{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T20:07:02Z","timestamp":1791230822077,"version":"4.1.0"},"reference-count":19,"publisher":"Cambridge University Press (CUP)","license":[{"start":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T00:00:00Z","timestamp":1777852800000},"content-version":"unspecified","delay-in-days":123,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Epidemiol. Infect."],"published-print":{"date-parts":[[2026]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    In 2024, an outbreak of\n                    <jats:italic>Salmonella typhimurium<\/jats:italic>\n                    affected two regions in Portugal. To identify the vehicle, we conducted a case\u2013case study using a \u2018same disease, different time period\u2019 design. We compared\n                    <jats:italic>S. typhimurium<\/jats:italic>\n                    cases linked by whole-genome sequencing (WGS) (cluster cases) with salmonellosis cases notified in 2023 (historical cases) and calculated odds ratios (OR) for food exposures in surveillance data using logistic regression. We performed WGS on 58 isolates from the outbreak period (11\/03\/2024\u20132118\/06\/2024), and all belonged to a single cgMLST cluster (HierCC HC5_410,410). Compared with the 552 historical cases, cluster cases more frequently reported fresh cheese consumption (OR 18; 95% CI: 8.5\u201338). We visited the implicated cheese production site, identified food safety non-conformities, and enforced hygiene measures. Environmental and product specimens collected at the visit tested negative for Salmonella spp. Taken together, the most plausible vehicle in this outbreak was fresh cheese. The case\u2013case design enabled a rapid, low-cost analysis to support targeted investigation using surveillance data. Using WGS cluster cases as the case definition, rather than all\n                    <jats:italic>S. typhimurium<\/jats:italic>\n                    cases during the outbreak period, yielded a higher OR in the case\u2013case study, increasing confidence in the findings. We recommend this combined approach as part of the toolkit for foodborne outbreak investigations in Portugal in similar contexts.\n                  <\/jats:p>","DOI":"10.1017\/s0950268826101538","type":"journal-article","created":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T04:27:37Z","timestamp":1777868857000},"update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":1,"title":["Interregional outbreak of\n                    <i>Salmonella Typhimurium<\/i>\n                    linked to fresh cheese: A case\u2013case study guided by whole-genome sequencing (WGS), Portugal, March\u2013June 2024"],"prefix":"10.1017","volume":"154","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1442-2621","authenticated-orcid":false,"given":"Sebastian","family":"von Schreeb","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"},{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"},{"id":[{"id":"https:\/\/ror.org\/00s9v1h75","id-type":"ROR","asserted-by":"publisher"}],"name":"European Centre for Disease Prevention and Control"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leonor","family":"Silveira","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03mx8d427","id-type":"ROR","asserted-by":"publisher"}],"name":"National Institute of Health Doctor Ricardo Jorge"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00c2ngela","family":"Pista","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03mx8d427","id-type":"ROR","asserted-by":"publisher"}],"name":"National Institute of Health Doctor Ricardo Jorge"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jo\u00e3o Paulo","family":"Gomes","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03mx8d427","id-type":"ROR","asserted-by":"publisher"}],"name":"National Institute of Health Doctor Ricardo Jorge"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6360-2576","authenticated-orcid":false,"given":"M\u00f3nica","family":"Oleastro","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03mx8d427","id-type":"ROR","asserted-by":"publisher"}],"name":"National Institute of Health Doctor Ricardo Jorge"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara Gomes","family":"Raposo","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/020j5zv28","id-type":"ROR","asserted-by":"publisher"}],"name":"Arr\u00e1bida Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Valentyna","family":"Lutsiv","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/020j5zv28","id-type":"ROR","asserted-by":"publisher"}],"name":"Arr\u00e1bida Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan","family":"Rachadell","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05kftaj26","id-type":"ROR","asserted-by":"publisher"}],"name":"Central Alentejo Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helder","family":"Pinto","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05kftaj26","id-type":"ROR","asserted-by":"publisher"}],"name":"Central Alentejo Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patr\u00edcia","family":"Correia Rico","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05kftaj26","id-type":"ROR","asserted-by":"publisher"}],"name":"Central Alentejo Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lu\u00edsa","family":"Pestana","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05kftaj26","id-type":"ROR","asserted-by":"publisher"}],"name":"Central Alentejo Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vera