title: Population dynamics of Bordetella pertussis in Finland and Sweden, neighbouring countries with different vaccination histories.
abstract: Pertussis is an infectious disease of the respiratory tract in humans caused by Bordetella pertussis. Despite extensive vaccinations, pertussis has remained endemic and re-emerged. In Finland, a whole-cell pertussis vaccine has been used since 1952 with high coverage. In Sweden, whole-cell vaccinations were introduced in 1953 but ceased in 1979, and pertussis vaccinations with acellular vaccines were introduced in 1996. Two epidemic peaks occurred in Sweden in 1999 and 2002 and in Finland in 1999 and 2003. We compared Finnish (N=193) and Swedish (N=455) B. pertussis isolates circulating in 1998-2003 together with vaccine strains used in these neighbouring countries with different vaccination histories. The isolates were analysed by serotyping, genotyping of pertussis toxin S1 subunit and pertactin, and pulsed-field gel electrophoresis. The results suggest that the sequential epidemics were caused by clonal expansion of a certain B. pertussis strain possibly transmitted from Sweden to Finland. The roles of antigenic variation in immunity-driven evolution of B. pertussis in both countries are discussed.
authors.affiliation: Pertussis Reference Laboratory, National Public Health Institute, Turku, Finland. annika.elomaa@utu.fi
authors.forename: Annika
authors.initials: A
authors.lastname: Elomaa
authors.forename: Abdolreza
authors.initials: A
authors.lastname: Advani
authors.forename: Declan
authors.initials: D
authors.lastname: Donnelly
authors.forename: Mia
authors.initials: M
authors.lastname: Antila
authors.forename: Jussi
authors.initials: J
authors.lastname: Mertsola
authors.forename: Qiushui
authors.initials: Q
authors.lastname: He
authors.forename: Hans
authors.initials: H
authors.lastname: Hallander
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001886:Bordetella pertussis / Q000235:genetics / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D019143:Evolution, Molecular; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D010567:Pertussis Vaccine / Q000276:immunology*; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D014611:Vaccination; D014917:Whooping Cough / Q000276:immunology / Q000517:prevention & control
chemical_list: D010567:Pertussis Vaccine