title: Landscape epidemiology of tularemia outbreaks in Sweden.
abstract: Summer outbreaks of tularemia that occurred from 1995 through 2005 in 2 locations in Sweden affected 441 persons. We performed an epidemiologic investigation of these outbreaks using a novel strategy, involving high-resolution genotyping of Francisella tularensis isolates obtained from 136 patients (using 18 genetic markers developed from 6 F. tularensis genome sequences) and interviews with the patients. Strong spatial associations were found between F. tularensis subpopulations and the places of disease transmission; infection by some subpopulations occurred within areas as small as 2 km(2), indicating unidentified environmental point sources of tularemia. In both locations, disease clusters were associated with recreational areas beside water, and genetic subpopulations were present throughout the tularemia season and persisted over years. High-resolution genotyping in combination with patients' statements about geographic places of disease transmission provided valuable indications of likely sources of infection and the causal genotypes during these tularemia outbreaks.
authors: Swedish Defense Research Agency, Umea, Sweden.
authors: Kerstin
authors: K
authors: Svensson
authors: Erik
authors: E
authors: Bäck
authors: Henrik
authors: H
authors: Eliasson
authors: Lennart
authors: L
authors: Berglund
authors: Malin
authors: M
authors: Granberg
authors: Linda
authors: L
authors: Karlsson
authors: Pär
authors: P
authors: Larsson
authors: Mats
authors: M
authors: Forsman
authors: Anders
authors: A
authors: Johansson
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D005604:Francisella tularensis / Q000145:classification / Q000235:genetics; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D014406:Tularemia / Q000453:epidemiology* / Q000382:microbiology