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Gene-edited pigs are resistant to billion dollar virus , study finds
Scientists have produced pigs that can resist one of the world ’ s most costly animal diseases , by changing their genetic code .
T ests with the virus – called Porcine Reproductive and Respiratory Syndrome , or PRRS – found the pigs do not become infected at all .
The animals show no signs that the change in their DNA has had any other impact on their health or wellbeing .
PRRS costs the pig industry around $ 2.5 billion (£ 1.75bn ) each year in lost revenue in the US and Europe alone .
The disease causes breathing problems and deaths in young animals and if pregnant sows become infected , it can cause them to lose their litter .
The virus infects pigs using a receptor on their cells ’ surface called CD163 . Researchers at the University of Edinburgh ’ s Roslin Institute used gene editing techniques to remove a
08 | Farming Monthly | July 2018 small section of the CD163 gene .
They focused on the section of the receptor that the virus attaches to , leaving the rest of the molecule intact .
The team collaborated with Genus PLC , a leading global animal genetics company , to produce pigs with the specific DNA change .
Previous studies had shown that cells from these animals were resistant to the virus in lab tests .
This is the first time researchers have exposed these pigs to the virus to see if they become infected .
They found that none of the animals became ill when exposed to the virus . Blood tests found no trace of the infection .
This research , co-funded by the Biotechnology and Biological Sciences Research Council and Genus PLC , is published in the Journal of Virology .
PRRS is endemic in most pig producing countries worldwide . Vaccines have mostly failed to stop the spread of the virus – which continues to evolve rapidly .
Other groups have used gene editing to create PRRS-resistant pigs by removing the whole CD163 receptor .
Removing only a section of CD163 allows the receptor to retain its ordinary function in the body and reduces the risk of side effects , the researchers say .
Dr Christine Tait-Burkard , of the University of Edinburgh ’ s Roslin Institute , said : “ These results are exciting but it will still likely be several years before we ’ re eating bacon sandwiches from PRRS-resistant pigs .
“ First and foremost we need broader public discussion on the acceptability of gene-edited
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