife and destroy our ecosystems, we can expect a steady stream of these diseases jumping from animals to humans in the years to come,” warned UNEP Executive Director Inger Andersen. The report shows that contributing factors include, among others, the growing demand for animal proteins, increasing urbanisation, and climate change.

Rise in Zoonoses

The coronavirus disease Covid-19 is cited as an example of the rise in zoonoses – that is, diseases that jump from animals to humans. The coronavirus Sars-CoV-2 was presumably transmitted from bats via another animal to humans.

“This was a highly predictable pandemic,” said Delia Randolph, a veterinary epidemiologist at ILRI. Since the 1930s, she noted, there has been a “clear trend” of a rising number of human diseases – and around 75 percent of these originate from wild animals.

According to the report, several human factors are responsible for this increase. One contributing factor is the globally growing demand for animal proteins and the expansion of animal farming. This leads to ever greater numbers of genetically similar animals that are more susceptible to infection.

The increasing exploitation of wildlife through hunting, trade, and consumption of wild animals also plays a role, the report stated.

Rapid Urbanisation as a Factor

Another reason cited is population growth and rapid urbanization. Cities are expanding, forests are being cleared — as a result, people are coming into increasing contact with nature and animals. In some areas, human activities would "tear down the natural buffers that once protected humans from these pathogens," said Doreen Robinson, head of the wildlife division at UNEP.

Also the climate change is fueling the rise of diseases. Warmer temperatures can create ideal conditions for pathogens and vectors, as the report explains. Climatic changes could influence where bats and monkeys — some of which are sources of pathogens — and mosquitoes, which often transmit pathogens, live.

These problems would need to be addressed in order to reduce the danger of increasing diseases such as Covid-19, the researchers warned. Simply combating the epidemics would not be sustainable. That would be like treating only the symptoms in a sick person, and not the underlying causes, said Randolph.