title: The Long and Short Incubation Periods of Plasmodium vivax Malaria in Korea: The Characteristics and Relating Factors.
abstract: BACKGROUND
  The cases of Plasmodium vivax malaria in Korea are mixed with long and short incubation periods. This study aims to define clinico-epidemiologic chracteristcs of Plasmodium vivax malaria in Korea.
  
  
  METHODS
  We selected the civilian cases infected with P. vivax malaria in Korea from the epidemiological investigation data of 2001 to 2010, whose incubation periods could be estimated. The long and short incubation periods were defined by duration of infection and onset time, and the cases were compared by demographic factors and clinical symptom, infection and onset time. The correlation was analyzed between the proportion of cases in the infected region with the long incubation period and meteorological factors along with latitude.
  
  
  RESULTS
  The length of the mean short and long incubation periods for the cases were 25.5 days and 329.4 days, respectively. The total number of the study subjects was 897, and the number cases of short and long incubation periods was 575 (64.1%) and 322 (35.9%), respectively. The aspect of incubation period showed a significant difference by region of infection; there was a higher proportion of long incubation period infection cases in Gangwon-do than in Gyeonggi-do and Incheon. The proportion of long incubation period cases showed significant correlation with latitude and temperature of August and September of the infected regions.
  
  
  CONCLUSIONS
  Incubation period of P. vivax malaria in Korea showed significant difference by infected region, infection and onset time and the proportion of long incubation period cases showed significant correlation with latitude and meteorological factors of the infected regions.
authors.affiliation: Division of Epidemic Intelligence Service, Korea Centers for Disease Control & Prevention, Osong, Korea.
authors.forename: Sun-Ja
authors.initials: SJ
authors.lastname: Kim
authors.forename: Si-Heon
authors.initials: SH
authors.lastname: Kim
authors.forename: Soo-Nam
authors.initials: SN
authors.lastname: Jo
authors.forename: Jin
authors.initials: J
authors.lastname: Gwack
authors.forename: Seung-Ki
authors.initials: SK
authors.lastname: Youn
authors.forename: Jae-Yeon
authors.initials: JY
authors.lastname: Jang
keywords: Epidemiology; Incubation period; Malaria; Plasmodium vivax