{"id":16182,"date":"2026-07-24T23:24:09","date_gmt":"2026-07-24T18:24:09","guid":{"rendered":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/?p=16182"},"modified":"2026-07-24T23:24:09","modified_gmt":"2026-07-24T18:24:09","slug":"the-cyclosporiasis-detectives-hunting-diarrhea-causing-parasite","status":"publish","type":"post","link":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/?p=16182","title":{"rendered":"The cyclosporiasis detectives hunting diarrhea-causing parasite"},"content":{"rendered":"<p><script>\r\n  atOptions = {\r\n    'key' : '644b717812d811d6a1c1fc5b6ccd6fa6',\r\n    'format' : 'iframe',\r\n    'height' : 90,\r\n    'width' : 728,\r\n    'params' : {}\r\n  };\r\n<\/script>\r\n<script src=\"https:\/\/www.highperformanceformat.com\/644b717812d811d6a1c1fc5b6ccd6fa6\/invoke.js\"><\/script>\r\n<br \/>\n<\/p>\n<div data-element=\"story-body\" data-subscriber-content=\"\">\n<p>Identifying the source of a food-borne illness such as cyclosporiasis \u2014 a diarrhea-causing parasite that has sickened thousands of people in the United States \u2014 is almost as difficult as finding a needle in a haystack.<\/p>\n<p>It\u2019s not impossible to narrow down the culprit but it is a challenge because public health investigators are analyzing multiple pieces of evidence from available public health data, following a potential food source through the supply chain and testing samples of <a class=\"link\" href=\"https:\/\/www.latimes.com\/california\/story\/2026-07-15\/how-to-eat-safely-amid-outbreak-of-diarrhea-causing-cyclosporiasis\">potentially contaminated food<\/a><b>.<\/b><\/p>\n<p>Public health officials \u201care trying to align multiple pieces of evidence in a way that lets us protect the public\u2019s health to the best that we can,\u201d said Gregory Stevens, professor and chair of the Department of Public Health with Cal State Los Angeles. <\/p>\n<p>On <a class=\"link\" href=\"https:\/\/www.latimes.com\/california\/story\/2026-07-23\/new-cyclosporiasis-outbreak\">Wednesday the U.S. Food and Drug Administration announced it was initiating<\/a> a traceback investigation into a second cyclosporiasis outbreak. The agency has yet to link the latest outbreak to a specific product or location. <\/p>\n<p>The announcement follows a larger outbreak with cases that date back to May and that has affected more than 10,000 people across five states \u2014 Indiana, Kentucky, Michigan, Ohio and West Virginia \u2014 who reported feeling ill after eating Taco Bell meals with shredded iceberg lettuce. <\/p>\n<p>On Friday, the Centers for Disease Control and Prevention expanded the first outbreak to include four more states \u2014 Illinois, Kansas, Oklahoma and Pennsylvania. <\/p>\n<p>Based on epidemiological information collected by the CDC, a total of 1,947 people infected with cyclosporiasis across those states said they became ill after eating Taco Bell between June 22 and July 20. <\/p>\n<p>\u201cWe also expect to continue to see the number of confirmed cases rise, despite the recall, due to the fact that it can take as long as six weeks for CDC and state officials to determine if a sick person is part of this outbreak,\u201d the agency said in a statement. <\/p>\n<p>Officials say traceback and outbreak data have  linked the largest outbreak to lettuce supplied to the affected Taco Bell eateries to a Taylor Farms\u2019 facility, Taylor Farms de Mexico, located in central Mexico. <\/p>\n<p>But a recent false positive detection of cyclosporiasis in a sample of the California-based company\u2019s lettuce and statements made by Mexico\u2019s public health officials have raised questions about how federal health officials investigate these types of outbreaks. <\/p>\n<h2 id=\"what-does-the-false-positive-test-result-mean\" class=\"subhead\">What does the false positive test result mean?<\/h2>\n<p>A recent sample of lettuce from Taylor Farms de Mexico gave a false positive test result for the cyclosporiasis parasite. <\/p>\n<p>On <a class=\"link\" href=\"https:\/\/x.com\/US_FDA\/status\/2079238466118865220?s=20\" target=\"_blank\">X, the FDA stated<\/a>, \u201cTo clarify, this false positive lab sample does not change the basis for FDA\u2019s ongoing outbreak investigation or the overwhelming epidemiological data supporting the current voluntary recall by Taylor Farms.