{"id":3593,"date":"2026-07-26T08:57:18","date_gmt":"2026-07-26T08:57:18","guid":{"rendered":"https:\/\/blog.cedritech.com\/?p=3593"},"modified":"2026-07-26T08:57:18","modified_gmt":"2026-07-26T08:57:18","slug":"scientists-discover-1st-known-likely-transmissible-cancer-in-wild-catfish","status":"publish","type":"post","link":"https:\/\/blog.cedritech.com\/?p=3593","title":{"rendered":"Scientists discover 1st known likely transmissible cancer in wild catfish"},"content":{"rendered":"<p class=\"mb-4 text-lg md:leading-8 break-words\">The mystery began in 2013 along Lake Memphremagog, a large freshwater lake that spans the border of Vermont and Quebec. Anglers and biologists began pulling up brown bullhead catfish with\u00a0raised black spots on their bodies. It was later found that 23% to 37% of those\u00a0sampled had\u00a0confirmed\u00a0melanoma lesions, a type of skin cancer, according to a new study published in\u00a0Nature.<\/p>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Melanomas had been previously reported in brown bullhead catfish in other areas, but not at such a high rate.\u00a0At first, experts suspected an environmental cause. Tropical Storm Irene had caused massive regional flooding in 2011, leading some to question\u00a0whether\u00a0pollution had triggered unusual cancer rates in the fish through cancer-causing contaminants, according to the study<\/p>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">The new study, however,\u00a0points to a more unusual\u00a0explanation &#8212; these cancer cells may be transferring from one catfish to the next.\u00a0The finding represents the first known transmissible cancer in fish and the first identified in a freshwater\u00a0setting.<\/p>\n<h3 class=\"mb-4 text-lg font-bold\">Is cancer ever contagious?<\/h3>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">According to the American Cancer Society,\u00a0catching cancer\u00a0from another person is essentially impossible. Cancer usually begins when a person&#8217;s own cells sustain DNA\u00a0damage, grow out of control and form a tumor. Cancer cannot be spread through touching, sharing food, or breathing the same air as someone with cancer.<\/p>\n<figure class=\"relative mb-4\">\n<div class=\"relative\"><img loading=\"lazy\" decoding=\"async\" class=\"rounded-lg\" src=\"https:\/\/s.yimg.com\/lo\/mysterio\/api\/84e53fcc5695ff505af4e73fa247b68b7efaa48d51c2e597e39ca60312d9db96\/lightyear_networkapi\/resizefill_w960;quality_80;format_webp\/https:%2F%2Fmedia.zenfs.com%2Fen%2Fus.abcnews.go.com%2F2d5362205ce676be393c02dca7fa25be\" alt=\"C. Galasso\/De Agostini via Getty Images, FILE - PHOTO: In this undated file photo, a brown bullhead catfish, (Ameirurus nebulosus) is shown.\" width=\"960\" height=\"644\" data-nimg=\"1\" \/><button class=\"group absolute bottom-0 size-full\" aria-label=\"View larger image\" data-ylk=\"elm:expand;itc:1;sec:image-lightbox;slk:lightbox-open;\" data-rapid_p=\"9\" data-y-link-id=\"0muugby1ysvkyq153pzq\"><\/button><\/div><figcaption class=\"relative text-sm mt-1 pr-2.5\">\n<div>\n<p>C. Galasso\/De Agostini via Getty Images, FILE &#8211; PHOTO: In this undated file photo, a brown bullhead catfish, (Ameirurus nebulosus) is shown.<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Direct transmission of cancer cells between humans is extremely rare and usually involves unusual medical circumstances. The American Cancer Society says one situation in which cancer can spread from one person to another is through an organ or tissue transplant, although that risk is very low. Rare pregnancy-related cases have also been reported.<\/p>\n<div class=\"max-md:faux-bleed mb-4 bg-accent\/2 pb-5 md:invisible md:mb-0 md:h-0 md:overflow-hidden md:pb-0\">\n<div class=\"py-2 text-center text-xs uppercase\"><\/div>\n<div class=\"flex w-full flex-nowrap justify-center\"><\/div>\n<\/div>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">The American Cancer Society also says that some infections, like\u00a0human papillomavirus and hepatitis B, can spread from person to person and increase\u00a0the long-term\u00a0risk of developing\u00a0certain cancers over time. In these cases, the virus is what spreads between people, not the cancer itself.<\/p>\n<div class=\"mb-4\"><\/div>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Experimental pancreatic cancer drug offers new hope in major trial<\/p>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">The idea behind a\u00a0true transmissible cancer works differently. The cancer cell itself would have to leave\u00a0its original host and continue\u00a0growing elsewhere, according to the study authors. But\u00a0scientists still do not know exactly how this process works in the brown\u00a0bullhead catfish found in\u00a0Lake Memphremagog.<\/p>\n<h3 class=\"mb-4 text-lg font-bold\">Solving the catfish mystery<\/h3>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">When researchers examined the affected catfish, they found no\u00a0infectious reason\u00a0that could explain the melanoma, prompting them to look more closely at the tumors using\u00a0whole-genome sequencing, a technique that maps and compares DNA.