Humans infect animals that infect humans – from COVID-19 to bird flu, preventing pandemics requires protecting all species

When the World Health Organization declared COVID-19 a pandemic As of March 11, 2020, humans were the only species to have reported cases of the disease. While early genetic analyses indicated horseshoe bats As evolutionary hosts of SARS-CoV-2, the virus that causes COVID-19, no reports had yet surfaced indicating that it could be transmitted from humans to other animal species.

Less than two weeks later, a report from Belgium marked the first infection in a domestic cat – presumably by its owner. The summer of 2020 saw news of COVID-19 outbreaks and slaughterings in mink farms across Europe and fears of similar calls to slaughtering in North America. Humans and other animals living in and around mink farms have tested positive, raising questions about the possibility of a secondary reservoir of COVID-19 in wildlife. In other words, the virus could infect and establish a cycle of transmission in a species other than the one from which it originated.

Researchers have documented this phenomenon of transmission from humans to animals, colloquially called reverse or back zoonotic transmissionin domestic and wild animals. Wild animals can be infected either directly by humans or indirectly by domestic animals infected by humans. This springboard effect provides new opportunities for the evolution of pathogens and can radically change their mode of spread, as seen with flu And tuberculosis.

For example, fallout has long posed a threat to endangered great apeseven among populations with little human contact. The chimpanzees of Gombe National Park, made famous by the work of Jane Goodall, have suffered from outbreaks of measles and other respiratory diseases likely due to environmental persistence of pathogens spread by people living nearby or by ecotourists.

We are researchers who study the mechanisms underlying interspecies transmission of diseases and how The disease affects both wildlife conservation and humansNew outbreaks have highlighted the importance of understanding how wildlife health threats influence the emergence and spread of zoonotic pathogens. Our research suggests that studying historical outbreaks can help predict and prevent the next pandemic.

A backlash has happened before

Our research group wanted to assess how frequently spillover events were reported in the years leading up to the COVID-19 pandemic. A retrospective analysis not only allows us to identify specific trends or barriers in spillover event reporting, but also helps us understand where new emerging threats are most likely to occur.

We examined historical spillover events involving different pathogen groups in the animal kingdom, taking into account geographic variations, methods, and sample sizes. scientific reports synthesized on the fallout for nearly a century before the COVID-19 pandemic – from the 1920s to 2019 – which included diseases ranging from salmonella and intestinal parasites to human tuberculosis, influenza and polio.

We were also interested in determining whether…