\u201d<\/p>\n<p>The regulatory agency continues to work with Taylor Farms to ensure \u201cproduct implicated in this outbreak has been removed from the market,\u201d the regulatory agency stated. <\/p>\n<p>The false positive test was brought up during a Tuesday morning news conference in Mexico, where Health Secretary David Kershenobich said Mexican officials have traveled to Guanajuato \u2014 where Taylor Farms de Mexico is located \u2014 to conduct their own investigation in conjunction with the U.S.<\/p>\n<p>\u201cSo far, no evidence has been found to indicate that it originated here, yet we are taking every precaution in case that turns out to be the case,\u201d Kershenobich said. <\/p>\n<p>The FDA reiterated on Friday that its traceback investigation and outbreak data continue to point to shredded iceberg lettuce from Taylor Farms in central Mexico, despite no samples from the facility yet testing positive for the cyclosporiasis parasite.<\/p>\n<p>\u201cWe encourage the public to continue to avoid all products listed in Taylor Farms\u2019 voluntary recall,\u201d the regulatory agency said in a statement. <\/p>\n<p>A complete list of the recalled items can be found <a class=\"link\" href=\"https:\/\/www.fda.gov\/safety\/recalls-market-withdrawals-safety-alerts\/taylor-fresh-foods-recalls-iceberg-lettuce-central-mexico-because-possible-health-risk\" target=\"_blank\">here<\/a>.<\/p>\n<h2 id=\"how-public-health-investigates-a-food-borne-illness\" class=\"subhead\">How public health investigates a food-borne illness<\/h2>\n<p>Food- and water-borne outbreak investigations start with sick people, said Stevens, the public health professor. <\/p>\n<p>A person has to feel sick enough to seek medical care and their healthcare provider must test for a food-borne illness by obtaining a a stool sample.<\/p>\n<p>The results of that sample are then reported to local health departments who alert state and federal health agencies if they identify a cluster of people diagnosed with the same food-borne illness. In this case, it\u2019s the cyclosporiasis parasite.<\/p>\n<p>\u201cWhen a cluster is big enough everybody\u2019s ears perk up, communication starts,\u201d and multiple avenues of investigation begin, Stevens said.<\/p>\n<p>State and federal officials conduct interviews with the people who tested positive for the particular illness to understand when they first felt sick, their symptoms, the level of care they needed, whether they traveled, what they\u2019ve eaten and where they\u2019ve dined or shopped for food. <\/p>\n<p>When a specific restaurant, retailer or food product has been identified as a potential source for the cluster of sick people, public health officials then conduct traceback investigations, a process where they trace the food that the ill people reported eating all the way back to the farm or the production facility.<\/p>\n<p>The agency then tests a sample of the crop or a batch of a product looking for whatever is causing people to get sick.<\/p>\n<h2 id=\"what-are-the-challenges-of-investigating-cyclosporiasis\" class=\"subhead\">What are the challenges of investigating cyclosporiasis?<\/h2>\n<p>There are many natural flaws that come with this investigative process. <\/p>\n<p>To start, if a person gets sickened from a food-borne illness, they might not seek medical care, Stevens said.<\/p>\n<p>And if they do, \u201cthat provider may not test for food-borne illnesses,\u201d he said. <\/p>\n<p>As a result, a diagnosis is never made and that information never makes it to the local health department. Instead, the medical provider may just tell their patient to keep an eye on their symptoms, wait and hydrate.<\/p>\n<p>In the case where an investigation is initiated by public health agencies, \u201cthere is often a significant delay between when someone ate the contaminated food, when they became sick, when they were diagnosed and when public health officials were able to interview them,\u201d said Anne Rimoin, professor in the department of epidemiology with the UCLA Fielding School of Public Health.