Leal","family":"Pessoa","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05kftaj26","id-type":"ROR","asserted-by":"publisher"}],"name":"Central Alentejo Local Health Unit"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ant\u00f3nio","family":"Carlos Silva","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana","family":"Dinis","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria Helena","family":"Almeida","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kostas","family":"Danis","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00s9v1h75","id-type":"ROR","asserted-by":"publisher"}],"name":"European Centre for Disease Prevention and Control"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paula","family":"Vasconcelos","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pedro","family":"Pinto Leite","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vasco","family":"Ricoca Peixoto","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01hgwb793","id-type":"ROR","asserted-by":"publisher"}],"name":"Direc\u00e7\u00e3o-Geral da Sa\u00fade"},{"id":[{"id":"https:\/\/ror.org\/02xankh89","id-type":"ROR","asserted-by":"publisher"}],"name":"NOVA University Lisbon"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"56","published-online":{"date-parts":[[2026,5,4]]},"reference":[{"key":"S0950268826101538_r6","doi-asserted-by":"publisher","DOI":"10.1101\/gr.232397.117"},{"key":"S0950268826101538_r7","doi-asserted-by":"publisher","DOI":"10.1093\/nar\/gkae902"},{"key":"S0950268826101538_r1","volume-title":"Salmonellosis. Annual Epidemiological Report for 2022","year":"2024"},{"key":"S0950268826101538_r11","doi-asserted-by":"publisher","DOI":"10.5740\/jaoacint.CS2011_03"},{"key":"S0950268826101538_r12","doi-asserted-by":"publisher","DOI":"10.1017\/S0950268820001132"},{"key":"S0950268826101538_r13","doi-asserted-by":"publisher","DOI":"10.2807\/1560-7917.ES.2017.22.49.17-00037"},{"key":"S0950268826101538_r14","doi-asserted-by":"publisher","DOI":"10.1186\/s13073-021-00934-7"},{"key":"S0950268826101538_r8","doi-asserted-by":"publisher","DOI":"10.1093\/bioinformatics\/btab234"},{"key":"S0950268826101538_r19","unstructured":"[19] European Commission (2025) Commission Implementing Regulation (EU) 2025\/179 of 31 January 2025 on the collection and transmission of molecular analytical data within the frame of epidemiological investigations of food-borne outbreaks."},{"key":"S0950268826101538_r9","first-page":"1","article-title":"Commission implementing decision (EU) 2018\/945 of 22 June 2018 on the communicable diseases and related special health issues to be covered by epidemiological surveillance as well as relevant case definitions","volume":"L170","year":"2018","journal-title":"Official Journal of the European Union"},{"key":"S0950268826101538_r18","unstructured":"[18] European Commission (2025) Whole genome sequencing within the frame of foodborne outbreak investigations (implementation of Regulation (EU) 2025\/179)."},{"key":"S0950268826101538_r3","volume-title":"Antigenic Formulae of the Salmonella serovars","author":"Grimont","year":"2007"},{"key":"S0950268826101538_r15","doi-asserted-by":"publisher","DOI":"10.4315\/0362-028X-63.5.579"},{"key":"S0950268826101538_r4","unstructured":"[4] European Committee on Antimicrobial Susceptibility Testing. (2024) Breakpoint tables for interpretation of MICs and zone diameters, version 14.1. https:\/\/www.eucast.org (accessed 30 March 2025)."},{"key":"S0950268826101538_r16","unstructured":"[16] Food and Agriculture Organization of the United Nations (2010) FAO fisheries and aquaculture report no. 937: Application of biosecurity measures to control Salmonella contamination in sustainable aquaculture."},{"key":"S0950268826101538_r10","first-page":"7","article-title":"Case-case methods for studying enteric diseases: A review and approach for standardization","volume":"2","author":"Pogreba-Brown","year":"2014","journal-title":"OA Epidemiology"},{"key":"S0950268826101538_r5","doi-asserted-by":"publisher","DOI":"10.3390\/antibiotics13100957"},{"key":"S0950268826101538_r17","unstructured":"[17] Direc\u00e7\u00e3o-Geral da Sa\u00fade (2001) Vigil\u00e2ncia e controlo das toxi-infec\u00e7\u00f5es alimentares colectivas."},{"key":"S0950268826101538_r2","unstructured":"[2] European Centre for Disease Prevention and Control (2025) Surveillance Atlas of Infectious Diseases. https:\/\/atlas.ecdc.europa.eu\/public\/index.aspx (accessed 29 July 2025)."}],"container-title":["Epidemiology and Infection"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0950268826101538","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,17]],"date-time":"2026-07-17T07:06:37Z","timestamp":1784271997000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0950268826101538\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026]]},"references-count":19,"alternative-id":["S0950268826101538"],"URL":"https:\/\/doi.org\/10.1017\/s0950268826101538","relation":{},"ISSN":["0950-2688","1469-4409"],"issn-type":[{"value":"0950-2688","type":"print"},{"value":"1469-4409","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026]]},"assertion":[{"value":"\u00a9 The Author(s), 2026. Published by Cambridge University Press","name":"copyright","label":"Copyright","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http:\/\/creativecommons.org\/licenses\/by\/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.","name":"license","label":"License","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This content has been made available to all.","name":"free","label":"Free to read"}],"article-number":"e68"}}