Paris (AFP) – With the spread of monkey pox around the world on the heels of Covid-19, there are fears that increasing outbreaks of diseases that spread from animals to humans could spark another pandemic.
While such diseases — called zoonoses — have been around for millennia, they have become increasingly common in recent decades due to deforestation, mass ranching, climate change and other man-made upheavals in the animal world, experts say.
Other diseases that can pass from animals to humans are HIV, Ebola, Zika, SARS, MERS, bird flu and the bubonic plague.
The World Health Organization said on Thursday it is still investigating the origins of Covid, but the “strongest evidence is still around zoonotic transmission”.
And with more than 1,000 cases of monkeypox recorded worldwide in the past month, the UN agency has warned there is a “real” risk that the disease could spread to dozens of countries.
WHO director Michael Ryan said last week that “it’s not just monkey pox” – the way humans and animals interact has become “unstable”.
“The number of times these diseases invade humans are increasing and then our ability to amplify and transmit that disease within our communities increases,” he said.
Monkeypox has not recently passed to humans – the first human case was identified in 1970 in DR Congo and has since been confined to areas of Central and West Africa.
Despite its name, “the latest monkeypox outbreak has nothing to do with monkeys,” said Olivier Restif, an epidemiologist at the University of Cambridge.
Although it was first discovered in macaques, “the zoonotic transmission usually comes from rodents and outbreaks are spread through personal contact,” he told AFP.
Is yet to come?
According to the UN Environment Programme, about 60 percent of all known human infections are zoonotic, as are 75 percent of all new and emerging infectious diseases.
Restif said the number of zoonotic pathogens and outbreaks has increased in recent decades due to “population growth, livestock growth and degradation of wildlife habitats.”
“Wild animals have drastically changed their behavior in response to human activities and are migrating from their depleted habitats,” he said.
“Immune-weakened animals hanging out around people and pets is a surefire way to get more pathogen transmission.”
Benjamin Roche, a zoonoses specialist at the French Institute of Research for Development, said deforestation has had a major effect.
“Deforestation reduces biodiversity: we lose animals that naturally regulate viruses, making it easier for them to spread,” he told AFP.
And perhaps worse is to come, with a major study published earlier this year warning that climate change is increasing the risk of another pandemic.
As animals flee their warming natural habitat, they will encounter other species for the first time — potentially infecting them with some of the 10,000 zoonotic viruses believed to “circulate silently” among wild mammals, mostly in tropical forests, the study said.
Greg Albery, a disease ecologist at Georgetown University who co-authored the study, told AFP that “the network of host pathogens is about to change substantially.”
– ‘We must be ready’ –
“We need better surveillance in both urban and wild animals so that we can identify when a pathogen has jumped from one species to another – and if the host host is in the city or near people, we especially need to worry,” he said.
Eric Fevre, an infectious disease specialist at the British University of Liverpool and the International Livestock Research Institute in Kenya, said that “a whole host of new, potentially dangerous diseases could emerge – we need to be ready”.
This includes “focusing on the public health of populations” in remote environments and “studying better the ecology of these natural areas to understand how different species interact”.
Restif said there is “no panacea – our best bet is to trade at all levels to reduce risk”.
“We need massive investments in primary health care and testing capacity for underserved communities around the world so that outbreaks can be detected, identified and controlled without delay,” he said.
On Thursday, a WHO scientific advisory group released a preliminary report outlining what to do if a new zoonotic pathogen emerges.
It lists a series of early studies on how and where the pathogen jumped to humans, determining the potential risk as well as longer-term environmental impacts.
© 2022 AFP