<\/p>\n<p>The delay could make it more difficult for ill people to remember all the foods they ate, \u201cdown to a single ingredient in a salad,\u201d before they were stricken, Rimoin said.<\/p>\n<p>\u201cAnd if you\u2019re like me, I don\u2019t even remember what I ate two days ago,\u201d Stevens quipped.<\/p>\n<p>Because this type of multipoint investigation is reactive, the product that\u2019s suspected of causing the illness may have already moved through the supply chain into stores or restaurants and has already been consumed.<\/p>\n<p>\u201cEven when food is available for testing, contamination can be uneven, so a negative test does not necessarily rule a product out,\u201d Rimoin said. <\/p>\n<h2 id=\"do-public-healths-investigation-always-pinpoint-the-cause\" class=\"subhead\">Do public health\u2019s investigation always pinpoint the cause?<\/h2>\n<p>Experts say that when a food-borne outbreak occurs, the public understandably wants to know which product is causing the illness, where it came from and how to protect themselves. <\/p>\n<p>\u201cIt\u2019s completely reasonable to want certainty, especially with something as common and essential as food safety,\u201d Stevens said. \u201cBut public health, I think, is more about reaching the strongest evidence-supported conclusions possible, and it\u2019s not always perfect.\u201d<\/p>\n<p>An investigation might not come up with a singular answer. <\/p>\n<p>\u201cInvestigators may be able to identify a likely source for one cluster of cases while other cases remain unexplained or may be linked to a different source,\u201d Rimoin said. \u201cFinding a likely source does not necessarily mean finding the source of every single case.\u201d<\/p>\n<p>One of the largest cyclosporiasis outbreaks in North America was linked, through data collection from clinicians and laboratories, to <a class=\"link\" href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/9164810\/\" target=\"_blank\">imported raspberries from an estimated five Guatemalan farms in 1996<\/a>. At the time, more than 1,400 cases of the disease were reported in 20 states, the District of Columbia and Canada.<\/p>\n<p>\u201cThese investigations are rarely about one single piece of proof,\u201d Rimoin said. \u201cThey are about putting together epidemiology, traceback, supply chain information and laboratory evidence to determine the most likely source.\u201d<\/p>\n<\/p><\/div>\n<script async=\"async\" data-cfasync=\"false\" src=\"https:\/\/pl30214220.effectivecpmnetwork.com\/9ab3d4df8a7e1a6171e16ddbf732cc19\/invoke.js\"><\/script>\r\n<div id=\"container-9ab3d4df8a7e1a6171e16ddbf732cc19\"><\/div>\r\n\n","protected":false},"excerpt":{"rendered":"<p>Identifying the source of a food-borne illness such as cyclosporiasis \u2014 a diarrhea-causing parasite that has sickened thousands of people in the United States \u2014 is almost as difficult as finding a needle in a haystack. It\u2019s not impossible to narrow down the culprit but it is a challenge because public health investigators are analyzing&#8230;<\/p>\n","protected":false},"author":1,"featured_media":16183,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"https:\/\/ca-times.brightspotcdn.com\/dims4\/default\/0a6e836\/2147483647\/strip\/true\/crop\/5000x2625+0+355\/resize\/1200x630!\/quality\/75\/?url=https%3A%2F%2Fcalifornia-times-brightspot.s3.amazonaws.com%2F45%2Fcd%2Fe6e86474496a8cd3fcb199531556%2F2285927521.jpg","fifu_image_alt":"","footnotes":""},"categories":[4],"tags":[],"class_list":["post-16182","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news-hub"],"brizy_media":[],"_links":{"self":[{"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=\/wp\/v2\/posts\/16182","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=16182"}],"version-history":[{"count":0,"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=\/wp\/v2\/posts\/16182\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=\/wp\/v2\/media\/16183"}],"wp:attachment":[{"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16182"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16182"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/usnews-14267fa.ingress-comporellon.ewp.live\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16182"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}