{"id":1073,"date":"2024-01-15T08:32:50","date_gmt":"2024-01-15T08:32:50","guid":{"rendered":"https:\/\/aiecasia.org\/?page_id=1073"},"modified":"2024-01-15T09:28:58","modified_gmt":"2024-01-15T09:28:58","slug":"food_detail_2","status":"publish","type":"page","link":"https:\/\/aiecasia.org\/?page_id=1073","title":{"rendered":"FOOD_DETAIL_2"},"content":{"rendered":"\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\">FOOD<\/a><\/div>\n\n\n\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\"><strong>NOVEMBER 12, 2023<\/strong><\/a><\/div>\n<\/div>\n\n\n\n<p><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Scientists Are Gene-Editing Chickens to Resist Avian Flu<\/h2>\n\n\n\n<ul>\n<li>But experts urge caution, since viruses are endlessly adapting.<\/li>\n\n\n\n<li>EMILY MULLIN<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"990\" height=\"556\" src=\"http:\/\/aiecasia.org\/wp-content\/uploads\/2024\/01\/2023-11-9-chickens.webp\" alt=\"\" class=\"wp-image-629\" style=\"width:760px;height:auto\" srcset=\"https:\/\/aiecasia.org\/wp-content\/uploads\/2024\/01\/2023-11-9-chickens.webp 990w, https:\/\/aiecasia.org\/wp-content\/uploads\/2024\/01\/2023-11-9-chickens-300x168.webp 300w, https:\/\/aiecasia.org\/wp-content\/uploads\/2024\/01\/2023-11-9-chickens-768x431.webp 768w\" sizes=\"(max-width: 990px) 100vw, 990px\" \/><figcaption class=\"wp-element-caption\"><strong>Charlie Neibergall\/AP<\/strong><\/figcaption><\/figure><\/div>\n\n\n<p><strong>This month,\u00a0<\/strong>the Cambodian government reported that two people there\u00a0died of highly pathogenic avian influenza, or H5N1 bird flu, after being exposed to infected poultry. For people, the risk of getting infected is low, but outbreaks in animals\u00a0have been rising worldwide, wiping out chicken flocks and\u00a0wild bird populations. The virus is devastating to poultry producers, who are forced to\u00a0slaughter infected flocks.<\/p>\n\n\n\n<p>A growing number of countries are starting to\u00a0vaccinate chickens against bird flu, while the United States and United Kingdom are still holding out because of uncertainties about immunization\u2019s cost and effectiveness. Meanwhile, researchers in the UK have come up with another possible approach to protecting poultry flocks: gene editing. Scientists from the University of Edinburgh, Imperial College London, and the Pirbright Institute used\u00a0the gene-editing tool Crispr\u00a0to make the first chickens that are partially resistant to the virus. They published their results last week in the journal\u00a0<em>Nature Communications<\/em>.<\/p>\n\n\n\n<p>Like tiny molecular scissors, Crispr allows scientists to make targeted cuts to an organism\u2019s genetic code. The UK team used the technology to tweak a chicken gene that is responsible for producing the protein ANP32A. During infection, the bird flu virus takes over this protein to help make copies of itself.<\/p>\n\n\n\n<p>\u201cAll viruses are obligate parasites,\u201d said Wendy Barclay, a study author and virologist at Imperial College London, during a press briefing on October 5. When viruses get inside a host cell, she said, \u201cthey hijack various proteins inside the cell to help themselves replicate.\u201d In 2016,\u00a0Barclay\u2019s lab discovered\u00a0that influenza viruses use the ANP32A protein in this way.\u201cEven if we protected every single chicken on the globe, flu wouldn\u2019t go anywhere.\u201d<\/p>\n\n\n\n<p>The researchers produced 10 chickens with this edited gene and exposed them to the H9N2 strain of bird flu, using a dose size that mimicked what animals would likely experience in the real world. They used this strain, rather than the more deadly H5N1, because it is the one chickens would most likely encounter during an outbreak. Only one of the 10 birds got infected, and the virus didn\u2019t spread to other chickens.<\/p>\n\n\n\n<p>The team then exposed the gene-edited birds to an artificially high dose of the virus. This time, five out of 10 birds became infected, but the gene edit still provided some level of protection. The amount of virus found in the infected animals was much lower than the level typically detected among chickens that are ill with bird flu.<\/p>\n\n\n\n<p>The gene edit also helped limit the spread of the virus. Four ordinary chickens were placed in the same incubator with the gene-edited birds that had already been exposed to high levels of the virus. Out of the four, only one became infected.<\/p>\n\n\n\n<p>Researchers monitored the gene-edited birds over the course of two years and found that the gene changes had no adverse effects on their health or egg production.<\/p>\n\n\n\n<p>\u201cThis is showing a potential mechanism for reducing the susceptibility of chickens to avian flu,\u201d says Carol Cardona, a veterinarian and professor of avian health at the University of Minnesota College of Veterinary Medicine, who wasn\u2019t involved in the study. \u201cBut even if we protected every single chicken on the globe, flu wouldn\u2019t go anywhere.\u201d Avian influenza has been identified in more than 100 different species of birds.<\/p>\n\n\n\n<p>The fact that some breakthrough infections occurred means that the virus still has a chance to infect other birds, and could \u201cescape\u201d the vaccine\u2019s effects by mutating away from using the ANP32A protein to reproduce. In fact, when the UK researchers took samples of the virus from the infected gene-edited chickens, they found some mutations in the part of the virus that this protein interacts with. \u201cThe flu virus replicates rapidly, and every time it enters a new host, there\u2019s an opportunity for that virus to adapt and change,\u201d Cardona says.