<\/p>\n<div class=\"max-md:faux-bleed mb-4 bg-accent\/2 pb-5 md:invisible md:mb-0 md:h-0 md:overflow-hidden md:pb-0\">\n<div class=\"py-2 text-center text-xs uppercase\"><\/div>\n<div class=\"flex w-full flex-nowrap justify-center\"><\/div>\n<\/div>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Researchers compared malignant melanoma\u00a0DNA found on these catfish\u00a0with DNA from healthy catfish\u00a0tissue. They found that the tumors &#8212; taken from multiple catfish samples &#8212; were strikingly similar to one another, and markedly\u00a0different\u00a0from the catfish carrying them. In other words,\u00a0the tumors appear to have come from a single line of cancer cells that have then spread from fish to fish, rather than occurring\u00a0independently.<\/p>\n<figure class=\"relative mb-4\">\n<div class=\"relative\"><img loading=\"lazy\" decoding=\"async\" class=\"rounded-lg\" src=\"https:\/\/s.yimg.com\/lo\/mysterio\/api\/225ec238054ee9129283eddc329e22ff7e9938041838f1202c0d9367b3c1515e\/lightyear_networkapi\/resizefill_w960;quality_80;format_webp\/https:%2F%2Fmedia.zenfs.com%2Fen%2Fus.abcnews.go.com%2F72fb1048acdb1517f76ad51a19b52bfd\" alt=\"Paul Thomas\/Florida Fish &amp; Wildlife Conservation Commission - PHOTO: In this photo released by the Florida Fish &amp; Wildlife Conservation Commission, a brown bullhead catfish is shown.\" width=\"960\" height=\"399\" data-nimg=\"1\" \/><button class=\"group absolute bottom-0 size-full\" aria-label=\"View larger image\" data-ylk=\"elm:expand;itc:1;sec:image-lightbox;slk:lightbox-open;\" data-rapid_p=\"11\" data-y-link-id=\"07hlsx31jicvcy1y1r04\" data-v9y=\"1\"><\/button><\/div><figcaption class=\"relative text-sm mt-1 pr-2.5\">\n<div>\n<p>Paul Thomas\/Florida Fish &amp; Wildlife Conservation Commission &#8211; PHOTO: In this photo released by the Florida Fish &amp; Wildlife Conservation Commission, a brown bullhead catfish is shown.<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Researchers are still investigating how the cancer spreads in this specific population of catfish.\u00a0Brown bullheads are known to\u00a0gather closely during spawning season, which could give cancer cells opportunities to\u00a0move from one host to another\u00a0through\u00a0close proximity. But the exact route of transmission has not yet been proven.<\/p>\n<h3 class=\"mb-4 text-lg font-bold\">What it means for humans<\/h3>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Lake Memphremagog is a drinking water source for more than 175,000 people. But scientists say there is no known risk of this potentially transmissible melanoma found in catfish to transfer\u00a0to humans.<\/p>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Researchers have said the cancer cells do not appear able to\u00a0affect\u00a0other species in the area,\u00a0and there is no evidence that people can catch cancer from these fish or from the lake water.<\/p>\n<div class=\"max-md:faux-bleed mb-4 bg-accent\/2 pb-5 md:invisible md:mb-0 md:h-0 md:overflow-hidden md:pb-0\">\n<div class=\"py-2 text-center text-xs uppercase\"><\/div>\n<div class=\"flex w-full flex-nowrap justify-center\"><\/div>\n<\/div>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">Adolescent and young adult cancers increase risk of developing future cancers<\/p>\n<div class=\"mb-4\">\n<div id=\"recirc-3f521204-67f0-32bb-9ce0-8c653bcd60f3\" class=\"mb-4\">\n<div class=\"mb-3.5 flex items-center gap-2\"><\/div>\n<div class=\"grid gap-4 lg:grid-cols-2 lg:grid-rows-[auto_auto_1fr]\">\n<div class=\"relative w-full\">\n<div id=\"_r_3s_\" class=\"absolute inset-0 rounded-[4px] focus-within:ring-2 focus-within:ring-link trc_related_container tbl-trecs-container trc_spotlight_widget trc_elastic trc_elastic_stream-i-v3\" data-placement-name=\"taboola-article-center\">\n<div class=\"trc_rbox_container\">\n<div>\n<div id=\"trc_wrapper_6244783143\" class=\"trc_rbox stream-i-v3 trc-content-sponsored\">\n<div class=\"trc_clearer\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">According to the study, previously known naturally transmissible cancers have been found in dogs, Tasmanian devils, and bivalve mollusks, such as clams and mussels. And now, scientists can add catfish\u00a0to that short list.<\/p>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">This discovery\u00a0could help researchers better\u00a0understand how cancer cells avoid the immune system, replicate, and survive in their host.<\/p>\n<p class=\"mb-4 text-lg md:leading-8 break-words\">The Lake Memphremagog catfish study\u00a0suggests\u00a0that nature still holds unexpected lessons about cancer and\u00a0may help scientists better understand one of cancer&#8217;s most puzzling abilities: how malignant cells survive, spread, and keep growing in places they do not belong.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The mystery began in 2013 along Lake Memphremagog, a large freshwater lake that spans the border of Vermont<\/p>\n","protected":false},"author":6,"featured_media":3594,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[7,9],"tags":[],"class_list":["post-3593","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","category-science"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts\/3593","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3593"}],"version-history":[{"count":1,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts\/3593\/revisions"}],"predecessor-version":[{"id":3595,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts\/3593\/revisions\/3595"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/media\/3594"}],"wp:attachment":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3593"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3593"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3593"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}