title: Cheese-related listeriosis outbreak, Portugal, March 2009 to February 2012.
abstract: In Portugal, listeriosis has been notifiable since April 2014, but there is no active surveillance programme for the disease. A retrospective study involving 25 national hospitals led to the detection of an outbreak that occurred between March 2009 and February 2012. The amount of time between the start of the outbreak and its detection was 16 months. Of the 30 cases of listeriosis reported, 27 were in the Lisbon and Vale do Tejo region. Two cases were maternal/neonatal infections and one resulted in fetal loss. The mean age of the non-maternal/neonatal cases was 59 years (standard deviation: 17); 13 cases were more than 65 years old. The case fatality rate was 36.7%. All cases were caused by molecular serogroup IVb isolates indistinguishable by pulsed-field gel electrophoresis and ribotype profiles. Collaborative investigations with the national health and food safety authorities identified cheese as the probable source of infection, traced to a processing plant. The magnitude of this outbreak, the first reported food-borne listeriosis outbreak in Portugal, highlights the importance of having an effective listeriosis surveillance system in place for early detection and resolution of outbreaks, as well as the need for a process for the prompt submission of Listeria monocytogenes isolates for routine laboratory typing.
authors.affiliation: Centro de Biotecnologia e Quimica Fina - Laboratorio Associado, Escola Superior de Biotecnologia, Universidade Catolica Portuguesa/Porto, Porto, Portugal.
authors.forename: R
authors.initials: R
authors.lastname: Magalhaes
authors.affiliation: Centro de Biotecnologia e Quimica Fina - Laboratorio Associado, Escola Superior de Biotecnologia, Universidade Catolica Portuguesa/Porto, Porto, Portugal.
authors.forename: G
authors.initials: G
authors.lastname: Almeida
authors.affiliation: Centro de Biotecnologia e Quimica Fina - Laboratorio Associado, Escola Superior de Biotecnologia, Universidade Catolica Portuguesa/Porto, Porto, Portugal.
authors.forename: V
authors.initials: V
authors.lastname: Ferreira
authors.affiliation: Centro de Biotecnologia e Quimica Fina - Laboratorio Associado, Escola Superior de Biotecnologia, Universidade Catolica Portuguesa/Porto, Porto, Portugal.
authors.forename: I
authors.initials: I
authors.lastname: Santos
authors.affiliation: Centro de Biotecnologia e Quimica Fina - Laboratorio Associado, Escola Superior de Biotecnologia, Universidade Catolica Portuguesa/Porto, Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Silva
authors.affiliation: Autoridade de Segurança Alimentar e Económica, Lisbon, Portugal
authors.forename: M M
authors.initials: MM
authors.lastname: Mendes
authors.affiliation: Autoridade de Segurança Alimentar e Económica, Lisbon, Portugal
authors.forename: J
authors.initials: J
authors.lastname: Pita
authors.affiliation: Autoridade de Segurança Alimentar e Económica, Lisbon, Portugal
authors.forename: G
authors.initials: G
authors.lastname: Mariano
authors.affiliation: Autoridade de Segurança Alimentar e Económica, Lisbon, Portugal
authors.forename: I
authors.initials: I
authors.lastname: Mancio
authors.affiliation: Administração Regional de Saúde de Lisboa e Vale do Tejo, Lisbon, Portugal
authors.forename: M M
authors.initials: MM
authors.lastname: Sousa
authors.affiliation: Listeriosis Reference Centre for Canada, Bureau of Microbial Hazards, Health Canada, Ottawa, Ontario, Canada
authors.forename: J
authors.initials: J
authors.lastname: Farber
authors.affiliation: Listeriosis Reference Centre for Canada, Bureau of Microbial Hazards, Health Canada, Ottawa, Ontario, Canada
authors.forename: F
authors.initials: F
authors.lastname: Pagotto
authors.affiliation: Centro de Biotecnologia e Quimica Fina - Laboratorio Associado, Escola Superior de Biotecnologia, Universidade Catolica Portuguesa/Porto, Porto, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Teixeira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002611:Cheese / Q000821:virology*; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D059022:Food Safety; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008088:Listeriosis / Q000453:epidemiology* / Q000382:microbiology; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D012189:Retrospective Studies; D021521:Ribotyping; D018571:Sentinel Surveillance; D012703:Serotyping