<\/p>\n\n\n\n<p>During the press briefing, Barclay said those viral mutations didn\u2019t make the chickens any sicker. The team also wanted to make sure those changes wouldn\u2019t cause more severe infection in people, so they added the mutated viruses to human airway cells that had been cultivated in a dish. They found that the mutations didn\u2019t help the virus grow in a way that would pose an increased risk to people.\u201cWe\u2019re not there yet. We would need more edits, more robust edits to really shut down the virus replication.\u201d<\/p>\n\n\n\n<p>It\u2019s also not known how the gene-edited chickens will fare against the much more aggressive bird flu strains such as H5N1, which weren\u2019t tested in the study. Barclay said they chose H9N2, considered a low pathogenicity virus that causes little to no signs of disease, in part because it\u2019s more common. Also, deliberately infecting chickens with H5N1 raises animal welfare concerns, since it causes serious illness and is often fatal.<\/p>\n\n\n\n<p>The authors identified two other related proteins, ANP32B and ANP32E, that they think would prevent virus replication. In chicken cells grown in the lab, they edited the genes that code for all three proteins and exposed them to the flu virus. The edits successfully blocked growth of the virus in the cells, but the researchers have not yet bred chickens with all three edits.<\/p>\n\n\n\n<p>Susan Lamont, an expert on poultry genetics at Iowa State University, says that making multiple genetic modifications could reduce the possibility that the viruses will escape. \u201cWhen you start doing that, it really makes it much more difficult for the virus population to find its way around the resistance properties of that animal,\u201d she says.<\/p>\n\n\n\n<p>But Brian Ladman, senior scientist at the University of Delaware Poultry Health System, says removing too many genes could be deleterious to the animals\u2019 health. \u201cThese genes are there for a reason,\u201d he says. For broiler chickens, which live only eight to 12 weeks before they are slaughtered, the health effects of gene editing may not have time to manifest during their lives, Ladman says. But laying chickens are kept commercially for two to three years.<\/p>\n\n\n\n<p>While the research is still in very early stages and isn\u2019t ready to be deployed widely, Lamont says she can imagine that future poultry producers may combine vaccination against avian flu with gene editing to boost viral resistance. \u201cThis disease is so prevalent and so important that any strategies that we can bring together to help protect the health of the birds is, in my view, very good,\u201d she says.<\/p>\n\n\n\n<p>Poultry producers already combine vaccination plus genetic selection\u2014that is, choosing which chickens to breed based on certain traits\u2014to prevent disease. Decades ago, scientists identified genetic variations that enhance resistance to the virus that causes Marek\u2019s disease, a common and highly contagious illness that produces paralysis and tumors. Chicken producers began breeding birds with this trait while also vaccinating them against the disease. Lamont says this two-pronged approach is more protective than either on its own.<\/p>\n\n\n\n<p>The UK researchers say their gene-edited chickens are a proof of concept that shows a possible way to make chickens resistant to bird flu. \u201cWe\u2019re not there yet,\u201d Barclay said. \u201cWe would need more edits, more robust edits to really shut down the virus replication.\u201d<\/p>\n\n\n\n<p>And in England at least, it will likely take some time for gene-edited chickens to make it to people\u2019s plates. The government\u00a0passed a law in March\u00a0legalizing the commercial development of gene-edited foods, but a second vote is needed to allow farm animals with edited genomes. In the US, the first gene-edited food animal\u2014a\u00a0cow edited to have a short, slick-hair coat\u2014was approved in 2022. The trait has been found to help cattle tolerate hot weather.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Scientists Are Gene-Editing Chickens to Resist Avian Flu This month,\u00a0the Cambodian government reported that two people there\u00a0died of highly pathogenic avian influenza, or H5N1 bird flu, after being exposed to infected poultry. For people, the risk of getting infected is low, but outbreaks in animals\u00a0have been rising worldwide, wiping out chicken flocks and\u00a0wild bird populations.&hellip;&nbsp;<a href=\"https:\/\/aiecasia.org\/?page_id=1073\" class=\"\" rel=\"bookmark\">Read More &raquo;<span class=\"screen-reader-text\">FOOD_DETAIL_2<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":370,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"on","_themeisle_gutenberg_block_has_review":false,"_ti_tpc_template_sync":false,"_ti_tpc_template_id":"","footnotes":""},"_links":{"self":[{"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/pages\/1073"}],"collection":[{"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aiecasia.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1073"}],"version-history":[{"count":2,"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/pages\/1073\/revisions"}],"predecessor-version":[{"id":1104,"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/pages\/1073\/revisions\/1104"}],"up":[{"embeddable":true,"href":"https:\/\/aiecasia.org\/index.php?rest_route=\/wp\/v2\/pages\/370"}],"wp:attachment":[{"href":"https:\/\/aiecasia.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1073"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}