Earlier this year, scientists identified a new strain of swine flu that they say has “all the main features of a candidate pandemic virus.”
In addition to finding that the virus – called G4 – is highly contagious, they also found that 10.4% of pig workers have antibodies to the disease, indicating that human transmission is possible. However, there is still no evidence that the virus can be transmitted from person to person.
In an article published in PNAS, they wrote that pigs are important “mixing vessels” for influenza viruses with the potential to infect humans, and so monitoring emerging viruses in pigs provides an important early warning of strains that could become pandemic.
Enter another potential zoonotic pathogen with an alarming-sounding name. In a new study from the University of North Carolina at Chapel Hill, researchers took a closer look at another virus in pigs with the potential to spread to humans. A highly pathogenic virus called coronavirus of acute swine diarrhea syndrome (SADS-CoV) first appeared in bats before infecting herds of pigs in China in 201
The team, publishing its findings in PNAS, injected a synthetic version of SADS-CoV into various cell types in the lab to determine if it could replicate in human cells, including human liver, lungs and intestinal cells.
“The concern is that rSADS-CoV also reproduces efficiently in several different primary types of human lung cells as well as primary human intestinal cells,” the team wrote in the article. “The effective growth of primary human lung and intestinal cells suggests SADS-CoV as a potential higher-risk emerging coronavirus pathogen that could adversely affect the global economy and human health.”
The virus replicates at a higher rate of growth in intestinal cells; this is in contrast to SARS-CoV-2, the virus that causes Covid-19, which mainly infects lung cells. However, although it needs to be monitored, it has not yet been established that the virus infects people outside the laboratory. The team also tested a broad-spectrum antiviral remdezivir – which also showed promise for the treatment of Covid-19 – and found in preliminary results that it “effectively blocks the replication of rSADS-CoV in vitro”.
“Promising data with remdezivir offer a potential treatment option in the event of a human transfusion,” said Caitlin Edwards, a research specialist and master of public health at UNC-Chapel Hill. “We recommend that both pig workers and pig populations be monitored continuously for indications of SADS-CoV infections to prevent outbreaks and huge economic losses.”
The team is now investigating potential vaccines against the virus to protect swine herds.
“While monitoring and early isolation of infected piglets from sows allows mothers to mitigate larger outbreaks and the potential for spread in humans,” Edwards said, “vaccines may be key to limiting global spread and future human events. .