Swine coronavirus replicates in human cells
Scientists reveal potential of swine coronavirus jumping from animals to people

Date:
October 14, 2020
Source:
University of North Carolina at Chapel Hill
Summary:
A strain of coronavirus that has devastated the pork industry has
the potential to infect humans as well, according to new research.



FULL STORY ==========================================================================
New research from the University of North Carolina at Chapel Hill suggests
that a strain of coronavirus that has recently alarmed the swine industry
may have the potential to spread to humans as well.


==========================================================================
The coronavirus strain, known as swine acute diarrhea syndrome coronavirus (SADS-CoV), emerged from bats and has infected swine herds throughout
China since it was first discovered in 2016. Outbreaks of such an illness
have the potential to wreak economic havoc in many countries across the
globe that rely on the pork industry.

The virus' potential threat to people was demonstrated in lab tests that revealed SADS-CoV efficiently replicated in human liver and gut cells,
as well as airway cells. The findings were published Oct. 12 in PNAS.

Though it is in the same family of viruses as the betacoronavirus
SARS-CoV-2, which causes the respiratory illness COVID-19 in humans,
SADS-CoV is an alphacoronavirus that causes gastrointestinal illness
in swine. The virus causes severe diarrhea and vomiting and has been
especially deadly to young piglets.

SADS-COV is also distinct from two circulating common cold
alphacoronaviruses in humans, HCoV-229E and HCoV-NL63.

"While many investigators focus on the emergent potential of the betacoronaviruses like SARS and MERS, actually the alphacoronaviruses may
prove equally prominent -- if not greater -- concerns to human health,
given their potential to rapidly jump between species," said Ralph Baric, professor of epidemiology at UNC-Chapel Hill Gillings School of Global
Public Health.



========================================================================== While SADS-CoV has not been known to affect humans to-date, the COVID-19 pandemic serves as a potent reminder that many coronavirus strains found
in animals have the potential to infect humans as well -- an effect
known as spillover.

The Baric lab worked with Caitlin Edwards, a research specialist and
master of public health student at UNC-Chapel Hill, on the study which
suggests humans may be susceptible to spillover of SADS-CoV.

Edwards, the study's first author, tested several types of cells by
infecting them with a synthetic form of SADS-CoV to understand just how
high the risk of cross-species contamination could be.

Evidence from the study indicates that a wide range of mammalian cells, including primary human lung and intestinal cells, are susceptible
to infection. According to Edwards, SADS-CoV shows a higher rate of
growth in intestinal cells found in the human gut, unlike SARS-CoV-2,
which primarily infects lung cells.

Cross-protective herd immunity often prevents humans from contracting
many coronaviruses found in animals. However, results from the testing
done by Edwards and her team suggest that humans have not yet developed
such immunity to SADS-CoV.



========================================================================== "SADS-CoV is derived from bat coronaviruses called HKU2, which is a heterogenous group of viruses with a worldwide distribution," Edwards
said. "It is impossible to predict if this virus, or a closely related
HKU2 bat strain, could emerge and infect human populations. However,
the broad host range of SADS-CoV, coupled with an ability to replicate
in primary human lung and enteric cells, demonstrates potential risk for
future emergence events in human and animal populations." In response
to these findings, Edwards and colleagues tested the broad-spectrum
antiviral remdesivir as a potential method of treatment for the infection.

Working with Gilead Sciences, remdesivir was developed by the Baric Lab
to combat all known coronaviruses, including SADS-CoV. It is currently
being used to treat COVID-19 infections in humans, including the United
States president.

Preliminary results from this study show that it has robust activity
against SADS-CoV, though Edwards cautions that more testing is necessary
on additional cell types and in animals to confirm these findings.

"Promising data with remdesivir provides a potential treatment option
in the case of a human spillover event," she said. "We recommend that
both swine workers and the swine population be continually monitored
for indications of SADS-CoV infections to prevent outbreaks and massive economic losses." SADS-CoV could also pose a threat to the U.S. economy,
which was third in global pork production in 2019. In 2012, the U.S. pork industry was devastated by different swine coronavirus that emerged
from China.

"Not surprisingly, we are currently looking for partners to investigate
the potential of SADS-CoV vaccine candidates to protect swine," Baric
said. "While surveillance and early separation of infected piglets
from sows provide an opportunity to mitigate larger outbreaks and the
potential for spillover into humans, vaccines may be key for limiting
global spread and human emergence events in the future." Other members of
the Department of Epidemiology involved in the study include Boyd Yount, Assistant Professor Rachel Graham, PhD; Sarah Leist, PhD; Yixuan Hou,
PhD; Associate Professor Amy Sims, PhD; Jesica Swanstrom, Trevor Scobey, Michelle Cooley and Caroline Currie.


========================================================================== Story Source: Materials provided by University_of_North_Carolina_at_Chapel_Hill. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Caitlin E. Edwards, Boyd L. Yount, Rachel L. Graham, Sarah R. Leist,
Yixuan J. Hou, Kenneth H. Dinnon, Amy C. Sims, Jesica Swanstrom,
Kendra Gully, Trevor D. Scobey, Michelle R. Cooley, Caroline
G. Currie, Scott H.

Randell, Ralph S. Baric. Swine acute diarrhea syndrome coronavirus
replication in primary human cells reveals potential susceptibility
to infection. Proceedings of the National Academy of Sciences,
2020; 202001046 DOI: 10.1073/pnas.2001046117 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201014082754.htm

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