title: An epidemiologic study of Lyme disease in southern Sweden.
abstract: BACKGROUND
  Lyme disease is the most common vector-borne infection in some temperate regions of the Northern Hemisphere. However, for most areas of endemic disease reliable epidemiologic data are sparse.
  
  
  METHODS
  Over a one-year period, we conducted a prospective, population-based survey of cases of Lyme disease in southern Sweden. The diagnosis was made on the basis of the presence of erythema migrans at least 5 cm in diameter or characteristic clinical manifestations such as arthritis, neuroborreliosis, and carditis.
  
  
  RESULTS
  We identified 1471 patients with Lyme disease, for an overall annual incidence of 69 cases per 100,000 inhabitants. The incidence varied markedly according to geographic region, and there were several areas where disease was widely prevalent. The incidence varied according to age, with the highest rates among people 5 to 9 and 60 to 74 years of age, but not according to sex. The most frequent clinical manifestation was erythema migrans (seen in 77 percent of all cases), followed by neuroborreliosis (16 percent) and arthritis (7 percent). Carditis was rare. A preceding tick bite was reported by 79 percent of the patients. Bites in the head and neck region were more common among children than among adults and were associated with an increased risk of neuroborreliosis.
  
  
  CONCLUSIONS
  Lyme disease is very common in southern Sweden, with a relatively high frequency of neurologic complications and arthritis. With the exception of the low incidence of carditis, the pattern of disease we found in Sweden was similar to that reported in the United States.
authors.affiliation: Department of Community Health Sciences, University of Lund, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Berglund
authors.forename: R
authors.initials: R
authors.lastname: Eitrem
authors.forename: K
authors.initials: K
authors.lastname: Ornstein
authors.forename: A
authors.initials: A
authors.lastname: Lindberg
authors.forename: A
authors.initials: A
authors.lastname: Ringér
authors.forename: H
authors.initials: H
authors.lastname: Elmrud
authors.forename: M
authors.initials: M
authors.lastname: Carlsson
authors.forename: A
authors.initials: A
authors.lastname: Runehagen
authors.forename: C
authors.initials: C
authors.lastname: Svanborg
authors.forename: R
authors.initials: R
authors.lastname: Norrby
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003625:Data Collection; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007299:Insect Bites and Stings / Q000453:epidemiology; D018884:Ixodes; D008193:Lyme Disease / Q000150:complications / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology; D011446:Prospective Studies; D012621:Seasons; D016036:Seroepidemiologic Studies; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology