Weekend Argus (Saturday Edition)
Zoonotic diseases on the rise
Scientists link the sharp increase to wildlife exploitation
THERE has been a rise in the new, emerging, infectious diseases that come from animals in the past 60 years.
This is one of the findings by the World Wide Fund for Nature (WWF) global science team reviewing scientific literature to look for a connection between emerging zoonotic diseases and human and nature conservation over the past few months.
The research looks specifically at the intensifying enabling conditions or drivers of zoonotic diseases.
The team launched the WWF internal science brief “Beyond Boundaries: Insights into emerging zoonotic diseases, nature and human well-being”, led by chief scientist Rebecca Shaw.
“If you look at the last 60 years, the majority of emerging diseases are zoonotics. So 75% of all emerging diseases are zoonotic,” explained Shaw in a webinar this week.
Zoonotic diseases result from a phenomenon known as “spillover” – the transfer of pathogens from animals to humans.
“The animal that passes it to a human could be wild or domestic. Pathogens can be a virus, a bacteria, a fungus or a parasite. We wanted to know what are the pathogens that create spillover when it comes to humans,” she said.
The majority of zoonotic diseases had a domestic or livestock animal link.
“The pathogen of the virus doesn’t always come directly from a bat to a human, but comes through other intermediate hosts which can be wild or domestic,” she explained.
We need to understand the drivers of the disease, the emergence and how conservation intervention could make a difference, Shaw said. They graphed various pathogens, the transmissions from humans and the drivers of those transmissions.
“We start with seven different zoonotic pathogens. Each pathogen has an animal host, which could be a bird, rat, duck or bat, among others,” she said. A pathogen type has different ways of transmitting to people, and some transmissions result in human-tohuman transmission.
They focused on the main drivers of coronavirus spillover – land use change, animal agriculture intensification and exploitation of wildlife.
“The rapid rise has been driven by wildlife exploitation,” Shaw said.
To reduce numbers, we will have to consume less wildlife and other animal protein, she said.
Tatjana von Bormann, programmes and innovation lead at WWF SA, said
Covid-19 “may be a once-in-a-lifetime opportunity for us to really pay attention to the signs”.
“This is to understand how we might design and implement conservation intervention that may reduce the risk of pandemics,” said Von Bormann.
The team compiled a graph with a number of virus species identified yearly and a rise of zoonotic events in the spillover events during those years. “One or two infectious diseases emerged yearly. The number of spillover events is increasing,” she said.
Shaw stressed that at the beginning of the pandemic that many in conservation were asking for simple fixes such as closing down wet markets in Asia.
Meanwhile, the South African government proposed changes to the country’s Meat Safety Act legislation (MSA), suggesting that threatened species such as rhino, elephant and giraffe could be consumed.
The Department of Agriculture, Land Reform and Rural Development received about 30 000 comments before Tuesday relating to the draft amendment to the MSA.
Department spokesperson Reggie Ngcobo said the amendment of schedule one (of the act) did not require parliamentary approval.
In response to the draft, Jo Shaw, wildlife programme senior manager at WWF SA, said: “We are concerned by the inclusion of threatened species, especially rhinoceros, which have not been typically harvested for meat, the lack of clarity around how ‘animal products’ are covered by the act, especially in relation to conservation implications due to illegal trade in high-value products.”